1 /*------------------------------------------------------------------------- 2 * 3 * postgres.h 4 * Primary include file for PostgreSQL server .c files 5 * 6 * This should be the first file included by PostgreSQL backend modules. 7 * Client-side code should include postgres_fe.h instead. 8 * 9 * 10 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group 11 * Portions Copyright (c) 1995, Regents of the University of California 12 * 13 * src/include/postgres.h 14 * 15 *------------------------------------------------------------------------- 16 */ 17 /* 18 *---------------------------------------------------------------- 19 * TABLE OF CONTENTS 20 * 21 * When adding stuff to this file, please try to put stuff 22 * into the relevant section, or add new sections as appropriate. 23 * 24 * section description 25 * ------- ------------------------------------------------ 26 * 1) variable-length datatypes (TOAST support) 27 * 2) datum type + support macros 28 * 3) exception handling backend support 29 * 30 * NOTES 31 * 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. 34 * 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. 41 * 42 *---------------------------------------------------------------- 43 */ 44 #ifndef POSTGRES_H 45 #define POSTGRES_H 46 47 #include "c.h" 48 #include "utils/elog.h" 49 #include "utils/palloc.h" 50 51 /* ---------------------------------------------------------------- 52 * Section 1: variable-length datatypes (TOAST support) 53 * ---------------------------------------------------------------- 54 */ 55 56 /* 57 * struct varatt_external is a traditional "TOAST pointer", that is, the 58 * information needed to fetch a Datum stored out-of-line in a TOAST table. 59 * The data is compressed if and only if va_extsize < va_rawsize - VARHDRSZ. 60 * This struct must not contain any padding, because we sometimes compare 61 * these pointers using memcmp. 62 * 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...) 67 */ 68 typedef struct varatt_external 69 { 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 */ 74 } varatt_external; 75 76 /* 77 * struct varatt_indirect is a "TOAST pointer" representing an out-of-line 78 * Datum that's stored in memory, not in an external toast relation. 79 * The creator of such a Datum is entirely responsible that the referenced 80 * storage survives for as long as referencing pointer Datums can exist. 81 * 82 * Note that just as for struct varatt_external, this struct is stored 83 * unaligned within any containing tuple. 84 */ 85 typedef struct varatt_indirect 86 { 87 struct varlena *pointer; /* Pointer to in-memory varlena */ 88 } varatt_indirect; 89 90 /* 91 * struct varatt_expanded is a "TOAST pointer" representing an out-of-line 92 * Datum that is stored in memory, in some type-specific, not necessarily 93 * physically contiguous format that is convenient for computation not 94 * storage. APIs for this, in particular the definition of struct 95 * ExpandedObjectHeader, are in src/include/utils/expandeddatum.h. 96 * 97 * Note that just as for struct varatt_external, this struct is stored 98 * unaligned within any containing tuple. 99 */ 100 typedef struct ExpandedObjectHeader ExpandedObjectHeader; 101 102 typedef struct varatt_expanded 103 { 104 ExpandedObjectHeader *eohptr; 105 } varatt_expanded; 106 107 /* 108 * Type tag for the various sorts of "TOAST pointer" datums. The peculiar 109 * value for VARTAG_ONDISK comes from a requirement for on-disk compatibility 110 * with a previous notion that the tag field was the pointer datum's length. 111 */ 112 typedef enum vartag_external 113 { 114 VARTAG_INDIRECT = 1, 115 VARTAG_EXPANDED_RO = 2, 116 VARTAG_EXPANDED_RW = 3, 117 VARTAG_ONDISK = 18 118 } vartag_external; 119 120 /* this test relies on the specific tag values above */ 121 #define VARTAG_IS_EXPANDED(tag) \ 122 (((tag) & ~1) == VARTAG_EXPANDED_RO) 123 124 #define VARTAG_SIZE(tag) \ 125 ((tag) == VARTAG_INDIRECT ? sizeof(varatt_indirect) : \ 126 VARTAG_IS_EXPANDED(tag) ? sizeof(varatt_expanded) : \ 127 (tag) == VARTAG_ONDISK ? sizeof(varatt_external) : \ 128 TrapMacro(true, "unrecognized TOAST vartag")) 129 130 /* 131 * These structs describe the header of a varlena object that may have been 132 * TOASTed. Generally, don't reference these structs directly, but use the 133 * macros below. 134 * 135 * We use separate structs for the aligned and unaligned cases because the 136 * compiler might otherwise think it could generate code that assumes 137 * alignment while touching fields of a 1-byte-header varlena. 138 */ 139 typedef union 140 { 141 struct /* Normal varlena (4-byte length) */ 142 { 143 uint32 va_header; 144 char va_data[FLEXIBLE_ARRAY_MEMBER]; 145 } va_4byte; 146 struct /* Compressed-in-line format */ 147 { 148 uint32 va_header; 149 uint32 va_rawsize; /* Original data size (excludes header) */ 150 char va_data[FLEXIBLE_ARRAY_MEMBER]; /* Compressed data */ 151 } va_compressed; 152 } varattrib_4b; 153 154 typedef struct 155 { 156 uint8 va_header; 157 char va_data[FLEXIBLE_ARRAY_MEMBER]; /* Data begins here */ 158 } varattrib_1b; 159 160 /* TOAST pointers are a subset of varattrib_1b with an identifying tag byte */ 161 typedef struct 162 { 163 uint8 va_header; /* Always 0x80 or 0x01 */ 164 uint8 va_tag; /* Type of datum */ 165 char va_data[FLEXIBLE_ARRAY_MEMBER]; /* Type-specific data */ 166 } varattrib_1b_e; 167 168 /* 169 * Bit layouts for varlena headers on big-endian machines: 170 * 171 * 00xxxxxx 4-byte length word, aligned, uncompressed data (up to 1G) 172 * 01xxxxxx 4-byte length word, aligned, *compressed* data (up to 1G) 173 * 10000000 1-byte length word, unaligned, TOAST pointer 174 * 1xxxxxxx 1-byte length word, unaligned, uncompressed data (up to 126b) 175 * 176 * Bit layouts for varlena headers on little-endian machines: 177 * 178 * xxxxxx00 4-byte length word, aligned, uncompressed data (up to 1G) 179 * xxxxxx10 4-byte length word, aligned, *compressed* data (up to 1G) 180 * 00000001 1-byte length word, unaligned, TOAST pointer 181 * xxxxxxx1 1-byte length word, unaligned, uncompressed data (up to 126b) 182 * 183 * The "xxx" bits are the length field (which includes itself in all cases). 184 * In the big-endian case we mask to extract the length, in the little-endian 185 * case we shift. Note that in both cases the flag bits are in the physically 186 * first byte. Also, it is not possible for a 1-byte length word to be zero; 187 * this lets us disambiguate alignment padding bytes from the start of an 188 * unaligned datum. (We now *require* pad bytes to be filled with zero!) 189 * 190 * In TOAST pointers the va_tag field (see varattrib_1b_e) is used to discern 191 * the specific type and length of the pointer datum. 192 */ 193 194 /* 195 * Endian-dependent macros. These are considered internal --- use the 196 * external macros below instead of using these directly. 197 * 198 * Note: IS_1B is true for external toast records but VARSIZE_1B will return 0 199 * for such records. Hence you should usually check for IS_EXTERNAL before 200 * checking for IS_1B. 201 */ 202 203 #ifdef WORDS_BIGENDIAN 204 205 #define VARATT_IS_4B(PTR) \ 206 ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x00) 207 #define VARATT_IS_4B_U(PTR) \ 208 ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x00) 209 #define VARATT_IS_4B_C(PTR) \ 210 ((((varattrib_1b *) (PTR))->va_header & 0xC0) == 0x40) 211 #define VARATT_IS_1B(PTR) \ 212 ((((varattrib_1b *) (PTR))->va_header & 0x80) == 0x80) 213 #define VARATT_IS_1B_E(PTR) \ 214 ((((varattrib_1b *) (PTR))->va_header) == 0x80) 215 #define VARATT_NOT_PAD_BYTE(PTR) \ 216 (*((uint8 *) (PTR)) != 0) 217 218 /* VARSIZE_4B() should only be used on known-aligned data */ 219 #define VARSIZE_4B(PTR) \ 220 (((varattrib_4b *) (PTR))->va_4byte.va_header & 0x3FFFFFFF) 221 #define VARSIZE_1B(PTR) \ 222 (((varattrib_1b *) (PTR))->va_header & 0x7F) 223 #define VARTAG_1B_E(PTR) \ 224 (((varattrib_1b_e *) (PTR))->va_tag) 225 226 #define SET_VARSIZE_4B(PTR,len) \ 227 (((varattrib_4b *) (PTR))->va_4byte.va_header = (len) & 0x3FFFFFFF) 228 #define SET_VARSIZE_4B_C(PTR,len) \ 229 (((varattrib_4b *) (PTR))->va_4byte.va_header = ((len) & 0x3FFFFFFF) | 0x40000000) 230 #define SET_VARSIZE_1B(PTR,len) \ 231 (((varattrib_1b *) (PTR))->va_header = (len) | 0x80) 232 #define SET_VARTAG_1B_E(PTR,tag) \ 233 (((varattrib_1b_e *) (PTR))->va_header = 0x80, \ 234 ((varattrib_1b_e *) (PTR))->va_tag = (tag)) 235 #else /* !WORDS_BIGENDIAN */ 236 237 #define VARATT_IS_4B(PTR) \ 238 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x00) 239 #define VARATT_IS_4B_U(PTR) \ 240 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x00) 241 #define VARATT_IS_4B_C(PTR) \ 242 ((((varattrib_1b *) (PTR))->va_header & 0x03) == 0x02) 243 #define VARATT_IS_1B(PTR) \ 244 ((((varattrib_1b *) (PTR))->va_header & 0x01) == 0x01) 245 #define VARATT_IS_1B_E(PTR) \ 246 ((((varattrib_1b *) (PTR))->va_header) == 0x01) 247 #define VARATT_NOT_PAD_BYTE(PTR) \ 248 (*((uint8 *) (PTR)) != 0) 249 250 /* VARSIZE_4B() should only be used on known-aligned data */ 251 #define VARSIZE_4B(PTR) \ 252 ((((varattrib_4b *) (PTR))->va_4byte.va_header >> 2) & 0x3FFFFFFF) 253 #define VARSIZE_1B(PTR) \ 254 ((((varattrib_1b *) (PTR))->va_header >> 1) & 0x7F) 255 #define VARTAG_1B_E(PTR) \ 256 (((varattrib_1b_e *) (PTR))->va_tag) 257 258 #define SET_VARSIZE_4B(PTR,len) \ 259 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2)) 260 #define SET_VARSIZE_4B_C(PTR,len) \ 261 (((varattrib_4b *) (PTR))->va_4byte.va_header = (((uint32) (len)) << 2) | 0x02) 262 #define SET_VARSIZE_1B(PTR,len) \ 263 (((varattrib_1b *) (PTR))->va_header = (((uint8) (len)) << 1) | 0x01) 264 #define SET_VARTAG_1B_E(PTR,tag) \ 265 (((varattrib_1b_e *) (PTR))->va_header = 0x01, \ 266 ((varattrib_1b_e *) (PTR))->va_tag = (tag)) 267 #endif /* WORDS_BIGENDIAN */ 268 269 #define VARHDRSZ_SHORT offsetof(varattrib_1b, va_data) 270 #define VARATT_SHORT_MAX 0x7F 271 #define VARATT_CAN_MAKE_SHORT(PTR) \ 272 (VARATT_IS_4B_U(PTR) && \ 273 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) <= VARATT_SHORT_MAX) 274 #define VARATT_CONVERTED_SHORT_SIZE(PTR) \ 275 (VARSIZE(PTR) - VARHDRSZ + VARHDRSZ_SHORT) 276 277 #define VARHDRSZ_EXTERNAL offsetof(varattrib_1b_e, va_data) 278 279 #define VARDATA_4B(PTR) (((varattrib_4b *) (PTR))->va_4byte.va_data) 280 #define VARDATA_4B_C(PTR) (((varattrib_4b *) (PTR))->va_compressed.va_data) 281 #define VARDATA_1B(PTR) (((varattrib_1b *) (PTR))->va_data) 282 #define VARDATA_1B_E(PTR) (((varattrib_1b_e *) (PTR))->va_data) 283 284 #define VARRAWSIZE_4B_C(PTR) \ 285 (((varattrib_4b *) (PTR))->va_compressed.va_rawsize) 286 287 /* Externally visible macros */ 288 289 /* 290 * VARDATA, VARSIZE, and SET_VARSIZE are the recommended API for most code 291 * for varlena datatypes. Note that they only work on untoasted, 292 * 4-byte-header Datums! 293 * 294 * Code that wants to use 1-byte-header values without detoasting should 295 * use VARSIZE_ANY/VARSIZE_ANY_EXHDR/VARDATA_ANY. The other macros here 296 * should usually be used only by tuple assembly/disassembly code and 297 * code that specifically wants to work with still-toasted Datums. 298 * 299 * WARNING: It is only safe to use VARDATA_ANY() -- typically with 300 * PG_DETOAST_DATUM_PACKED() -- if you really don't care about the alignment. 301 * Either because you're working with something like text where the alignment 302 * doesn't matter or because you're not going to access its constituent parts 303 * and just use things like memcpy on it anyways. 304 */ 305 #define VARDATA(PTR) VARDATA_4B(PTR) 306 #define VARSIZE(PTR) VARSIZE_4B(PTR) 307 308 #define VARSIZE_SHORT(PTR) VARSIZE_1B(PTR) 309 #define VARDATA_SHORT(PTR) VARDATA_1B(PTR) 310 311 #define VARTAG_EXTERNAL(PTR) VARTAG_1B_E(PTR) 312 #define VARSIZE_EXTERNAL(PTR) (VARHDRSZ_EXTERNAL + VARTAG_SIZE(VARTAG_EXTERNAL(PTR))) 313 #define VARDATA_EXTERNAL(PTR) VARDATA_1B_E(PTR) 314 315 #define VARATT_IS_COMPRESSED(PTR) VARATT_IS_4B_C(PTR) 316 #define VARATT_IS_EXTERNAL(PTR) VARATT_IS_1B_E(PTR) 317 #define VARATT_IS_EXTERNAL_ONDISK(PTR) \ 318 (VARATT_IS_EXTERNAL(PTR) && VARTAG_EXTERNAL(PTR) == VARTAG_ONDISK) 319 #define VARATT_IS_EXTERNAL_INDIRECT(PTR) \ 320 (VARATT_IS_EXTERNAL(PTR) && VARTAG_EXTERNAL(PTR) == VARTAG_INDIRECT) 321 #define VARATT_IS_EXTERNAL_EXPANDED_RO(PTR) \ 322 (VARATT_IS_EXTERNAL(PTR) && VARTAG_EXTERNAL(PTR) == VARTAG_EXPANDED_RO) 323 #define VARATT_IS_EXTERNAL_EXPANDED_RW(PTR) \ 324 (VARATT_IS_EXTERNAL(PTR) && VARTAG_EXTERNAL(PTR) == VARTAG_EXPANDED_RW) 325 #define VARATT_IS_EXTERNAL_EXPANDED(PTR) \ 326 (VARATT_IS_EXTERNAL(PTR) && VARTAG_IS_EXPANDED(VARTAG_EXTERNAL(PTR))) 327 #define VARATT_IS_SHORT(PTR) VARATT_IS_1B(PTR) 328 #define VARATT_IS_EXTENDED(PTR) (!VARATT_IS_4B_U(PTR)) 329 330 #define SET_VARSIZE(PTR, len) SET_VARSIZE_4B(PTR, len) 331 #define SET_VARSIZE_SHORT(PTR, len) SET_VARSIZE_1B(PTR, len) 332 #define SET_VARSIZE_COMPRESSED(PTR, len) SET_VARSIZE_4B_C(PTR, len) 333 334 #define SET_VARTAG_EXTERNAL(PTR, tag) SET_VARTAG_1B_E(PTR, tag) 335 336 #define VARSIZE_ANY(PTR) \ 337 (VARATT_IS_1B_E(PTR) ? VARSIZE_EXTERNAL(PTR) : \ 338 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR) : \ 339 VARSIZE_4B(PTR))) 340 341 /* Size of a varlena data, excluding header */ 342 #define VARSIZE_ANY_EXHDR(PTR) \ 343 (VARATT_IS_1B_E(PTR) ? VARSIZE_EXTERNAL(PTR)-VARHDRSZ_EXTERNAL : \ 344 (VARATT_IS_1B(PTR) ? VARSIZE_1B(PTR)-VARHDRSZ_SHORT : \ 345 VARSIZE_4B(PTR)-VARHDRSZ)) 346 347 /* caution: this will not work on an external or compressed-in-line Datum */ 348 /* caution: this will return a possibly unaligned pointer */ 349 #define VARDATA_ANY(PTR) \ 350 (VARATT_IS_1B(PTR) ? VARDATA_1B(PTR) : VARDATA_4B(PTR)) 351 352 353 /* ---------------------------------------------------------------- 354 * Section 2: datum type + support macros 355 * ---------------------------------------------------------------- 356 */ 357 358 /* 359 * Port Notes: 360 * Postgres makes the following assumptions about datatype sizes: 361 * 362 * sizeof(Datum) == sizeof(void *) == 4 or 8 363 * sizeof(char) == 1 364 * sizeof(short) == 2 365 * 366 * When a type narrower than Datum is stored in a Datum, we place it in the 367 * low-order bits and are careful that the DatumGetXXX macro for it discards 368 * the unused high-order bits (as opposed to, say, assuming they are zero). 369 * This is needed to support old-style user-defined functions, since depending 370 * on architecture and compiler, the return value of a function returning char 371 * or short may contain garbage when called as if it returned Datum. 372 */ 373 374 typedef uintptr_t Datum; 375 376 #define SIZEOF_DATUM SIZEOF_VOID_P 377 378 typedef Datum *DatumPtr; 379 380 #define GET_1_BYTE(datum) (((Datum) (datum)) & 0x000000ff) 381 #define GET_2_BYTES(datum) (((Datum) (datum)) & 0x0000ffff) 382 #define GET_4_BYTES(datum) (((Datum) (datum)) & 0xffffffff) 383 #if SIZEOF_DATUM == 8 384 #define GET_8_BYTES(datum) ((Datum) (datum)) 385 #endif 386 #define SET_1_BYTE(value) (((Datum) (value)) & 0x000000ff) 387 #define SET_2_BYTES(value) (((Datum) (value)) & 0x0000ffff) 388 #define SET_4_BYTES(value) (((Datum) (value)) & 0xffffffff) 389 #if SIZEOF_DATUM == 8 390 #define SET_8_BYTES(value) ((Datum) (value)) 391 #endif 392 393 /* 394 * DatumGetBool 395 * Returns boolean value of a datum. 396 * 397 * Note: any nonzero value will be considered TRUE, but we ignore bits to 398 * the left of the width of bool, per comment above. 399 */ 400 401 #define DatumGetBool(X) ((bool) (GET_1_BYTE(X) != 0)) 402 403 /* 404 * BoolGetDatum 405 * Returns datum representation for a boolean. 406 * 407 * Note: any nonzero value will be considered TRUE. 408 */ 409 410 #define BoolGetDatum(X) ((Datum) ((X) ? 1 : 0)) 411 412 /* 413 * DatumGetChar 414 * Returns character value of a datum. 415 */ 416 417 #define DatumGetChar(X) ((char) GET_1_BYTE(X)) 418 419 /* 420 * CharGetDatum 421 * Returns datum representation for a character. 422 */ 423 424 #define CharGetDatum(X) ((Datum) SET_1_BYTE(X)) 425 426 /* 427 * Int8GetDatum 428 * Returns datum representation for an 8-bit integer. 429 */ 430 431 #define Int8GetDatum(X) ((Datum) SET_1_BYTE(X)) 432 433 /* 434 * DatumGetUInt8 435 * Returns 8-bit unsigned integer value of a datum. 436 */ 437 438 #define DatumGetUInt8(X) ((uint8) GET_1_BYTE(X)) 439 440 /* 441 * UInt8GetDatum 442 * Returns datum representation for an 8-bit unsigned integer. 443 */ 444 445 #define UInt8GetDatum(X) ((Datum) SET_1_BYTE(X)) 446 447 /* 448 * DatumGetInt16 449 * Returns 16-bit integer value of a datum. 450 */ 451 452 #define DatumGetInt16(X) ((int16) GET_2_BYTES(X)) 453 454 /* 455 * Int16GetDatum 456 * Returns datum representation for a 16-bit integer. 457 */ 458 459 #define Int16GetDatum(X) ((Datum) SET_2_BYTES(X)) 460 461 /* 462 * DatumGetUInt16 463 * Returns 16-bit unsigned integer value of a datum. 464 */ 465 466 #define DatumGetUInt16(X) ((uint16) GET_2_BYTES(X)) 467 468 /* 469 * UInt16GetDatum 470 * Returns datum representation for a 16-bit unsigned integer. 471 */ 472 473 #define UInt16GetDatum(X) ((Datum) SET_2_BYTES(X)) 474 475 /* 476 * DatumGetInt32 477 * Returns 32-bit integer value of a datum. 478 */ 479 480 #define DatumGetInt32(X) ((int32) GET_4_BYTES(X)) 481 482 /* 483 * Int32GetDatum 484 * Returns datum representation for a 32-bit integer. 485 */ 486 487 #define Int32GetDatum(X) ((Datum) SET_4_BYTES(X)) 488 489 /* 490 * DatumGetUInt32 491 * Returns 32-bit unsigned integer value of a datum. 492 */ 493 494 #define DatumGetUInt32(X) ((uint32) GET_4_BYTES(X)) 495 496 /* 497 * UInt32GetDatum 498 * Returns datum representation for a 32-bit unsigned integer. 499 */ 500 501 #define UInt32GetDatum(X) ((Datum) SET_4_BYTES(X)) 502 503 /* 504 * DatumGetObjectId 505 * Returns object identifier value of a datum. 506 */ 507 508 #define DatumGetObjectId(X) ((Oid) GET_4_BYTES(X)) 509 510 /* 511 * ObjectIdGetDatum 512 * Returns datum representation for an object identifier. 513 */ 514 515 #define ObjectIdGetDatum(X) ((Datum) SET_4_BYTES(X)) 516 517 /* 518 * DatumGetTransactionId 519 * Returns transaction identifier value of a datum. 520 */ 521 522 #define DatumGetTransactionId(X) ((TransactionId) GET_4_BYTES(X)) 523 524 /* 525 * TransactionIdGetDatum 526 * Returns datum representation for a transaction identifier. 527 */ 528 529 #define TransactionIdGetDatum(X) ((Datum) SET_4_BYTES((X))) 530 531 /* 532 * MultiXactIdGetDatum 533 * Returns datum representation for a multixact identifier. 534 */ 535 536 #define MultiXactIdGetDatum(X) ((Datum) SET_4_BYTES((X))) 537 538 /* 539 * DatumGetCommandId 540 * Returns command identifier value of a datum. 541 */ 542 543 #define DatumGetCommandId(X) ((CommandId) GET_4_BYTES(X)) 544 545 /* 546 * CommandIdGetDatum 547 * Returns datum representation for a command identifier. 548 */ 549 550 #define CommandIdGetDatum(X) ((Datum) SET_4_BYTES(X)) 551 552 /* 553 * DatumGetPointer 554 * Returns pointer value of a datum. 555 */ 556 557 #define DatumGetPointer(X) ((Pointer) (X)) 558 559 /* 560 * PointerGetDatum 561 * Returns datum representation for a pointer. 562 */ 563 564 #define PointerGetDatum(X) ((Datum) (X)) 565 566 /* 567 * DatumGetCString 568 * Returns C string (null-terminated string) value of a datum. 569 * 570 * Note: C string is not a full-fledged Postgres type at present, 571 * but type input functions use this conversion for their inputs. 572 */ 573 574 #define DatumGetCString(X) ((char *) DatumGetPointer(X)) 575 576 /* 577 * CStringGetDatum 578 * Returns datum representation for a C string (null-terminated string). 579 * 580 * Note: C string is not a full-fledged Postgres type at present, 581 * but type output functions use this conversion for their outputs. 582 * Note: CString is pass-by-reference; caller must ensure the pointed-to 583 * value has adequate lifetime. 584 */ 585 586 #define CStringGetDatum(X) PointerGetDatum(X) 587 588 /* 589 * DatumGetName 590 * Returns name value of a datum. 591 */ 592 593 #define DatumGetName(X) ((Name) DatumGetPointer(X)) 594 595 /* 596 * NameGetDatum 597 * Returns datum representation for a name. 598 * 599 * Note: Name is pass-by-reference; caller must ensure the pointed-to 600 * value has adequate lifetime. 601 */ 602 603 #define NameGetDatum(X) PointerGetDatum(X) 604 605 /* 606 * DatumGetInt64 607 * Returns 64-bit integer value of a datum. 608 * 609 * Note: this macro hides whether int64 is pass by value or by reference. 610 */ 611 612 #ifdef USE_FLOAT8_BYVAL 613 #define DatumGetInt64(X) ((int64) GET_8_BYTES(X)) 614 #else 615 #define DatumGetInt64(X) (* ((int64 *) DatumGetPointer(X))) 616 #endif 617 618 /* 619 * Int64GetDatum 620 * Returns datum representation for a 64-bit integer. 621 * 622 * Note: if int64 is pass by reference, this function returns a reference 623 * to palloc'd space. 624 */ 625 626 #ifdef USE_FLOAT8_BYVAL 627 #define Int64GetDatum(X) ((Datum) SET_8_BYTES(X)) 628 #else 629 extern Datum Int64GetDatum(int64 X); 630 #endif 631 632 /* 633 * DatumGetUInt64 634 * Returns 64-bit unsigned integer value of a datum. 635 * 636 * Note: this macro hides whether int64 is pass by value or by reference. 637 */ 638 639 #ifdef USE_FLOAT8_BYVAL 640 #define DatumGetUInt64(X) ((uint64) GET_8_BYTES(X)) 641 #else 642 #define DatumGetUInt64(X) (* ((uint64 *) DatumGetPointer(X))) 643 #endif 644 645 /* 646 * UInt64GetDatum 647 * Returns datum representation for a 64-bit unsigned integer. 648 * 649 * Note: if int64 is pass by reference, this function returns a reference 650 * to palloc'd space. 651 */ 652 653 #ifdef USE_FLOAT8_BYVAL 654 #define UInt64GetDatum(X) ((Datum) SET_8_BYTES(X)) 655 #else 656 #define UInt64GetDatum(X) Int64GetDatum((int64) (X)) 657 #endif 658 659 /* 660 * DatumGetFloat4 661 * Returns 4-byte floating point value of a datum. 662 * 663 * Note: this macro hides whether float4 is pass by value or by reference. 664 */ 665 666 #ifdef USE_FLOAT4_BYVAL 667 extern float4 DatumGetFloat4(Datum X); 668 #else 669 #define DatumGetFloat4(X) (* ((float4 *) DatumGetPointer(X))) 670 #endif 671 672 /* 673 * Float4GetDatum 674 * Returns datum representation for a 4-byte floating point number. 675 * 676 * Note: if float4 is pass by reference, this function returns a reference 677 * to palloc'd space. 678 */ 679 680 extern Datum Float4GetDatum(float4 X); 681 682 /* 683 * DatumGetFloat8 684 * Returns 8-byte floating point value of a datum. 685 * 686 * Note: this macro hides whether float8 is pass by value or by reference. 687 */ 688 689 #ifdef USE_FLOAT8_BYVAL 690 extern float8 DatumGetFloat8(Datum X); 691 #else 692 #define DatumGetFloat8(X) (* ((float8 *) DatumGetPointer(X))) 693 #endif 694 695 /* 696 * Float8GetDatum 697 * Returns datum representation for an 8-byte floating point number. 698 * 699 * Note: if float8 is pass by reference, this function returns a reference 700 * to palloc'd space. 701 */ 702 703 extern Datum Float8GetDatum(float8 X); 704 705 706 /* 707 * Int64GetDatumFast 708 * Float8GetDatumFast 709 * Float4GetDatumFast 710 * 711 * These macros are intended to allow writing code that does not depend on 712 * whether int64, float8, float4 are pass-by-reference types, while not 713 * sacrificing performance when they are. The argument must be a variable 714 * that will exist and have the same value for as long as the Datum is needed. 715 * In the pass-by-ref case, the address of the variable is taken to use as 716 * the Datum. In the pass-by-val case, these will be the same as the non-Fast 717 * macros. 718 */ 719 720 #ifdef USE_FLOAT8_BYVAL 721 #define Int64GetDatumFast(X) Int64GetDatum(X) 722 #define Float8GetDatumFast(X) Float8GetDatum(X) 723 #else 724 #define Int64GetDatumFast(X) PointerGetDatum(&(X)) 725 #define Float8GetDatumFast(X) PointerGetDatum(&(X)) 726 #endif 727 728 #ifdef USE_FLOAT4_BYVAL 729 #define Float4GetDatumFast(X) Float4GetDatum(X) 730 #else 731 #define Float4GetDatumFast(X) PointerGetDatum(&(X)) 732 #endif 733 734 735 /* ---------------------------------------------------------------- 736 * Section 3: exception handling backend support 737 * ---------------------------------------------------------------- 738 */ 739 740 /* 741 * Backend only infrastructure for the assertion-related macros in c.h. 742 * 743 * ExceptionalCondition must be present even when assertions are not enabled. 744 */ 745 extern void ExceptionalCondition(const char *conditionName, 746 const char *errorType, 747 const char *fileName, int lineNumber) pg_attribute_noreturn(); 748 749 #endif /* POSTGRES_H */ 750