1 /*-------------------------------------------------------------------------
4 * Primary include file for PostgreSQL server .c files
6 * This should be the first file included by PostgreSQL backend modules.
7 * Client-side code should include postgres_fe.h instead.
10 * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
11 * Portions Copyright (c) 1995, Regents of the University of California
13 * $PostgreSQL: pgsql/src/include/postgres.h,v 1.82 2007/07/25 12:22:53 mha Exp $
15 *-------------------------------------------------------------------------
18 *----------------------------------------------------------------
21 * When adding stuff to this file, please try to put stuff
22 * into the relevant section, or add new sections as appropriate.
25 * ------- ------------------------------------------------
26 * 1) variable-length datatypes (TOAST support)
27 * 2) datum type + support macros
28 * 3) exception handling definitions
29 * 4) genbki macros used by catalog/pg_xxx.h files
33 * In general, this file should contain declarations that are widely needed
34 * in the backend environment, but are of no interest outside the backend.
36 * Simple type definitions live in c.h, where they are shared with
37 * postgres_fe.h. We do that since those type definitions are needed by
38 * frontend modules that want to deal with binary data transmission to or
39 * from the backend. Type definitions in this file should be for
40 * representations that never escape the backend, such as Datum or
41 * TOASTed varlena objects.
43 *----------------------------------------------------------------
49 #include "utils/elog.h"
50 #include "utils/palloc.h"
52 /* ----------------------------------------------------------------
53 * Section 1: variable-length datatypes (TOAST support)
54 * ----------------------------------------------------------------
58 * struct varatt_external is a "TOAST pointer", that is, the information
59 * needed to fetch a stored-out-of-line Datum. The data is compressed
60 * if and only if va_extsize < va_rawsize - VARHDRSZ. This struct must not
61 * contain any padding, because we sometimes compare pointers using memcmp.
63 * Note that this information is stored unaligned within actual tuples, so
64 * you need to memcpy from the tuple into a local struct variable before
65 * you can look at these fields! (The reason we use memcmp is to avoid
66 * having to do that just to detect equality of two TOAST pointers...)
68 struct varatt_external
70 int32 va_rawsize; /* Original data size (includes header) */
71 int32 va_extsize; /* External saved size (doesn't) */
72 Oid va_valueid; /* Unique ID of value within TOAST table */
73 Oid va_toastrelid; /* RelID of TOAST table containing it */
77 * These structs describe the header of a varlena object that may have been
78 * TOASTed. Generally, don't reference these structs directly, but use the
81 * We use separate structs for the aligned and unaligned cases because the
82 * compiler might otherwise think it could generate code that assumes
83 * alignment while touching fields of a 1-byte-header varlena.
87 struct /* Normal varlena (4-byte length) */
92 struct /* Compressed-in-line format */
95 uint32 va_rawsize; /* Original data size (excludes header) */
96 char va_data[1]; /* Compressed data */
103 char va_data[1]; /* Data or TOAST pointer */
109 char va_data[sizeof(struct varatt_external)];
113 * Bit layouts for varlena headers on big-endian machines:
115 * 00xxxxxx 4-byte length word, aligned, uncompressed data (up to 1G)
116 * 01xxxxxx 4-byte length word, aligned, *compressed* data (up to 1G)
117 * 10000000 1-byte length word, unaligned, TOAST pointer
118 * 1xxxxxxx 1-byte length word, unaligned, uncompressed data (up to 126b)
120 * Bit layouts for varlena headers on little-endian machines:
122 * xxxxxx00 4-byte length word, aligned, uncompressed data (up to 1G)
123 * xxxxxx10 4-byte length word, aligned, *compressed* data (up to 1G)
124 * 00000001 1-byte length word, unaligned, TOAST pointer
125 * xxxxxxx1 1-byte length word, unaligned, uncompressed data (up to 126b)
127 * The "xxx" bits are the length field (which includes itself in all cases).
128 * In the big-endian case we mask to extract the length, in the little-endian
129 * case we shift. Note that in both cases the flag bits are in the physically
130 * first byte. Also, it is not possible for a 1-byte length word to be zero;
131 * this lets us disambiguate alignment padding bytes from the start of an
132 * unaligned datum. (We now *require* pad bytes to be filled with zero!)
136 * Endian-dependent macros. These are considered internal --- use the
137 * external macros below instead of using these directly.
139 * Note: IS_1B is true for external toast records but VARSIZE_1B will return 0
140 * for such records. Hence you should usually check for IS_EXTERNAL before
141 * checking for IS_1B.
144 #ifdef WORDS_BIGENDIAN
146 #define VARATT_IS_4B(PTR) \
147 ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x00)
148 #define VARATT_IS_4B_U(PTR) \
149 ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x00)
150 #define VARATT_IS_4B_C(PTR) \
151 ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x40)
152 #define VARATT_IS_1B(PTR) \
153 ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x80)
154 #define VARATT_IS_1B_E(PTR) \
155 ((((varattrib_1b *) (PTR))->va_header) == 0x80)
156 #define VARATT_NOT_PAD_BYTE(PTR) \
157 (*((uint8 *) (PTR)) != 0)
159 /* VARSIZE_4B() should only be used on known-aligned data */
160 #define VARSIZE_4B(PTR) \
161 (((varattrib_4b *) (PTR))->va_4byte.va_header & 0x3FFFFFFF)
162 #define VARSIZE_1B(PTR) \
163 (((varattrib_1b *) (PTR))->va_header & 0x7F)
164 /* Currently there is only one size of toast pointer, but someday maybe not */
165 #define VARSIZE_1B_E(PTR) \
166 (sizeof(varattrib_pointer))
168 #define SET_VARSIZE_4B(PTR,len) \
169 (((varattrib_4b *) (PTR))->va_4byte.va_header = (len) & 0x3FFFFFFF)
170 #define SET_VARSIZE_4B_C(PTR,len) \
171 (((varattrib_4b *) (PTR))->va_4byte.va_header = ((len) & 0x3FFFFFFF) | 0x40000000)
172 #define SET_VARSIZE_1B(PTR,len) \
173 (((varattrib_1b *) (PTR))->va_header = (len) | 0x80)
174 #define SET_VARSIZE_1B_E(PTR) \
175 (((varattrib_1b *) (PTR))->va_header = 0x80)
177 #else /* !WORDS_BIGENDIAN */
179 #define VARATT_IS_4B(PTR) \
180 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x00)
181 #define VARATT_IS_4B_U(PTR) \
182 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x00)
183 #define VARATT_IS_4B_C(PTR) \
184 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x02)
185 #define VARATT_IS_1B(PTR) \
186 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x01)
187 #define VARATT_IS_1B_E(PTR) \
188 ((((varattrib_1b *) (PTR))->va_header) == 0x01)
189 #define VARATT_NOT_PAD_BYTE(PTR) \
190 (*((uint8 *) (PTR)) != 0)
192 /* VARSIZE_4B() should only be used on known-aligned data */
193 #define VARSIZE_4B(PTR) \
194 ((((varattrib_4b *) (PTR))->va_4byte.va_header >> 2) & 0x3FFFFFFF)
195 #define VARSIZE_1B(PTR) \
196 ((((varattrib_1b *) (PTR))->va_header >> 1) & 0x7F)
197 /* Currently there is only one size of toast pointer, but someday maybe not */
198 #define VARSIZE_1B_E(PTR) \
199 (sizeof(varattrib_pointer))
201 #define SET_VARSIZE_4B(PTR,len) \
202 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2))
203 #define SET_VARSIZE_4B_C(PTR,len) \
204 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2) | 0x02)
205 #define SET_VARSIZE_1B(PTR,len) \
206 (((varattrib_1b *) (PTR))->va_header = (((uint8) (len)) << 1) | 0x01)
207 #define SET_VARSIZE_1B_E(PTR) \
208 (((varattrib_1b *) (PTR))->va_header = 0x01)
210 #endif /* WORDS_BIGENDIAN */
212 #define VARHDRSZ_SHORT 1
213 #define VARATT_SHORT_MAX 0x7F
214 #define VARATT_CAN_MAKE_SHORT(PTR) \
215 (VARATT_IS_4B_U(PTR) && \
216 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX)
217 #define VARATT_CONVERTED_SHORT_SIZE(PTR) \
218 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT)
220 #define VARDATA_4B(PTR) (((varattrib_4b *) (PTR))->va_4byte.va_data)
221 #define VARDATA_4B_C(PTR) (((varattrib_4b *) (PTR))->va_compressed.va_data)
222 #define VARDATA_1B(PTR) (((varattrib_1b *) (PTR))->va_data)
224 #define VARRAWSIZE_4B_C(PTR) \
225 (((varattrib_4b *) (PTR))->va_compressed.va_rawsize)
227 /* Externally visible macros */
230 * VARDATA, VARSIZE, and SET_VARSIZE are the recommended API for most code
231 * for varlena datatypes. Note that they only work on untoasted,
232 * 4-byte-header Datums!
234 * Code that wants to use 1-byte-header values without detoasting should
235 * use VARSIZE_ANY/VARSIZE_ANY_EXHDR/VARDATA_ANY. The other macros here
236 * should usually be used only by tuple assembly/disassembly code and
237 * code that specifically wants to work with still-toasted Datums.
239 * WARNING: It is only safe to use VARDATA_ANY() -- typically with
240 * PG_DETOAST_DATUM_UNPACKED() -- if you really don't care about the alignment.
241 * Either because you're working with something like text where the alignment
242 * doesn't matter or because you're not going to access its constituent parts
243 * and just use things like memcpy on it anyways.
245 #define VARDATA(PTR) VARDATA_4B(PTR)
246 #define VARSIZE(PTR) VARSIZE_4B(PTR)
248 #define VARSIZE_SHORT(PTR) VARSIZE_1B(PTR)
249 #define VARDATA_SHORT(PTR) VARDATA_1B(PTR)
251 #define VARSIZE_EXTERNAL(PTR) VARSIZE_1B_E(PTR)
253 #define VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR)
254 #define VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR)
255 #define VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR)
256 #define VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR))
258 #define SET_VARSIZE(PTR, len) SET_VARSIZE_4B(PTR, len)
259 #define SET_VARSIZE_SHORT(PTR, len) SET_VARSIZE_1B(PTR, len)
260 #define SET_VARSIZE_COMPRESSED(PTR, len) SET_VARSIZE_4B_C(PTR, len)
261 #define SET_VARSIZE_EXTERNAL(PTR) SET_VARSIZE_1B_E(PTR)
263 #define VARSIZE_ANY(PTR) \
264 (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR) : \
265 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR) : \
268 #define VARSIZE_ANY_EXHDR(PTR) \
269 (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR)-1 : \
270 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR)-1 : \
273 /* caution: this will not work on an external or compressed-in-line Datum */
274 /* caution: this will return a possibly unaligned pointer */
275 #define VARDATA_ANY(PTR) \
276 (VARATT_IS_1B(PTR) ? VARDATA_1B(PTR) : VARDATA_4B(PTR))
279 /* ----------------------------------------------------------------
280 * Section 2: datum type + support macros
281 * ----------------------------------------------------------------
286 * Postgres makes the following assumption about machines:
288 * sizeof(Datum) == sizeof(long) >= sizeof(void *) >= 4
290 * Postgres also assumes that
298 * When a type narrower than Datum is stored in a Datum, we place it in the
299 * low-order bits and are careful that the DatumGetXXX macro for it discards
300 * the unused high-order bits (as opposed to, say, assuming they are zero).
301 * This is needed to support old-style user-defined functions, since depending
302 * on architecture and compiler, the return value of a function returning char
303 * or short may contain garbage when called as if it returned Datum.
306 typedef unsigned long Datum; /* XXX sizeof(long) >= sizeof(void *) */
308 #define SIZEOF_DATUM SIZEOF_UNSIGNED_LONG
310 typedef Datum *DatumPtr;
312 #define GET_1_BYTE(datum) (((Datum) (datum)) & 0x000000ff)
313 #define GET_2_BYTES(datum) (((Datum) (datum)) & 0x0000ffff)
314 #define GET_4_BYTES(datum) (((Datum) (datum)) & 0xffffffff)
315 #define SET_1_BYTE(value) (((Datum) (value)) & 0x000000ff)
316 #define SET_2_BYTES(value) (((Datum) (value)) & 0x0000ffff)
317 #define SET_4_BYTES(value) (((Datum) (value)) & 0xffffffff)
321 * Returns boolean value of a datum.
323 * Note: any nonzero value will be considered TRUE, but we ignore bits to
324 * the left of the width of bool, per comment above.
327 #define DatumGetBool(X) ((bool) (((bool) (X)) != 0))
331 * Returns datum representation for a boolean.
333 * Note: any nonzero value will be considered TRUE.
336 #define BoolGetDatum(X) ((Datum) ((X) ? 1 : 0))
340 * Returns character value of a datum.
343 #define DatumGetChar(X) ((char) GET_1_BYTE(X))
347 * Returns datum representation for a character.
350 #define CharGetDatum(X) ((Datum) SET_1_BYTE(X))
354 * Returns datum representation for an 8-bit integer.
357 #define Int8GetDatum(X) ((Datum) SET_1_BYTE(X))
361 * Returns 8-bit unsigned integer value of a datum.
364 #define DatumGetUInt8(X) ((uint8) GET_1_BYTE(X))
368 * Returns datum representation for an 8-bit unsigned integer.
371 #define UInt8GetDatum(X) ((Datum) SET_1_BYTE(X))
375 * Returns 16-bit integer value of a datum.
378 #define DatumGetInt16(X) ((int16) GET_2_BYTES(X))
382 * Returns datum representation for a 16-bit integer.
385 #define Int16GetDatum(X) ((Datum) SET_2_BYTES(X))
389 * Returns 16-bit unsigned integer value of a datum.
392 #define DatumGetUInt16(X) ((uint16) GET_2_BYTES(X))
396 * Returns datum representation for a 16-bit unsigned integer.
399 #define UInt16GetDatum(X) ((Datum) SET_2_BYTES(X))
403 * Returns 32-bit integer value of a datum.
406 #define DatumGetInt32(X) ((int32) GET_4_BYTES(X))
410 * Returns datum representation for a 32-bit integer.
413 #define Int32GetDatum(X) ((Datum) SET_4_BYTES(X))
417 * Returns 32-bit unsigned integer value of a datum.
420 #define DatumGetUInt32(X) ((uint32) GET_4_BYTES(X))
424 * Returns datum representation for a 32-bit unsigned integer.
427 #define UInt32GetDatum(X) ((Datum) SET_4_BYTES(X))
431 * Returns object identifier value of a datum.
434 #define DatumGetObjectId(X) ((Oid) GET_4_BYTES(X))
438 * Returns datum representation for an object identifier.
441 #define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X))
444 * DatumGetTransactionId
445 * Returns transaction identifier value of a datum.
448 #define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X))
451 * TransactionIdGetDatum
452 * Returns datum representation for a transaction identifier.
455 #define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X)))
459 * Returns command identifier value of a datum.
462 #define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X))
466 * Returns datum representation for a command identifier.
469 #define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X))
473 * Returns pointer value of a datum.
476 #define DatumGetPointer(X) ((Pointer) (X))
480 * Returns datum representation for a pointer.
483 #define PointerGetDatum(X) ((Datum) (X))
487 * Returns C string (null-terminated string) value of a datum.
489 * Note: C string is not a full-fledged Postgres type at present,
490 * but type input functions use this conversion for their inputs.
493 #define DatumGetCString(X) ((char *) DatumGetPointer(X))
497 * Returns datum representation for a C string (null-terminated string).
499 * Note: C string is not a full-fledged Postgres type at present,
500 * but type output functions use this conversion for their outputs.
501 * Note: CString is pass-by-reference; caller must ensure the pointed-to
502 * value has adequate lifetime.
505 #define CStringGetDatum(X) PointerGetDatum(X)
509 * Returns name value of a datum.
512 #define DatumGetName(X) ((Name) DatumGetPointer(X))
516 * Returns datum representation for a name.
518 * Note: Name is pass-by-reference; caller must ensure the pointed-to
519 * value has adequate lifetime.
522 #define NameGetDatum(X) PointerGetDatum(X)
526 * Returns 64-bit integer value of a datum.
528 * Note: this macro hides the fact that int64 is currently a
529 * pass-by-reference type. Someday it may be pass-by-value,
530 * at least on some platforms.
533 #define DatumGetInt64(X) (* ((int64 *) DatumGetPointer(X)))
537 * Returns datum representation for a 64-bit integer.
539 * Note: this routine returns a reference to palloc'd space.
542 extern Datum Int64GetDatum(int64 X);
546 * Returns 4-byte floating point value of a datum.
548 * Note: this macro hides the fact that float4 is currently a
549 * pass-by-reference type. Someday it may be pass-by-value.
552 #define DatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X)))
556 * Returns datum representation for a 4-byte floating point number.
558 * Note: this routine returns a reference to palloc'd space.
561 extern Datum Float4GetDatum(float4 X);
565 * Returns 8-byte floating point value of a datum.
567 * Note: this macro hides the fact that float8 is currently a
568 * pass-by-reference type. Someday it may be pass-by-value,
569 * at least on some platforms.
572 #define DatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X)))
576 * Returns datum representation for an 8-byte floating point number.
578 * Note: this routine returns a reference to palloc'd space.
581 extern Datum Float8GetDatum(float8 X);
586 * Returns 32-bit floating point value of a datum.
587 * This is really a pointer, of course.
589 * XXX: this macro is now deprecated in favor of DatumGetFloat4.
590 * It will eventually go away.
593 #define DatumGetFloat32(X) ((float32) DatumGetPointer(X))
597 * Returns datum representation for a 32-bit floating point number.
598 * This is really a pointer, of course.
600 * XXX: this macro is now deprecated in favor of Float4GetDatum.
601 * It will eventually go away.
604 #define Float32GetDatum(X) PointerGetDatum(X)
608 * Returns 64-bit floating point value of a datum.
609 * This is really a pointer, of course.
611 * XXX: this macro is now deprecated in favor of DatumGetFloat8.
612 * It will eventually go away.
615 #define DatumGetFloat64(X) ((float64) DatumGetPointer(X))
619 * Returns datum representation for a 64-bit floating point number.
620 * This is really a pointer, of course.
622 * XXX: this macro is now deprecated in favor of Float8GetDatum.
623 * It will eventually go away.
626 #define Float64GetDatum(X) PointerGetDatum(X)
633 * These macros are intended to allow writing code that does not depend on
634 * whether int64, float4, float8 are pass-by-reference types, while not
635 * sacrificing performance when they are. The argument must be a variable
636 * that will exist and have the same value for as long as the Datum is needed.
637 * In the pass-by-ref case, the address of the variable is taken to use as
638 * the Datum. In the pass-by-val case, these will be the same as the non-Fast
642 #define Int64GetDatumFast(X) PointerGetDatum(&(X))
643 #define Float4GetDatumFast(X) PointerGetDatum(&(X))
644 #define Float8GetDatumFast(X) PointerGetDatum(&(X))
647 /* ----------------------------------------------------------------
648 * Section 3: exception handling definitions
649 * Assert, Trap, etc macros
650 * ----------------------------------------------------------------
653 extern PGDLLIMPORT bool assert_enabled;
656 * USE_ASSERT_CHECKING, if defined, turns on all the assertions.
659 * It should _NOT_ be defined in releases or in benchmark copies
664 * Generates an exception if the given condition is true.
666 #define Trap(condition, errorType) \
668 if ((assert_enabled) && (condition)) \
669 ExceptionalCondition(CppAsString(condition), (errorType), \
670 __FILE__, __LINE__); \
674 * TrapMacro is the same as Trap but it's intended for use in macros:
676 * #define foo(x) (AssertMacro(x != 0) && bar(x))
680 #define TrapMacro(condition, errorType) \
681 ((bool) ((! assert_enabled) || ! (condition) || \
682 (ExceptionalCondition(CppAsString(condition), (errorType), \
683 __FILE__, __LINE__))))
685 #ifndef USE_ASSERT_CHECKING
686 #define Assert(condition)
687 #define AssertMacro(condition) ((void)true)
688 #define AssertArg(condition)
689 #define AssertState(condition)
691 #define Assert(condition) \
692 Trap(!(condition), "FailedAssertion")
694 #define AssertMacro(condition) \
695 ((void) TrapMacro(!(condition), "FailedAssertion"))
697 #define AssertArg(condition) \
698 Trap(!(condition), "BadArgument")
700 #define AssertState(condition) \
701 Trap(!(condition), "BadState")
702 #endif /* USE_ASSERT_CHECKING */
704 extern int ExceptionalCondition(const char *conditionName,
705 const char *errorType,
706 const char *fileName, int lineNumber);
708 /* ----------------------------------------------------------------
709 * Section 4: genbki macros used by catalog/pg_xxx.h files
710 * ----------------------------------------------------------------
712 #define CATALOG(name,oid) typedef struct CppConcat(FormData_,name)
714 #define BKI_BOOTSTRAP
715 #define BKI_SHARED_RELATION
716 #define BKI_WITHOUT_OIDS
718 /* these need to expand into some harmless, repeatable declaration */
719 #define DATA(x) extern int no_such_variable
720 #define DESCR(x) extern int no_such_variable
721 #define SHDESCR(x) extern int no_such_variable
723 typedef int4 aclitem; /* PHONY definition for catalog use only */
725 #endif /* POSTGRES_H */