mately with Perl 5.10, including support for UTF-8 encoded strings and
Unicode general category properties. However, UTF-8 and Unicode support
has to be explicitly enabled; it is not the default. The Unicode tables
- correspond to Unicode release 5.0.0.
+ correspond to Unicode release 5.1.
In addition to the Perl-compatible matching function, PCRE contains an
alternative matching function that matches the same compiled patterns
pcrestack discussion of stack usage
pcretest description of the pcretest testing command
- In addition, in the "man" and HTML formats, there is a short page for
+ In addition, in the "man" and HTML formats, there is a short page for
each C library function, listing its arguments and results.
LIMITATIONS
- There are some size limitations in PCRE but it is hoped that they will
+ There are some size limitations in PCRE but it is hoped that they will
never in practice be relevant.
- The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE
+ The maximum length of a compiled pattern is 65539 (sic) bytes if PCRE
is compiled with the default internal linkage size of 2. If you want to
- process regular expressions that are truly enormous, you can compile
- PCRE with an internal linkage size of 3 or 4 (see the README file in
- the source distribution and the pcrebuild documentation for details).
- In these cases the limit is substantially larger. However, the speed
+ process regular expressions that are truly enormous, you can compile
+ PCRE with an internal linkage size of 3 or 4 (see the README file in
+ the source distribution and the pcrebuild documentation for details).
+ In these cases the limit is substantially larger. However, the speed
of execution is slower.
All values in repeating quantifiers must be less than 65536.
The maximum length of name for a named subpattern is 32 characters, and
the maximum number of named subpatterns is 10000.
- The maximum length of a subject string is the largest positive number
- that an integer variable can hold. However, when using the traditional
+ The maximum length of a subject string is the largest positive number
+ that an integer variable can hold. However, when using the traditional
matching function, PCRE uses recursion to handle subpatterns and indef-
- inite repetition. This means that the available stack space may limit
+ inite repetition. This means that the available stack space may limit
the size of a subject string that can be processed by certain patterns.
For a discussion of stack issues, see the pcrestack documentation.
UTF-8 AND UNICODE PROPERTY SUPPORT
- From release 3.3, PCRE has had some support for character strings
- encoded in the UTF-8 format. For release 4.0 this was greatly extended
- to cover most common requirements, and in release 5.0 additional sup-
+ From release 3.3, PCRE has had some support for character strings
+ encoded in the UTF-8 format. For release 4.0 this was greatly extended
+ to cover most common requirements, and in release 5.0 additional sup-
port for Unicode general category properties was added.
- In order process UTF-8 strings, you must build PCRE to include UTF-8
- support in the code, and, in addition, you must call pcre_compile()
- with the PCRE_UTF8 option flag. When you do this, both the pattern and
- any subject strings that are matched against it are treated as UTF-8
- strings instead of just strings of bytes.
+ In order process UTF-8 strings, you must build PCRE to include UTF-8
+ support in the code, and, in addition, you must call pcre_compile()
+ with the PCRE_UTF8 option flag, or the pattern must start with the
+ sequence (*UTF8). When either of these is the case, both the pattern
+ and any subject strings that are matched against it are treated as
+ UTF-8 strings instead of just strings of bytes.
If you compile PCRE with UTF-8 support, but do not use it at run time,
the library will be a bit bigger, but the additional run time overhead
includes Unicode property support, because to do otherwise would slow
down PCRE in many common cases. If you really want to test for a wider
sense of, say, "digit", you must use Unicode property tests such as
- \p{Nd}.
+ \p{Nd}. Note that this also applies to \b, because it is defined in
+ terms of \w and \W.
- 7. Similarly, characters that match the POSIX named character classes
+ 7. Similarly, characters that match the POSIX named character classes
are all low-valued characters.
- 8. However, the Perl 5.10 horizontal and vertical whitespace matching
+ 8. However, the Perl 5.10 horizontal and vertical whitespace matching
escapes (\h, \H, \v, and \V) do match all the appropriate Unicode char-
acters.
- 9. Case-insensitive matching applies only to characters whose values
- are less than 128, unless PCRE is built with Unicode property support.
- Even when Unicode property support is available, PCRE still uses its
- own character tables when checking the case of low-valued characters,
- so as not to degrade performance. The Unicode property information is
+ 9. Case-insensitive matching applies only to characters whose values
+ are less than 128, unless PCRE is built with Unicode property support.
+ Even when Unicode property support is available, PCRE still uses its
+ own character tables when checking the case of low-valued characters,
+ so as not to degrade performance. The Unicode property information is
used only for characters with higher values. Even when Unicode property
support is available, PCRE supports case-insensitive matching only when
- there is a one-to-one mapping between a letter's cases. There are a
- small number of many-to-one mappings in Unicode; these are not sup-
+ there is a one-to-one mapping between a letter's cases. There are a
+ small number of many-to-one mappings in Unicode; these are not sup-
ported by PCRE.
University Computing Service
Cambridge CB2 3QH, England.
- Putting an actual email address here seems to have been a spam magnet,
- so I've taken it away. If you want to email me, use my two initials,
+ Putting an actual email address here seems to have been a spam magnet,
+ so I've taken it away. If you want to email me, use my two initials,
followed by the two digits 10, at the domain cam.ac.uk.
REVISION
- Last updated: 12 April 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 11 April 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
UTF-8 SUPPORT
- To build PCRE with support for UTF-8 character strings, add
+ To build PCRE with support for UTF-8 Unicode character strings, add
--enable-utf8
have have to set the PCRE_UTF8 option when you call the pcre_compile()
function.
+ If you set --enable-utf8 when compiling in an EBCDIC environment, PCRE
+ expects its input to be either ASCII or UTF-8 (depending on the runtime
+ option). It is not possible to support both EBCDIC and UTF-8 codes in
+ the same version of the library. Consequently, --enable-utf8 and
+ --enable-ebcdic are mutually exclusive.
+
UNICODE CHARACTER PROPERTY SUPPORT
CODE VALUE OF NEWLINE
- By default, PCRE interprets character 10 (linefeed, LF) as indicating
+ By default, PCRE interprets the linefeed (LF) character as indicating
the end of a line. This is the normal newline character on Unix-like
- systems. You can compile PCRE to use character 13 (carriage return, CR)
- instead, by adding
+ systems. You can compile PCRE to use carriage return (CR) instead, by
+ adding
--enable-newline-is-cr
causes PCRE to recognize any Unicode newline sequence.
- Whatever line ending convention is selected when PCRE is built can be
- overridden when the library functions are called. At build time it is
+ Whatever line ending convention is selected when PCRE is built can be
+ overridden when the library functions are called. At build time it is
conventional to use the standard for your operating system.
WHAT \R MATCHES
- By default, the sequence \R in a pattern matches any Unicode newline
- sequence, whatever has been selected as the line ending sequence. If
+ By default, the sequence \R in a pattern matches any Unicode newline
+ sequence, whatever has been selected as the line ending sequence. If
you specify
--enable-bsr-anycrlf
- the default is changed so that \R matches only CR, LF, or CRLF. What-
- ever is selected when PCRE is built can be overridden when the library
+ the default is changed so that \R matches only CR, LF, or CRLF. What-
+ ever is selected when PCRE is built can be overridden when the library
functions are called.
BUILDING SHARED AND STATIC LIBRARIES
- The PCRE building process uses libtool to build both shared and static
- Unix libraries by default. You can suppress one of these by adding one
+ The PCRE building process uses libtool to build both shared and static
+ Unix libraries by default. You can suppress one of these by adding one
of
--disable-shared
POSIX MALLOC USAGE
When PCRE is called through the POSIX interface (see the pcreposix doc-
- umentation), additional working storage is required for holding the
- pointers to capturing substrings, because PCRE requires three integers
- per substring, whereas the POSIX interface provides only two. If the
+ umentation), additional working storage is required for holding the
+ pointers to capturing substrings, because PCRE requires three integers
+ per substring, whereas the POSIX interface provides only two. If the
number of expected substrings is small, the wrapper function uses space
on the stack, because this is faster than using malloc() for each call.
The default threshold above which the stack is no longer used is 10; it
HANDLING VERY LARGE PATTERNS
- Within a compiled pattern, offset values are used to point from one
- part to another (for example, from an opening parenthesis to an alter-
- nation metacharacter). By default, two-byte values are used for these
- offsets, leading to a maximum size for a compiled pattern of around
- 64K. This is sufficient to handle all but the most gigantic patterns.
- Nevertheless, some people do want to process enormous patterns, so it
- is possible to compile PCRE to use three-byte or four-byte offsets by
+ Within a compiled pattern, offset values are used to point from one
+ part to another (for example, from an opening parenthesis to an alter-
+ nation metacharacter). By default, two-byte values are used for these
+ offsets, leading to a maximum size for a compiled pattern of around
+ 64K. This is sufficient to handle all but the most gigantic patterns.
+ Nevertheless, some people do want to process enormous patterns, so it
+ is possible to compile PCRE to use three-byte or four-byte offsets by
adding a setting such as
--with-link-size=3
- to the configure command. The value given must be 2, 3, or 4. Using
- longer offsets slows down the operation of PCRE because it has to load
+ to the configure command. The value given must be 2, 3, or 4. Using
+ longer offsets slows down the operation of PCRE because it has to load
additional bytes when handling them.
AVOIDING EXCESSIVE STACK USAGE
When matching with the pcre_exec() function, PCRE implements backtrack-
- ing by making recursive calls to an internal function called match().
- In environments where the size of the stack is limited, this can se-
- verely limit PCRE's operation. (The Unix environment does not usually
+ ing by making recursive calls to an internal function called match().
+ In environments where the size of the stack is limited, this can se-
+ verely limit PCRE's operation. (The Unix environment does not usually
suffer from this problem, but it may sometimes be necessary to increase
- the maximum stack size. There is a discussion in the pcrestack docu-
- mentation.) An alternative approach to recursion that uses memory from
- the heap to remember data, instead of using recursive function calls,
- has been implemented to work round the problem of limited stack size.
+ the maximum stack size. There is a discussion in the pcrestack docu-
+ mentation.) An alternative approach to recursion that uses memory from
+ the heap to remember data, instead of using recursive function calls,
+ has been implemented to work round the problem of limited stack size.
If you want to build a version of PCRE that works this way, add
--disable-stack-for-recursion
- to the configure command. With this configuration, PCRE will use the
- pcre_stack_malloc and pcre_stack_free variables to call memory manage-
- ment functions. By default these point to malloc() and free(), but you
+ to the configure command. With this configuration, PCRE will use the
+ pcre_stack_malloc and pcre_stack_free variables to call memory manage-
+ ment functions. By default these point to malloc() and free(), but you
can replace the pointers so that your own functions are used.
- Separate functions are provided rather than using pcre_malloc and
- pcre_free because the usage is very predictable: the block sizes
- requested are always the same, and the blocks are always freed in
- reverse order. A calling program might be able to implement optimized
- functions that perform better than malloc() and free(). PCRE runs
+ Separate functions are provided rather than using pcre_malloc and
+ pcre_free because the usage is very predictable: the block sizes
+ requested are always the same, and the blocks are always freed in
+ reverse order. A calling program might be able to implement optimized
+ functions that perform better than malloc() and free(). PCRE runs
noticeably more slowly when built in this way. This option affects only
- the pcre_exec() function; it is not relevant for the the
+ the pcre_exec() function; it is not relevant for the the
pcre_dfa_exec() function.
LIMITING PCRE RESOURCE USAGE
- Internally, PCRE has a function called match(), which it calls repeat-
- edly (sometimes recursively) when matching a pattern with the
- pcre_exec() function. By controlling the maximum number of times this
- function may be called during a single matching operation, a limit can
- be placed on the resources used by a single call to pcre_exec(). The
- limit can be changed at run time, as described in the pcreapi documen-
- tation. The default is 10 million, but this can be changed by adding a
+ Internally, PCRE has a function called match(), which it calls repeat-
+ edly (sometimes recursively) when matching a pattern with the
+ pcre_exec() function. By controlling the maximum number of times this
+ function may be called during a single matching operation, a limit can
+ be placed on the resources used by a single call to pcre_exec(). The
+ limit can be changed at run time, as described in the pcreapi documen-
+ tation. The default is 10 million, but this can be changed by adding a
setting such as
--with-match-limit=500000
- to the configure command. This setting has no effect on the
+ to the configure command. This setting has no effect on the
pcre_dfa_exec() matching function.
- In some environments it is desirable to limit the depth of recursive
+ In some environments it is desirable to limit the depth of recursive
calls of match() more strictly than the total number of calls, in order
- to restrict the maximum amount of stack (or heap, if --disable-stack-
+ to restrict the maximum amount of stack (or heap, if --disable-stack-
for-recursion is specified) that is used. A second limit controls this;
- it defaults to the value that is set for --with-match-limit, which
- imposes no additional constraints. However, you can set a lower limit
+ it defaults to the value that is set for --with-match-limit, which
+ imposes no additional constraints. However, you can set a lower limit
by adding, for example,
--with-match-limit-recursion=10000
- to the configure command. This value can also be overridden at run
+ to the configure command. This value can also be overridden at run
time.
CREATING CHARACTER TABLES AT BUILD TIME
- PCRE uses fixed tables for processing characters whose code values are
- less than 256. By default, PCRE is built with a set of tables that are
- distributed in the file pcre_chartables.c.dist. These tables are for
+ PCRE uses fixed tables for processing characters whose code values are
+ less than 256. By default, PCRE is built with a set of tables that are
+ distributed in the file pcre_chartables.c.dist. These tables are for
ASCII codes only. If you add
--enable-rebuild-chartables
- to the configure command, the distributed tables are no longer used.
- Instead, a program called dftables is compiled and run. This outputs
+ to the configure command, the distributed tables are no longer used.
+ Instead, a program called dftables is compiled and run. This outputs
the source for new set of tables, created in the default locale of your
C runtime system. (This method of replacing the tables does not work if
- you are cross compiling, because dftables is run on the local host. If
- you need to create alternative tables when cross compiling, you will
+ you are cross compiling, because dftables is run on the local host. If
+ you need to create alternative tables when cross compiling, you will
have to do so "by hand".)
USING EBCDIC CODE
- PCRE assumes by default that it will run in an environment where the
- character code is ASCII (or Unicode, which is a superset of ASCII).
- This is the case for most computer operating systems. PCRE can, how-
+ PCRE assumes by default that it will run in an environment where the
+ character code is ASCII (or Unicode, which is a superset of ASCII).
+ This is the case for most computer operating systems. PCRE can, how-
ever, be compiled to run in an EBCDIC environment by adding
--enable-ebcdic
to the configure command. This setting implies --enable-rebuild-charta-
- bles. You should only use it if you know that you are in an EBCDIC
- environment (for example, an IBM mainframe operating system).
+ bles. You should only use it if you know that you are in an EBCDIC
+ environment (for example, an IBM mainframe operating system). The
+ --enable-ebcdic option is incompatible with --enable-utf8.
PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT
REVISION
- Last updated: 13 April 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 17 March 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
pcre_malloc, pcre_free, pcre_stack_malloc, and pcre_stack_free, and the
callout function pointed to by pcre_callout, are shared by all threads.
- The compiled form of a regular expression is not altered during match-
+ The compiled form of a regular expression is not altered during match-
ing, so the same compiled pattern can safely be used by several threads
at once.
SAVING PRECOMPILED PATTERNS FOR LATER USE
The compiled form of a regular expression can be saved and re-used at a
- later time, possibly by a different program, and even on a host other
- than the one on which it was compiled. Details are given in the
- pcreprecompile documentation. However, compiling a regular expression
- with one version of PCRE for use with a different version is not guar-
+ later time, possibly by a different program, and even on a host other
+ than the one on which it was compiled. Details are given in the
+ pcreprecompile documentation. However, compiling a regular expression
+ with one version of PCRE for use with a different version is not guar-
anteed to work and may cause crashes.
int pcre_config(int what, void *where);
- The function pcre_config() makes it possible for a PCRE client to dis-
+ The function pcre_config() makes it possible for a PCRE client to dis-
cover which optional features have been compiled into the PCRE library.
- The pcrebuild documentation has more details about these optional fea-
+ The pcrebuild documentation has more details about these optional fea-
tures.
- The first argument for pcre_config() is an integer, specifying which
+ The first argument for pcre_config() is an integer, specifying which
information is required; the second argument is a pointer to a variable
- into which the information is placed. The following information is
+ into which the information is placed. The following information is
available:
PCRE_CONFIG_UTF8
- The output is an integer that is set to one if UTF-8 support is avail-
+ The output is an integer that is set to one if UTF-8 support is avail-
able; otherwise it is set to zero.
PCRE_CONFIG_UNICODE_PROPERTIES
- The output is an integer that is set to one if support for Unicode
+ The output is an integer that is set to one if support for Unicode
character properties is available; otherwise it is set to zero.
PCRE_CONFIG_NEWLINE
- The output is an integer whose value specifies the default character
- sequence that is recognized as meaning "newline". The four values that
+ The output is an integer whose value specifies the default character
+ sequence that is recognized as meaning "newline". The four values that
are supported are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF,
- and -1 for ANY. The default should normally be the standard sequence
- for your operating system.
+ and -1 for ANY. Though they are derived from ASCII, the same values
+ are returned in EBCDIC environments. The default should normally corre-
+ spond to the standard sequence for your operating system.
PCRE_CONFIG_BSR
PCRE_CONFIG_MATCH_LIMIT
- The output is an integer that gives the default limit for the number of
- internal matching function calls in a pcre_exec() execution. Further
- details are given with pcre_exec() below.
+ The output is a long integer that gives the default limit for the num-
+ ber of internal matching function calls in a pcre_exec() execution.
+ Further details are given with pcre_exec() below.
PCRE_CONFIG_MATCH_LIMIT_RECURSION
- The output is an integer that gives the default limit for the depth of
- recursion when calling the internal matching function in a pcre_exec()
- execution. Further details are given with pcre_exec() below.
+ The output is a long integer that gives the default limit for the depth
+ of recursion when calling the internal matching function in a
+ pcre_exec() execution. Further details are given with pcre_exec()
+ below.
PCRE_CONFIG_STACKRECURSE
- The output is an integer that is set to one if internal recursion when
+ The output is an integer that is set to one if internal recursion when
running pcre_exec() is implemented by recursive function calls that use
- the stack to remember their state. This is the usual way that PCRE is
+ the stack to remember their state. This is the usual way that PCRE is
compiled. The output is zero if PCRE was compiled to use blocks of data
- on the heap instead of recursive function calls. In this case,
- pcre_stack_malloc and pcre_stack_free are called to manage memory
+ on the heap instead of recursive function calls. In this case,
+ pcre_stack_malloc and pcre_stack_free are called to manage memory
blocks on the heap, thus avoiding the use of the stack.
Either of the functions pcre_compile() or pcre_compile2() can be called
to compile a pattern into an internal form. The only difference between
- the two interfaces is that pcre_compile2() has an additional argument,
+ the two interfaces is that pcre_compile2() has an additional argument,
errorcodeptr, via which a numerical error code can be returned.
The pattern is a C string terminated by a binary zero, and is passed in
- the pattern argument. A pointer to a single block of memory that is
- obtained via pcre_malloc is returned. This contains the compiled code
+ the pattern argument. A pointer to a single block of memory that is
+ obtained via pcre_malloc is returned. This contains the compiled code
and related data. The pcre type is defined for the returned block; this
is a typedef for a structure whose contents are not externally defined.
It is up to the caller to free the memory (via pcre_free) when it is no
longer required.
- Although the compiled code of a PCRE regex is relocatable, that is, it
+ Although the compiled code of a PCRE regex is relocatable, that is, it
does not depend on memory location, the complete pcre data block is not
- fully relocatable, because it may contain a copy of the tableptr argu-
+ fully relocatable, because it may contain a copy of the tableptr argu-
ment, which is an address (see below).
The options argument contains various bit settings that affect the com-
- pilation. It should be zero if no options are required. The available
- options are described below. Some of them, in particular, those that
- are compatible with Perl, can also be set and unset from within the
- pattern (see the detailed description in the pcrepattern documenta-
- tion). For these options, the contents of the options argument speci-
- fies their initial settings at the start of compilation and execution.
- The PCRE_ANCHORED and PCRE_NEWLINE_xxx options can be set at the time
- of matching as well as at compile time.
+ pilation. It should be zero if no options are required. The available
+ options are described below. Some of them (in particular, those that
+ are compatible with Perl, but also some others) can also be set and
+ unset from within the pattern (see the detailed description in the
+ pcrepattern documentation). For those options that can be different in
+ different parts of the pattern, the contents of the options argument
+ specifies their initial settings at the start of compilation and execu-
+ tion. The PCRE_ANCHORED and PCRE_NEWLINE_xxx options can be set at the
+ time of matching as well as at compile time.
If errptr is NULL, pcre_compile() returns NULL immediately. Otherwise,
if compilation of a pattern fails, pcre_compile() returns NULL, and
and are therefore ignored.
The newline option that is set at compile time becomes the default that
- is used for pcre_exec() and pcre_dfa_exec(), but it can be overridden.
+ is used for pcre_exec() and pcre_dfa_exec(), but it can be overridden.
PCRE_NO_AUTO_CAPTURE
If this option is set, it disables the use of numbered capturing paren-
- theses in the pattern. Any opening parenthesis that is not followed by
- ? behaves as if it were followed by ?: but named parentheses can still
- be used for capturing (and they acquire numbers in the usual way).
+ theses in the pattern. Any opening parenthesis that is not followed by
+ ? behaves as if it were followed by ?: but named parentheses can still
+ be used for capturing (and they acquire numbers in the usual way).
There is no equivalent of this option in Perl.
PCRE_UNGREEDY
- This option inverts the "greediness" of the quantifiers so that they
- are not greedy by default, but become greedy if followed by "?". It is
- not compatible with Perl. It can also be set by a (?U) option setting
+ This option inverts the "greediness" of the quantifiers so that they
+ are not greedy by default, but become greedy if followed by "?". It is
+ not compatible with Perl. It can also be set by a (?U) option setting
within the pattern.
PCRE_UTF8
- This option causes PCRE to regard both the pattern and the subject as
- strings of UTF-8 characters instead of single-byte character strings.
- However, it is available only when PCRE is built to include UTF-8 sup-
- port. If not, the use of this option provokes an error. Details of how
- this option changes the behaviour of PCRE are given in the section on
+ This option causes PCRE to regard both the pattern and the subject as
+ strings of UTF-8 characters instead of single-byte character strings.
+ However, it is available only when PCRE is built to include UTF-8 sup-
+ port. If not, the use of this option provokes an error. Details of how
+ this option changes the behaviour of PCRE are given in the section on
UTF-8 support in the main pcre page.
PCRE_NO_UTF8_CHECK
When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
- automatically checked. There is a discussion about the validity of
- UTF-8 strings in the main pcre page. If an invalid UTF-8 sequence of
- bytes is found, pcre_compile() returns an error. If you already know
+ automatically checked. There is a discussion about the validity of
+ UTF-8 strings in the main pcre page. If an invalid UTF-8 sequence of
+ bytes is found, pcre_compile() returns an error. If you already know
that your pattern is valid, and you want to skip this check for perfor-
- mance reasons, you can set the PCRE_NO_UTF8_CHECK option. When it is
- set, the effect of passing an invalid UTF-8 string as a pattern is
- undefined. It may cause your program to crash. Note that this option
- can also be passed to pcre_exec() and pcre_dfa_exec(), to suppress the
+ mance reasons, you can set the PCRE_NO_UTF8_CHECK option. When it is
+ set, the effect of passing an invalid UTF-8 string as a pattern is
+ undefined. It may cause your program to crash. Note that this option
+ can also be passed to pcre_exec() and pcre_dfa_exec(), to suppress the
UTF-8 validity checking of subject strings.
COMPILATION ERROR CODES
- The following table lists the error codes than may be returned by
- pcre_compile2(), along with the error messages that may be returned by
- both compiling functions. As PCRE has developed, some error codes have
+ The following table lists the error codes than may be returned by
+ pcre_compile2(), along with the error messages that may be returned by
+ both compiling functions. As PCRE has developed, some error codes have
fallen out of use. To avoid confusion, they have not been re-used.
0 no error
50 [this code is not in use]
51 octal value is greater than \377 (not in UTF-8 mode)
52 internal error: overran compiling workspace
- 53 internal error: previously-checked referenced subpattern not
+ 53 internal error: previously-checked referenced subpattern not
found
54 DEFINE group contains more than one branch
55 repeating a DEFINE group is not allowed
63 digit expected after (?+
64 ] is an invalid data character in JavaScript compatibility mode
- The numbers 32 and 10000 in errors 48 and 49 are defaults; different
+ The numbers 32 and 10000 in errors 48 and 49 are defaults; different
values may be used if the limits were changed when PCRE was built.
pcre_extra *pcre_study(const pcre *code, int options
const char **errptr);
- If a compiled pattern is going to be used several times, it is worth
+ If a compiled pattern is going to be used several times, it is worth
spending more time analyzing it in order to speed up the time taken for
- matching. The function pcre_study() takes a pointer to a compiled pat-
+ matching. The function pcre_study() takes a pointer to a compiled pat-
tern as its first argument. If studying the pattern produces additional
- information that will help speed up matching, pcre_study() returns a
- pointer to a pcre_extra block, in which the study_data field points to
+ information that will help speed up matching, pcre_study() returns a
+ pointer to a pcre_extra block, in which the study_data field points to
the results of the study.
The returned value from pcre_study() can be passed directly to
- pcre_exec(). However, a pcre_extra block also contains other fields
- that can be set by the caller before the block is passed; these are
+ pcre_exec(). However, a pcre_extra block also contains other fields
+ that can be set by the caller before the block is passed; these are
described below in the section on matching a pattern.
- If studying the pattern does not produce any additional information
+ If studying the pattern does not produce any additional information
pcre_study() returns NULL. In that circumstance, if the calling program
- wants to pass any of the other fields to pcre_exec(), it must set up
+ wants to pass any of the other fields to pcre_exec(), it must set up
its own pcre_extra block.
- The second argument of pcre_study() contains option bits. At present,
+ The second argument of pcre_study() contains option bits. At present,
no options are defined, and this argument should always be zero.
- The third argument for pcre_study() is a pointer for an error message.
- If studying succeeds (even if no data is returned), the variable it
- points to is set to NULL. Otherwise it is set to point to a textual
+ The third argument for pcre_study() is a pointer for an error message.
+ If studying succeeds (even if no data is returned), the variable it
+ points to is set to NULL. Otherwise it is set to point to a textual
error message. This is a static string that is part of the library. You
- must not try to free it. You should test the error pointer for NULL
+ must not try to free it. You should test the error pointer for NULL
after calling pcre_study(), to be sure that it has run successfully.
This is a typical call to pcre_study():
&error); /* set to NULL or points to a message */
At present, studying a pattern is useful only for non-anchored patterns
- that do not have a single fixed starting character. A bitmap of possi-
+ that do not have a single fixed starting character. A bitmap of possi-
ble starting bytes is created.
LOCALE SUPPORT
- PCRE handles caseless matching, and determines whether characters are
- letters, digits, or whatever, by reference to a set of tables, indexed
- by character value. When running in UTF-8 mode, this applies only to
- characters with codes less than 128. Higher-valued codes never match
- escapes such as \w or \d, but can be tested with \p if PCRE is built
- with Unicode character property support. The use of locales with Uni-
- code is discouraged. If you are handling characters with codes greater
- than 128, you should either use UTF-8 and Unicode, or use locales, but
+ PCRE handles caseless matching, and determines whether characters are
+ letters, digits, or whatever, by reference to a set of tables, indexed
+ by character value. When running in UTF-8 mode, this applies only to
+ characters with codes less than 128. Higher-valued codes never match
+ escapes such as \w or \d, but can be tested with \p if PCRE is built
+ with Unicode character property support. The use of locales with Uni-
+ code is discouraged. If you are handling characters with codes greater
+ than 128, you should either use UTF-8 and Unicode, or use locales, but
not try to mix the two.
- PCRE contains an internal set of tables that are used when the final
- argument of pcre_compile() is NULL. These are sufficient for many
+ PCRE contains an internal set of tables that are used when the final
+ argument of pcre_compile() is NULL. These are sufficient for many
applications. Normally, the internal tables recognize only ASCII char-
acters. However, when PCRE is built, it is possible to cause the inter-
nal tables to be rebuilt in the default "C" locale of the local system,
which may cause them to be different.
- The internal tables can always be overridden by tables supplied by the
+ The internal tables can always be overridden by tables supplied by the
application that calls PCRE. These may be created in a different locale
- from the default. As more and more applications change to using Uni-
+ from the default. As more and more applications change to using Uni-
code, the need for this locale support is expected to die away.
- External tables are built by calling the pcre_maketables() function,
- which has no arguments, in the relevant locale. The result can then be
- passed to pcre_compile() or pcre_exec() as often as necessary. For
- example, to build and use tables that are appropriate for the French
- locale (where accented characters with values greater than 128 are
+ External tables are built by calling the pcre_maketables() function,
+ which has no arguments, in the relevant locale. The result can then be
+ passed to pcre_compile() or pcre_exec() as often as necessary. For
+ example, to build and use tables that are appropriate for the French
+ locale (where accented characters with values greater than 128 are
treated as letters), the following code could be used:
setlocale(LC_CTYPE, "fr_FR");
tables = pcre_maketables();
re = pcre_compile(..., tables);
- The locale name "fr_FR" is used on Linux and other Unix-like systems;
+ The locale name "fr_FR" is used on Linux and other Unix-like systems;
if you are using Windows, the name for the French locale is "french".
- When pcre_maketables() runs, the tables are built in memory that is
- obtained via pcre_malloc. It is the caller's responsibility to ensure
- that the memory containing the tables remains available for as long as
+ When pcre_maketables() runs, the tables are built in memory that is
+ obtained via pcre_malloc. It is the caller's responsibility to ensure
+ that the memory containing the tables remains available for as long as
it is needed.
The pointer that is passed to pcre_compile() is saved with the compiled
- pattern, and the same tables are used via this pointer by pcre_study()
+ pattern, and the same tables are used via this pointer by pcre_study()
and normally also by pcre_exec(). Thus, by default, for any single pat-
tern, compilation, studying and matching all happen in the same locale,
but different patterns can be compiled in different locales.
- It is possible to pass a table pointer or NULL (indicating the use of
- the internal tables) to pcre_exec(). Although not intended for this
- purpose, this facility could be used to match a pattern in a different
+ It is possible to pass a table pointer or NULL (indicating the use of
+ the internal tables) to pcre_exec(). Although not intended for this
+ purpose, this facility could be used to match a pattern in a different
locale from the one in which it was compiled. Passing table pointers at
run time is discussed below in the section on matching a pattern.
int pcre_fullinfo(const pcre *code, const pcre_extra *extra,
int what, void *where);
- The pcre_fullinfo() function returns information about a compiled pat-
+ The pcre_fullinfo() function returns information about a compiled pat-
tern. It replaces the obsolete pcre_info() function, which is neverthe-
less retained for backwards compability (and is documented below).
- The first argument for pcre_fullinfo() is a pointer to the compiled
- pattern. The second argument is the result of pcre_study(), or NULL if
- the pattern was not studied. The third argument specifies which piece
- of information is required, and the fourth argument is a pointer to a
- variable to receive the data. The yield of the function is zero for
+ The first argument for pcre_fullinfo() is a pointer to the compiled
+ pattern. The second argument is the result of pcre_study(), or NULL if
+ the pattern was not studied. The third argument specifies which piece
+ of information is required, and the fourth argument is a pointer to a
+ variable to receive the data. The yield of the function is zero for
success, or one of the following negative numbers:
PCRE_ERROR_NULL the argument code was NULL
PCRE_ERROR_BADMAGIC the "magic number" was not found
PCRE_ERROR_BADOPTION the value of what was invalid
- The "magic number" is placed at the start of each compiled pattern as
- an simple check against passing an arbitrary memory pointer. Here is a
- typical call of pcre_fullinfo(), to obtain the length of the compiled
+ The "magic number" is placed at the start of each compiled pattern as
+ an simple check against passing an arbitrary memory pointer. Here is a
+ typical call of pcre_fullinfo(), to obtain the length of the compiled
pattern:
int rc;
PCRE_INFO_SIZE, /* what is required */
&length); /* where to put the data */
- The possible values for the third argument are defined in pcre.h, and
+ The possible values for the third argument are defined in pcre.h, and
are as follows:
PCRE_INFO_BACKREFMAX
- Return the number of the highest back reference in the pattern. The
- fourth argument should point to an int variable. Zero is returned if
+ Return the number of the highest back reference in the pattern. The
+ fourth argument should point to an int variable. Zero is returned if
there are no back references.
PCRE_INFO_CAPTURECOUNT
- Return the number of capturing subpatterns in the pattern. The fourth
+ Return the number of capturing subpatterns in the pattern. The fourth
argument should point to an int variable.
PCRE_INFO_DEFAULT_TABLES
- Return a pointer to the internal default character tables within PCRE.
- The fourth argument should point to an unsigned char * variable. This
+ Return a pointer to the internal default character tables within PCRE.
+ The fourth argument should point to an unsigned char * variable. This
information call is provided for internal use by the pcre_study() func-
- tion. External callers can cause PCRE to use its internal tables by
+ tion. External callers can cause PCRE to use its internal tables by
passing a NULL table pointer.
PCRE_INFO_FIRSTBYTE
- Return information about the first byte of any matched string, for a
- non-anchored pattern. The fourth argument should point to an int vari-
- able. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name
+ Return information about the first byte of any matched string, for a
+ non-anchored pattern. The fourth argument should point to an int vari-
+ able. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name
is still recognized for backwards compatibility.)
- If there is a fixed first byte, for example, from a pattern such as
+ If there is a fixed first byte, for example, from a pattern such as
(cat|cow|coyote), its value is returned. Otherwise, if either
- (a) the pattern was compiled with the PCRE_MULTILINE option, and every
+ (a) the pattern was compiled with the PCRE_MULTILINE option, and every
branch starts with "^", or
(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not
set (if it were set, the pattern would be anchored),
- -1 is returned, indicating that the pattern matches only at the start
- of a subject string or after any newline within the string. Otherwise
+ -1 is returned, indicating that the pattern matches only at the start
+ of a subject string or after any newline within the string. Otherwise
-2 is returned. For anchored patterns, -2 is returned.
PCRE_INFO_FIRSTTABLE
- If the pattern was studied, and this resulted in the construction of a
+ If the pattern was studied, and this resulted in the construction of a
256-bit table indicating a fixed set of bytes for the first byte in any
- matching string, a pointer to the table is returned. Otherwise NULL is
- returned. The fourth argument should point to an unsigned char * vari-
+ matching string, a pointer to the table is returned. Otherwise NULL is
+ returned. The fourth argument should point to an unsigned char * vari-
able.
PCRE_INFO_HASCRORLF
- Return 1 if the pattern contains any explicit matches for CR or LF
- characters, otherwise 0. The fourth argument should point to an int
- variable. An explicit match is either a literal CR or LF character, or
+ Return 1 if the pattern contains any explicit matches for CR or LF
+ characters, otherwise 0. The fourth argument should point to an int
+ variable. An explicit match is either a literal CR or LF character, or
\r or \n.
PCRE_INFO_JCHANGED
- Return 1 if the (?J) or (?-J) option setting is used in the pattern,
- otherwise 0. The fourth argument should point to an int variable. (?J)
+ Return 1 if the (?J) or (?-J) option setting is used in the pattern,
+ otherwise 0. The fourth argument should point to an int variable. (?J)
and (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
PCRE_INFO_LASTLITERAL
- Return the value of the rightmost literal byte that must exist in any
- matched string, other than at its start, if such a byte has been
+ Return the value of the rightmost literal byte that must exist in any
+ matched string, other than at its start, if such a byte has been
recorded. The fourth argument should point to an int variable. If there
- is no such byte, -1 is returned. For anchored patterns, a last literal
- byte is recorded only if it follows something of variable length. For
+ is no such byte, -1 is returned. For anchored patterns, a last literal
+ byte is recorded only if it follows something of variable length. For
example, for the pattern /^a\d+z\d+/ the returned value is "z", but for
/^a\dz\d/ the returned value is -1.
PCRE_INFO_NAMEENTRYSIZE
PCRE_INFO_NAMETABLE
- PCRE supports the use of named as well as numbered capturing parenthe-
- ses. The names are just an additional way of identifying the parenthe-
+ PCRE supports the use of named as well as numbered capturing parenthe-
+ ses. The names are just an additional way of identifying the parenthe-
ses, which still acquire numbers. Several convenience functions such as
- pcre_get_named_substring() are provided for extracting captured sub-
- strings by name. It is also possible to extract the data directly, by
- first converting the name to a number in order to access the correct
+ pcre_get_named_substring() are provided for extracting captured sub-
+ strings by name. It is also possible to extract the data directly, by
+ first converting the name to a number in order to access the correct
pointers in the output vector (described with pcre_exec() below). To do
- the conversion, you need to use the name-to-number map, which is
+ the conversion, you need to use the name-to-number map, which is
described by these three values.
The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT
gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size
- of each entry; both of these return an int value. The entry size
- depends on the length of the longest name. PCRE_INFO_NAMETABLE returns
- a pointer to the first entry of the table (a pointer to char). The
+ of each entry; both of these return an int value. The entry size
+ depends on the length of the longest name. PCRE_INFO_NAMETABLE returns
+ a pointer to the first entry of the table (a pointer to char). The
first two bytes of each entry are the number of the capturing parenthe-
- sis, most significant byte first. The rest of the entry is the corre-
- sponding name, zero terminated. The names are in alphabetical order.
+ sis, most significant byte first. The rest of the entry is the corre-
+ sponding name, zero terminated. The names are in alphabetical order.
When PCRE_DUPNAMES is set, duplicate names are in order of their paren-
- theses numbers. For example, consider the following pattern (assume
- PCRE_EXTENDED is set, so white space - including newlines - is
+ theses numbers. For example, consider the following pattern (assume
+ PCRE_EXTENDED is set, so white space - including newlines - is
ignored):
(?<date> (?<year>(\d\d)?\d\d) -
(?<month>\d\d) - (?<day>\d\d) )
- There are four named subpatterns, so the table has four entries, and
- each entry in the table is eight bytes long. The table is as follows,
+ There are four named subpatterns, so the table has four entries, and
+ each entry in the table is eight bytes long. The table is as follows,
with non-printing bytes shows in hexadecimal, and undefined bytes shown
as ??:
00 04 m o n t h 00
00 02 y e a r 00 ??
- When writing code to extract data from named subpatterns using the
- name-to-number map, remember that the length of the entries is likely
+ When writing code to extract data from named subpatterns using the
+ name-to-number map, remember that the length of the entries is likely
to be different for each compiled pattern.
PCRE_INFO_OKPARTIAL
- Return 1 if the pattern can be used for partial matching, otherwise 0.
- The fourth argument should point to an int variable. The pcrepartial
- documentation lists the restrictions that apply to patterns when par-
+ Return 1 if the pattern can be used for partial matching, otherwise 0.
+ The fourth argument should point to an int variable. The pcrepartial
+ documentation lists the restrictions that apply to patterns when par-
tial matching is used.
PCRE_INFO_OPTIONS
- Return a copy of the options with which the pattern was compiled. The
- fourth argument should point to an unsigned long int variable. These
+ Return a copy of the options with which the pattern was compiled. The
+ fourth argument should point to an unsigned long int variable. These
option bits are those specified in the call to pcre_compile(), modified
by any top-level option settings at the start of the pattern itself. In
- other words, they are the options that will be in force when matching
- starts. For example, if the pattern /(?im)abc(?-i)d/ is compiled with
- the PCRE_EXTENDED option, the result is PCRE_CASELESS, PCRE_MULTILINE,
+ other words, they are the options that will be in force when matching
+ starts. For example, if the pattern /(?im)abc(?-i)d/ is compiled with
+ the PCRE_EXTENDED option, the result is PCRE_CASELESS, PCRE_MULTILINE,
and PCRE_EXTENDED.
- A pattern is automatically anchored by PCRE if all of its top-level
+ A pattern is automatically anchored by PCRE if all of its top-level
alternatives begin with one of the following:
^ unless PCRE_MULTILINE is set
PCRE_INFO_SIZE
- Return the size of the compiled pattern, that is, the value that was
+ Return the size of the compiled pattern, that is, the value that was
passed as the argument to pcre_malloc() when PCRE was getting memory in
which to place the compiled data. The fourth argument should point to a
size_t variable.
PCRE_INFO_STUDYSIZE
Return the size of the data block pointed to by the study_data field in
- a pcre_extra block. That is, it is the value that was passed to
+ a pcre_extra block. That is, it is the value that was passed to
pcre_malloc() when PCRE was getting memory into which to place the data
- created by pcre_study(). The fourth argument should point to a size_t
+ created by pcre_study(). The fourth argument should point to a size_t
variable.
int pcre_info(const pcre *code, int *optptr, int *firstcharptr);
- The pcre_info() function is now obsolete because its interface is too
- restrictive to return all the available data about a compiled pattern.
- New programs should use pcre_fullinfo() instead. The yield of
- pcre_info() is the number of capturing subpatterns, or one of the fol-
+ The pcre_info() function is now obsolete because its interface is too
+ restrictive to return all the available data about a compiled pattern.
+ New programs should use pcre_fullinfo() instead. The yield of
+ pcre_info() is the number of capturing subpatterns, or one of the fol-
lowing negative numbers:
PCRE_ERROR_NULL the argument code was NULL
PCRE_ERROR_BADMAGIC the "magic number" was not found
- If the optptr argument is not NULL, a copy of the options with which
- the pattern was compiled is placed in the integer it points to (see
+ If the optptr argument is not NULL, a copy of the options with which
+ the pattern was compiled is placed in the integer it points to (see
PCRE_INFO_OPTIONS above).
- If the pattern is not anchored and the firstcharptr argument is not
- NULL, it is used to pass back information about the first character of
+ If the pattern is not anchored and the firstcharptr argument is not
+ NULL, it is used to pass back information about the first character of
any matched string (see PCRE_INFO_FIRSTBYTE above).
int pcre_refcount(pcre *code, int adjust);
- The pcre_refcount() function is used to maintain a reference count in
+ The pcre_refcount() function is used to maintain a reference count in
the data block that contains a compiled pattern. It is provided for the
- benefit of applications that operate in an object-oriented manner,
+ benefit of applications that operate in an object-oriented manner,
where different parts of the application may be using the same compiled
pattern, but you want to free the block when they are all done.
When a pattern is compiled, the reference count field is initialized to
- zero. It is changed only by calling this function, whose action is to
- add the adjust value (which may be positive or negative) to it. The
+ zero. It is changed only by calling this function, whose action is to
+ add the adjust value (which may be positive or negative) to it. The
yield of the function is the new value. However, the value of the count
- is constrained to lie between 0 and 65535, inclusive. If the new value
+ is constrained to lie between 0 and 65535, inclusive. If the new value
is outside these limits, it is forced to the appropriate limit value.
- Except when it is zero, the reference count is not correctly preserved
- if a pattern is compiled on one host and then transferred to a host
+ Except when it is zero, the reference count is not correctly preserved
+ if a pattern is compiled on one host and then transferred to a host
whose byte-order is different. (This seems a highly unlikely scenario.)
the total number of calls, because not all calls to match() are recur-
sive. This limit is of use only if it is set smaller than match_limit.
- Limiting the recursion depth limits the amount of stack that can be
+ Limiting the recursion depth limits the amount of stack that can be
used, or, when PCRE has been compiled to use memory on the heap instead
of the stack, the amount of heap memory that can be used.
- The default value for match_limit_recursion can be set when PCRE is
- built; the default default is the same value as the default for
- match_limit. You can override the default by suppling pcre_exec() with
- a pcre_extra block in which match_limit_recursion is set, and
- PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the flags field. If the
+ The default value for match_limit_recursion can be set when PCRE is
+ built; the default default is the same value as the default for
+ match_limit. You can override the default by suppling pcre_exec() with
+ a pcre_extra block in which match_limit_recursion is set, and
+ PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in the flags field. If the
limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.
- The pcre_callout field is used in conjunction with the "callout" fea-
+ The pcre_callout field is used in conjunction with the "callout" fea-
ture, which is described in the pcrecallout documentation.
- The tables field is used to pass a character tables pointer to
- pcre_exec(); this overrides the value that is stored with the compiled
- pattern. A non-NULL value is stored with the compiled pattern only if
- custom tables were supplied to pcre_compile() via its tableptr argu-
+ The tables field is used to pass a character tables pointer to
+ pcre_exec(); this overrides the value that is stored with the compiled
+ pattern. A non-NULL value is stored with the compiled pattern only if
+ custom tables were supplied to pcre_compile() via its tableptr argu-
ment. If NULL is passed to pcre_exec() using this mechanism, it forces
- PCRE's internal tables to be used. This facility is helpful when re-
- using patterns that have been saved after compiling with an external
- set of tables, because the external tables might be at a different
- address when pcre_exec() is called. See the pcreprecompile documenta-
+ PCRE's internal tables to be used. This facility is helpful when re-
+ using patterns that have been saved after compiling with an external
+ set of tables, because the external tables might be at a different
+ address when pcre_exec() is called. See the pcreprecompile documenta-
tion for a discussion of saving compiled patterns for later use.
Option bits for pcre_exec()
- The unused bits of the options argument for pcre_exec() must be zero.
- The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_xxx,
- PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and
- PCRE_PARTIAL.
+ The unused bits of the options argument for pcre_exec() must be zero.
+ The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_xxx,
+ PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_START_OPTIMIZE,
+ PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
PCRE_ANCHORED
- The PCRE_ANCHORED option limits pcre_exec() to matching at the first
- matching position. If a pattern was compiled with PCRE_ANCHORED, or
- turned out to be anchored by virtue of its contents, it cannot be made
+ The PCRE_ANCHORED option limits pcre_exec() to matching at the first
+ matching position. If a pattern was compiled with PCRE_ANCHORED, or
+ turned out to be anchored by virtue of its contents, it cannot be made
unachored at matching time.
PCRE_BSR_ANYCRLF
PCRE_BSR_UNICODE
These options (which are mutually exclusive) control what the \R escape
- sequence matches. The choice is either to match only CR, LF, or CRLF,
- or to match any Unicode newline sequence. These options override the
+ sequence matches. The choice is either to match only CR, LF, or CRLF,
+ or to match any Unicode newline sequence. These options override the
choice that was made or defaulted when the pattern was compiled.
PCRE_NEWLINE_CR
PCRE_NEWLINE_ANYCRLF
PCRE_NEWLINE_ANY
- These options override the newline definition that was chosen or
- defaulted when the pattern was compiled. For details, see the descrip-
- tion of pcre_compile() above. During matching, the newline choice
- affects the behaviour of the dot, circumflex, and dollar metacharac-
- ters. It may also alter the way the match position is advanced after a
+ These options override the newline definition that was chosen or
+ defaulted when the pattern was compiled. For details, see the descrip-
+ tion of pcre_compile() above. During matching, the newline choice
+ affects the behaviour of the dot, circumflex, and dollar metacharac-
+ ters. It may also alter the way the match position is advanced after a
match failure for an unanchored pattern.
- When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is
- set, and a match attempt for an unanchored pattern fails when the cur-
- rent position is at a CRLF sequence, and the pattern contains no
- explicit matches for CR or LF characters, the match position is
+ When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is
+ set, and a match attempt for an unanchored pattern fails when the cur-
+ rent position is at a CRLF sequence, and the pattern contains no
+ explicit matches for CR or LF characters, the match position is
advanced by two characters instead of one, in other words, to after the
CRLF.
The above rule is a compromise that makes the most common cases work as
- expected. For example, if the pattern is .+A (and the PCRE_DOTALL
+ expected. For example, if the pattern is .+A (and the PCRE_DOTALL
option is not set), it does not match the string "\r\nA" because, after
- failing at the start, it skips both the CR and the LF before retrying.
- However, the pattern [\r\n]A does match that string, because it con-
+ failing at the start, it skips both the CR and the LF before retrying.
+ However, the pattern [\r\n]A does match that string, because it con-
tains an explicit CR or LF reference, and so advances only by one char-
acter after the first failure.
An explicit match for CR of LF is either a literal appearance of one of
- those characters, or one of the \r or \n escape sequences. Implicit
- matches such as [^X] do not count, nor does \s (which includes CR and
+ those characters, or one of the \r or \n escape sequences. Implicit
+ matches such as [^X] do not count, nor does \s (which includes CR and
LF in the characters that it matches).
- Notwithstanding the above, anomalous effects may still occur when CRLF
+ Notwithstanding the above, anomalous effects may still occur when CRLF
is a valid newline sequence and explicit \r or \n escapes appear in the
pattern.
PCRE_NOTBOL
This option specifies that first character of the subject string is not
- the beginning of a line, so the circumflex metacharacter should not
- match before it. Setting this without PCRE_MULTILINE (at compile time)
- causes circumflex never to match. This option affects only the behav-
+ the beginning of a line, so the circumflex metacharacter should not
+ match before it. Setting this without PCRE_MULTILINE (at compile time)
+ causes circumflex never to match. This option affects only the behav-
iour of the circumflex metacharacter. It does not affect \A.
PCRE_NOTEOL
This option specifies that the end of the subject string is not the end
- of a line, so the dollar metacharacter should not match it nor (except
- in multiline mode) a newline immediately before it. Setting this with-
+ of a line, so the dollar metacharacter should not match it nor (except
+ in multiline mode) a newline immediately before it. Setting this with-
out PCRE_MULTILINE (at compile time) causes dollar never to match. This
- option affects only the behaviour of the dollar metacharacter. It does
+ option affects only the behaviour of the dollar metacharacter. It does
not affect \Z or \z.
PCRE_NOTEMPTY
An empty string is not considered to be a valid match if this option is
- set. If there are alternatives in the pattern, they are tried. If all
- the alternatives match the empty string, the entire match fails. For
+ set. If there are alternatives in the pattern, they are tried. If all
+ the alternatives match the empty string, the entire match fails. For
example, if the pattern
a?b?
- is applied to a string not beginning with "a" or "b", it matches the
- empty string at the start of the subject. With PCRE_NOTEMPTY set, this
+ is applied to a string not beginning with "a" or "b", it matches the
+ empty string at the start of the subject. With PCRE_NOTEMPTY set, this
match is not valid, so PCRE searches further into the string for occur-
rences of "a" or "b".
Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
- cial case of a pattern match of the empty string within its split()
- function, and when using the /g modifier. It is possible to emulate
+ cial case of a pattern match of the empty string within its split()
+ function, and when using the /g modifier. It is possible to emulate
Perl's behaviour after matching a null string by first trying the match
again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
- if that fails by advancing the starting offset (see below) and trying
+ if that fails by advancing the starting offset (see below) and trying
an ordinary match again. There is some code that demonstrates how to do
this in the pcredemo.c sample program.
+ PCRE_NO_START_OPTIMIZE
+
+ There are a number of optimizations that pcre_exec() uses at the start
+ of a match, in order to speed up the process. For example, if it is
+ known that a match must start with a specific character, it searches
+ the subject for that character, and fails immediately if it cannot find
+ it, without actually running the main matching function. When callouts
+ are in use, these optimizations can cause them to be skipped. This
+ option disables the "start-up" optimizations, causing performance to
+ suffer, but ensuring that the callouts do occur.
+
PCRE_NO_UTF8_CHECK
When PCRE_UTF8 is set at compile time, the validity of the subject as a
PCRE_ERROR_BADCOUNT (-15)
- This error is given if the value of the ovecsize argument is negative.
+ This error is given if the value of the ovecsize argument is negative.
PCRE_ERROR_RECURSIONLIMIT (-21)
The internal recursion limit, as specified by the match_limit_recursion
- field in a pcre_extra structure (or defaulted) was reached. See the
+ field in a pcre_extra structure (or defaulted) was reached. See the
description above.
PCRE_ERROR_BADNEWLINE (-23)
int pcre_get_substring_list(const char *subject,
int *ovector, int stringcount, const char ***listptr);
- Captured substrings can be accessed directly by using the offsets
- returned by pcre_exec() in ovector. For convenience, the functions
+ Captured substrings can be accessed directly by using the offsets
+ returned by pcre_exec() in ovector. For convenience, the functions
pcre_copy_substring(), pcre_get_substring(), and pcre_get_sub-
- string_list() are provided for extracting captured substrings as new,
- separate, zero-terminated strings. These functions identify substrings
- by number. The next section describes functions for extracting named
+ string_list() are provided for extracting captured substrings as new,
+ separate, zero-terminated strings. These functions identify substrings
+ by number. The next section describes functions for extracting named
substrings.
- A substring that contains a binary zero is correctly extracted and has
- a further zero added on the end, but the result is not, of course, a C
- string. However, you can process such a string by referring to the
- length that is returned by pcre_copy_substring() and pcre_get_sub-
+ A substring that contains a binary zero is correctly extracted and has
+ a further zero added on the end, but the result is not, of course, a C
+ string. However, you can process such a string by referring to the
+ length that is returned by pcre_copy_substring() and pcre_get_sub-
string(). Unfortunately, the interface to pcre_get_substring_list() is
- not adequate for handling strings containing binary zeros, because the
+ not adequate for handling strings containing binary zeros, because the
end of the final string is not independently indicated.
- The first three arguments are the same for all three of these func-
- tions: subject is the subject string that has just been successfully
+ The first three arguments are the same for all three of these func-
+ tions: subject is the subject string that has just been successfully
matched, ovector is a pointer to the vector of integer offsets that was
passed to pcre_exec(), and stringcount is the number of substrings that
- were captured by the match, including the substring that matched the
+ were captured by the match, including the substring that matched the
entire regular expression. This is the value returned by pcre_exec() if
- it is greater than zero. If pcre_exec() returned zero, indicating that
- it ran out of space in ovector, the value passed as stringcount should
+ it is greater than zero. If pcre_exec() returned zero, indicating that
+ it ran out of space in ovector, the value passed as stringcount should
be the number of elements in the vector divided by three.
- The functions pcre_copy_substring() and pcre_get_substring() extract a
- single substring, whose number is given as stringnumber. A value of
- zero extracts the substring that matched the entire pattern, whereas
- higher values extract the captured substrings. For pcre_copy_sub-
- string(), the string is placed in buffer, whose length is given by
- buffersize, while for pcre_get_substring() a new block of memory is
- obtained via pcre_malloc, and its address is returned via stringptr.
- The yield of the function is the length of the string, not including
+ The functions pcre_copy_substring() and pcre_get_substring() extract a
+ single substring, whose number is given as stringnumber. A value of
+ zero extracts the substring that matched the entire pattern, whereas
+ higher values extract the captured substrings. For pcre_copy_sub-
+ string(), the string is placed in buffer, whose length is given by
+ buffersize, while for pcre_get_substring() a new block of memory is
+ obtained via pcre_malloc, and its address is returned via stringptr.
+ The yield of the function is the length of the string, not including
the terminating zero, or one of these error codes:
PCRE_ERROR_NOMEMORY (-6)
- The buffer was too small for pcre_copy_substring(), or the attempt to
+ The buffer was too small for pcre_copy_substring(), or the attempt to
get memory failed for pcre_get_substring().
PCRE_ERROR_NOSUBSTRING (-7)
There is no substring whose number is stringnumber.
- The pcre_get_substring_list() function extracts all available sub-
- strings and builds a list of pointers to them. All this is done in a
+ The pcre_get_substring_list() function extracts all available sub-
+ strings and builds a list of pointers to them. All this is done in a
single block of memory that is obtained via pcre_malloc. The address of
- the memory block is returned via listptr, which is also the start of
- the list of string pointers. The end of the list is marked by a NULL
- pointer. The yield of the function is zero if all went well, or the
+ the memory block is returned via listptr, which is also the start of
+ the list of string pointers. The end of the list is marked by a NULL
+ pointer. The yield of the function is zero if all went well, or the
error code
PCRE_ERROR_NOMEMORY (-6)
if the attempt to get the memory block failed.
- When any of these functions encounter a substring that is unset, which
- can happen when capturing subpattern number n+1 matches some part of
- the subject, but subpattern n has not been used at all, they return an
+ When any of these functions encounter a substring that is unset, which
+ can happen when capturing subpattern number n+1 matches some part of
+ the subject, but subpattern n has not been used at all, they return an
empty string. This can be distinguished from a genuine zero-length sub-
- string by inspecting the appropriate offset in ovector, which is nega-
+ string by inspecting the appropriate offset in ovector, which is nega-
tive for unset substrings.
- The two convenience functions pcre_free_substring() and pcre_free_sub-
- string_list() can be used to free the memory returned by a previous
+ The two convenience functions pcre_free_substring() and pcre_free_sub-
+ string_list() can be used to free the memory returned by a previous
call of pcre_get_substring() or pcre_get_substring_list(), respec-
- tively. They do nothing more than call the function pointed to by
- pcre_free, which of course could be called directly from a C program.
- However, PCRE is used in some situations where it is linked via a spe-
- cial interface to another programming language that cannot use
- pcre_free directly; it is for these cases that the functions are pro-
+ tively. They do nothing more than call the function pointed to by
+ pcre_free, which of course could be called directly from a C program.
+ However, PCRE is used in some situations where it is linked via a spe-
+ cial interface to another programming language that cannot use
+ pcre_free directly; it is for these cases that the functions are pro-
vided.
int stringcount, const char *stringname,
const char **stringptr);
- To extract a substring by name, you first have to find associated num-
+ To extract a substring by name, you first have to find associated num-
ber. For example, for this pattern
(a+)b(?<xxx>\d+)...
be unique (PCRE_DUPNAMES was not set), you can find the number from the
name by calling pcre_get_stringnumber(). The first argument is the com-
piled pattern, and the second is the name. The yield of the function is
- the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no
+ the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no
subpattern of that name.
Given the number, you can extract the substring directly, or use one of
the functions described in the previous section. For convenience, there
are also two functions that do the whole job.
- Most of the arguments of pcre_copy_named_substring() and
- pcre_get_named_substring() are the same as those for the similarly
- named functions that extract by number. As these are described in the
- previous section, they are not re-described here. There are just two
+ Most of the arguments of pcre_copy_named_substring() and
+ pcre_get_named_substring() are the same as those for the similarly
+ named functions that extract by number. As these are described in the
+ previous section, they are not re-described here. There are just two
differences:
- First, instead of a substring number, a substring name is given. Sec-
+ First, instead of a substring number, a substring name is given. Sec-
ond, there is an extra argument, given at the start, which is a pointer
- to the compiled pattern. This is needed in order to gain access to the
+ to the compiled pattern. This is needed in order to gain access to the
name-to-number translation table.
- These functions call pcre_get_stringnumber(), and if it succeeds, they
- then call pcre_copy_substring() or pcre_get_substring(), as appropri-
- ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate names, the
+ These functions call pcre_get_stringnumber(), and if it succeeds, they
+ then call pcre_copy_substring() or pcre_get_substring(), as appropri-
+ ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate names, the
behaviour may not be what you want (see the next section).
+ Warning: If the pattern uses the "(?|" feature to set up multiple sub-
+ patterns with the same number, you cannot use names to distinguish
+ them, because names are not included in the compiled code. The matching
+ process uses only numbers.
+
DUPLICATE SUBPATTERN NAMES
SEE ALSO
pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar-
- tial(3), pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).
+ tial(3), pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).
AUTHOR
REVISION
- Last updated: 24 August 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 11 April 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
MISSING CALLOUTS
You should be aware that, because of optimizations in the way PCRE
- matches patterns, callouts sometimes do not happen. For example, if the
- pattern is
+ matches patterns by default, callouts sometimes do not happen. For
+ example, if the pattern is
ab(?C4)cd
ever start, and the callout is never reached. However, with "abyd",
though the result is still no match, the callout is obeyed.
+ You can disable these optimizations by passing the PCRE_NO_START_OPTI-
+ MIZE option to pcre_exec() or pcre_dfa_exec(). This slows down the
+ matching process, but does ensure that callouts such as the example
+ above are obeyed.
+
THE CALLOUT INTERFACE
- During matching, when PCRE reaches a callout point, the external func-
- tion defined by pcre_callout is called (if it is set). This applies to
- both the pcre_exec() and the pcre_dfa_exec() matching functions. The
- only argument to the callout function is a pointer to a pcre_callout
+ During matching, when PCRE reaches a callout point, the external func-
+ tion defined by pcre_callout is called (if it is set). This applies to
+ both the pcre_exec() and the pcre_dfa_exec() matching functions. The
+ only argument to the callout function is a pointer to a pcre_callout
block. This structure contains the following fields:
int version;
int pattern_position;
int next_item_length;
- The version field is an integer containing the version number of the
- block format. The initial version was 0; the current version is 1. The
- version number will change again in future if additional fields are
+ The version field is an integer containing the version number of the
+ block format. The initial version was 0; the current version is 1. The
+ version number will change again in future if additional fields are
added, but the intention is never to remove any of the existing fields.
The callout_number field contains the number of the callout, as com-
REVISION
- Last updated: 29 May 2007
- Copyright (c) 1997-2007 University of Cambridge.
+ Last updated: 15 March 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
The original operation of PCRE was on strings of one-byte characters.
However, there is now also support for UTF-8 character strings. To use
this, you must build PCRE to include UTF-8 support, and then call
- pcre_compile() with the PCRE_UTF8 option. How this affects pattern
- matching is mentioned in several places below. There is also a summary
- of UTF-8 features in the section on UTF-8 support in the main pcre
- page.
+ pcre_compile() with the PCRE_UTF8 option. There is also a special
+ sequence that can be given at the start of a pattern:
+
+ (*UTF8)
+
+ Starting a pattern with this sequence is equivalent to setting the
+ PCRE_UTF8 option. This feature is not Perl-compatible. How setting
+ UTF-8 mode affects pattern matching is mentioned in several places
+ below. There is also a summary of UTF-8 features in the section on
+ UTF-8 support in the main pcre page.
The remainder of this document discusses the patterns that are sup-
ported by PCRE when its main matching function, pcre_exec(), is used.
syntax)
] terminates the character class
- The following sections describe the use of each of the metacharacters.
+ The following sections describe the use of each of the metacharacters.
BACKSLASH
The backslash character has several uses. Firstly, if it is followed by
- a non-alphanumeric character, it takes away any special meaning that
- character may have. This use of backslash as an escape character
+ a non-alphanumeric character, it takes away any special meaning that
+ character may have. This use of backslash as an escape character
applies both inside and outside character classes.
- For example, if you want to match a * character, you write \* in the
- pattern. This escaping action applies whether or not the following
- character would otherwise be interpreted as a metacharacter, so it is
- always safe to precede a non-alphanumeric with backslash to specify
- that it stands for itself. In particular, if you want to match a back-
+ For example, if you want to match a * character, you write \* in the
+ pattern. This escaping action applies whether or not the following
+ character would otherwise be interpreted as a metacharacter, so it is
+ always safe to precede a non-alphanumeric with backslash to specify
+ that it stands for itself. In particular, if you want to match a back-
slash, you write \\.
- If a pattern is compiled with the PCRE_EXTENDED option, whitespace in
- the pattern (other than in a character class) and characters between a
+ If a pattern is compiled with the PCRE_EXTENDED option, whitespace in
+ the pattern (other than in a character class) and characters between a
# outside a character class and the next newline are ignored. An escap-
- ing backslash can be used to include a whitespace or # character as
+ ing backslash can be used to include a whitespace or # character as
part of the pattern.
- If you want to remove the special meaning from a sequence of charac-
- ters, you can do so by putting them between \Q and \E. This is differ-
- ent from Perl in that $ and @ are handled as literals in \Q...\E
- sequences in PCRE, whereas in Perl, $ and @ cause variable interpola-
+ If you want to remove the special meaning from a sequence of charac-
+ ters, you can do so by putting them between \Q and \E. This is differ-
+ ent from Perl in that $ and @ are handled as literals in \Q...\E
+ sequences in PCRE, whereas in Perl, $ and @ cause variable interpola-
tion. Note the following examples:
Pattern PCRE matches Perl matches
\Qabc\$xyz\E abc\$xyz abc\$xyz
\Qabc\E\$\Qxyz\E abc$xyz abc$xyz
- The \Q...\E sequence is recognized both inside and outside character
+ The \Q...\E sequence is recognized both inside and outside character
classes.
Non-printing characters
A second use of backslash provides a way of encoding non-printing char-
- acters in patterns in a visible manner. There is no restriction on the
- appearance of non-printing characters, apart from the binary zero that
- terminates a pattern, but when a pattern is being prepared by text
- editing, it is usually easier to use one of the following escape
+ acters in patterns in a visible manner. There is no restriction on the
+ appearance of non-printing characters, apart from the binary zero that
+ terminates a pattern, but when a pattern is being prepared by text
+ editing, it is usually easier to use one of the following escape
sequences than the binary character it represents:
\a alarm, that is, the BEL character (hex 07)
\xhh character with hex code hh
\x{hhh..} character with hex code hhh..
- The precise effect of \cx is as follows: if x is a lower case letter,
- it is converted to upper case. Then bit 6 of the character (hex 40) is
- inverted. Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c;
+ The precise effect of \cx is as follows: if x is a lower case letter,
+ it is converted to upper case. Then bit 6 of the character (hex 40) is
+ inverted. Thus \cz becomes hex 1A, but \c{ becomes hex 3B, while \c;
becomes hex 7B.
- After \x, from zero to two hexadecimal digits are read (letters can be
- in upper or lower case). Any number of hexadecimal digits may appear
- between \x{ and }, but the value of the character code must be less
+ After \x, from zero to two hexadecimal digits are read (letters can be
+ in upper or lower case). Any number of hexadecimal digits may appear
+ between \x{ and }, but the value of the character code must be less
than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode. That is,
- the maximum value in hexadecimal is 7FFFFFFF. Note that this is bigger
+ the maximum value in hexadecimal is 7FFFFFFF. Note that this is bigger
than the largest Unicode code point, which is 10FFFF.
- If characters other than hexadecimal digits appear between \x{ and },
+ If characters other than hexadecimal digits appear between \x{ and },
or if there is no terminating }, this form of escape is not recognized.
- Instead, the initial \x will be interpreted as a basic hexadecimal
- escape, with no following digits, giving a character whose value is
+ Instead, the initial \x will be interpreted as a basic hexadecimal
+ escape, with no following digits, giving a character whose value is
zero.
Characters whose value is less than 256 can be defined by either of the
- two syntaxes for \x. There is no difference in the way they are han-
+ two syntaxes for \x. There is no difference in the way they are han-
dled. For example, \xdc is exactly the same as \x{dc}.
- After \0 up to two further octal digits are read. If there are fewer
- than two digits, just those that are present are used. Thus the
+ After \0 up to two further octal digits are read. If there are fewer
+ than two digits, just those that are present are used. Thus the
sequence \0\x\07 specifies two binary zeros followed by a BEL character
- (code value 7). Make sure you supply two digits after the initial zero
+ (code value 7). Make sure you supply two digits after the initial zero
if the pattern character that follows is itself an octal digit.
The handling of a backslash followed by a digit other than 0 is compli-
cated. Outside a character class, PCRE reads it and any following dig-
- its as a decimal number. If the number is less than 10, or if there
+ its as a decimal number. If the number is less than 10, or if there
have been at least that many previous capturing left parentheses in the
- expression, the entire sequence is taken as a back reference. A
- description of how this works is given later, following the discussion
+ expression, the entire sequence is taken as a back reference. A
+ description of how this works is given later, following the discussion
of parenthesized subpatterns.
- Inside a character class, or if the decimal number is greater than 9
- and there have not been that many capturing subpatterns, PCRE re-reads
+ Inside a character class, or if the decimal number is greater than 9
+ and there have not been that many capturing subpatterns, PCRE re-reads
up to three octal digits following the backslash, and uses them to gen-
- erate a data character. Any subsequent digits stand for themselves. In
- non-UTF-8 mode, the value of a character specified in octal must be
- less than \400. In UTF-8 mode, values up to \777 are permitted. For
+ erate a data character. Any subsequent digits stand for themselves. In
+ non-UTF-8 mode, the value of a character specified in octal must be
+ less than \400. In UTF-8 mode, values up to \777 are permitted. For
example:
\040 is another way of writing a space
\81 is either a back reference, or a binary zero
followed by the two characters "8" and "1"
- Note that octal values of 100 or greater must not be introduced by a
+ Note that octal values of 100 or greater must not be introduced by a
leading zero, because no more than three octal digits are ever read.
All the sequences that define a single character value can be used both
- inside and outside character classes. In addition, inside a character
- class, the sequence \b is interpreted as the backspace character (hex
- 08), and the sequences \R and \X are interpreted as the characters "R"
- and "X", respectively. Outside a character class, these sequences have
+ inside and outside character classes. In addition, inside a character
+ class, the sequence \b is interpreted as the backspace character (hex
+ 08), and the sequences \R and \X are interpreted as the characters "R"
+ and "X", respectively. Outside a character class, these sequences have
different meanings (see below).
Absolute and relative back references
- The sequence \g followed by an unsigned or a negative number, option-
- ally enclosed in braces, is an absolute or relative back reference. A
+ The sequence \g followed by an unsigned or a negative number, option-
+ ally enclosed in braces, is an absolute or relative back reference. A
named back reference can be coded as \g{name}. Back references are dis-
cussed later, following the discussion of parenthesized subpatterns.
Absolute and relative subroutine calls
- For compatibility with Oniguruma, the non-Perl syntax \g followed by a
+ For compatibility with Oniguruma, the non-Perl syntax \g followed by a
name or a number enclosed either in angle brackets or single quotes, is
- an alternative syntax for referencing a subpattern as a "subroutine".
- Details are discussed later. Note that \g{...} (Perl syntax) and
- \g<...> (Oniguruma syntax) are not synonymous. The former is a back
+ an alternative syntax for referencing a subpattern as a "subroutine".
+ Details are discussed later. Note that \g{...} (Perl syntax) and
+ \g<...> (Oniguruma syntax) are not synonymous. The former is a back
reference; the latter is a subroutine call.
Generic character types
\W any "non-word" character
Each pair of escape sequences partitions the complete set of characters
- into two disjoint sets. Any given character matches one, and only one,
+ into two disjoint sets. Any given character matches one, and only one,
of each pair.
These character type sequences can appear both inside and outside char-
- acter classes. They each match one character of the appropriate type.
- If the current matching point is at the end of the subject string, all
+ acter classes. They each match one character of the appropriate type.
+ If the current matching point is at the end of the subject string, all
of them fail, since there is no character to match.
- For compatibility with Perl, \s does not match the VT character (code
- 11). This makes it different from the the POSIX "space" class. The \s
- characters are HT (9), LF (10), FF (12), CR (13), and space (32). If
+ For compatibility with Perl, \s does not match the VT character (code
+ 11). This makes it different from the the POSIX "space" class. The \s
+ characters are HT (9), LF (10), FF (12), CR (13), and space (32). If
"use locale;" is included in a Perl script, \s may match the VT charac-
ter. In PCRE, it never does.
- In UTF-8 mode, characters with values greater than 128 never match \d,
+ In UTF-8 mode, characters with values greater than 128 never match \d,
\s, or \w, and always match \D, \S, and \W. This is true even when Uni-
- code character property support is available. These sequences retain
+ code character property support is available. These sequences retain
their original meanings from before UTF-8 support was available, mainly
- for efficiency reasons.
+ for efficiency reasons. Note that this also affects \b, because it is
+ defined in terms of \w and \W.
The sequences \h, \H, \v, and \V are Perl 5.10 features. In contrast to
the other sequences, these do match certain high-valued codepoints in
VERTICAL BAR
- Vertical bar characters are used to separate alternative patterns. For
+ Vertical bar characters are used to separate alternative patterns. For
example, the pattern
gilbert|sullivan
- matches either "gilbert" or "sullivan". Any number of alternatives may
- appear, and an empty alternative is permitted (matching the empty
+ matches either "gilbert" or "sullivan". Any number of alternatives may
+ appear, and an empty alternative is permitted (matching the empty
string). The matching process tries each alternative in turn, from left
- to right, and the first one that succeeds is used. If the alternatives
- are within a subpattern (defined below), "succeeds" means matching the
- rest of the main pattern as well as the alternative in the subpattern.
+ to right, and the first one that succeeds is used. If the alternatives
+ are within a subpattern (defined below), "succeeds" means matching the
+ rest of the main pattern as well as the alternative in the subpattern.
INTERNAL OPTION SETTING
can be changed in the same way as the Perl-compatible options by using
the characters J, U and X respectively.
- When an option change occurs at top level (that is, not inside subpat-
- tern parentheses), the change applies to the remainder of the pattern
- that follows. If the change is placed right at the start of a pattern,
- PCRE extracts it into the global options (and it will therefore show up
- in data extracted by the pcre_fullinfo() function).
+ When one of these option changes occurs at top level (that is, not
+ inside subpattern parentheses), the change applies to the remainder of
+ the pattern that follows. If the change is placed right at the start of
+ a pattern, PCRE extracts it into the global options (and it will there-
+ fore show up in data extracted by the pcre_fullinfo() function).
An option change within a subpattern (see below for a description of
subpatterns) affects only that part of the current pattern that follows
Note: There are other PCRE-specific options that can be set by the
application when the compile or match functions are called. In some
- cases the pattern can contain special leading sequences to override
- what the application has set or what has been defaulted. Details are
- given in the section entitled "Newline sequences" above.
+ cases the pattern can contain special leading sequences such as (*CRLF)
+ to override what the application has set or what has been defaulted.
+ Details are given in the section entitled "Newline sequences" above.
+ There is also the (*UTF8) leading sequence that can be used to set
+ UTF-8 mode; this is equivalent to setting the PCRE_UTF8 option.
SUBPATTERNS
lowest number is used. For further details of the interfaces for han-
dling named subpatterns, see the pcreapi documentation.
+ Warning: You cannot use different names to distinguish between two sub-
+ patterns with the same number (see the previous section) because PCRE
+ uses only the numbers when matching.
+
REPETITION
the syntax of a quantifier, is taken as a literal character. For exam-
ple, {,6} is not a quantifier, but a literal string of four characters.
- In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to
+ In UTF-8 mode, quantifiers apply to UTF-8 characters rather than to
individual bytes. Thus, for example, \x{100}{2} matches two UTF-8 char-
acters, each of which is represented by a two-byte sequence. Similarly,
when Unicode property support is available, \X{3} matches three Unicode
- extended sequences, each of which may be several bytes long (and they
+ extended sequences, each of which may be several bytes long (and they
may be of different lengths).
The quantifier {0} is permitted, causing the expression to behave as if
the previous item and the quantifier were not present. This may be use-
- ful for subpatterns that are referenced as subroutines from elsewhere
+ ful for subpatterns that are referenced as subroutines from elsewhere
in the pattern. Items other than subpatterns that have a {0} quantifier
are omitted from the compiled pattern.
- For convenience, the three most common quantifiers have single-charac-
+ For convenience, the three most common quantifiers have single-charac-
ter abbreviations:
* is equivalent to {0,}
+ is equivalent to {1,}
? is equivalent to {0,1}
- It is possible to construct infinite loops by following a subpattern
+ It is possible to construct infinite loops by following a subpattern
that can match no characters with a quantifier that has no upper limit,
for example:
(a?)*
Earlier versions of Perl and PCRE used to give an error at compile time
- for such patterns. However, because there are cases where this can be
- useful, such patterns are now accepted, but if any repetition of the
- subpattern does in fact match no characters, the loop is forcibly bro-
+ for such patterns. However, because there are cases where this can be
+ useful, such patterns are now accepted, but if any repetition of the
+ subpattern does in fact match no characters, the loop is forcibly bro-
ken.
- By default, the quantifiers are "greedy", that is, they match as much
- as possible (up to the maximum number of permitted times), without
- causing the rest of the pattern to fail. The classic example of where
+ By default, the quantifiers are "greedy", that is, they match as much
+ as possible (up to the maximum number of permitted times), without
+ causing the rest of the pattern to fail. The classic example of where
this gives problems is in trying to match comments in C programs. These
- appear between /* and */ and within the comment, individual * and /
- characters may appear. An attempt to match C comments by applying the
+ appear between /* and */ and within the comment, individual * and /
+ characters may appear. An attempt to match C comments by applying the
pattern
/\*.*\*/
/* first comment */ not comment /* second comment */
- fails, because it matches the entire string owing to the greediness of
+ fails, because it matches the entire string owing to the greediness of
the .* item.
- However, if a quantifier is followed by a question mark, it ceases to
+ However, if a quantifier is followed by a question mark, it ceases to
be greedy, and instead matches the minimum number of times possible, so
the pattern
/\*.*?\*/
- does the right thing with the C comments. The meaning of the various
- quantifiers is not otherwise changed, just the preferred number of
- matches. Do not confuse this use of question mark with its use as a
- quantifier in its own right. Because it has two uses, it can sometimes
+ does the right thing with the C comments. The meaning of the various
+ quantifiers is not otherwise changed, just the preferred number of
+ matches. Do not confuse this use of question mark with its use as a
+ quantifier in its own right. Because it has two uses, it can sometimes
appear doubled, as in
\d??\d
which matches one digit by preference, but can match two if that is the
only way the rest of the pattern matches.
- If the PCRE_UNGREEDY option is set (an option that is not available in
- Perl), the quantifiers are not greedy by default, but individual ones
- can be made greedy by following them with a question mark. In other
+ If the PCRE_UNGREEDY option is set (an option that is not available in
+ Perl), the quantifiers are not greedy by default, but individual ones
+ can be made greedy by following them with a question mark. In other
words, it inverts the default behaviour.
- When a parenthesized subpattern is quantified with a minimum repeat
- count that is greater than 1 or with a limited maximum, more memory is
- required for the compiled pattern, in proportion to the size of the
+ When a parenthesized subpattern is quantified with a minimum repeat
+ count that is greater than 1 or with a limited maximum, more memory is
+ required for the compiled pattern, in proportion to the size of the
minimum or maximum.
If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equiv-
- alent to Perl's /s) is set, thus allowing the dot to match newlines,
- the pattern is implicitly anchored, because whatever follows will be
- tried against every character position in the subject string, so there
- is no point in retrying the overall match at any position after the
- first. PCRE normally treats such a pattern as though it were preceded
+ alent to Perl's /s) is set, thus allowing the dot to match newlines,
+ the pattern is implicitly anchored, because whatever follows will be
+ tried against every character position in the subject string, so there
+ is no point in retrying the overall match at any position after the
+ first. PCRE normally treats such a pattern as though it were preceded
by \A.
- In cases where it is known that the subject string contains no new-
- lines, it is worth setting PCRE_DOTALL in order to obtain this opti-
+ In cases where it is known that the subject string contains no new-
+ lines, it is worth setting PCRE_DOTALL in order to obtain this opti-
mization, or alternatively using ^ to indicate anchoring explicitly.
- However, there is one situation where the optimization cannot be used.
- When .* is inside capturing parentheses that are the subject of a
- backreference elsewhere in the pattern, a match at the start may fail
+ However, there is one situation where the optimization cannot be used.
+ When .* is inside capturing parentheses that are the subject of a
+ backreference elsewhere in the pattern, a match at the start may fail
where a later one succeeds. Consider, for example:
(.*)abc\1
- If the subject is "xyz123abc123" the match point is the fourth charac-
+ If the subject is "xyz123abc123" the match point is the fourth charac-
ter. For this reason, such a pattern is not implicitly anchored.
When a capturing subpattern is repeated, the value captured is the sub-
(tweedle[dume]{3}\s*)+
has matched "tweedledum tweedledee" the value of the captured substring
- is "tweedledee". However, if there are nested capturing subpatterns,
- the corresponding captured values may have been set in previous itera-
+ is "tweedledee". However, if there are nested capturing subpatterns,
+ the corresponding captured values may have been set in previous itera-
tions. For example, after
/(a|(b))+/
ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS
- With both maximizing ("greedy") and minimizing ("ungreedy" or "lazy")
- repetition, failure of what follows normally causes the repeated item
- to be re-evaluated to see if a different number of repeats allows the
- rest of the pattern to match. Sometimes it is useful to prevent this,
- either to change the nature of the match, or to cause it fail earlier
- than it otherwise might, when the author of the pattern knows there is
+ With both maximizing ("greedy") and minimizing ("ungreedy" or "lazy")
+ repetition, failure of what follows normally causes the repeated item
+ to be re-evaluated to see if a different number of repeats allows the
+ rest of the pattern to match. Sometimes it is useful to prevent this,
+ either to change the nature of the match, or to cause it fail earlier
+ than it otherwise might, when the author of the pattern knows there is
no point in carrying on.
- Consider, for example, the pattern \d+foo when applied to the subject
+ Consider, for example, the pattern \d+foo when applied to the subject
line
123456bar
After matching all 6 digits and then failing to match "foo", the normal
- action of the matcher is to try again with only 5 digits matching the
- \d+ item, and then with 4, and so on, before ultimately failing.
- "Atomic grouping" (a term taken from Jeffrey Friedl's book) provides
- the means for specifying that once a subpattern has matched, it is not
+ action of the matcher is to try again with only 5 digits matching the
+ \d+ item, and then with 4, and so on, before ultimately failing.
+ "Atomic grouping" (a term taken from Jeffrey Friedl's book) provides
+ the means for specifying that once a subpattern has matched, it is not
to be re-evaluated in this way.
- If we use atomic grouping for the previous example, the matcher gives
- up immediately on failing to match "foo" the first time. The notation
+ If we use atomic grouping for the previous example, the matcher gives
+ up immediately on failing to match "foo" the first time. The notation
is a kind of special parenthesis, starting with (?> as in this example:
(?>\d+)foo
((?>\D+)|<\d+>)*[!?]
- sequences of non-digits cannot be broken, and failure happens quickly.
+ sequences of non-digits cannot be broken, and failure happens quickly.
BACK REFERENCES
Outside a character class, a backslash followed by a digit greater than
0 (and possibly further digits) is a back reference to a capturing sub-
- pattern earlier (that is, to its left) in the pattern, provided there
+ pattern earlier (that is, to its left) in the pattern, provided there
have been that many previous capturing left parentheses.
However, if the decimal number following the backslash is less than 10,
- it is always taken as a back reference, and causes an error only if
- there are not that many capturing left parentheses in the entire pat-
- tern. In other words, the parentheses that are referenced need not be
- to the left of the reference for numbers less than 10. A "forward back
- reference" of this type can make sense when a repetition is involved
- and the subpattern to the right has participated in an earlier itera-
+ it is always taken as a back reference, and causes an error only if
+ there are not that many capturing left parentheses in the entire pat-
+ tern. In other words, the parentheses that are referenced need not be
+ to the left of the reference for numbers less than 10. A "forward back
+ reference" of this type can make sense when a repetition is involved
+ and the subpattern to the right has participated in an earlier itera-
tion.
- It is not possible to have a numerical "forward back reference" to a
- subpattern whose number is 10 or more using this syntax because a
- sequence such as \50 is interpreted as a character defined in octal.
+ It is not possible to have a numerical "forward back reference" to a
+ subpattern whose number is 10 or more using this syntax because a
+ sequence such as \50 is interpreted as a character defined in octal.
See the subsection entitled "Non-printing characters" above for further
- details of the handling of digits following a backslash. There is no
- such problem when named parentheses are used. A back reference to any
+ details of the handling of digits following a backslash. There is no
+ such problem when named parentheses are used. A back reference to any
subpattern is possible using named parentheses (see below).
- Another way of avoiding the ambiguity inherent in the use of digits
+ Another way of avoiding the ambiguity inherent in the use of digits
following a backslash is to use the \g escape sequence, which is a fea-
- ture introduced in Perl 5.10. This escape must be followed by an
- unsigned number or a negative number, optionally enclosed in braces.
+ ture introduced in Perl 5.10. This escape must be followed by an
+ unsigned number or a negative number, optionally enclosed in braces.
These examples are all identical:
(ring), \1
(ring), \g1
(ring), \g{1}
- An unsigned number specifies an absolute reference without the ambigu-
+ An unsigned number specifies an absolute reference without the ambigu-
ity that is present in the older syntax. It is also useful when literal
digits follow the reference. A negative number is a relative reference.
Consider this example:
(abc(def)ghi)\g{-1}
The sequence \g{-1} is a reference to the most recently started captur-
- ing subpattern before \g, that is, is it equivalent to \2. Similarly,
+ ing subpattern before \g, that is, is it equivalent to \2. Similarly,
\g{-2} would be equivalent to \1. The use of relative references can be
- helpful in long patterns, and also in patterns that are created by
+ helpful in long patterns, and also in patterns that are created by
joining together fragments that contain references within themselves.
- A back reference matches whatever actually matched the capturing sub-
- pattern in the current subject string, rather than anything matching
+ A back reference matches whatever actually matched the capturing sub-
+ pattern in the current subject string, rather than anything matching
the subpattern itself (see "Subpatterns as subroutines" below for a way
of doing that). So the pattern
(sens|respons)e and \1ibility
- matches "sense and sensibility" and "response and responsibility", but
- not "sense and responsibility". If caseful matching is in force at the
- time of the back reference, the case of letters is relevant. For exam-
+ matches "sense and sensibility" and "response and responsibility", but
+ not "sense and responsibility". If caseful matching is in force at the
+ time of the back reference, the case of letters is relevant. For exam-
ple,
((?i)rah)\s+\1
- matches "rah rah" and "RAH RAH", but not "RAH rah", even though the
+ matches "rah rah" and "RAH RAH", but not "RAH rah", even though the
original capturing subpattern is matched caselessly.
- There are several different ways of writing back references to named
- subpatterns. The .NET syntax \k{name} and the Perl syntax \k<name> or
- \k'name' are supported, as is the Python syntax (?P=name). Perl 5.10's
+ There are several different ways of writing back references to named
+ subpatterns. The .NET syntax \k{name} and the Perl syntax \k<name> or
+ \k'name' are supported, as is the Python syntax (?P=name). Perl 5.10's
unified back reference syntax, in which \g can be used for both numeric
- and named references, is also supported. We could rewrite the above
+ and named references, is also supported. We could rewrite the above
example in any of the following ways:
(?<p1>(?i)rah)\s+\k<p1>
(?P<p1>(?i)rah)\s+(?P=p1)
(?<p1>(?i)rah)\s+\g{p1}
- A subpattern that is referenced by name may appear in the pattern
+ A subpattern that is referenced by name may appear in the pattern
before or after the reference.
- There may be more than one back reference to the same subpattern. If a
- subpattern has not actually been used in a particular match, any back
+ There may be more than one back reference to the same subpattern. If a
+ subpattern has not actually been used in a particular match, any back
references to it always fail. For example, the pattern
(a|(bc))\2
- always fails if it starts to match "a" rather than "bc". Because there
- may be many capturing parentheses in a pattern, all digits following
- the backslash are taken as part of a potential back reference number.
+ always fails if it starts to match "a" rather than "bc". Because there
+ may be many capturing parentheses in a pattern, all digits following
+ the backslash are taken as part of a potential back reference number.
If the pattern continues with a digit character, some delimiter must be
- used to terminate the back reference. If the PCRE_EXTENDED option is
- set, this can be whitespace. Otherwise an empty comment (see "Com-
+ used to terminate the back reference. If the PCRE_EXTENDED option is
+ set, this can be whitespace. Otherwise an empty comment (see "Com-
ments" below) can be used.
- A back reference that occurs inside the parentheses to which it refers
- fails when the subpattern is first used, so, for example, (a\1) never
- matches. However, such references can be useful inside repeated sub-
+ A back reference that occurs inside the parentheses to which it refers
+ fails when the subpattern is first used, so, for example, (a\1) never
+ matches. However, such references can be useful inside repeated sub-
patterns. For example, the pattern
(a|b\1)+
matches any number of "a"s and also "aba", "ababbaa" etc. At each iter-
- ation of the subpattern, the back reference matches the character
- string corresponding to the previous iteration. In order for this to
- work, the pattern must be such that the first iteration does not need
- to match the back reference. This can be done using alternation, as in
+ ation of the subpattern, the back reference matches the character
+ string corresponding to the previous iteration. In order for this to
+ work, the pattern must be such that the first iteration does not need
+ to match the back reference. This can be done using alternation, as in
the example above, or by a quantifier with a minimum of zero.
ASSERTIONS
- An assertion is a test on the characters following or preceding the
- current matching point that does not actually consume any characters.
- The simple assertions coded as \b, \B, \A, \G, \Z, \z, ^ and $ are
+ An assertion is a test on the characters following or preceding the
+ current matching point that does not actually consume any characters.
+ The simple assertions coded as \b, \B, \A, \G, \Z, \z, ^ and $ are
described above.
- More complicated assertions are coded as subpatterns. There are two
- kinds: those that look ahead of the current position in the subject
- string, and those that look behind it. An assertion subpattern is
- matched in the normal way, except that it does not cause the current
+ More complicated assertions are coded as subpatterns. There are two
+ kinds: those that look ahead of the current position in the subject
+ string, and those that look behind it. An assertion subpattern is
+ matched in the normal way, except that it does not cause the current
matching position to be changed.
- Assertion subpatterns are not capturing subpatterns, and may not be
- repeated, because it makes no sense to assert the same thing several
- times. If any kind of assertion contains capturing subpatterns within
- it, these are counted for the purposes of numbering the capturing sub-
+ Assertion subpatterns are not capturing subpatterns, and may not be
+ repeated, because it makes no sense to assert the same thing several
+ times. If any kind of assertion contains capturing subpatterns within
+ it, these are counted for the purposes of numbering the capturing sub-
patterns in the whole pattern. However, substring capturing is carried
- out only for positive assertions, because it does not make sense for
+ out only for positive assertions, because it does not make sense for
negative assertions.
Lookahead assertions
\w+(?=;)
- matches a word followed by a semicolon, but does not include the semi-
+ matches a word followed by a semicolon, but does not include the semi-
colon in the match, and
foo(?!bar)
- matches any occurrence of "foo" that is not followed by "bar". Note
+ matches any occurrence of "foo" that is not followed by "bar". Note
that the apparently similar pattern
(?!foo)bar
- does not find an occurrence of "bar" that is preceded by something
- other than "foo"; it finds any occurrence of "bar" whatsoever, because
+ does not find an occurrence of "bar" that is preceded by something
+ other than "foo"; it finds any occurrence of "bar" whatsoever, because
the assertion (?!foo) is always true when the next three characters are
"bar". A lookbehind assertion is needed to achieve the other effect.
If you want to force a matching failure at some point in a pattern, the
- most convenient way to do it is with (?!) because an empty string
- always matches, so an assertion that requires there not to be an empty
+ most convenient way to do it is with (?!) because an empty string
+ always matches, so an assertion that requires there not to be an empty
string must always fail.
Lookbehind assertions
- Lookbehind assertions start with (?<= for positive assertions and (?<!
+ Lookbehind assertions start with (?<= for positive assertions and (?<!
for negative assertions. For example,
(?<!foo)bar
- does find an occurrence of "bar" that is not preceded by "foo". The
- contents of a lookbehind assertion are restricted such that all the
+ does find an occurrence of "bar" that is not preceded by "foo". The
+ contents of a lookbehind assertion are restricted such that all the
strings it matches must have a fixed length. However, if there are sev-
- eral top-level alternatives, they do not all have to have the same
+ eral top-level alternatives, they do not all have to have the same
fixed length. Thus
(?<=bullock|donkey)
(?<!dogs?|cats?)
- causes an error at compile time. Branches that match different length
- strings are permitted only at the top level of a lookbehind assertion.
- This is an extension compared with Perl (at least for 5.8), which
- requires all branches to match the same length of string. An assertion
+ causes an error at compile time. Branches that match different length
+ strings are permitted only at the top level of a lookbehind assertion.
+ This is an extension compared with Perl (at least for 5.8), which
+ requires all branches to match the same length of string. An assertion
such as
(?<=ab(c|de))
- is not permitted, because its single top-level branch can match two
- different lengths, but it is acceptable if rewritten to use two top-
+ is not permitted, because its single top-level branch can match two
+ different lengths, but it is acceptable if rewritten to use two top-
level branches:
(?<=abc|abde)
In some cases, the Perl 5.10 escape sequence \K (see above) can be used
- instead of a lookbehind assertion; this is not restricted to a fixed-
+ instead of a lookbehind assertion; this is not restricted to a fixed-
length.
- The implementation of lookbehind assertions is, for each alternative,
- to temporarily move the current position back by the fixed length and
+ The implementation of lookbehind assertions is, for each alternative,
+ to temporarily move the current position back by the fixed length and
then try to match. If there are insufficient characters before the cur-
rent position, the assertion fails.
PCRE does not allow the \C escape (which matches a single byte in UTF-8
- mode) to appear in lookbehind assertions, because it makes it impossi-
- ble to calculate the length of the lookbehind. The \X and \R escapes,
+ mode) to appear in lookbehind assertions, because it makes it impossi-
+ ble to calculate the length of the lookbehind. The \X and \R escapes,
which can match different numbers of bytes, are also not permitted.
- Possessive quantifiers can be used in conjunction with lookbehind
- assertions to specify efficient matching at the end of the subject
+ Possessive quantifiers can be used in conjunction with lookbehind
+ assertions to specify efficient matching at the end of the subject
string. Consider a simple pattern such as
abcd$
- when applied to a long string that does not match. Because matching
+ when applied to a long string that does not match. Because matching
proceeds from left to right, PCRE will look for each "a" in the subject
- and then see if what follows matches the rest of the pattern. If the
+ and then see if what follows matches the rest of the pattern. If the
pattern is specified as
^.*abcd$
- the initial .* matches the entire string at first, but when this fails
+ the initial .* matches the entire string at first, but when this fails
(because there is no following "a"), it backtracks to match all but the
- last character, then all but the last two characters, and so on. Once
- again the search for "a" covers the entire string, from right to left,
+ last character, then all but the last two characters, and so on. Once
+ again the search for "a" covers the entire string, from right to left,
so we are no better off. However, if the pattern is written as
^.*+(?<=abcd)
- there can be no backtracking for the .*+ item; it can match only the
- entire string. The subsequent lookbehind assertion does a single test
- on the last four characters. If it fails, the match fails immediately.
- For long strings, this approach makes a significant difference to the
+ there can be no backtracking for the .*+ item; it can match only the
+ entire string. The subsequent lookbehind assertion does a single test
+ on the last four characters. If it fails, the match fails immediately.
+ For long strings, this approach makes a significant difference to the
processing time.
Using multiple assertions
(?<=\d{3})(?<!999)foo
- matches "foo" preceded by three digits that are not "999". Notice that
- each of the assertions is applied independently at the same point in
- the subject string. First there is a check that the previous three
- characters are all digits, and then there is a check that the same
+ matches "foo" preceded by three digits that are not "999". Notice that
+ each of the assertions is applied independently at the same point in
+ the subject string. First there is a check that the previous three
+ characters are all digits, and then there is a check that the same
three characters are not "999". This pattern does not match "foo" pre-
- ceded by six characters, the first of which are digits and the last
- three of which are not "999". For example, it doesn't match "123abc-
+ ceded by six characters, the first of which are digits and the last
+ three of which are not "999". For example, it doesn't match "123abc-
foo". A pattern to do that is
(?<=\d{3}...)(?<!999)foo
- This time the first assertion looks at the preceding six characters,
+ This time the first assertion looks at the preceding six characters,
checking that the first three are digits, and then the second assertion
checks that the preceding three characters are not "999".
(?<=(?<!foo)bar)baz
- matches an occurrence of "baz" that is preceded by "bar" which in turn
+ matches an occurrence of "baz" that is preceded by "bar" which in turn
is not preceded by "foo", while
(?<=\d{3}(?!999)...)foo
- is another pattern that matches "foo" preceded by three digits and any
+ is another pattern that matches "foo" preceded by three digits and any
three characters that are not "999".
CONDITIONAL SUBPATTERNS
- It is possible to cause the matching process to obey a subpattern con-
- ditionally or to choose between two alternative subpatterns, depending
- on the result of an assertion, or whether a previous capturing subpat-
- tern matched or not. The two possible forms of conditional subpattern
+ It is possible to cause the matching process to obey a subpattern con-
+ ditionally or to choose between two alternative subpatterns, depending
+ on the result of an assertion, or whether a previous capturing subpat-
+ tern matched or not. The two possible forms of conditional subpattern
are
(?(condition)yes-pattern)
(?(condition)yes-pattern|no-pattern)
- If the condition is satisfied, the yes-pattern is used; otherwise the
- no-pattern (if present) is used. If there are more than two alterna-
+ If the condition is satisfied, the yes-pattern is used; otherwise the
+ no-pattern (if present) is used. If there are more than two alterna-
tives in the subpattern, a compile-time error occurs.
- There are four kinds of condition: references to subpatterns, refer-
+ There are four kinds of condition: references to subpatterns, refer-
ences to recursion, a pseudo-condition called DEFINE, and assertions.
Checking for a used subpattern by number
- If the text between the parentheses consists of a sequence of digits,
- the condition is true if the capturing subpattern of that number has
- previously matched. An alternative notation is to precede the digits
+ If the text between the parentheses consists of a sequence of digits,
+ the condition is true if the capturing subpattern of that number has
+ previously matched. An alternative notation is to precede the digits
with a plus or minus sign. In this case, the subpattern number is rela-
tive rather than absolute. The most recently opened parentheses can be
- referenced by (?(-1), the next most recent by (?(-2), and so on. In
+ referenced by (?(-1), the next most recent by (?(-2), and so on. In
looping constructs it can also make sense to refer to subsequent groups
with constructs such as (?(+2).
- Consider the following pattern, which contains non-significant white
+ Consider the following pattern, which contains non-significant white
space to make it more readable (assume the PCRE_EXTENDED option) and to
divide it into three parts for ease of discussion:
( \( )? [^()]+ (?(1) \) )
- The first part matches an optional opening parenthesis, and if that
+ The first part matches an optional opening parenthesis, and if that
character is present, sets it as the first captured substring. The sec-
- ond part matches one or more characters that are not parentheses. The
+ ond part matches one or more characters that are not parentheses. The
third part is a conditional subpattern that tests whether the first set
of parentheses matched or not. If they did, that is, if subject started
with an opening parenthesis, the condition is true, and so the yes-pat-
- tern is executed and a closing parenthesis is required. Otherwise,
- since no-pattern is not present, the subpattern matches nothing. In
- other words, this pattern matches a sequence of non-parentheses,
+ tern is executed and a closing parenthesis is required. Otherwise,
+ since no-pattern is not present, the subpattern matches nothing. In
+ other words, this pattern matches a sequence of non-parentheses,
optionally enclosed in parentheses.
- If you were embedding this pattern in a larger one, you could use a
+ If you were embedding this pattern in a larger one, you could use a
relative reference:
...other stuff... ( \( )? [^()]+ (?(-1) \) ) ...
- This makes the fragment independent of the parentheses in the larger
+ This makes the fragment independent of the parentheses in the larger
pattern.
Checking for a used subpattern by name
- Perl uses the syntax (?(<name>)...) or (?('name')...) to test for a
- used subpattern by name. For compatibility with earlier versions of
- PCRE, which had this facility before Perl, the syntax (?(name)...) is
- also recognized. However, there is a possible ambiguity with this syn-
- tax, because subpattern names may consist entirely of digits. PCRE
- looks first for a named subpattern; if it cannot find one and the name
- consists entirely of digits, PCRE looks for a subpattern of that num-
- ber, which must be greater than zero. Using subpattern names that con-
+ Perl uses the syntax (?(<name>)...) or (?('name')...) to test for a
+ used subpattern by name. For compatibility with earlier versions of
+ PCRE, which had this facility before Perl, the syntax (?(name)...) is
+ also recognized. However, there is a possible ambiguity with this syn-
+ tax, because subpattern names may consist entirely of digits. PCRE
+ looks first for a named subpattern; if it cannot find one and the name
+ consists entirely of digits, PCRE looks for a subpattern of that num-
+ ber, which must be greater than zero. Using subpattern names that con-
sist entirely of digits is not recommended.
Rewriting the above example to use a named subpattern gives this:
Checking for pattern recursion
If the condition is the string (R), and there is no subpattern with the
- name R, the condition is true if a recursive call to the whole pattern
+ name R, the condition is true if a recursive call to the whole pattern
or any subpattern has been made. If digits or a name preceded by amper-
sand follow the letter R, for example:
(?(R3)...) or (?(R&name)...)
- the condition is true if the most recent recursion is into the subpat-
- tern whose number or name is given. This condition does not check the
+ the condition is true if the most recent recursion is into the subpat-
+ tern whose number or name is given. This condition does not check the
entire recursion stack.
- At "top level", all these recursion test conditions are false. Recur-
+ At "top level", all these recursion test conditions are false. Recur-
sive patterns are described below.
Defining subpatterns for use by reference only
- If the condition is the string (DEFINE), and there is no subpattern
- with the name DEFINE, the condition is always false. In this case,
- there may be only one alternative in the subpattern. It is always
- skipped if control reaches this point in the pattern; the idea of
- DEFINE is that it can be used to define "subroutines" that can be ref-
- erenced from elsewhere. (The use of "subroutines" is described below.)
- For example, a pattern to match an IPv4 address could be written like
+ If the condition is the string (DEFINE), and there is no subpattern
+ with the name DEFINE, the condition is always false. In this case,
+ there may be only one alternative in the subpattern. It is always
+ skipped if control reaches this point in the pattern; the idea of
+ DEFINE is that it can be used to define "subroutines" that can be ref-
+ erenced from elsewhere. (The use of "subroutines" is described below.)
+ For example, a pattern to match an IPv4 address could be written like
this (ignore whitespace and line breaks):
(?(DEFINE) (?<byte> 2[0-4]\d | 25[0-5] | 1\d\d | [1-9]?\d) )
\b (?&byte) (\.(?&byte)){3} \b
- The first part of the pattern is a DEFINE group inside which a another
- group named "byte" is defined. This matches an individual component of
- an IPv4 address (a number less than 256). When matching takes place,
- this part of the pattern is skipped because DEFINE acts like a false
+ The first part of the pattern is a DEFINE group inside which a another
+ group named "byte" is defined. This matches an individual component of
+ an IPv4 address (a number less than 256). When matching takes place,
+ this part of the pattern is skipped because DEFINE acts like a false
condition.
The rest of the pattern uses references to the named group to match the
- four dot-separated components of an IPv4 address, insisting on a word
+ four dot-separated components of an IPv4 address, insisting on a word
boundary at each end.
Assertion conditions
- If the condition is not in any of the above formats, it must be an
- assertion. This may be a positive or negative lookahead or lookbehind
- assertion. Consider this pattern, again containing non-significant
+ If the condition is not in any of the above formats, it must be an
+ assertion. This may be a positive or negative lookahead or lookbehind
+ assertion. Consider this pattern, again containing non-significant
white space, and with the two alternatives on the second line:
(?(?=[^a-z]*[a-z])
\d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} )
- The condition is a positive lookahead assertion that matches an
- optional sequence of non-letters followed by a letter. In other words,
- it tests for the presence of at least one letter in the subject. If a
- letter is found, the subject is matched against the first alternative;
- otherwise it is matched against the second. This pattern matches
- strings in one of the two forms dd-aaa-dd or dd-dd-dd, where aaa are
+ The condition is a positive lookahead assertion that matches an
+ optional sequence of non-letters followed by a letter. In other words,
+ it tests for the presence of at least one letter in the subject. If a
+ letter is found, the subject is matched against the first alternative;
+ otherwise it is matched against the second. This pattern matches
+ strings in one of the two forms dd-aaa-dd or dd-dd-dd, where aaa are
letters and dd are digits.
COMMENTS
- The sequence (?# marks the start of a comment that continues up to the
- next closing parenthesis. Nested parentheses are not permitted. The
- characters that make up a comment play no part in the pattern matching
+ The sequence (?# marks the start of a comment that continues up to the
+ next closing parenthesis. Nested parentheses are not permitted. The
+ characters that make up a comment play no part in the pattern matching
at all.
- If the PCRE_EXTENDED option is set, an unescaped # character outside a
- character class introduces a comment that continues to immediately
+ If the PCRE_EXTENDED option is set, an unescaped # character outside a
+ character class introduces a comment that continues to immediately
after the next newline in the pattern.
RECURSIVE PATTERNS
- Consider the problem of matching a string in parentheses, allowing for
- unlimited nested parentheses. Without the use of recursion, the best
- that can be done is to use a pattern that matches up to some fixed
- depth of nesting. It is not possible to handle an arbitrary nesting
+ Consider the problem of matching a string in parentheses, allowing for
+ unlimited nested parentheses. Without the use of recursion, the best
+ that can be done is to use a pattern that matches up to some fixed
+ depth of nesting. It is not possible to handle an arbitrary nesting
depth.
For some time, Perl has provided a facility that allows regular expres-
- sions to recurse (amongst other things). It does this by interpolating
- Perl code in the expression at run time, and the code can refer to the
+ sions to recurse (amongst other things). It does this by interpolating
+ Perl code in the expression at run time, and the code can refer to the
expression itself. A Perl pattern using code interpolation to solve the
parentheses problem can be created like this:
refers recursively to the pattern in which it appears.
Obviously, PCRE cannot support the interpolation of Perl code. Instead,
- it supports special syntax for recursion of the entire pattern, and
- also for individual subpattern recursion. After its introduction in
- PCRE and Python, this kind of recursion was introduced into Perl at
+ it supports special syntax for recursion of the entire pattern, and
+ also for individual subpattern recursion. After its introduction in
+ PCRE and Python, this kind of recursion was introduced into Perl at
release 5.10.
- A special item that consists of (? followed by a number greater than
+ A special item that consists of (? followed by a number greater than
zero and a closing parenthesis is a recursive call of the subpattern of
- the given number, provided that it occurs inside that subpattern. (If
- not, it is a "subroutine" call, which is described in the next sec-
- tion.) The special item (?R) or (?0) is a recursive call of the entire
+ the given number, provided that it occurs inside that subpattern. (If
+ not, it is a "subroutine" call, which is described in the next sec-
+ tion.) The special item (?R) or (?0) is a recursive call of the entire
regular expression.
- In PCRE (like Python, but unlike Perl), a recursive subpattern call is
+ In PCRE (like Python, but unlike Perl), a recursive subpattern call is
always treated as an atomic group. That is, once it has matched some of
the subject string, it is never re-entered, even if it contains untried
alternatives and there is a subsequent matching failure.
- This PCRE pattern solves the nested parentheses problem (assume the
+ This PCRE pattern solves the nested parentheses problem (assume the
PCRE_EXTENDED option is set so that white space is ignored):
\( ( (?>[^()]+) | (?R) )* \)
- First it matches an opening parenthesis. Then it matches any number of
- substrings which can either be a sequence of non-parentheses, or a
- recursive match of the pattern itself (that is, a correctly parenthe-
+ First it matches an opening parenthesis. Then it matches any number of
+ substrings which can either be a sequence of non-parentheses, or a
+ recursive match of the pattern itself (that is, a correctly parenthe-
sized substring). Finally there is a closing parenthesis.
- If this were part of a larger pattern, you would not want to recurse
+ If this were part of a larger pattern, you would not want to recurse
the entire pattern, so instead you could use this:
( \( ( (?>[^()]+) | (?1) )* \) )
- We have put the pattern into parentheses, and caused the recursion to
+ We have put the pattern into parentheses, and caused the recursion to
refer to them instead of the whole pattern.
- In a larger pattern, keeping track of parenthesis numbers can be
- tricky. This is made easier by the use of relative references. (A Perl
- 5.10 feature.) Instead of (?1) in the pattern above you can write
+ In a larger pattern, keeping track of parenthesis numbers can be
+ tricky. This is made easier by the use of relative references. (A Perl
+ 5.10 feature.) Instead of (?1) in the pattern above you can write
(?-2) to refer to the second most recently opened parentheses preceding
- the recursion. In other words, a negative number counts capturing
+ the recursion. In other words, a negative number counts capturing
parentheses leftwards from the point at which it is encountered.
- It is also possible to refer to subsequently opened parentheses, by
- writing references such as (?+2). However, these cannot be recursive
- because the reference is not inside the parentheses that are refer-
- enced. They are always "subroutine" calls, as described in the next
+ It is also possible to refer to subsequently opened parentheses, by
+ writing references such as (?+2). However, these cannot be recursive
+ because the reference is not inside the parentheses that are refer-
+ enced. They are always "subroutine" calls, as described in the next
section.
- An alternative approach is to use named parentheses instead. The Perl
- syntax for this is (?&name); PCRE's earlier syntax (?P>name) is also
+ An alternative approach is to use named parentheses instead. The Perl
+ syntax for this is (?&name); PCRE's earlier syntax (?P>name) is also
supported. We could rewrite the above example as follows:
(?<pn> \( ( (?>[^()]+) | (?&pn) )* \) )
- If there is more than one subpattern with the same name, the earliest
+ If there is more than one subpattern with the same name, the earliest
one is used.
- This particular example pattern that we have been looking at contains
- nested unlimited repeats, and so the use of atomic grouping for match-
- ing strings of non-parentheses is important when applying the pattern
+ This particular example pattern that we have been looking at contains
+ nested unlimited repeats, and so the use of atomic grouping for match-
+ ing strings of non-parentheses is important when applying the pattern
to strings that do not match. For example, when this pattern is applied
to
(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
- it yields "no match" quickly. However, if atomic grouping is not used,
- the match runs for a very long time indeed because there are so many
- different ways the + and * repeats can carve up the subject, and all
+ it yields "no match" quickly. However, if atomic grouping is not used,
+ the match runs for a very long time indeed because there are so many
+ different ways the + and * repeats can carve up the subject, and all
have to be tested before failure can be reported.
At the end of a match, the values set for any capturing subpatterns are
those from the outermost level of the recursion at which the subpattern
- value is set. If you want to obtain intermediate values, a callout
- function can be used (see below and the pcrecallout documentation). If
+ value is set. If you want to obtain intermediate values, a callout
+ function can be used (see below and the pcrecallout documentation). If
the pattern above is matched against
(ab(cd)ef)
- the value for the capturing parentheses is "ef", which is the last
- value taken on at the top level. If additional parentheses are added,
+ the value for the capturing parentheses is "ef", which is the last
+ value taken on at the top level. If additional parentheses are added,
giving
\( ( ( (?>[^()]+) | (?R) )* ) \)
^ ^
^ ^
- the string they capture is "ab(cd)ef", the contents of the top level
- parentheses. If there are more than 15 capturing parentheses in a pat-
+ the string they capture is "ab(cd)ef", the contents of the top level
+ parentheses. If there are more than 15 capturing parentheses in a pat-
tern, PCRE has to obtain extra memory to store data during a recursion,
- which it does by using pcre_malloc, freeing it via pcre_free after-
- wards. If no memory can be obtained, the match fails with the
+ which it does by using pcre_malloc, freeing it via pcre_free after-
+ wards. If no memory can be obtained, the match fails with the
PCRE_ERROR_NOMEMORY error.
- Do not confuse the (?R) item with the condition (R), which tests for
- recursion. Consider this pattern, which matches text in angle brack-
- ets, allowing for arbitrary nesting. Only digits are allowed in nested
- brackets (that is, when recursing), whereas any characters are permit-
+ Do not confuse the (?R) item with the condition (R), which tests for
+ recursion. Consider this pattern, which matches text in angle brack-
+ ets, allowing for arbitrary nesting. Only digits are allowed in nested
+ brackets (that is, when recursing), whereas any characters are permit-
ted at the outer level.
< (?: (?(R) \d++ | [^<>]*+) | (?R)) * >
- In this pattern, (?(R) is the start of a conditional subpattern, with
- two different alternatives for the recursive and non-recursive cases.
+ In this pattern, (?(R) is the start of a conditional subpattern, with
+ two different alternatives for the recursive and non-recursive cases.
The (?R) item is the actual recursive call.
SUBPATTERNS AS SUBROUTINES
If the syntax for a recursive subpattern reference (either by number or
- by name) is used outside the parentheses to which it refers, it oper-
- ates like a subroutine in a programming language. The "called" subpat-
+ by name) is used outside the parentheses to which it refers, it oper-
+ ates like a subroutine in a programming language. The "called" subpat-
tern may be defined before or after the reference. A numbered reference
can be absolute or relative, as in these examples:
(sens|respons)e and \1ibility
- matches "sense and sensibility" and "response and responsibility", but
+ matches "sense and sensibility" and "response and responsibility", but
not "sense and responsibility". If instead the pattern
(sens|respons)e and (?1)ibility
- is used, it does match "sense and responsibility" as well as the other
- two strings. Another example is given in the discussion of DEFINE
+ is used, it does match "sense and responsibility" as well as the other
+ two strings. Another example is given in the discussion of DEFINE
above.
Like recursive subpatterns, a "subroutine" call is always treated as an
- atomic group. That is, once it has matched some of the subject string,
- it is never re-entered, even if it contains untried alternatives and
+ atomic group. That is, once it has matched some of the subject string,
+ it is never re-entered, even if it contains untried alternatives and
there is a subsequent matching failure.
- When a subpattern is used as a subroutine, processing options such as
+ When a subpattern is used as a subroutine, processing options such as
case-independence are fixed when the subpattern is defined. They cannot
be changed for different calls. For example, consider this pattern:
(abc)(?i:(?-1))
- It matches "abcabc". It does not match "abcABC" because the change of
+ It matches "abcabc". It does not match "abcABC" because the change of
processing option does not affect the called subpattern.
ONIGURUMA SUBROUTINE SYNTAX
- For compatibility with Oniguruma, the non-Perl syntax \g followed by a
+ For compatibility with Oniguruma, the non-Perl syntax \g followed by a
name or a number enclosed either in angle brackets or single quotes, is
- an alternative syntax for referencing a subpattern as a subroutine,
- possibly recursively. Here are two of the examples used above, rewrit-
+ an alternative syntax for referencing a subpattern as a subroutine,
+ possibly recursively. Here are two of the examples used above, rewrit-
ten using this syntax:
(?<pn> \( ( (?>[^()]+) | \g<pn> )* \) )
(sens|respons)e and \g'1'ibility
- PCRE supports an extension to Oniguruma: if a number is preceded by a
+ PCRE supports an extension to Oniguruma: if a number is preceded by a
plus or a minus sign it is taken as a relative reference. For example:
(abc)(?i:\g<-1>)
- Note that \g{...} (Perl syntax) and \g<...> (Oniguruma syntax) are not
- synonymous. The former is a back reference; the latter is a subroutine
+ Note that \g{...} (Perl syntax) and \g<...> (Oniguruma syntax) are not
+ synonymous. The former is a back reference; the latter is a subroutine
call.
CALLOUTS
Perl has a feature whereby using the sequence (?{...}) causes arbitrary
- Perl code to be obeyed in the middle of matching a regular expression.
+ Perl code to be obeyed in the middle of matching a regular expression.
This makes it possible, amongst other things, to extract different sub-
strings that match the same pair of parentheses when there is a repeti-
tion.
PCRE provides a similar feature, but of course it cannot obey arbitrary
Perl code. The feature is called "callout". The caller of PCRE provides
- an external function by putting its entry point in the global variable
- pcre_callout. By default, this variable contains NULL, which disables
+ an external function by putting its entry point in the global variable
+ pcre_callout. By default, this variable contains NULL, which disables
all calling out.
- Within a regular expression, (?C) indicates the points at which the
- external function is to be called. If you want to identify different
- callout points, you can put a number less than 256 after the letter C.
- The default value is zero. For example, this pattern has two callout
+ Within a regular expression, (?C) indicates the points at which the
+ external function is to be called. If you want to identify different
+ callout points, you can put a number less than 256 after the letter C.
+ The default value is zero. For example, this pattern has two callout
points:
(?C1)abc(?C2)def
If the PCRE_AUTO_CALLOUT flag is passed to pcre_compile(), callouts are
- automatically installed before each item in the pattern. They are all
+ automatically installed before each item in the pattern. They are all
numbered 255.
During matching, when PCRE reaches a callout point (and pcre_callout is
- set), the external function is called. It is provided with the number
- of the callout, the position in the pattern, and, optionally, one item
- of data originally supplied by the caller of pcre_exec(). The callout
- function may cause matching to proceed, to backtrack, or to fail alto-
+ set), the external function is called. It is provided with the number
+ of the callout, the position in the pattern, and, optionally, one item
+ of data originally supplied by the caller of pcre_exec(). The callout
+ function may cause matching to proceed, to backtrack, or to fail alto-
gether. A complete description of the interface to the callout function
is given in the pcrecallout documentation.
BACKTRACKING CONTROL
- Perl 5.10 introduced a number of "Special Backtracking Control Verbs",
+ Perl 5.10 introduced a number of "Special Backtracking Control Verbs",
which are described in the Perl documentation as "experimental and sub-
- ject to change or removal in a future version of Perl". It goes on to
- say: "Their usage in production code should be noted to avoid problems
+ ject to change or removal in a future version of Perl". It goes on to
+ say: "Their usage in production code should be noted to avoid problems
during upgrades." The same remarks apply to the PCRE features described
in this section.
- Since these verbs are specifically related to backtracking, most of
- them can be used only when the pattern is to be matched using
+ Since these verbs are specifically related to backtracking, most of
+ them can be used only when the pattern is to be matched using
pcre_exec(), which uses a backtracking algorithm. With the exception of
(*FAIL), which behaves like a failing negative assertion, they cause an
error if encountered by pcre_dfa_exec().
- The new verbs make use of what was previously invalid syntax: an open-
+ The new verbs make use of what was previously invalid syntax: an open-
ing parenthesis followed by an asterisk. In Perl, they are generally of
the form (*VERB:ARG) but PCRE does not support the use of arguments, so
- its general form is just (*VERB). Any number of these verbs may occur
+ its general form is just (*VERB). Any number of these verbs may occur
in a pattern. There are two kinds:
Verbs that act immediately
(*ACCEPT)
- This verb causes the match to end successfully, skipping the remainder
- of the pattern. When inside a recursion, only the innermost pattern is
- ended immediately. PCRE differs from Perl in what happens if the
- (*ACCEPT) is inside capturing parentheses. In Perl, the data so far is
+ This verb causes the match to end successfully, skipping the remainder
+ of the pattern. When inside a recursion, only the innermost pattern is
+ ended immediately. PCRE differs from Perl in what happens if the
+ (*ACCEPT) is inside capturing parentheses. In Perl, the data so far is
captured: in PCRE no data is captured. For example:
A(A|B(*ACCEPT)|C)D
- This matches "AB", "AAD", or "ACD", but when it matches "AB", no data
+ This matches "AB", "AAD", or "ACD", but when it matches "AB", no data
is captured.
(*FAIL) or (*F)
- This verb causes the match to fail, forcing backtracking to occur. It
- is equivalent to (?!) but easier to read. The Perl documentation notes
- that it is probably useful only when combined with (?{}) or (??{}).
- Those are, of course, Perl features that are not present in PCRE. The
- nearest equivalent is the callout feature, as for example in this pat-
+ This verb causes the match to fail, forcing backtracking to occur. It
+ is equivalent to (?!) but easier to read. The Perl documentation notes
+ that it is probably useful only when combined with (?{}) or (??{}).
+ Those are, of course, Perl features that are not present in PCRE. The
+ nearest equivalent is the callout feature, as for example in this pat-
tern:
a+(?C)(*FAIL)
- A match with the string "aaaa" always fails, but the callout is taken
+ A match with the string "aaaa" always fails, but the callout is taken
before each backtrack happens (in this example, 10 times).
Verbs that act after backtracking
The following verbs do nothing when they are encountered. Matching con-
- tinues with what follows, but if there is no subsequent match, a fail-
- ure is forced. The verbs differ in exactly what kind of failure
+ tinues with what follows, but if there is no subsequent match, a fail-
+ ure is forced. The verbs differ in exactly what kind of failure
occurs.
(*COMMIT)
- This verb causes the whole match to fail outright if the rest of the
- pattern does not match. Even if the pattern is unanchored, no further
- attempts to find a match by advancing the start point take place. Once
- (*COMMIT) has been passed, pcre_exec() is committed to finding a match
+ This verb causes the whole match to fail outright if the rest of the
+ pattern does not match. Even if the pattern is unanchored, no further
+ attempts to find a match by advancing the start point take place. Once
+ (*COMMIT) has been passed, pcre_exec() is committed to finding a match
at the current starting point, or not at all. For example:
a+(*COMMIT)b
- This matches "xxaab" but not "aacaab". It can be thought of as a kind
+ This matches "xxaab" but not "aacaab". It can be thought of as a kind
of dynamic anchor, or "I've started, so I must finish."
(*PRUNE)
- This verb causes the match to fail at the current position if the rest
+ This verb causes the match to fail at the current position if the rest
of the pattern does not match. If the pattern is unanchored, the normal
- "bumpalong" advance to the next starting character then happens. Back-
- tracking can occur as usual to the left of (*PRUNE), or when matching
- to the right of (*PRUNE), but if there is no match to the right, back-
- tracking cannot cross (*PRUNE). In simple cases, the use of (*PRUNE)
+ "bumpalong" advance to the next starting character then happens. Back-
+ tracking can occur as usual to the left of (*PRUNE), or when matching
+ to the right of (*PRUNE), but if there is no match to the right, back-
+ tracking cannot cross (*PRUNE). In simple cases, the use of (*PRUNE)
is just an alternative to an atomic group or possessive quantifier, but
- there are some uses of (*PRUNE) that cannot be expressed in any other
+ there are some uses of (*PRUNE) that cannot be expressed in any other
way.
(*SKIP)
- This verb is like (*PRUNE), except that if the pattern is unanchored,
- the "bumpalong" advance is not to the next character, but to the posi-
- tion in the subject where (*SKIP) was encountered. (*SKIP) signifies
- that whatever text was matched leading up to it cannot be part of a
+ This verb is like (*PRUNE), except that if the pattern is unanchored,
+ the "bumpalong" advance is not to the next character, but to the posi-
+ tion in the subject where (*SKIP) was encountered. (*SKIP) signifies
+ that whatever text was matched leading up to it cannot be part of a
successful match. Consider:
a+(*SKIP)b
- If the subject is "aaaac...", after the first match attempt fails
- (starting at the first character in the string), the starting point
+ If the subject is "aaaac...", after the first match attempt fails
+ (starting at the first character in the string), the starting point
skips on to start the next attempt at "c". Note that a possessive quan-
- tifer does not have the same effect in this example; although it would
- suppress backtracking during the first match attempt, the second
- attempt would start at the second character instead of skipping on to
+ tifer does not have the same effect in this example; although it would
+ suppress backtracking during the first match attempt, the second
+ attempt would start at the second character instead of skipping on to
"c".
(*THEN)
This verb causes a skip to the next alternation if the rest of the pat-
tern does not match. That is, it cancels pending backtracking, but only
- within the current alternation. Its name comes from the observation
+ within the current alternation. Its name comes from the observation
that it can be used for a pattern-based if-then-else block:
( COND1 (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ ) ...
- If the COND1 pattern matches, FOO is tried (and possibly further items
- after the end of the group if FOO succeeds); on failure the matcher
- skips to the second alternative and tries COND2, without backtracking
- into COND1. If (*THEN) is used outside of any alternation, it acts
+ If the COND1 pattern matches, FOO is tried (and possibly further items
+ after the end of the group if FOO succeeds); on failure the matcher
+ skips to the second alternative and tries COND2, without backtracking
+ into COND1. If (*THEN) is used outside of any alternation, it acts
exactly like (*PRUNE).
REVISION
- Last updated: 19 April 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 11 April 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
SCRIPT NAMES FOR \p AND \P
Arabic, Armenian, Balinese, Bengali, Bopomofo, Braille, Buginese,
- Buhid, Canadian_Aboriginal, Cherokee, Common, Coptic, Cuneiform,
- Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian, Glagolitic,
- Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew, Hira-
- gana, Inherited, Kannada, Katakana, Kharoshthi, Khmer, Lao, Latin,
- Limbu, Linear_B, Malayalam, Mongolian, Myanmar, New_Tai_Lue, Nko,
- Ogham, Old_Italic, Old_Persian, Oriya, Osmanya, Phags_Pa, Phoenician,
- Runic, Shavian, Sinhala, Syloti_Nagri, Syriac, Tagalog, Tagbanwa,
- Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh, Ugaritic, Yi.
+ Buhid, Canadian_Aboriginal, Carian, Cham, Cherokee, Common, Coptic, Cu-
+ neiform, Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian,
+ Glagolitic, Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo,
+ Hebrew, Hiragana, Inherited, Kannada, Katakana, Kayah_Li, Kharoshthi,
+ Khmer, Lao, Latin, Lepcha, Limbu, Linear_B, Lycian, Lydian, Malayalam,
+ Mongolian, Myanmar, New_Tai_Lue, Nko, Ogham, Old_Italic, Old_Persian,
+ Ol_Chiki, Oriya, Osmanya, Phags_Pa, Phoenician, Rejang, Runic, Saurash-
+ tra, Shavian, Sinhala, Sudanese, Syloti_Nagri, Syriac, Tagalog, Tag-
+ banwa, Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh,
+ Ugaritic, Vai, Yi.
CHARACTER CLASSES
ANCHORS AND SIMPLE ASSERTIONS
- \b word boundary
+ \b word boundary (only ASCII letters recognized)
\B not a word boundary
^ start of subject
also after internal newline in multiline mode
CAPTURING
- (...) capturing group
- (?<name>...) named capturing group (Perl)
- (?'name'...) named capturing group (Perl)
- (?P<name>...) named capturing group (Python)
- (?:...) non-capturing group
- (?|...) non-capturing group; reset group numbers for
- capturing groups in each alternative
+ (...) capturing group
+ (?<name>...) named capturing group (Perl)
+ (?'name'...) named capturing group (Perl)
+ (?P<name>...) named capturing group (Python)
+ (?:...) non-capturing group
+ (?|...) non-capturing group; reset group numbers for
+ capturing groups in each alternative
ATOMIC GROUPS
- (?>...) atomic, non-capturing group
+ (?>...) atomic, non-capturing group
COMMENT
- (?#....) comment (not nestable)
+ (?#....) comment (not nestable)
OPTION SETTING
- (?i) caseless
- (?J) allow duplicate names
- (?m) multiline
- (?s) single line (dotall)
- (?U) default ungreedy (lazy)
- (?x) extended (ignore white space)
- (?-...) unset option(s)
+ (?i) caseless
+ (?J) allow duplicate names
+ (?m) multiline
+ (?s) single line (dotall)
+ (?U) default ungreedy (lazy)
+ (?x) extended (ignore white space)
+ (?-...) unset option(s)
+
+ The following is recognized only at the start of a pattern or after one
+ of the newline-setting options with similar syntax:
+
+ (*UTF8) set UTF-8 mode
LOOKAHEAD AND LOOKBEHIND ASSERTIONS
- (?=...) positive look ahead
- (?!...) negative look ahead
- (?<=...) positive look behind
- (?<!...) negative look behind
+ (?=...) positive look ahead
+ (?!...) negative look ahead
+ (?<=...) positive look behind
+ (?<!...) negative look behind
Each top-level branch of a look behind must be of a fixed length.
BACKREFERENCES
- \n reference by number (can be ambiguous)
- \gn reference by number
- \g{n} reference by number
- \g{-n} relative reference by number
- \k<name> reference by name (Perl)
- \k'name' reference by name (Perl)
- \g{name} reference by name (Perl)
- \k{name} reference by name (.NET)
- (?P=name) reference by name (Python)
+ \n reference by number (can be ambiguous)
+ \gn reference by number
+ \g{n} reference by number
+ \g{-n} relative reference by number
+ \k<name> reference by name (Perl)
+ \k'name' reference by name (Perl)
+ \g{name} reference by name (Perl)
+ \k{name} reference by name (.NET)
+ (?P=name) reference by name (Python)
SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)
- (?R) recurse whole pattern
- (?n) call subpattern by absolute number
- (?+n) call subpattern by relative number
- (?-n) call subpattern by relative number
- (?&name) call subpattern by name (Perl)
- (?P>name) call subpattern by name (Python)
- \g<name> call subpattern by name (Oniguruma)
- \g'name' call subpattern by name (Oniguruma)
- \g<n> call subpattern by absolute number (Oniguruma)
- \g'n' call subpattern by absolute number (Oniguruma)
- \g<+n> call subpattern by relative number (PCRE extension)
- \g'+n' call subpattern by relative number (PCRE extension)
- \g<-n> call subpattern by relative number (PCRE extension)
- \g'-n' call subpattern by relative number (PCRE extension)
+ (?R) recurse whole pattern
+ (?n) call subpattern by absolute number
+ (?+n) call subpattern by relative number
+ (?-n) call subpattern by relative number
+ (?&name) call subpattern by name (Perl)
+ (?P>name) call subpattern by name (Python)
+ \g<name> call subpattern by name (Oniguruma)
+ \g'name' call subpattern by name (Oniguruma)
+ \g<n> call subpattern by absolute number (Oniguruma)
+ \g'n' call subpattern by absolute number (Oniguruma)
+ \g<+n> call subpattern by relative number (PCRE extension)
+ \g'+n' call subpattern by relative number (PCRE extension)
+ \g<-n> call subpattern by relative number (PCRE extension)
+ \g'-n' call subpattern by relative number (PCRE extension)
CONDITIONAL PATTERNS
(?(condition)yes-pattern)
(?(condition)yes-pattern|no-pattern)
- (?(n)... absolute reference condition
- (?(+n)... relative reference condition
- (?(-n)... relative reference condition
- (?(<name>)... named reference condition (Perl)
- (?('name')... named reference condition (Perl)
- (?(name)... named reference condition (PCRE)
- (?(R)... overall recursion condition
- (?(Rn)... specific group recursion condition
- (?(R&name)... specific recursion condition
- (?(DEFINE)... define subpattern for reference
- (?(assert)... assertion condition
+ (?(n)... absolute reference condition
+ (?(+n)... relative reference condition
+ (?(-n)... relative reference condition
+ (?(<name>)... named reference condition (Perl)
+ (?('name')... named reference condition (Perl)
+ (?(name)... named reference condition (PCRE)
+ (?(R)... overall recursion condition
+ (?(Rn)... specific group recursion condition
+ (?(R&name)... specific recursion condition
+ (?(DEFINE)... define subpattern for reference
+ (?(assert)... assertion condition
BACKTRACKING CONTROL
The following act immediately they are reached:
- (*ACCEPT) force successful match
- (*FAIL) force backtrack; synonym (*F)
+ (*ACCEPT) force successful match
+ (*FAIL) force backtrack; synonym (*F)
- The following act only when a subsequent match failure causes a back-
+ The following act only when a subsequent match failure causes a back-
track to reach them. They all force a match failure, but they differ in
what happens afterwards. Those that advance the start-of-match point do
so only if the pattern is not anchored.
- (*COMMIT) overall failure, no advance of starting point
- (*PRUNE) advance to next starting character
- (*SKIP) advance start to current matching position
- (*THEN) local failure, backtrack to next alternation
+ (*COMMIT) overall failure, no advance of starting point
+ (*PRUNE) advance to next starting character
+ (*SKIP) advance start to current matching position
+ (*THEN) local failure, backtrack to next alternation
NEWLINE CONVENTIONS
- These are recognized only at the very start of the pattern or after a
- (*BSR_...) option.
+ These are recognized only at the very start of the pattern or after a
+ (*BSR_...) or (*UTF8) option.
- (*CR)
- (*LF)
- (*CRLF)
- (*ANYCRLF)
- (*ANY)
+ (*CR) carriage return only
+ (*LF) linefeed only
+ (*CRLF) carriage return followed by linefeed
+ (*ANYCRLF) all three of the above
+ (*ANY) any Unicode newline sequence
WHAT \R MATCHES
- These are recognized only at the very start of the pattern or after a
- (*...) option that sets the newline convention.
+ These are recognized only at the very start of the pattern or after a
+ (*...) option that sets the newline convention or UTF-8 mode.
- (*BSR_ANYCRLF)
- (*BSR_UNICODE)
+ (*BSR_ANYCRLF) CR, LF, or CRLF
+ (*BSR_UNICODE) any Unicode newline sequence
CALLOUTS
REVISION
- Last updated: 09 April 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 11 April 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
0: dogsbody
1: dog
- The pattern matches the words "dog" or "dogsbody". When the subject is
- presented in several parts ("do" and "gsb" being the first two) the
- match stops when "dog" has been found, and it is not possible to con-
- tinue. On the other hand, if "dogsbody" is presented as a single
+ The pattern matches the words "dog" or "dogsbody". When the subject is
+ presented in several parts ("do" and "gsb" being the first two) the
+ match stops when "dog" has been found, and it is not possible to con-
+ tinue. On the other hand, if "dogsbody" is presented as a single
string, both matches are found.
- Because of this phenomenon, it does not usually make sense to end a
+ Because of this phenomenon, it does not usually make sense to end a
pattern that is going to be matched in this way with a variable repeat.
4. Patterns that contain alternatives at the top level which do not all
command for linking an application that uses them. Because the POSIX
functions call the native ones, it is also necessary to add -lpcre.
- I have implemented only those option bits that can be reasonably mapped
- to PCRE native options. In addition, the option REG_EXTENDED is defined
- with the value zero. This has no effect, but since programs that are
- written to the POSIX interface often use it, this makes it easier to
- slot in PCRE as a replacement library. Other POSIX options are not even
- defined.
+ I have implemented only those POSIX option bits that can be reasonably
+ mapped to PCRE native options. In addition, the option REG_EXTENDED is
+ defined with the value zero. This has no effect, but since programs
+ that are written to the POSIX interface often use it, this makes it
+ easier to slot in PCRE as a replacement library. Other POSIX options
+ are not even defined.
When PCRE is called via these functions, it is only the API that is
POSIX-like in style. The syntax and semantics of the regular expres-
MATCHING NEWLINE CHARACTERS
This area is not simple, because POSIX and Perl take different views of
- things. It is not possible to get PCRE to obey POSIX semantics, but
- then PCRE was never intended to be a POSIX engine. The following table
- lists the different possibilities for matching newline characters in
+ things. It is not possible to get PCRE to obey POSIX semantics, but
+ then PCRE was never intended to be a POSIX engine. The following table
+ lists the different possibilities for matching newline characters in
PCRE:
Default Change with
^ matches \n in middle no REG_NEWLINE
PCRE's behaviour is the same as Perl's, except that there is no equiva-
- lent for PCRE_DOLLAR_ENDONLY in Perl. In both PCRE and Perl, there is
+ lent for PCRE_DOLLAR_ENDONLY in Perl. In both PCRE and Perl, there is
no way to stop newline from matching [^a].
- The default POSIX newline handling can be obtained by setting
- PCRE_DOTALL and PCRE_DOLLAR_ENDONLY, but there is no way to make PCRE
+ The default POSIX newline handling can be obtained by setting
+ PCRE_DOTALL and PCRE_DOLLAR_ENDONLY, but there is no way to make PCRE
behave exactly as for the REG_NEWLINE action.
MATCHING A PATTERN
- The function regexec() is called to match a compiled pattern preg
- against a given string, which is by default terminated by a zero byte
- (but see REG_STARTEND below), subject to the options in eflags. These
+ The function regexec() is called to match a compiled pattern preg
+ against a given string, which is by default terminated by a zero byte
+ (but see REG_STARTEND below), subject to the options in eflags. These
can be:
REG_NOTBOL
The PCRE_NOTBOL option is set when calling the underlying PCRE matching
function.
+ REG_NOTEMPTY
+
+ The PCRE_NOTEMPTY option is set when calling the underlying PCRE match-
+ ing function. Note that REG_NOTEMPTY is not part of the POSIX standard.
+ However, setting this option can give more POSIX-like behaviour in some
+ situations.
+
REG_NOTEOL
The PCRE_NOTEOL option is set when calling the underlying PCRE matching
REVISION
- Last updated: 05 April 2008
- Copyright (c) 1997-2008 University of Cambridge.
+ Last updated: 11 March 2009
+ Copyright (c) 1997-2009 University of Cambridge.
------------------------------------------------------------------------------
need more, consider using the more general interface
pcrecpp::RE::DoMatch. See pcrecpp.h for the signature for DoMatch.
+ NOTE: Do not use no_arg, which is used internally to mark the end of a
+ list of optional arguments, as a placeholder for missing arguments, as
+ this can lead to segfaults.
+
QUOTING METACHARACTERS
REVISION
- Last updated: 12 November 2007
+ Last updated: 17 March 2009
------------------------------------------------------------------------------
on. Zero means further processing is needed (for things like \x), or the escape
is invalid. */
-#ifndef EBCDIC /* This is the "normal" table for ASCII systems */
+#ifndef EBCDIC
+
+/* This is the "normal" table for ASCII systems or for EBCDIC systems running
+in UTF-8 mode. */
+
static const short int escapes[] = {
- 0, 0, 0, 0, 0, 0, 0, 0, /* 0 - 7 */
- 0, 0, ':', ';', '<', '=', '>', '?', /* 8 - ? */
- '@', -ESC_A, -ESC_B, -ESC_C, -ESC_D, -ESC_E, 0, -ESC_G, /* @ - G */
--ESC_H, 0, 0, -ESC_K, 0, 0, 0, 0, /* H - O */
--ESC_P, -ESC_Q, -ESC_R, -ESC_S, 0, 0, -ESC_V, -ESC_W, /* P - W */
--ESC_X, 0, -ESC_Z, '[', '\\', ']', '^', '_', /* X - _ */
- '`', 7, -ESC_b, 0, -ESC_d, ESC_e, ESC_f, 0, /* ` - g */
--ESC_h, 0, 0, -ESC_k, 0, 0, ESC_n, 0, /* h - o */
--ESC_p, 0, ESC_r, -ESC_s, ESC_tee, 0, -ESC_v, -ESC_w, /* p - w */
- 0, 0, -ESC_z /* x - z */
+ 0, 0,
+ 0, 0,
+ 0, 0,
+ 0, 0,
+ 0, 0,
+ CHAR_COLON, CHAR_SEMICOLON,
+ CHAR_LESS_THAN_SIGN, CHAR_EQUALS_SIGN,
+ CHAR_GREATER_THAN_SIGN, CHAR_QUESTION_MARK,
+ CHAR_COMMERCIAL_AT, -ESC_A,
+ -ESC_B, -ESC_C,
+ -ESC_D, -ESC_E,
+ 0, -ESC_G,
+ -ESC_H, 0,
+ 0, -ESC_K,
+ 0, 0,
+ 0, 0,
+ -ESC_P, -ESC_Q,
+ -ESC_R, -ESC_S,
+ 0, 0,
+ -ESC_V, -ESC_W,
+ -ESC_X, 0,
+ -ESC_Z, CHAR_LEFT_SQUARE_BRACKET,
+ CHAR_BACKSLASH, CHAR_RIGHT_SQUARE_BRACKET,
+ CHAR_CIRCUMFLEX_ACCENT, CHAR_UNDERSCORE,
+ CHAR_GRAVE_ACCENT, 7,
+ -ESC_b, 0,
+ -ESC_d, ESC_e,
+ ESC_f, 0,
+ -ESC_h, 0,
+ 0, -ESC_k,
+ 0, 0,
+ ESC_n, 0,
+ -ESC_p, 0,
+ ESC_r, -ESC_s,
+ ESC_tee, 0,
+ -ESC_v, -ESC_w,
+ 0, 0,
+ -ESC_z
};
-#else /* This is the "abnormal" table for EBCDIC systems */
+#else
+
+/* This is the "abnormal" table for EBCDIC systems without UTF-8 support. */
+
static const short int escapes[] = {
/* 48 */ 0, 0, 0, '.', '<', '(', '+', '|',
/* 50 */ '&', 0, 0, 0, 0, 0, 0, 0,
/* Table of special "verbs" like (*PRUNE). This is a short table, so it is
searched linearly. Put all the names into a single string, in order to reduce
-the number of relocations when a shared library is dynamically linked. */
+the number of relocations when a shared library is dynamically linked. The
+string is built from string macros so that it works in UTF-8 mode on EBCDIC
+platforms. */
typedef struct verbitem {
int len;
} verbitem;
static const char verbnames[] =
- "ACCEPT\0"
- "COMMIT\0"
- "F\0"
- "FAIL\0"
- "PRUNE\0"
- "SKIP\0"
- "THEN";
+ STRING_ACCEPT0
+ STRING_COMMIT0
+ STRING_F0
+ STRING_FAIL0
+ STRING_PRUNE0
+ STRING_SKIP0
+ STRING_THEN;
static const verbitem verbs[] = {
{ 6, OP_ACCEPT },
for handling case independence. */
static const char posix_names[] =
- "alpha\0" "lower\0" "upper\0" "alnum\0" "ascii\0" "blank\0"
- "cntrl\0" "digit\0" "graph\0" "print\0" "punct\0" "space\0"
- "word\0" "xdigit";
+ STRING_alpha0 STRING_lower0 STRING_upper0 STRING_alnum0
+ STRING_ascii0 STRING_blank0 STRING_cntrl0 STRING_digit0
+ STRING_graph0 STRING_print0 STRING_punct0 STRING_space0
+ STRING_word0 STRING_xdigit;
static const uschar posix_name_lengths[] = {
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 4, 6, 0 };
Then we can use ctype_digit and ctype_xdigit in the code. */
-#ifndef EBCDIC /* This is the "normal" case, for ASCII systems */
+#ifndef EBCDIC
+
+/* This is the "normal" case, for ASCII systems, and EBCDIC systems running in
+UTF-8 mode. */
+
static const unsigned char digitab[] =
{
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 0- 7 */
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 240-247 */
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};/* 248-255 */
-#else /* This is the "abnormal" case, for EBCDIC systems */
+#else
+
+/* This is the "abnormal" case, for EBCDIC systems not running in UTF-8 mode. */
+
static const unsigned char digitab[] =
{
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, /* 0- 7 0 */
in a table. A non-zero result is something that can be returned immediately.
Otherwise further processing may be required. */
-#ifndef EBCDIC /* ASCII coding */
-else if (c < '0' || c > 'z') {} /* Not alphanumeric */
-else if ((i = escapes[c - '0']) != 0) c = i;
+#ifndef EBCDIC /* ASCII/UTF-8 coding */
+else if (c < CHAR_0 || c > CHAR_z) {} /* Not alphanumeric */
+else if ((i = escapes[c - CHAR_0]) != 0) c = i;
#else /* EBCDIC coding */
else if (c < 'a' || (ebcdic_chartab[c] & 0x0E) == 0) {} /* Not alphanumeric */
/* A number of Perl escapes are not handled by PCRE. We give an explicit
error. */
- case 'l':
- case 'L':
- case 'N':
- case 'u':
- case 'U':
+ case CHAR_l:
+ case CHAR_L:
+ case CHAR_N:
+ case CHAR_u:
+ case CHAR_U:
*errorcodeptr = ERR37;
break;
(possibly recursive) subroutine calls, _not_ backreferences. Just return
the -ESC_g code (cf \k). */
- case 'g':
- if (ptr[1] == '<' || ptr[1] == '\'')
+ case CHAR_g:
+ if (ptr[1] == CHAR_LESS_THAN_SIGN || ptr[1] == CHAR_APOSTROPHE)
{
c = -ESC_g;
break;
/* Handle the Perl-compatible cases */
- if (ptr[1] == '{')
+ if (ptr[1] == CHAR_LEFT_CURLY_BRACKET)
{
const uschar *p;
- for (p = ptr+2; *p != 0 && *p != '}'; p++)
- if (*p != '-' && (digitab[*p] & ctype_digit) == 0) break;
- if (*p != 0 && *p != '}')
+ for (p = ptr+2; *p != 0 && *p != CHAR_RIGHT_CURLY_BRACKET; p++)
+ if (*p != CHAR_MINUS && (digitab[*p] & ctype_digit) == 0) break;
+ if (*p != 0 && *p != CHAR_RIGHT_CURLY_BRACKET)
{
c = -ESC_k;
break;
}
else braced = FALSE;
- if (ptr[1] == '-')
+ if (ptr[1] == CHAR_MINUS)
{
negated = TRUE;
ptr++;
c = 0;
while ((digitab[ptr[1]] & ctype_digit) != 0)
- c = c * 10 + *(++ptr) - '0';
+ c = c * 10 + *(++ptr) - CHAR_0;
if (c < 0) /* Integer overflow */
{
break;
}
- if (braced && *(++ptr) != '}')
+ if (braced && *(++ptr) != CHAR_RIGHT_CURLY_BRACKET)
{
*errorcodeptr = ERR57;
break;
value is greater than 377, the least significant 8 bits are taken. Inside a
character class, \ followed by a digit is always an octal number. */
- case '1': case '2': case '3': case '4': case '5':
- case '6': case '7': case '8': case '9':
+ case CHAR_1: case CHAR_2: case CHAR_3: case CHAR_4: case CHAR_5:
+ case CHAR_6: case CHAR_7: case CHAR_8: case CHAR_9:
if (!isclass)
{
oldptr = ptr;
- c -= '0';
+ c -= CHAR_0;
while ((digitab[ptr[1]] & ctype_digit) != 0)
- c = c * 10 + *(++ptr) - '0';
+ c = c * 10 + *(++ptr) - CHAR_0;
if (c < 0) /* Integer overflow */
{
*errorcodeptr = ERR61;
generates a binary zero byte and treats the digit as a following literal.
Thus we have to pull back the pointer by one. */
- if ((c = *ptr) >= '8')
+ if ((c = *ptr) >= CHAR_8)
{
ptr--;
c = 0;
to do). Nowadays we allow for larger numbers in UTF-8 mode, but no more
than 3 octal digits. */
- case '0':
- c -= '0';
- while(i++ < 2 && ptr[1] >= '0' && ptr[1] <= '7')
- c = c * 8 + *(++ptr) - '0';
+ case CHAR_0:
+ c -= CHAR_0;
+ while(i++ < 2 && ptr[1] >= CHAR_0 && ptr[1] <= CHAR_7)
+ c = c * 8 + *(++ptr) - CHAR_0;
if (!utf8 && c > 255) *errorcodeptr = ERR51;
break;
than 0xff in utf8 mode, but only if the ddd are hex digits. If not, { is
treated as a data character. */
- case 'x':
- if (ptr[1] == '{')
+ case CHAR_x:
+ if (ptr[1] == CHAR_LEFT_CURLY_BRACKET)
{
const uschar *pt = ptr + 2;
int count = 0;
while ((digitab[*pt] & ctype_xdigit) != 0)
{
register int cc = *pt++;
- if (c == 0 && cc == '0') continue; /* Leading zeroes */
+ if (c == 0 && cc == CHAR_0) continue; /* Leading zeroes */
count++;
-#ifndef EBCDIC /* ASCII coding */
- if (cc >= 'a') cc -= 32; /* Convert to upper case */
- c = (c << 4) + cc - ((cc < 'A')? '0' : ('A' - 10));
+#ifndef EBCDIC /* ASCII/UTF-8 coding */
+ if (cc >= CHAR_a) cc -= 32; /* Convert to upper case */
+ c = (c << 4) + cc - ((cc < CHAR_A)? CHAR_0 : (CHAR_A - 10));
#else /* EBCDIC coding */
- if (cc >= 'a' && cc <= 'z') cc += 64; /* Convert to upper case */
- c = (c << 4) + cc - ((cc >= '0')? '0' : ('A' - 10));
+ if (cc >= CHAR_a && cc <= CHAR_z) cc += 64; /* Convert to upper case */
+ c = (c << 4) + cc - ((cc >= CHAR_0)? CHAR_0 : (CHAR_A - 10));
#endif
}
- if (*pt == '}')
+ if (*pt == CHAR_RIGHT_CURLY_BRACKET)
{
if (c < 0 || count > (utf8? 8 : 2)) *errorcodeptr = ERR34;
ptr = pt;
c = 0;
while (i++ < 2 && (digitab[ptr[1]] & ctype_xdigit) != 0)
{
- int cc; /* Some compilers don't like ++ */
- cc = *(++ptr); /* in initializers */
-#ifndef EBCDIC /* ASCII coding */
- if (cc >= 'a') cc -= 32; /* Convert to upper case */
- c = c * 16 + cc - ((cc < 'A')? '0' : ('A' - 10));
+ int cc; /* Some compilers don't like */
+ cc = *(++ptr); /* ++ in initializers */
+#ifndef EBCDIC /* ASCII/UTF-8 coding */
+ if (cc >= CHAR_a) cc -= 32; /* Convert to upper case */
+ c = c * 16 + cc - ((cc < CHAR_A)? CHAR_0 : (CHAR_A - 10));
#else /* EBCDIC coding */
- if (cc <= 'z') cc += 64; /* Convert to upper case */
- c = c * 16 + cc - ((cc >= '0')? '0' : ('A' - 10));
+ if (cc <= CHAR_z) cc += 64; /* Convert to upper case */
+ c = c * 16 + cc - ((cc >= CHAR_0)? CHAR_0 : (CHAR_A - 10));
#endif
}
break;
This coding is ASCII-specific, but then the whole concept of \cx is
ASCII-specific. (However, an EBCDIC equivalent has now been added.) */
- case 'c':
+ case CHAR_c:
c = *(++ptr);
if (c == 0)
{
break;
}
-#ifndef EBCDIC /* ASCII coding */
- if (c >= 'a' && c <= 'z') c -= 32;
+#ifndef EBCDIC /* ASCII/UTF-8 coding */
+ if (c >= CHAR_a && c <= CHAR_z) c -= 32;
c ^= 0x40;
#else /* EBCDIC coding */
- if (c >= 'a' && c <= 'z') c += 64;
+ if (c >= CHAR_a && c <= CHAR_z) c += 64;
c ^= 0xC0;
#endif
break;
/* \P or \p can be followed by a name in {}, optionally preceded by ^ for
negation. */
-if (c == '{')
+if (c == CHAR_LEFT_CURLY_BRACKET)
{
- if (ptr[1] == '^')
+ if (ptr[1] == CHAR_CIRCUMFLEX_ACCENT)
{
*negptr = TRUE;
ptr++;
{
c = *(++ptr);
if (c == 0) goto ERROR_RETURN;
- if (c == '}') break;
+ if (c == CHAR_RIGHT_CURLY_BRACKET) break;
name[i] = c;
}
- if (c !='}') goto ERROR_RETURN;
+ if (c != CHAR_RIGHT_CURLY_BRACKET) goto ERROR_RETURN;
name[i] = 0;
}
{
if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
while ((digitab[*p] & ctype_digit) != 0) p++;
-if (*p == '}') return TRUE;
+if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
-if (*p++ != ',') return FALSE;
-if (*p == '}') return TRUE;
+if (*p++ != CHAR_COMMA) return FALSE;
+if (*p == CHAR_RIGHT_CURLY_BRACKET) return TRUE;
if ((digitab[*p++] & ctype_digit) == 0) return FALSE;
while ((digitab[*p] & ctype_digit) != 0) p++;
-return (*p == '}');
+return (*p == CHAR_RIGHT_CURLY_BRACKET);
}
/* Read the minimum value and do a paranoid check: a negative value indicates
an integer overflow. */
-while ((digitab[*p] & ctype_digit) != 0) min = min * 10 + *p++ - '0';
+while ((digitab[*p] & ctype_digit) != 0) min = min * 10 + *p++ - CHAR_0;
if (min < 0 || min > 65535)
{
*errorcodeptr = ERR5;
/* Read the maximum value if there is one, and again do a paranoid on its size.
Also, max must not be less than min. */
-if (*p == '}') max = min; else
+if (*p == CHAR_RIGHT_CURLY_BRACKET) max = min; else
{
- if (*(++p) != '}')
+ if (*(++p) != CHAR_RIGHT_CURLY_BRACKET)
{
max = 0;
- while((digitab[*p] & ctype_digit) != 0) max = max * 10 + *p++ - '0';
+ while((digitab[*p] & ctype_digit) != 0) max = max * 10 + *p++ - CHAR_0;
if (max < 0 || max > 65535)
{
*errorcodeptr = ERR5;
/*************************************************
-* Find forward referenced subpattern *
+* Subroutine for finding forward reference *
*************************************************/
-/* This function scans along a pattern's text looking for capturing
+/* This recursive function is called only from find_parens() below. The
+top-level call starts at the beginning of the pattern. All other calls must
+start at a parenthesis. It scans along a pattern's text looking for capturing
subpatterns, and counting them. If it finds a named pattern that matches the
name it is given, it returns its number. Alternatively, if the name is NULL, it
-returns when it reaches a given numbered subpattern. This is used for forward
-references to subpatterns. We know that if (?P< is encountered, the name will
-be terminated by '>' because that is checked in the first pass.
+returns when it reaches a given numbered subpattern. We know that if (?P< is
+encountered, the name will be terminated by '>' because that is checked in the
+first pass. Recursion is used to keep track of subpatterns that reset the
+capturing group numbers - the (?| feature.
Arguments:
- ptr current position in the pattern
+ ptrptr address of the current character pointer (updated)
cd compile background data
name name to seek, or NULL if seeking a numbered subpattern
lorn name length, or subpattern number if name is NULL
xmode TRUE if we are in /x mode
+ count pointer to the current capturing subpattern number (updated)
Returns: the number of the named subpattern, or -1 if not found
*/
static int
-find_parens(const uschar *ptr, compile_data *cd, const uschar *name, int lorn,
- BOOL xmode)
+find_parens_sub(uschar **ptrptr, compile_data *cd, const uschar *name, int lorn,
+ BOOL xmode, int *count)
{
-const uschar *thisname;
-int count = cd->bracount;
+uschar *ptr = *ptrptr;
+int start_count = *count;
+int hwm_count = start_count;
+BOOL dup_parens = FALSE;
-for (; *ptr != 0; ptr++)
+/* If the first character is a parenthesis, check on the type of group we are
+dealing with. The very first call may not start with a parenthesis. */
+
+if (ptr[0] == CHAR_LEFT_PARENTHESIS)
{
- int term;
+ if (ptr[1] == CHAR_QUESTION_MARK &&
+ ptr[2] == CHAR_VERTICAL_LINE)
+ {
+ ptr += 3;
+ dup_parens = TRUE;
+ }
+
+ /* Handle a normal, unnamed capturing parenthesis */
+
+ else if (ptr[1] != CHAR_QUESTION_MARK && ptr[1] != CHAR_ASTERISK)
+ {
+ *count += 1;
+ if (name == NULL && *count == lorn) return *count;
+ ptr++;
+ }
+
+ /* Handle a condition. If it is an assertion, just carry on so that it
+ is processed as normal. If not, skip to the closing parenthesis of the
+ condition (there can't be any nested parens. */
+
+ else if (ptr[2] == CHAR_LEFT_PARENTHESIS)
+ {
+ ptr += 2;
+ if (ptr[1] != CHAR_QUESTION_MARK)
+ {
+ while (*ptr != 0 && *ptr != CHAR_RIGHT_PARENTHESIS) ptr++;
+ if (*ptr != 0) ptr++;
+ }
+ }
+
+ /* We have either (? or (* and not a condition */
+
+ else
+ {
+ ptr += 2;
+ if (*ptr == CHAR_P) ptr++; /* Allow optional P */
+
+ /* We have to disambiguate (?<! and (?<= from (?<name> for named groups */
+
+ if ((*ptr == CHAR_LESS_THAN_SIGN && ptr[1] != CHAR_EXCLAMATION_MARK &&
+ ptr[1] != CHAR_EQUALS_SIGN) || *ptr == CHAR_APOSTROPHE)
+ {
+ int term;
+ const uschar *thisname;
+ *count += 1;
+ if (name == NULL && *count == lorn) return *count;
+ term = *ptr++;
+ if (term == CHAR_LESS_THAN_SIGN) term = CHAR_GREATER_THAN_SIGN;
+ thisname = ptr;
+ while (*ptr != term) ptr++;
+ if (name != NULL && lorn == ptr - thisname &&
+ strncmp((const char *)name, (const char *)thisname, lorn) == 0)
+ return *count;
+ }
+ }
+ }
+/* Past any initial parenthesis handling, scan for parentheses or vertical
+bars. */
+
+for (; *ptr != 0; ptr++)
+ {
/* Skip over backslashed characters and also entire \Q...\E */
- if (*ptr == '\\')
+ if (*ptr == CHAR_BACKSLASH)
{
- if (*(++ptr) == 0) return -1;
- if (*ptr == 'Q') for (;;)
+ if (*(++ptr) == 0) goto FAIL_EXIT;
+ if (*ptr == CHAR_Q) for (;;)
{
- while (*(++ptr) != 0 && *ptr != '\\') {};
- if (*ptr == 0) return -1;
- if (*(++ptr) == 'E') break;
+ while (*(++ptr) != 0 && *ptr != CHAR_BACKSLASH) {};
+ if (*ptr == 0) goto FAIL_EXIT;
+ if (*(++ptr) == CHAR_E) break;
}
continue;
}
/* Skip over character classes; this logic must be similar to the way they
are handled for real. If the first character is '^', skip it. Also, if the
first few characters (either before or after ^) are \Q\E or \E we skip them
- too. This makes for compatibility with Perl. */
+ too. This makes for compatibility with Perl. Note the use of STR macros to
+ encode "Q\\E" so that it works in UTF-8 on EBCDIC platforms. */
- if (*ptr == '[')
+ if (*ptr == CHAR_LEFT_SQUARE_BRACKET)
{
BOOL negate_class = FALSE;
for (;;)
{
int c = *(++ptr);
- if (c == '\\')
+ if (c == CHAR_BACKSLASH)
{
- if (ptr[1] == 'E') ptr++;
- else if (strncmp((const char *)ptr+1, "Q\\E", 3) == 0) ptr += 3;
- else break;
+ if (ptr[1] == CHAR_E)
+ ptr++;
+ else if (strncmp((const char *)ptr+1,
+ STR_Q STR_BACKSLASH STR_E, 3) == 0)
+ ptr += 3;
+ else
+ break;
}
- else if (!negate_class && c == '^')
+ else if (!negate_class && c == CHAR_CIRCUMFLEX_ACCENT)
negate_class = TRUE;
else break;
}
/* If the next character is ']', it is a data character that must be
skipped, except in JavaScript compatibility mode. */
- if (ptr[1] == ']' && (cd->external_options & PCRE_JAVASCRIPT_COMPAT) == 0)
+ if (ptr[1] == CHAR_RIGHT_SQUARE_BRACKET &&
+ (cd->external_options & PCRE_JAVASCRIPT_COMPAT) == 0)
ptr++;
- while (*(++ptr) != ']')
+ while (*(++ptr) != CHAR_RIGHT_SQUARE_BRACKET)
{
if (*ptr == 0) return -1;
- if (*ptr == '\\')
+ if (*ptr == CHAR_BACKSLASH)
{
- if (*(++ptr) == 0) return -1;
- if (*ptr == 'Q') for (;;)
+ if (*(++ptr) == 0) goto FAIL_EXIT;
+ if (*ptr == CHAR_Q) for (;;)
{
- while (*(++ptr) != 0 && *ptr != '\\') {};
- if (*ptr == 0) return -1;
- if (*(++ptr) == 'E') break;
+ while (*(++ptr) != 0 && *ptr != CHAR_BACKSLASH) {};
+ if (*ptr == 0) goto FAIL_EXIT;
+ if (*(++ptr) == CHAR_E) break;
}
continue;
}
/* Skip comments in /x mode */
- if (xmode && *ptr == '#')
+ if (xmode && *ptr == CHAR_NUMBER_SIGN)
{
- while (*(++ptr) != 0 && *ptr != '\n') {};
- if (*ptr == 0) return -1;
+ while (*(++ptr) != 0 && *ptr != CHAR_NL) {};
+ if (*ptr == 0) goto FAIL_EXIT;
continue;
}
- /* An opening parens must now be a real metacharacter */
+ /* Check for the special metacharacters */
- if (*ptr != '(') continue;
- if (ptr[1] != '?' && ptr[1] != '*')
+ if (*ptr == CHAR_LEFT_PARENTHESIS)
{
- count++;
- if (name == NULL && count == lorn) return count;
- continue;
+ int rc = find_parens_sub(&ptr, cd, name, lorn, xmode, count);
+ if (rc > 0) return rc;
+ if (*ptr == 0) goto FAIL_EXIT;
+ }
+
+ else if (*ptr == CHAR_RIGHT_PARENTHESIS)
+ {
+ if (dup_parens && *count < hwm_count) *count = hwm_count;
+ *ptrptr = ptr;
+ return -1;
}
- ptr += 2;
- if (*ptr == 'P') ptr++; /* Allow optional P */
+ else if (*ptr == CHAR_VERTICAL_LINE && dup_parens)
+ {
+ if (*count > hwm_count) hwm_count = *count;
+ *count = start_count;
+ }
+ }
+
+FAIL_EXIT:
+*ptrptr = ptr;
+return -1;
+}
+
- /* We have to disambiguate (?<! and (?<= from (?<name> */
- if ((*ptr != '<' || ptr[1] == '!' || ptr[1] == '=') &&
- *ptr != '\'')
- continue;
- count++;
+/*************************************************
+* Find forward referenced subpattern *
+*************************************************/
+
+/* This function scans along a pattern's text looking for capturing
+subpatterns, and counting them. If it finds a named pattern that matches the
+name it is given, it returns its number. Alternatively, if the name is NULL, it
+returns when it reaches a given numbered subpattern. This is used for forward
+references to subpatterns. We used to be able to start this scan from the
+current compiling point, using the current count value from cd->bracount, and
+do it all in a single loop, but the addition of the possibility of duplicate
+subpattern numbers means that we have to scan from the very start, in order to
+take account of such duplicates, and to use a recursive function to keep track
+of the different types of group.
+
+Arguments:
+ cd compile background data
+ name name to seek, or NULL if seeking a numbered subpattern
+ lorn name length, or subpattern number if name is NULL
+ xmode TRUE if we are in /x mode
+
+Returns: the number of the found subpattern, or -1 if not found
+*/
+
+static int
+find_parens(compile_data *cd, const uschar *name, int lorn, BOOL xmode)
+{
+uschar *ptr = (uschar *)cd->start_pattern;
+int count = 0;
+int rc;
- if (name == NULL && count == lorn) return count;
- term = *ptr++;
- if (term == '<') term = '>';
- thisname = ptr;
- while (*ptr != term) ptr++;
- if (name != NULL && lorn == ptr - thisname &&
- strncmp((const char *)name, (const char *)thisname, lorn) == 0)
- return count;
+/* If the pattern does not start with an opening parenthesis, the first call
+to find_parens_sub() will scan right to the end (if necessary). However, if it
+does start with a parenthesis, find_parens_sub() will return when it hits the
+matching closing parens. That is why we have to have a loop. */
+
+for (;;)
+ {
+ rc = find_parens_sub(&ptr, cd, name, lorn, xmode, &count);
+ if (rc > 0 || *ptr++ == 0) break;
}
-return -1;
+return rc;
}
+
/*************************************************
* Find first significant op code *
*************************************************/
BOOL empty_branch;
if (GET(code, 1) == 0) return TRUE; /* Hit unclosed bracket */
- /* Scan a closed bracket */
+ /* If a conditional group has only one branch, there is a second, implied,
+ empty branch, so just skip over the conditional, because it could be empty.
+ Otherwise, scan the individual branches of the group. */
- empty_branch = FALSE;
- do
- {
- if (!empty_branch && could_be_empty_branch(code, endcode, utf8))
- empty_branch = TRUE;
+ if (c == OP_COND && code[GET(code, 1)] != OP_ALT)
code += GET(code, 1);
+ else
+ {
+ empty_branch = FALSE;
+ do
+ {
+ if (!empty_branch && could_be_empty_branch(code, endcode, utf8))
+ empty_branch = TRUE;
+ code += GET(code, 1);
+ }
+ while (*code == OP_ALT);
+ if (!empty_branch) return FALSE; /* All branches are non-empty */
}
- while (*code == OP_ALT);
- if (!empty_branch) return FALSE; /* All branches are non-empty */
+
c = *code;
continue;
}
terminator = *(++ptr); /* compiler warns about "non-constant" initializer. */
for (++ptr; *ptr != 0; ptr++)
{
- if (*ptr == '\\' && ptr[1] == ']') ptr++; else
+ if (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_RIGHT_SQUARE_BRACKET) ptr++; else
{
- if (*ptr == ']') return FALSE;
- if (*ptr == terminator && ptr[1] == ']')
+ if (*ptr == CHAR_RIGHT_SQUARE_BRACKET) return FALSE;
+ if (*ptr == terminator && ptr[1] == CHAR_RIGHT_SQUARE_BRACKET)
{
*endptr = ptr;
return TRUE;
for (;;)
{
while ((cd->ctypes[*ptr] & ctype_space) != 0) ptr++;
- if (*ptr == '#')
+ if (*ptr == CHAR_NUMBER_SIGN)
{
while (*(++ptr) != 0)
if (IS_NEWLINE(ptr)) { ptr += cd->nllen; break; }
/* If the next item is one that we can handle, get its value. A non-negative
value is a character, a negative value is an escape value. */
-if (*ptr == '\\')
+if (*ptr == CHAR_BACKSLASH)
{
int temperrorcode = 0;
next = check_escape(&ptr, &temperrorcode, cd->bracount, options, FALSE);
for (;;)
{
while ((cd->ctypes[*ptr] & ctype_space) != 0) ptr++;
- if (*ptr == '#')
+ if (*ptr == CHAR_NUMBER_SIGN)
{
while (*(++ptr) != 0)
if (IS_NEWLINE(ptr)) { ptr += cd->nllen; break; }
/* If the next thing is itself optional, we have to give up. */
-if (*ptr == '*' || *ptr == '?' || strncmp((char *)ptr, "{0,", 3) == 0)
- return FALSE;
+if (*ptr == CHAR_ASTERISK || *ptr == CHAR_QUESTION_MARK ||
+ strncmp((char *)ptr, STR_LEFT_CURLY_BRACKET STR_0 STR_COMMA, 3) == 0)
+ return FALSE;
/* Now compare the next item with the previous opcode. If the previous is a
positive single character match, "item" either contains the character or, if
if (inescq && c != 0)
{
- if (c == '\\' && ptr[1] == 'E')
+ if (c == CHAR_BACKSLASH && ptr[1] == CHAR_E)
{
inescq = FALSE;
ptr++;
/* Fill in length of a previous callout, except when the next thing is
a quantifier. */
- is_quantifier = c == '*' || c == '+' || c == '?' ||
- (c == '{' && is_counted_repeat(ptr+1));
+ is_quantifier =
+ c == CHAR_ASTERISK || c == CHAR_PLUS || c == CHAR_QUESTION_MARK ||
+ (c == CHAR_LEFT_CURLY_BRACKET && is_counted_repeat(ptr+1));
if (!is_quantifier && previous_callout != NULL &&
after_manual_callout-- <= 0)
if ((options & PCRE_EXTENDED) != 0)
{
if ((cd->ctypes[c] & ctype_space) != 0) continue;
- if (c == '#')
+ if (c == CHAR_NUMBER_SIGN)
{
while (*(++ptr) != 0)
{
{
/* ===================================================================*/
case 0: /* The branch terminates at string end */
- case '|': /* or | or ) */
- case ')':
+ case CHAR_VERTICAL_LINE: /* or | or ) */
+ case CHAR_RIGHT_PARENTHESIS:
*firstbyteptr = firstbyte;
*reqbyteptr = reqbyte;
*codeptr = code;
/* Handle single-character metacharacters. In multiline mode, ^ disables
the setting of any following char as a first character. */
- case '^':
+ case CHAR_CIRCUMFLEX_ACCENT:
if ((options & PCRE_MULTILINE) != 0)
{
if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
*code++ = OP_CIRC;
break;
- case '$':
+ case CHAR_DOLLAR_SIGN:
previous = NULL;
*code++ = OP_DOLL;
break;
/* There can never be a first char if '.' is first, whatever happens about
repeats. The value of reqbyte doesn't change either. */
- case '.':
+ case CHAR_DOT:
if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
zerofirstbyte = firstbyte;
zeroreqbyte = reqbyte;
In JavaScript compatibility mode, an isolated ']' causes an error. In
default (Perl) mode, it is treated as a data character. */
- case ']':
+ case CHAR_RIGHT_SQUARE_BRACKET:
if ((cd->external_options & PCRE_JAVASCRIPT_COMPAT) != 0)
{
*errorcodeptr = ERR64;
}
goto NORMAL_CHAR;
- case '[':
+ case CHAR_LEFT_SQUARE_BRACKET:
previous = code;
/* PCRE supports POSIX class stuff inside a class. Perl gives an error if
they are encountered at the top level, so we'll do that too. */
- if ((ptr[1] == ':' || ptr[1] == '.' || ptr[1] == '=') &&
+ if ((ptr[1] == CHAR_COLON || ptr[1] == CHAR_DOT ||
+ ptr[1] == CHAR_EQUALS_SIGN) &&
check_posix_syntax(ptr, &tempptr))
{
- *errorcodeptr = (ptr[1] == ':')? ERR13 : ERR31;
+ *errorcodeptr = (ptr[1] == CHAR_COLON)? ERR13 : ERR31;
goto FAILED;
}
for (;;)
{
c = *(++ptr);
- if (c == '\\')
+ if (c == CHAR_BACKSLASH)
{
- if (ptr[1] == 'E') ptr++;
- else if (strncmp((const char *)ptr+1, "Q\\E", 3) == 0) ptr += 3;
- else break;
+ if (ptr[1] == CHAR_E)
+ ptr++;
+ else if (strncmp((const char *)ptr+1,
+ STR_Q STR_BACKSLASH STR_E, 3) == 0)
+ ptr += 3;
+ else
+ break;
}
- else if (!negate_class && c == '^')
+ else if (!negate_class && c == CHAR_CIRCUMFLEX_ACCENT)
negate_class = TRUE;
else break;
}
that. In JS mode, [] must always fail, so generate OP_FAIL, whereas
[^] must match any character, so generate OP_ALLANY. */
- if (c ==']' && (cd->external_options & PCRE_JAVASCRIPT_COMPAT) != 0)
+ if (c == CHAR_RIGHT_SQUARE_BRACKET &&
+ (cd->external_options & PCRE_JAVASCRIPT_COMPAT) != 0)
{
*code++ = negate_class? OP_ALLANY : OP_FAIL;
if (firstbyte == REQ_UNSET) firstbyte = REQ_NONE;
if (inescq)
{
- if (c == '\\' && ptr[1] == 'E') /* If we are at \E */
+ if (c == CHAR_BACKSLASH && ptr[1] == CHAR_E) /* If we are at \E */
{
inescq = FALSE; /* Reset literal state */
ptr++; /* Skip the 'E' */
[.ch.] and [=ch=] ("collating elements") and fault them, as Perl
5.6 and 5.8 do. */
- if (c == '[' &&
- (ptr[1] == ':' || ptr[1] == '.' || ptr[1] == '=') &&
- check_posix_syntax(ptr, &tempptr))
+ if (c == CHAR_LEFT_SQUARE_BRACKET &&
+ (ptr[1] == CHAR_COLON || ptr[1] == CHAR_DOT ||
+ ptr[1] == CHAR_EQUALS_SIGN) && check_posix_syntax(ptr, &tempptr))
{
BOOL local_negate = FALSE;
int posix_class, taboffset, tabopt;
register const uschar *cbits = cd->cbits;
uschar pbits[32];
- if (ptr[1] != ':')
+ if (ptr[1] != CHAR_COLON)
{
*errorcodeptr = ERR31;
goto FAILED;
}
ptr += 2;
- if (*ptr == '^')
+ if (*ptr == CHAR_CIRCUMFLEX_ACCENT)
{
local_negate = TRUE;
should_flip_negation = TRUE; /* Note negative special */
to 'or' into the one we are building. We assume they have more than one
character in them, so set class_charcount bigger than one. */
- if (c == '\\')
+ if (c == CHAR_BACKSLASH)
{
c = check_escape(&ptr, errorcodeptr, cd->bracount, options, TRUE);
if (*errorcodeptr != 0) goto FAILED;
- if (-c == ESC_b) c = '\b'; /* \b is backspace in a class */
- else if (-c == ESC_X) c = 'X'; /* \X is literal X in a class */
- else if (-c == ESC_R) c = 'R'; /* \R is literal R in a class */
+ if (-c == ESC_b) c = CHAR_BS; /* \b is backspace in a class */
+ else if (-c == ESC_X) c = CHAR_X; /* \X is literal X in a class */
+ else if (-c == ESC_R) c = CHAR_R; /* \R is literal R in a class */
else if (-c == ESC_Q) /* Handle start of quoted string */
{
- if (ptr[1] == '\\' && ptr[2] == 'E')
+ if (ptr[1] == CHAR_BACKSLASH && ptr[2] == CHAR_E)
{
ptr += 2; /* avoid empty string */
}
entirely. The code for handling \Q and \E is messy. */
CHECK_RANGE:
- while (ptr[1] == '\\' && ptr[2] == 'E')
+ while (ptr[1] == CHAR_BACKSLASH && ptr[2] == CHAR_E)
{
inescq = FALSE;
ptr += 2;
/* Remember \r or \n */
- if (c == '\r' || c == '\n') cd->external_flags |= PCRE_HASCRORLF;
+ if (c == CHAR_CR || c == CHAR_NL) cd->external_flags |= PCRE_HASCRORLF;
/* Check for range */
- if (!inescq && ptr[1] == '-')
+ if (!inescq && ptr[1] == CHAR_MINUS)
{
int d;
ptr += 2;
- while (*ptr == '\\' && ptr[1] == 'E') ptr += 2;
+ while (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_E) ptr += 2;
/* If we hit \Q (not followed by \E) at this point, go into escaped
mode. */
- while (*ptr == '\\' && ptr[1] == 'Q')
+ while (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_Q)
{
ptr += 2;
- if (*ptr == '\\' && ptr[1] == 'E') { ptr += 2; continue; }
+ if (*ptr == CHAR_BACKSLASH && ptr[1] == CHAR_E)
+ { ptr += 2; continue; }
inescq = TRUE;
break;
}
- if (*ptr == 0 || (!inescq && *ptr == ']'))
+ if (*ptr == 0 || (!inescq && *ptr == CHAR_RIGHT_SQUARE_BRACKET))
{
ptr = oldptr;
goto LONE_SINGLE_CHARACTER;
not any of the other escapes. Perl 5.6 treats a hyphen as a literal
in such circumstances. */
- if (!inescq && d == '\\')
+ if (!inescq && d == CHAR_BACKSLASH)
{
d = check_escape(&ptr, errorcodeptr, cd->bracount, options, TRUE);
if (*errorcodeptr != 0) goto FAILED;
if (d < 0)
{
- if (d == -ESC_b) d = '\b';
- else if (d == -ESC_X) d = 'X';
- else if (d == -ESC_R) d = 'R'; else
+ if (d == -ESC_b) d = CHAR_BS;
+ else if (d == -ESC_X) d = CHAR_X;
+ else if (d == -ESC_R) d = CHAR_R; else
{
ptr = oldptr;
goto LONE_SINGLE_CHARACTER; /* A few lines below */
/* Remember \r or \n */
- if (d == '\r' || d == '\n') cd->external_flags |= PCRE_HASCRORLF;
+ if (d == CHAR_CR || d == CHAR_NL) cd->external_flags |= PCRE_HASCRORLF;
/* In UTF-8 mode, if the upper limit is > 255, or > 127 for caseless
matching, we have to use an XCLASS with extra data items. Caseless
/* Loop until ']' reached. This "while" is the end of the "do" above. */
- while ((c = *(++ptr)) != 0 && (c != ']' || inescq));
+ while ((c = *(++ptr)) != 0 && (c != CHAR_RIGHT_SQUARE_BRACKET || inescq));
if (c == 0) /* Missing terminating ']' */
{
/* Various kinds of repeat; '{' is not necessarily a quantifier, but this
has been tested above. */
- case '{':
+ case CHAR_LEFT_CURLY_BRACKET:
if (!is_quantifier) goto NORMAL_CHAR;
ptr = read_repeat_counts(ptr+1, &repeat_min, &repeat_max, errorcodeptr);
if (*errorcodeptr != 0) goto FAILED;
goto REPEAT;
- case '*':
+ case CHAR_ASTERISK:
repeat_min = 0;
repeat_max = -1;
goto REPEAT;
- case '+':
+ case CHAR_PLUS:
repeat_min = 1;
repeat_max = -1;
goto REPEAT;
- case '?':
+ case CHAR_QUESTION_MARK:
repeat_min = 0;
repeat_max = 1;
but if PCRE_UNGREEDY is set, it works the other way round. We change the
repeat type to the non-default. */
- if (ptr[1] == '+')
+ if (ptr[1] == CHAR_PLUS)
{
repeat_type = 0; /* Force greedy */
possessive_quantifier = TRUE;
ptr++;
}
- else if (ptr[1] == '?')
+ else if (ptr[1] == CHAR_QUESTION_MARK)
{
repeat_type = greedy_non_default;
ptr++;
lookbehind or option setting or condition or all the other extended
parenthesis forms. */
- case '(':
+ case CHAR_LEFT_PARENTHESIS:
newoptions = options;
skipbytes = 0;
bravalue = OP_CBRA;
/* First deal with various "verbs" that can be introduced by '*'. */
- if (*(++ptr) == '*' && (cd->ctypes[ptr[1]] & ctype_letter) != 0)
+ if (*(++ptr) == CHAR_ASTERISK && (cd->ctypes[ptr[1]] & ctype_letter) != 0)
{
int i, namelen;
const char *vn = verbnames;
const uschar *name = ++ptr;
previous = NULL;
while ((cd->ctypes[*++ptr] & ctype_letter) != 0) {};
- if (*ptr == ':')
+ if (*ptr == CHAR_COLON)
{
*errorcodeptr = ERR59; /* Not supported */
goto FAILED;
}
- if (*ptr != ')')
+ if (*ptr != CHAR_RIGHT_PARENTHESIS)
{
*errorcodeptr = ERR60;
goto FAILED;
/* Deal with the extended parentheses; all are introduced by '?', and the
appearance of any of them means that this is not a capturing group. */
- else if (*ptr == '?')
+ else if (*ptr == CHAR_QUESTION_MARK)
{
int i, set, unset, namelen;
int *optset;
switch (*(++ptr))
{
- case '#': /* Comment; skip to ket */
+ case CHAR_NUMBER_SIGN: /* Comment; skip to ket */
ptr++;
- while (*ptr != 0 && *ptr != ')') ptr++;
+ while (*ptr != 0 && *ptr != CHAR_RIGHT_PARENTHESIS) ptr++;
if (*ptr == 0)
{
*errorcodeptr = ERR18;
/* ------------------------------------------------------------ */
- case '|': /* Reset capture count for each branch */
+ case CHAR_VERTICAL_LINE: /* Reset capture count for each branch */
reset_bracount = TRUE;
/* Fall through */
/* ------------------------------------------------------------ */
- case ':': /* Non-capturing bracket */
+ case CHAR_COLON: /* Non-capturing bracket */
bravalue = OP_BRA;
ptr++;
break;
/* ------------------------------------------------------------ */
- case '(':
+ case CHAR_LEFT_PARENTHESIS:
bravalue = OP_COND; /* Conditional group */
/* A condition can be an assertion, a number (referring to a numbered
the switch. This will take control down to where bracketed groups,
including assertions, are processed. */
- if (ptr[1] == '?' && (ptr[2] == '=' || ptr[2] == '!' || ptr[2] == '<'))
+ if (ptr[1] == CHAR_QUESTION_MARK && (ptr[2] == CHAR_EQUALS_SIGN ||
+ ptr[2] == CHAR_EXCLAMATION_MARK || ptr[2] == CHAR_LESS_THAN_SIGN))
break;
/* Most other conditions use OP_CREF (a couple change to OP_RREF
/* Check for a test for recursion in a named group. */
- if (ptr[1] == 'R' && ptr[2] == '&')
+ if (ptr[1] == CHAR_R && ptr[2] == CHAR_AMPERSAND)
{
terminator = -1;
ptr += 2;
/* Check for a test for a named group's having been set, using the Perl
syntax (?(<name>) or (?('name') */
- else if (ptr[1] == '<')
+ else if (ptr[1] == CHAR_LESS_THAN_SIGN)
{
- terminator = '>';
+ terminator = CHAR_GREATER_THAN_SIGN;
ptr++;
}
- else if (ptr[1] == '\'')
+ else if (ptr[1] == CHAR_APOSTROPHE)
{
- terminator = '\'';
+ terminator = CHAR_APOSTROPHE;
ptr++;
}
else
{
terminator = 0;
- if (ptr[1] == '-' || ptr[1] == '+') refsign = *(++ptr);
+ if (ptr[1] == CHAR_MINUS || ptr[1] == CHAR_PLUS) refsign = *(++ptr);
}
/* We now expect to read a name; any thing else is an error */
{
if (recno >= 0)
recno = ((digitab[*ptr] & ctype_digit) != 0)?
- recno * 10 + *ptr - '0' : -1;
+ recno * 10 + *ptr - CHAR_0 : -1;
ptr++;
}
namelen = ptr - name;
- if ((terminator > 0 && *ptr++ != terminator) || *ptr++ != ')')
+ if ((terminator > 0 && *ptr++ != terminator) ||
+ *ptr++ != CHAR_RIGHT_PARENTHESIS)
{
ptr--; /* Error offset */
*errorcodeptr = ERR26;
*errorcodeptr = ERR58;
goto FAILED;
}
- recno = (refsign == '-')?
+ recno = (refsign == CHAR_MINUS)?
cd->bracount - recno + 1 : recno +cd->bracount;
if (recno <= 0 || recno > cd->final_bracount)
{
/* Search the pattern for a forward reference */
- else if ((i = find_parens(ptr, cd, name, namelen,
+ else if ((i = find_parens(cd, name, namelen,
(options & PCRE_EXTENDED) != 0)) > 0)
{
PUT2(code, 2+LINK_SIZE, i);
/* Check for (?(R) for recursion. Allow digits after R to specify a
specific group number. */
- else if (*name == 'R')
+ else if (*name == CHAR_R)
{
recno = 0;
for (i = 1; i < namelen; i++)
*errorcodeptr = ERR15;
goto FAILED;
}
- recno = recno * 10 + name[i] - '0';
+ recno = recno * 10 + name[i] - CHAR_0;
}
if (recno == 0) recno = RREF_ANY;
code[1+LINK_SIZE] = OP_RREF; /* Change test type */
/* Similarly, check for the (?(DEFINE) "condition", which is always
false. */
- else if (namelen == 6 && strncmp((char *)name, "DEFINE", 6) == 0)
+ else if (namelen == 6 && strncmp((char *)name, STRING_DEFINE, 6) == 0)
{
code[1+LINK_SIZE] = OP_DEF;
skipbytes = 1;
/* ------------------------------------------------------------ */
- case '=': /* Positive lookahead */
+ case CHAR_EQUALS_SIGN: /* Positive lookahead */
bravalue = OP_ASSERT;
ptr++;
break;
/* ------------------------------------------------------------ */
- case '!': /* Negative lookahead */
+ case CHAR_EXCLAMATION_MARK: /* Negative lookahead */
ptr++;
- if (*ptr == ')') /* Optimize (?!) */
+ if (*ptr == CHAR_RIGHT_PARENTHESIS) /* Optimize (?!) */
{
*code++ = OP_FAIL;
previous = NULL;
/* ------------------------------------------------------------ */
- case '<': /* Lookbehind or named define */
+ case CHAR_LESS_THAN_SIGN: /* Lookbehind or named define */
switch (ptr[1])
{
- case '=': /* Positive lookbehind */
+ case CHAR_EQUALS_SIGN: /* Positive lookbehind */
bravalue = OP_ASSERTBACK;
ptr += 2;
break;
- case '!': /* Negative lookbehind */
+ case CHAR_EXCLAMATION_MARK: /* Negative lookbehind */
bravalue = OP_ASSERTBACK_NOT;
ptr += 2;
break;
/* ------------------------------------------------------------ */
- case '>': /* One-time brackets */
+ case CHAR_GREATER_THAN_SIGN: /* One-time brackets */
bravalue = OP_ONCE;
ptr++;
break;
/* ------------------------------------------------------------ */
- case 'C': /* Callout - may be followed by digits; */
+ case CHAR_C: /* Callout - may be followed by digits; */
previous_callout = code; /* Save for later completion */
after_manual_callout = 1; /* Skip one item before completing */
*code++ = OP_CALLOUT;
{
int n = 0;
while ((digitab[*(++ptr)] & ctype_digit) != 0)
- n = n * 10 + *ptr - '0';
- if (*ptr != ')')
+ n = n * 10 + *ptr - CHAR_0;
+ if (*ptr != CHAR_RIGHT_PARENTHESIS)
{
*errorcodeptr = ERR39;
goto FAILED;
/* ------------------------------------------------------------ */
- case 'P': /* Python-style named subpattern handling */
- if (*(++ptr) == '=' || *ptr == '>') /* Reference or recursion */
+ case CHAR_P: /* Python-style named subpattern handling */
+ if (*(++ptr) == CHAR_EQUALS_SIGN ||
+ *ptr == CHAR_GREATER_THAN_SIGN) /* Reference or recursion */
{
- is_recurse = *ptr == '>';
- terminator = ')';
+ is_recurse = *ptr == CHAR_GREATER_THAN_SIGN;
+ terminator = CHAR_RIGHT_PARENTHESIS;
goto NAMED_REF_OR_RECURSE;
}
- else if (*ptr != '<') /* Test for Python-style definition */
+ else if (*ptr != CHAR_LESS_THAN_SIGN) /* Test for Python-style defn */
{
*errorcodeptr = ERR41;
goto FAILED;
/* ------------------------------------------------------------ */
DEFINE_NAME: /* Come here from (?< handling */
- case '\'':
+ case CHAR_APOSTROPHE:
{
- terminator = (*ptr == '<')? '>' : '\'';
+ terminator = (*ptr == CHAR_LESS_THAN_SIGN)?
+ CHAR_GREATER_THAN_SIGN : CHAR_APOSTROPHE;
name = ++ptr;
while ((cd->ctypes[*ptr] & ctype_word) != 0) ptr++;
/* ------------------------------------------------------------ */
- case '&': /* Perl recursion/subroutine syntax */
- terminator = ')';
+ case CHAR_AMPERSAND: /* Perl recursion/subroutine syntax */
+ terminator = CHAR_RIGHT_PARENTHESIS;
is_recurse = TRUE;
/* Fall through */
recno = GET2(slot, 0);
}
else if ((recno = /* Forward back reference */
- find_parens(ptr, cd, name, namelen,
+ find_parens(cd, name, namelen,
(options & PCRE_EXTENDED) != 0)) <= 0)
{
*errorcodeptr = ERR15;
/* ------------------------------------------------------------ */
- case 'R': /* Recursion */
+ case CHAR_R: /* Recursion */
ptr++; /* Same as (?0) */
/* Fall through */
/* ------------------------------------------------------------ */
- case '-': case '+':
- case '0': case '1': case '2': case '3': case '4': /* Recursion or */
- case '5': case '6': case '7': case '8': case '9': /* subroutine */
+ case CHAR_MINUS: case CHAR_PLUS: /* Recursion or subroutine */
+ case CHAR_0: case CHAR_1: case CHAR_2: case CHAR_3: case CHAR_4:
+ case CHAR_5: case CHAR_6: case CHAR_7: case CHAR_8: case CHAR_9:
{
const uschar *called;
- terminator = ')';
+ terminator = CHAR_RIGHT_PARENTHESIS;
/* Come here from the \g<...> and \g'...' code (Oniguruma
compatibility). However, the syntax has been checked to ensure that
HANDLE_NUMERICAL_RECURSION:
- if ((refsign = *ptr) == '+')
+ if ((refsign = *ptr) == CHAR_PLUS)
{
ptr++;
if ((digitab[*ptr] & ctype_digit) == 0)
goto FAILED;
}
}
- else if (refsign == '-')
+ else if (refsign == CHAR_MINUS)
{
if ((digitab[ptr[1]] & ctype_digit) == 0)
goto OTHER_CHAR_AFTER_QUERY;
recno = 0;
while((digitab[*ptr] & ctype_digit) != 0)
- recno = recno * 10 + *ptr++ - '0';
+ recno = recno * 10 + *ptr++ - CHAR_0;
if (*ptr != terminator)
{
goto FAILED;
}
- if (refsign == '-')
+ if (refsign == CHAR_MINUS)
{
if (recno == 0)
{
goto FAILED;
}
}
- else if (refsign == '+')
+ else if (refsign == CHAR_PLUS)
{
if (recno == 0)
{
if (called == NULL)
{
- if (find_parens(ptr, cd, NULL, recno,
+ if (find_parens(cd, NULL, recno,
(options & PCRE_EXTENDED) != 0) < 0)
{
*errorcodeptr = ERR15;
set = unset = 0;
optset = &set;
- while (*ptr != ')' && *ptr != ':')
+ while (*ptr != CHAR_RIGHT_PARENTHESIS && *ptr != CHAR_COLON)
{
switch (*ptr++)
{
- case '-': optset = &unset; break;
+ case CHAR_MINUS: optset = &unset; break;
- case 'J': /* Record that it changed in the external options */
+ case CHAR_J: /* Record that it changed in the external options */
*optset |= PCRE_DUPNAMES;
cd->external_flags |= PCRE_JCHANGED;
break;
- case 'i': *optset |= PCRE_CASELESS; break;
- case 'm': *optset |= PCRE_MULTILINE; break;
- case 's': *optset |= PCRE_DOTALL; break;
- case 'x': *optset |= PCRE_EXTENDED; break;
- case 'U': *optset |= PCRE_UNGREEDY; break;
- case 'X': *optset |= PCRE_EXTRA; break;
+ case CHAR_i: *optset |= PCRE_CASELESS; break;
+ case CHAR_m: *optset |= PCRE_MULTILINE; break;
+ case CHAR_s: *optset |= PCRE_DOTALL; break;
+ case CHAR_x: *optset |= PCRE_EXTENDED; break;
+ case CHAR_U: *optset |= PCRE_UNGREEDY; break;
+ case CHAR_X: *optset |= PCRE_EXTRA; break;
default: *errorcodeptr = ERR12;
ptr--; /* Correct the offset */
options if this setting actually changes any of them, and reset the
greedy defaults and the case value for firstbyte and reqbyte. */
- if (*ptr == ')')
+ if (*ptr == CHAR_RIGHT_PARENTHESIS)
{
if (code == cd->start_code + 1 + LINK_SIZE &&
(lengthptr == NULL || *lengthptr == 2 + 2*LINK_SIZE))
/* Error if hit end of pattern */
- if (*ptr != ')')
+ if (*ptr != CHAR_RIGHT_PARENTHESIS)
{
*errorcodeptr = ERR14;
goto FAILED;
We can test for values between ESC_b and ESC_Z for the latter; this may
have to change if any new ones are ever created. */
- case '\\':
+ case CHAR_BACKSLASH:
tempptr = ptr;
c = check_escape(&ptr, errorcodeptr, cd->bracount, options, FALSE);
if (*errorcodeptr != 0) goto FAILED;
{
if (-c == ESC_Q) /* Handle start of quoted string */
{
- if (ptr[1] == '\\' && ptr[2] == 'E') ptr += 2; /* avoid empty string */
- else inescq = TRUE;
+ if (ptr[1] == CHAR_BACKSLASH && ptr[2] == CHAR_E)
+ ptr += 2; /* avoid empty string */
+ else inescq = TRUE;
continue;
}
{
const uschar *p;
save_hwm = cd->hwm; /* Normally this is set when '(' is read */
- terminator = (*(++ptr) == '<')? '>' : '\'';
+ terminator = (*(++ptr) == CHAR_LESS_THAN_SIGN)?
+ CHAR_GREATER_THAN_SIGN : CHAR_APOSTROPHE;
/* These two statements stop the compiler for warning about possibly
unset variables caused by the jump to HANDLE_NUMERICAL_RECURSION. In
/* Test for a name */
- if (ptr[1] != '+' && ptr[1] != '-')
+ if (ptr[1] != CHAR_PLUS && ptr[1] != CHAR_MINUS)
{
BOOL isnumber = TRUE;
for (p = ptr + 1; *p != 0 && *p != terminator; p++)
/* \k<name> or \k'name' is a back reference by name (Perl syntax).
We also support \k{name} (.NET syntax) */
- if (-c == ESC_k && (ptr[1] == '<' || ptr[1] == '\'' || ptr[1] == '{'))
+ if (-c == ESC_k && (ptr[1] == CHAR_LESS_THAN_SIGN ||
+ ptr[1] == CHAR_APOSTROPHE || ptr[1] == CHAR_LEFT_CURLY_BRACKET))
{
is_recurse = FALSE;
- terminator = (*(++ptr) == '<')? '>' : (*ptr == '\'')? '\'' : '}';
+ terminator = (*(++ptr) == CHAR_LESS_THAN_SIGN)?
+ CHAR_GREATER_THAN_SIGN : (*ptr == CHAR_APOSTROPHE)?
+ CHAR_APOSTROPHE : CHAR_RIGHT_CURLY_BRACKET;
goto NAMED_REF_OR_RECURSE;
}
/* Remember if \r or \n were seen */
- if (mcbuffer[0] == '\r' || mcbuffer[0] == '\n')
+ if (mcbuffer[0] == CHAR_CR || mcbuffer[0] == CHAR_NL)
cd->external_flags |= PCRE_HASCRORLF;
/* Set the first and required bytes appropriately. If no previous first
compile a resetting op-code following, except at the very end of the pattern.
Return leaving the pointer at the terminating char. */
- if (*ptr != '|')
+ if (*ptr != CHAR_VERTICAL_LINE)
{
if (lengthptr == NULL)
{
/* Resetting option if needed */
- if ((options & PCRE_IMS) != oldims && *ptr == ')')
+ if ((options & PCRE_IMS) != oldims && *ptr == CHAR_RIGHT_PARENTHESIS)
{
*code++ = OP_OPT;
*code++ = oldims;
NULL, 0, FALSE);
register int op = *scode;
+ /* If we are at the start of a conditional assertion group, *both* the
+ conditional assertion *and* what follows the condition must satisfy the test
+ for start of line. Other kinds of condition fail. Note that there may be an
+ auto-callout at the start of a condition. */
+
+ if (op == OP_COND)
+ {
+ scode += 1 + LINK_SIZE;
+ if (*scode == OP_CALLOUT) scode += _pcre_OP_lengths[OP_CALLOUT];
+ switch (*scode)
+ {
+ case OP_CREF:
+ case OP_RREF:
+ case OP_DEF:
+ return FALSE;
+
+ default: /* Assertion */
+ if (!is_startline(scode, bracket_map, backref_map)) return FALSE;
+ do scode += GET(scode, 1); while (*scode == OP_ALT);
+ scode += 1 + LINK_SIZE;
+ break;
+ }
+ scode = first_significant_code(scode, NULL, 0, FALSE);
+ op = *scode;
+ }
+
/* Non-capturing brackets */
if (op == OP_BRA)
/* Other brackets */
- else if (op == OP_ASSERT || op == OP_ONCE || op == OP_COND)
- { if (!is_startline(scode, bracket_map, backref_map)) return FALSE; }
+ else if (op == OP_ASSERT || op == OP_ONCE)
+ {
+ if (!is_startline(scode, bracket_map, backref_map)) return FALSE;
+ }
/* .* means "start at start or after \n" if it isn't in brackets that
may be referenced. */
*erroroffset = 0;
-/* Can't support UTF8 unless PCRE has been compiled to include the code. */
-
-#ifdef SUPPORT_UTF8
-utf8 = (options & PCRE_UTF8) != 0;
-if (utf8 && (options & PCRE_NO_UTF8_CHECK) == 0 &&
- (*erroroffset = _pcre_valid_utf8((uschar *)pattern, -1)) >= 0)
- {
- errorcode = ERR44;
- goto PCRE_EARLY_ERROR_RETURN2;
- }
-#else
-if ((options & PCRE_UTF8) != 0)
- {
- errorcode = ERR32;
- goto PCRE_EARLY_ERROR_RETURN;
- }
-#endif
-
-if ((options & ~PUBLIC_OPTIONS) != 0)
- {
- errorcode = ERR17;
- goto PCRE_EARLY_ERROR_RETURN;
- }
-
/* Set up pointers to the individual character tables */
if (tables == NULL) tables = _pcre_default_tables;
cd->cbits = tables + cbits_offset;
cd->ctypes = tables + ctypes_offset;
+/* Check that all undefined public option bits are zero */
+
+if ((options & ~PUBLIC_COMPILE_OPTIONS) != 0)
+ {
+ errorcode = ERR17;
+ goto PCRE_EARLY_ERROR_RETURN;
+ }
+
/* Check for global one-time settings at the start of the pattern, and remember
the offset for later. */
-while (ptr[skipatstart] == '(' && ptr[skipatstart+1] == '*')
+while (ptr[skipatstart] == CHAR_LEFT_PARENTHESIS &&
+ ptr[skipatstart+1] == CHAR_ASTERISK)
{
int newnl = 0;
int newbsr = 0;
- if (strncmp((char *)(ptr+skipatstart+2), "CR)", 3) == 0)
+ if (strncmp((char *)(ptr+skipatstart+2), STRING_UTF8_RIGHTPAR, 5) == 0)
+ { skipatstart += 7; options |= PCRE_UTF8; continue; }
+
+ if (strncmp((char *)(ptr+skipatstart+2), STRING_CR_RIGHTPAR, 3) == 0)
{ skipatstart += 5; newnl = PCRE_NEWLINE_CR; }
- else if (strncmp((char *)(ptr+skipatstart+2), "LF)", 3) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_LF_RIGHTPAR, 3) == 0)
{ skipatstart += 5; newnl = PCRE_NEWLINE_LF; }
- else if (strncmp((char *)(ptr+skipatstart+2), "CRLF)", 5) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_CRLF_RIGHTPAR, 5) == 0)
{ skipatstart += 7; newnl = PCRE_NEWLINE_CR + PCRE_NEWLINE_LF; }
- else if (strncmp((char *)(ptr+skipatstart+2), "ANY)", 4) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_ANY_RIGHTPAR, 4) == 0)
{ skipatstart += 6; newnl = PCRE_NEWLINE_ANY; }
- else if (strncmp((char *)(ptr+skipatstart+2), "ANYCRLF)", 8) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_ANYCRLF_RIGHTPAR, 8) == 0)
{ skipatstart += 10; newnl = PCRE_NEWLINE_ANYCRLF; }
- else if (strncmp((char *)(ptr+skipatstart+2), "BSR_ANYCRLF)", 12) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_BSR_ANYCRLF_RIGHTPAR, 12) == 0)
{ skipatstart += 14; newbsr = PCRE_BSR_ANYCRLF; }
- else if (strncmp((char *)(ptr+skipatstart+2), "BSR_UNICODE)", 12) == 0)
+ else if (strncmp((char *)(ptr+skipatstart+2), STRING_BSR_UNICODE_RIGHTPAR, 12) == 0)
{ skipatstart += 14; newbsr = PCRE_BSR_UNICODE; }
if (newnl != 0)
else break;
}
+/* Can't support UTF8 unless PCRE has been compiled to include the code. */
+
+#ifdef SUPPORT_UTF8
+utf8 = (options & PCRE_UTF8) != 0;
+if (utf8 && (options & PCRE_NO_UTF8_CHECK) == 0 &&
+ (*erroroffset = _pcre_valid_utf8((uschar *)pattern, -1)) >= 0)
+ {
+ errorcode = ERR44;
+ goto PCRE_EARLY_ERROR_RETURN2;
+ }
+#else
+if ((options & PCRE_UTF8) != 0)
+ {
+ errorcode = ERR32;
+ goto PCRE_EARLY_ERROR_RETURN;
+ }
+#endif
+
/* Check validity of \R options. */
switch (options & (PCRE_BSR_ANYCRLF|PCRE_BSR_UNICODE))
switch (options & PCRE_NEWLINE_BITS)
{
case 0: newline = NEWLINE; break; /* Build-time default */
- case PCRE_NEWLINE_CR: newline = '\r'; break;
- case PCRE_NEWLINE_LF: newline = '\n'; break;
+ case PCRE_NEWLINE_CR: newline = CHAR_CR; break;
+ case PCRE_NEWLINE_LF: newline = CHAR_NL; break;
case PCRE_NEWLINE_CR+
- PCRE_NEWLINE_LF: newline = ('\r' << 8) | '\n'; break;
+ PCRE_NEWLINE_LF: newline = (CHAR_CR << 8) | CHAR_NL; break;
case PCRE_NEWLINE_ANY: newline = -1; break;
case PCRE_NEWLINE_ANYCRLF: newline = -2; break;
default: errorcode = ERR56; goto PCRE_EARLY_ERROR_RETURN;
projects / php / commitdiff