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) 1996-2012, PostgreSQL Global Development Group
11 * Portions Copyright (c) 1995, Regents of the University of California
13 * src/include/postgres.h
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
32 * In general, this file should contain declarations that are widely needed
33 * in the backend environment, but are of no interest outside the backend.
35 * Simple type definitions live in c.h, where they are shared with
36 * postgres_fe.h. We do that since those type definitions are needed by
37 * frontend modules that want to deal with binary data transmission to or
38 * from the backend. Type definitions in this file should be for
39 * representations that never escape the backend, such as Datum or
40 * TOASTed varlena objects.
42 *----------------------------------------------------------------
48 #include "utils/elog.h"
49 #include "utils/palloc.h"
51 /* ----------------------------------------------------------------
52 * Section 1: variable-length datatypes (TOAST support)
53 * ----------------------------------------------------------------
57 * struct varatt_external is a "TOAST pointer", that is, the information
58 * needed to fetch a stored-out-of-line Datum. The data is compressed
59 * if and only if va_extsize < va_rawsize - VARHDRSZ. This struct must not
60 * contain any padding, because we sometimes compare pointers using memcmp.
62 * Note that this information is stored unaligned within actual tuples, so
63 * you need to memcpy from the tuple into a local struct variable before
64 * you can look at these fields! (The reason we use memcmp is to avoid
65 * having to do that just to detect equality of two TOAST pointers...)
67 struct varatt_external
69 int32 va_rawsize; /* Original data size (includes header) */
70 int32 va_extsize; /* External saved size (doesn't) */
71 Oid va_valueid; /* Unique ID of value within TOAST table */
72 Oid va_toastrelid; /* RelID of TOAST table containing it */
76 * These structs describe the header of a varlena object that may have been
77 * TOASTed. Generally, don't reference these structs directly, but use the
80 * We use separate structs for the aligned and unaligned cases because the
81 * compiler might otherwise think it could generate code that assumes
82 * alignment while touching fields of a 1-byte-header varlena.
86 struct /* Normal varlena (4-byte length) */
91 struct /* Compressed-in-line format */
94 uint32 va_rawsize; /* Original data size (excludes header) */
95 char va_data[1]; /* Compressed data */
102 char va_data[1]; /* Data begins here */
107 uint8 va_header; /* Always 0x80 or 0x01 */
108 uint8 va_len_1be; /* Physical length of datum */
109 char va_data[1]; /* Data (for now always a TOAST pointer) */
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 #define VARSIZE_1B_E(PTR) \
165 (((varattrib_1b_e *) (PTR))->va_len_1be)
167 #define SET_VARSIZE_4B(PTR,len) \
168 (((varattrib_4b *) (PTR))->va_4byte.va_header = (len) & 0x3FFFFFFF)
169 #define SET_VARSIZE_4B_C(PTR,len) \
170 (((varattrib_4b *) (PTR))->va_4byte.va_header = ((len) & 0x3FFFFFFF) | 0x40000000)
171 #define SET_VARSIZE_1B(PTR,len) \
172 (((varattrib_1b *) (PTR))->va_header = (len) | 0x80)
173 #define SET_VARSIZE_1B_E(PTR,len) \
174 (((varattrib_1b_e *) (PTR))->va_header = 0x80, \
175 ((varattrib_1b_e *) (PTR))->va_len_1be = (len))
176 #else /* !WORDS_BIGENDIAN */
178 #define VARATT_IS_4B(PTR) \
179 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x00)
180 #define VARATT_IS_4B_U(PTR) \
181 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x00)
182 #define VARATT_IS_4B_C(PTR) \
183 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x02)
184 #define VARATT_IS_1B(PTR) \
185 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x01)
186 #define VARATT_IS_1B_E(PTR) \
187 ((((varattrib_1b *) (PTR))->va_header) == 0x01)
188 #define VARATT_NOT_PAD_BYTE(PTR) \
189 (*((uint8 *) (PTR)) != 0)
191 /* VARSIZE_4B() should only be used on known-aligned data */
192 #define VARSIZE_4B(PTR) \
193 ((((varattrib_4b *) (PTR))->va_4byte.va_header >> 2) & 0x3FFFFFFF)
194 #define VARSIZE_1B(PTR) \
195 ((((varattrib_1b *) (PTR))->va_header >> 1) & 0x7F)
196 #define VARSIZE_1B_E(PTR) \
197 (((varattrib_1b_e *) (PTR))->va_len_1be)
199 #define SET_VARSIZE_4B(PTR,len) \
200 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2))
201 #define SET_VARSIZE_4B_C(PTR,len) \
202 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2) | 0x02)
203 #define SET_VARSIZE_1B(PTR,len) \
204 (((varattrib_1b *) (PTR))->va_header = (((uint8) (len)) << 1) | 0x01)
205 #define SET_VARSIZE_1B_E(PTR,len) \
206 (((varattrib_1b_e *) (PTR))->va_header = 0x01, \
207 ((varattrib_1b_e *) (PTR))->va_len_1be = (len))
208 #endif /* WORDS_BIGENDIAN */
210 #define VARHDRSZ_SHORT 1
211 #define VARATT_SHORT_MAX 0x7F
212 #define VARATT_CAN_MAKE_SHORT(PTR) \
213 (VARATT_IS_4B_U(PTR) && \
214 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX)
215 #define VARATT_CONVERTED_SHORT_SIZE(PTR) \
216 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT)
218 #define VARHDRSZ_EXTERNAL 2
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)
223 #define VARDATA_1B_E(PTR) (((varattrib_1b_e *) (PTR))->va_data)
225 #define VARRAWSIZE_4B_C(PTR) \
226 (((varattrib_4b *) (PTR))->va_compressed.va_rawsize)
228 /* Externally visible macros */
231 * VARDATA, VARSIZE, and SET_VARSIZE are the recommended API for most code
232 * for varlena datatypes. Note that they only work on untoasted,
233 * 4-byte-header Datums!
235 * Code that wants to use 1-byte-header values without detoasting should
236 * use VARSIZE_ANY/VARSIZE_ANY_EXHDR/VARDATA_ANY. The other macros here
237 * should usually be used only by tuple assembly/disassembly code and
238 * code that specifically wants to work with still-toasted Datums.
240 * WARNING: It is only safe to use VARDATA_ANY() -- typically with
241 * PG_DETOAST_DATUM_PACKED() -- if you really don't care about the alignment.
242 * Either because you're working with something like text where the alignment
243 * doesn't matter or because you're not going to access its constituent parts
244 * and just use things like memcpy on it anyways.
246 #define VARDATA(PTR) VARDATA_4B(PTR)
247 #define VARSIZE(PTR) VARSIZE_4B(PTR)
249 #define VARSIZE_SHORT(PTR) VARSIZE_1B(PTR)
250 #define VARDATA_SHORT(PTR) VARDATA_1B(PTR)
252 #define VARSIZE_EXTERNAL(PTR) VARSIZE_1B_E(PTR)
253 #define VARDATA_EXTERNAL(PTR) VARDATA_1B_E(PTR)
255 #define VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR)
256 #define VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR)
257 #define VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR)
258 #define VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR))
260 #define SET_VARSIZE(PTR, len) SET_VARSIZE_4B(PTR, len)
261 #define SET_VARSIZE_SHORT(PTR, len) SET_VARSIZE_1B(PTR, len)
262 #define SET_VARSIZE_COMPRESSED(PTR, len) SET_VARSIZE_4B_C(PTR, len)
263 #define SET_VARSIZE_EXTERNAL(PTR, len) SET_VARSIZE_1B_E(PTR, len)
265 #define VARSIZE_ANY(PTR) \
266 (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR) : \
267 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR) : \
270 #define VARSIZE_ANY_EXHDR(PTR) \
271 (VARATT_IS_1B_E(PTR) ? VARSIZE_1B_E(PTR)-VARHDRSZ_EXTERNAL : \
272 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR)-VARHDRSZ_SHORT : \
273 VARSIZE_4B(PTR)-VARHDRSZ))
275 /* caution: this will not work on an external or compressed-in-line Datum */
276 /* caution: this will return a possibly unaligned pointer */
277 #define VARDATA_ANY(PTR) \
278 (VARATT_IS_1B(PTR) ? VARDATA_1B(PTR) : VARDATA_4B(PTR))
281 /* ----------------------------------------------------------------
282 * Section 2: datum type + support macros
283 * ----------------------------------------------------------------
288 * Postgres makes the following assumptions about datatype sizes:
290 * sizeof(Datum) == sizeof(void *) == 4 or 8
294 * When a type narrower than Datum is stored in a Datum, we place it in the
295 * low-order bits and are careful that the DatumGetXXX macro for it discards
296 * the unused high-order bits (as opposed to, say, assuming they are zero).
297 * This is needed to support old-style user-defined functions, since depending
298 * on architecture and compiler, the return value of a function returning char
299 * or short may contain garbage when called as if it returned Datum.
302 typedef uintptr_t Datum;
304 #define SIZEOF_DATUM SIZEOF_VOID_P
306 typedef Datum *DatumPtr;
308 #define GET_1_BYTE(datum) (((Datum) (datum)) & 0x000000ff)
309 #define GET_2_BYTES(datum) (((Datum) (datum)) & 0x0000ffff)
310 #define GET_4_BYTES(datum) (((Datum) (datum)) & 0xffffffff)
311 #if SIZEOF_DATUM == 8
312 #define GET_8_BYTES(datum) ((Datum) (datum))
314 #define SET_1_BYTE(value) (((Datum) (value)) & 0x000000ff)
315 #define SET_2_BYTES(value) (((Datum) (value)) & 0x0000ffff)
316 #define SET_4_BYTES(value) (((Datum) (value)) & 0xffffffff)
317 #if SIZEOF_DATUM == 8
318 #define SET_8_BYTES(value) ((Datum) (value))
323 * Returns boolean value of a datum.
325 * Note: any nonzero value will be considered TRUE, but we ignore bits to
326 * the left of the width of bool, per comment above.
329 #define DatumGetBool(X) ((bool) (((bool) (X)) != 0))
333 * Returns datum representation for a boolean.
335 * Note: any nonzero value will be considered TRUE.
338 #define BoolGetDatum(X) ((Datum) ((X) ? 1 : 0))
342 * Returns character value of a datum.
345 #define DatumGetChar(X) ((char) GET_1_BYTE(X))
349 * Returns datum representation for a character.
352 #define CharGetDatum(X) ((Datum) SET_1_BYTE(X))
356 * Returns datum representation for an 8-bit integer.
359 #define Int8GetDatum(X) ((Datum) SET_1_BYTE(X))
363 * Returns 8-bit unsigned integer value of a datum.
366 #define DatumGetUInt8(X) ((uint8) GET_1_BYTE(X))
370 * Returns datum representation for an 8-bit unsigned integer.
373 #define UInt8GetDatum(X) ((Datum) SET_1_BYTE(X))
377 * Returns 16-bit integer value of a datum.
380 #define DatumGetInt16(X) ((int16) GET_2_BYTES(X))
384 * Returns datum representation for a 16-bit integer.
387 #define Int16GetDatum(X) ((Datum) SET_2_BYTES(X))
391 * Returns 16-bit unsigned integer value of a datum.
394 #define DatumGetUInt16(X) ((uint16) GET_2_BYTES(X))
398 * Returns datum representation for a 16-bit unsigned integer.
401 #define UInt16GetDatum(X) ((Datum) SET_2_BYTES(X))
405 * Returns 32-bit integer value of a datum.
408 #define DatumGetInt32(X) ((int32) GET_4_BYTES(X))
412 * Returns datum representation for a 32-bit integer.
415 #define Int32GetDatum(X) ((Datum) SET_4_BYTES(X))
419 * Returns 32-bit unsigned integer value of a datum.
422 #define DatumGetUInt32(X) ((uint32) GET_4_BYTES(X))
426 * Returns datum representation for a 32-bit unsigned integer.
429 #define UInt32GetDatum(X) ((Datum) SET_4_BYTES(X))
433 * Returns object identifier value of a datum.
436 #define DatumGetObjectId(X) ((Oid) GET_4_BYTES(X))
440 * Returns datum representation for an object identifier.
443 #define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X))
446 * DatumGetTransactionId
447 * Returns transaction identifier value of a datum.
450 #define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X))
453 * TransactionIdGetDatum
454 * Returns datum representation for a transaction identifier.
457 #define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X)))
461 * Returns command identifier value of a datum.
464 #define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X))
468 * Returns datum representation for a command identifier.
471 #define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X))
475 * Returns pointer value of a datum.
478 #define DatumGetPointer(X) ((Pointer) (X))
482 * Returns datum representation for a pointer.
485 #define PointerGetDatum(X) ((Datum) (X))
489 * Returns C string (null-terminated string) value of a datum.
491 * Note: C string is not a full-fledged Postgres type at present,
492 * but type input functions use this conversion for their inputs.
495 #define DatumGetCString(X) ((char *) DatumGetPointer(X))
499 * Returns datum representation for a C string (null-terminated string).
501 * Note: C string is not a full-fledged Postgres type at present,
502 * but type output functions use this conversion for their outputs.
503 * Note: CString is pass-by-reference; caller must ensure the pointed-to
504 * value has adequate lifetime.
507 #define CStringGetDatum(X) PointerGetDatum(X)
511 * Returns name value of a datum.
514 #define DatumGetName(X) ((Name) DatumGetPointer(X))
518 * Returns datum representation for a name.
520 * Note: Name is pass-by-reference; caller must ensure the pointed-to
521 * value has adequate lifetime.
524 #define NameGetDatum(X) PointerGetDatum(X)
528 * Returns 64-bit integer value of a datum.
530 * Note: this macro hides whether int64 is pass by value or by reference.
533 #ifdef USE_FLOAT8_BYVAL
534 #define DatumGetInt64(X) ((int64) GET_8_BYTES(X))
536 #define DatumGetInt64(X) (* ((int64 *) DatumGetPointer(X)))
541 * Returns datum representation for a 64-bit integer.
543 * Note: if int64 is pass by reference, this function returns a reference
547 #ifdef USE_FLOAT8_BYVAL
548 #define Int64GetDatum(X) ((Datum) SET_8_BYTES(X))
550 extern Datum Int64GetDatum(int64 X);
555 * Returns 4-byte floating point value of a datum.
557 * Note: this macro hides whether float4 is pass by value or by reference.
560 #ifdef USE_FLOAT4_BYVAL
561 extern float4 DatumGetFloat4(Datum X);
563 #define DatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X)))
568 * Returns datum representation for a 4-byte floating point number.
570 * Note: if float4 is pass by reference, this function returns a reference
574 extern Datum Float4GetDatum(float4 X);
578 * Returns 8-byte floating point value of a datum.
580 * Note: this macro hides whether float8 is pass by value or by reference.
583 #ifdef USE_FLOAT8_BYVAL
584 extern float8 DatumGetFloat8(Datum X);
586 #define DatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X)))
591 * Returns datum representation for an 8-byte floating point number.
593 * Note: if float8 is pass by reference, this function returns a reference
597 extern Datum Float8GetDatum(float8 X);
605 * These macros are intended to allow writing code that does not depend on
606 * whether int64, float8, float4 are pass-by-reference types, while not
607 * sacrificing performance when they are. The argument must be a variable
608 * that will exist and have the same value for as long as the Datum is needed.
609 * In the pass-by-ref case, the address of the variable is taken to use as
610 * the Datum. In the pass-by-val case, these will be the same as the non-Fast
614 #ifdef USE_FLOAT8_BYVAL
615 #define Int64GetDatumFast(X) Int64GetDatum(X)
616 #define Float8GetDatumFast(X) Float8GetDatum(X)
618 #define Int64GetDatumFast(X) PointerGetDatum(&(X))
619 #define Float8GetDatumFast(X) PointerGetDatum(&(X))
622 #ifdef USE_FLOAT4_BYVAL
623 #define Float4GetDatumFast(X) Float4GetDatum(X)
625 #define Float4GetDatumFast(X) PointerGetDatum(&(X))
629 /* ----------------------------------------------------------------
630 * Section 3: exception handling definitions
631 * Assert, Trap, etc macros
632 * ----------------------------------------------------------------
635 extern PGDLLIMPORT bool assert_enabled;
638 * USE_ASSERT_CHECKING, if defined, turns on all the assertions.
641 * It should _NOT_ be defined in releases or in benchmark copies
646 * Generates an exception if the given condition is true.
648 #define Trap(condition, errorType) \
650 if ((assert_enabled) && (condition)) \
651 ExceptionalCondition(CppAsString(condition), (errorType), \
652 __FILE__, __LINE__); \
656 * TrapMacro is the same as Trap but it's intended for use in macros:
658 * #define foo(x) (AssertMacro(x != 0), bar(x))
662 #define TrapMacro(condition, errorType) \
663 ((bool) ((! assert_enabled) || ! (condition) || \
664 (ExceptionalCondition(CppAsString(condition), (errorType), \
665 __FILE__, __LINE__), 0)))
667 #ifndef USE_ASSERT_CHECKING
668 #define Assert(condition)
669 #define AssertMacro(condition) ((void)true)
670 #define AssertArg(condition)
671 #define AssertState(condition)
673 #define Assert(condition) \
674 Trap(!(condition), "FailedAssertion")
676 #define AssertMacro(condition) \
677 ((void) TrapMacro(!(condition), "FailedAssertion"))
679 #define AssertArg(condition) \
680 Trap(!(condition), "BadArgument")
682 #define AssertState(condition) \
683 Trap(!(condition), "BadState")
684 #endif /* USE_ASSERT_CHECKING */
686 extern void ExceptionalCondition(const char *conditionName,
687 const char *errorType,
688 const char *fileName, int lineNumber) __attribute__((noreturn));
690 #endif /* POSTGRES_H */