1 /*------------------------------------------------------------------------- 2 * 3 * array.h 4 * Declarations for Postgres arrays. 5 * 6 * A standard varlena array has the following internal structure: 7 * <vl_len_> - standard varlena header word 8 * <ndim> - number of dimensions of the array 9 * <dataoffset> - offset to stored data, or 0 if no nulls bitmap 10 * <elemtype> - element type OID 11 * <dimensions> - length of each array axis (C array of int) 12 * <lower bnds> - lower boundary of each dimension (C array of int) 13 * <null bitmap> - bitmap showing locations of nulls (OPTIONAL) 14 * <actual data> - whatever is the stored data 15 * 16 * The <dimensions> and <lower bnds> arrays each have ndim elements. 17 * 18 * The <null bitmap> may be omitted if the array contains no NULL elements. 19 * If it is absent, the <dataoffset> field is zero and the offset to the 20 * stored data must be computed on-the-fly. If the bitmap is present, 21 * <dataoffset> is nonzero and is equal to the offset from the array start 22 * to the first data element (including any alignment padding). The bitmap 23 * follows the same conventions as tuple null bitmaps, ie, a 1 indicates 24 * a non-null entry and the LSB of each bitmap byte is used first. 25 * 26 * The actual data starts on a MAXALIGN boundary. Individual items in the 27 * array are aligned as specified by the array element type. They are 28 * stored in row-major order (last subscript varies most rapidly). 29 * 30 * NOTE: it is important that array elements of toastable datatypes NOT be 31 * toasted, since the tupletoaster won't know they are there. (We could 32 * support compressed toasted items; only out-of-line items are dangerous. 33 * However, it seems preferable to store such items uncompressed and allow 34 * the toaster to compress the whole array as one input.) 35 * 36 * 37 * The OIDVECTOR and INT2VECTOR datatypes are storage-compatible with 38 * generic arrays, but they support only one-dimensional arrays with no 39 * nulls (and no null bitmap). They don't support being toasted, either. 40 * 41 * There are also some "fixed-length array" datatypes, such as NAME and 42 * POINT. These are simply a sequence of a fixed number of items each 43 * of a fixed-length datatype, with no overhead; the item size must be 44 * a multiple of its alignment requirement, because we do no padding. 45 * We support subscripting on these types, but array_in() and array_out() 46 * only work with varlena arrays. 47 * 48 * In addition, arrays are a major user of the "expanded object" TOAST 49 * infrastructure. This allows a varlena array to be converted to a 50 * separate representation that may include "deconstructed" Datum/isnull 51 * arrays holding the elements. 52 * 53 * 54 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group 55 * Portions Copyright (c) 1994, Regents of the University of California 56 * 57 * src/include/utils/array.h 58 * 59 *------------------------------------------------------------------------- 60 */ 61 #ifndef ARRAY_H 62 #define ARRAY_H 63 64 #include "fmgr.h" 65 #include "utils/expandeddatum.h" 66 67 /* avoid including execnodes.h here */ 68 struct ExprState; 69 struct ExprContext; 70 71 72 /* 73 * Maximum number of array subscripts (arbitrary limit) 74 */ 75 #define MAXDIM 6 76 77 /* 78 * Arrays are varlena objects, so must meet the varlena convention that 79 * the first int32 of the object contains the total object size in bytes. 80 * Be sure to use VARSIZE() and SET_VARSIZE() to access it, though! 81 * 82 * CAUTION: if you change the header for ordinary arrays you will also 83 * need to change the headers for oidvector and int2vector! 84 */ 85 typedef struct ArrayType 86 { 87 int32 vl_len_; /* varlena header (do not touch directly!) */ 88 int ndim; /* # of dimensions */ 89 int32 dataoffset; /* offset to data, or 0 if no bitmap */ 90 Oid elemtype; /* element type OID */ 91 } ArrayType; 92 93 /* 94 * An expanded array is contained within a private memory context (as 95 * all expanded objects must be) and has a control structure as below. 96 * 97 * The expanded array might contain a regular "flat" array if that was the 98 * original input and we've not modified it significantly. Otherwise, the 99 * contents are represented by Datum/isnull arrays plus dimensionality and 100 * type information. We could also have both forms, if we've deconstructed 101 * the original array for access purposes but not yet changed it. For pass- 102 * by-reference element types, the Datums would point into the flat array in 103 * this situation. Once we start modifying array elements, new pass-by-ref 104 * elements are separately palloc'd within the memory context. 105 */ 106 #define EA_MAGIC 689375833 /* ID for debugging crosschecks */ 107 108 typedef struct ExpandedArrayHeader 109 { 110 /* Standard header for expanded objects */ 111 ExpandedObjectHeader hdr; 112 113 /* Magic value identifying an expanded array (for debugging only) */ 114 int ea_magic; 115 116 /* Dimensionality info (always valid) */ 117 int ndims; /* # of dimensions */ 118 int *dims; /* array dimensions */ 119 int *lbound; /* index lower bounds for each dimension */ 120 121 /* Element type info (always valid) */ 122 Oid element_type; /* element type OID */ 123 int16 typlen; /* needed info about element datatype */ 124 bool typbyval; 125 char typalign; 126 127 /* 128 * If we have a Datum-array representation of the array, it's kept here; 129 * else dvalues/dnulls are NULL. The dvalues and dnulls arrays are always 130 * palloc'd within the object private context, but may change size from 131 * time to time. For pass-by-ref element types, dvalues entries might 132 * point either into the fstartptr..fendptr area, or to separately 133 * palloc'd chunks. Elements should always be fully detoasted, as they 134 * are in the standard flat representation. 135 * 136 * Even when dvalues is valid, dnulls can be NULL if there are no null 137 * elements. 138 */ 139 Datum *dvalues; /* array of Datums */ 140 bool *dnulls; /* array of is-null flags for Datums */ 141 int dvalueslen; /* allocated length of above arrays */ 142 int nelems; /* number of valid entries in above arrays */ 143 144 /* 145 * flat_size is the current space requirement for the flat equivalent of 146 * the expanded array, if known; otherwise it's 0. We store this to make 147 * consecutive calls of get_flat_size cheap. 148 */ 149 Size flat_size; 150 151 /* 152 * fvalue points to the flat representation if it is valid, else it is 153 * NULL. If we have or ever had a flat representation then 154 * fstartptr/fendptr point to the start and end+1 of its data area; this 155 * is so that we can tell which Datum pointers point into the flat 156 * representation rather than being pointers to separately palloc'd data. 157 */ 158 ArrayType *fvalue; /* must be a fully detoasted array */ 159 char *fstartptr; /* start of its data area */ 160 char *fendptr; /* end+1 of its data area */ 161 } ExpandedArrayHeader; 162 163 /* 164 * Functions that can handle either a "flat" varlena array or an expanded 165 * array use this union to work with their input. Don't refer to "flt"; 166 * instead, cast to ArrayType. This struct nominally requires 8-byte 167 * alignment on 64-bit, but it's often used for an ArrayType having 4-byte 168 * alignment. UBSan complains about referencing "flt" in such cases. 169 */ 170 typedef union AnyArrayType 171 { 172 ArrayType flt; 173 ExpandedArrayHeader xpn; 174 } AnyArrayType; 175 176 /* 177 * working state for accumArrayResult() and friends 178 * note that the input must be scalars (legal array elements) 179 */ 180 typedef struct ArrayBuildState 181 { 182 MemoryContext mcontext; /* where all the temp stuff is kept */ 183 Datum *dvalues; /* array of accumulated Datums */ 184 bool *dnulls; /* array of is-null flags for Datums */ 185 int alen; /* allocated length of above arrays */ 186 int nelems; /* number of valid entries in above arrays */ 187 Oid element_type; /* data type of the Datums */ 188 int16 typlen; /* needed info about datatype */ 189 bool typbyval; 190 char typalign; 191 bool private_cxt; /* use private memory context */ 192 } ArrayBuildState; 193 194 /* 195 * working state for accumArrayResultArr() and friends 196 * note that the input must be arrays, and the same array type is returned 197 */ 198 typedef struct ArrayBuildStateArr 199 { 200 MemoryContext mcontext; /* where all the temp stuff is kept */ 201 char *data; /* accumulated data */ 202 bits8 *nullbitmap; /* bitmap of is-null flags, or NULL if none */ 203 int abytes; /* allocated length of "data" */ 204 int nbytes; /* number of bytes used so far */ 205 int aitems; /* allocated length of bitmap (in elements) */ 206 int nitems; /* total number of elements in result */ 207 int ndims; /* current dimensions of result */ 208 int dims[MAXDIM]; 209 int lbs[MAXDIM]; 210 Oid array_type; /* data type of the arrays */ 211 Oid element_type; /* data type of the array elements */ 212 bool private_cxt; /* use private memory context */ 213 } ArrayBuildStateArr; 214 215 /* 216 * working state for accumArrayResultAny() and friends 217 * these functions handle both cases 218 */ 219 typedef struct ArrayBuildStateAny 220 { 221 /* Exactly one of these is not NULL: */ 222 ArrayBuildState *scalarstate; 223 ArrayBuildStateArr *arraystate; 224 } ArrayBuildStateAny; 225 226 /* 227 * structure to cache type metadata needed for array manipulation 228 */ 229 typedef struct ArrayMetaState 230 { 231 Oid element_type; 232 int16 typlen; 233 bool typbyval; 234 char typalign; 235 char typdelim; 236 Oid typioparam; 237 Oid typiofunc; 238 FmgrInfo proc; 239 } ArrayMetaState; 240 241 /* 242 * private state needed by array_map (here because caller must provide it) 243 */ 244 typedef struct ArrayMapState 245 { 246 ArrayMetaState inp_extra; 247 ArrayMetaState ret_extra; 248 } ArrayMapState; 249 250 /* ArrayIteratorData is private in arrayfuncs.c */ 251 typedef struct ArrayIteratorData *ArrayIterator; 252 253 /* fmgr macros for regular varlena array objects */ 254 #define DatumGetArrayTypeP(X) ((ArrayType *) PG_DETOAST_DATUM(X)) 255 #define DatumGetArrayTypePCopy(X) ((ArrayType *) PG_DETOAST_DATUM_COPY(X)) 256 #define PG_GETARG_ARRAYTYPE_P(n) DatumGetArrayTypeP(PG_GETARG_DATUM(n)) 257 #define PG_GETARG_ARRAYTYPE_P_COPY(n) DatumGetArrayTypePCopy(PG_GETARG_DATUM(n)) 258 #define PG_RETURN_ARRAYTYPE_P(x) PG_RETURN_POINTER(x) 259 260 /* fmgr macros for expanded array objects */ 261 #define PG_GETARG_EXPANDED_ARRAY(n) DatumGetExpandedArray(PG_GETARG_DATUM(n)) 262 #define PG_GETARG_EXPANDED_ARRAYX(n, metacache) \ 263 DatumGetExpandedArrayX(PG_GETARG_DATUM(n), metacache) 264 #define PG_RETURN_EXPANDED_ARRAY(x) PG_RETURN_DATUM(EOHPGetRWDatum(&(x)->hdr)) 265 266 /* fmgr macros for AnyArrayType (ie, get either varlena or expanded form) */ 267 #define PG_GETARG_ANY_ARRAY_P(n) DatumGetAnyArrayP(PG_GETARG_DATUM(n)) 268 269 /* 270 * Access macros for varlena array header fields. 271 * 272 * ARR_DIMS returns a pointer to an array of array dimensions (number of 273 * elements along the various array axes). 274 * 275 * ARR_LBOUND returns a pointer to an array of array lower bounds. 276 * 277 * That is: if the third axis of an array has elements 5 through 8, then 278 * ARR_DIMS(a)[2] == 4 and ARR_LBOUND(a)[2] == 5. 279 * 280 * Unlike C, the default lower bound is 1. 281 */ 282 #define ARR_SIZE(a) VARSIZE(a) 283 #define ARR_NDIM(a) ((a)->ndim) 284 #define ARR_HASNULL(a) ((a)->dataoffset != 0) 285 #define ARR_ELEMTYPE(a) ((a)->elemtype) 286 287 #define ARR_DIMS(a) \ 288 ((int *) (((char *) (a)) + sizeof(ArrayType))) 289 #define ARR_LBOUND(a) \ 290 ((int *) (((char *) (a)) + sizeof(ArrayType) + \ 291 sizeof(int) * ARR_NDIM(a))) 292 293 #define ARR_NULLBITMAP(a) \ 294 (ARR_HASNULL(a) ? \ 295 (bits8 *) (((char *) (a)) + sizeof(ArrayType) + \ 296 2 * sizeof(int) * ARR_NDIM(a)) \ 297 : (bits8 *) NULL) 298 299 /* 300 * The total array header size (in bytes) for an array with the specified 301 * number of dimensions and total number of items. 302 */ 303 #define ARR_OVERHEAD_NONULLS(ndims) \ 304 MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims)) 305 #define ARR_OVERHEAD_WITHNULLS(ndims, nitems) \ 306 MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims) + \ 307 ((nitems) + 7) / 8) 308 309 #define ARR_DATA_OFFSET(a) \ 310 (ARR_HASNULL(a) ? (a)->dataoffset : ARR_OVERHEAD_NONULLS(ARR_NDIM(a))) 311 312 /* 313 * Returns a pointer to the actual array data. 314 */ 315 #define ARR_DATA_PTR(a) \ 316 (((char *) (a)) + ARR_DATA_OFFSET(a)) 317 318 /* 319 * Macros for working with AnyArrayType inputs. Beware multiple references! 320 */ 321 #define AARR_NDIM(a) \ 322 (VARATT_IS_EXPANDED_HEADER(a) ? \ 323 (a)->xpn.ndims : ARR_NDIM((ArrayType *) (a))) 324 #define AARR_HASNULL(a) \ 325 (VARATT_IS_EXPANDED_HEADER(a) ? \ 326 ((a)->xpn.dvalues != NULL ? (a)->xpn.dnulls != NULL : ARR_HASNULL((a)->xpn.fvalue)) : \ 327 ARR_HASNULL((ArrayType *) (a))) 328 #define AARR_ELEMTYPE(a) \ 329 (VARATT_IS_EXPANDED_HEADER(a) ? \ 330 (a)->xpn.element_type : ARR_ELEMTYPE((ArrayType *) (a))) 331 #define AARR_DIMS(a) \ 332 (VARATT_IS_EXPANDED_HEADER(a) ? \ 333 (a)->xpn.dims : ARR_DIMS((ArrayType *) (a))) 334 #define AARR_LBOUND(a) \ 335 (VARATT_IS_EXPANDED_HEADER(a) ? \ 336 (a)->xpn.lbound : ARR_LBOUND((ArrayType *) (a))) 337 338 339 /* 340 * GUC parameter 341 */ 342 extern bool Array_nulls; 343 344 /* 345 * prototypes for functions defined in arrayfuncs.c 346 */ 347 extern void CopyArrayEls(ArrayType *array, 348 Datum *values, 349 bool *nulls, 350 int nitems, 351 int typlen, 352 bool typbyval, 353 char typalign, 354 bool freedata); 355 356 extern Datum array_get_element(Datum arraydatum, int nSubscripts, int *indx, 357 int arraytyplen, int elmlen, bool elmbyval, char elmalign, 358 bool *isNull); 359 extern Datum array_set_element(Datum arraydatum, int nSubscripts, int *indx, 360 Datum dataValue, bool isNull, 361 int arraytyplen, int elmlen, bool elmbyval, char elmalign); 362 extern Datum array_get_slice(Datum arraydatum, int nSubscripts, 363 int *upperIndx, int *lowerIndx, 364 bool *upperProvided, bool *lowerProvided, 365 int arraytyplen, int elmlen, bool elmbyval, char elmalign); 366 extern Datum array_set_slice(Datum arraydatum, int nSubscripts, 367 int *upperIndx, int *lowerIndx, 368 bool *upperProvided, bool *lowerProvided, 369 Datum srcArrayDatum, bool isNull, 370 int arraytyplen, int elmlen, bool elmbyval, char elmalign); 371 372 extern Datum array_ref(ArrayType *array, int nSubscripts, int *indx, 373 int arraytyplen, int elmlen, bool elmbyval, char elmalign, 374 bool *isNull); 375 extern ArrayType *array_set(ArrayType *array, int nSubscripts, int *indx, 376 Datum dataValue, bool isNull, 377 int arraytyplen, int elmlen, bool elmbyval, char elmalign); 378 379 extern Datum array_map(Datum arrayd, 380 struct ExprState *exprstate, struct ExprContext *econtext, 381 Oid retType, ArrayMapState *amstate); 382 383 extern void array_bitmap_copy(bits8 *destbitmap, int destoffset, 384 const bits8 *srcbitmap, int srcoffset, 385 int nitems); 386 387 extern ArrayType *construct_array(Datum *elems, int nelems, 388 Oid elmtype, 389 int elmlen, bool elmbyval, char elmalign); 390 extern ArrayType *construct_md_array(Datum *elems, 391 bool *nulls, 392 int ndims, 393 int *dims, 394 int *lbs, 395 Oid elmtype, int elmlen, bool elmbyval, char elmalign); 396 extern ArrayType *construct_empty_array(Oid elmtype); 397 extern ExpandedArrayHeader *construct_empty_expanded_array(Oid element_type, 398 MemoryContext parentcontext, 399 ArrayMetaState *metacache); 400 extern void deconstruct_array(ArrayType *array, 401 Oid elmtype, 402 int elmlen, bool elmbyval, char elmalign, 403 Datum **elemsp, bool **nullsp, int *nelemsp); 404 extern bool array_contains_nulls(ArrayType *array); 405 406 extern ArrayBuildState *initArrayResult(Oid element_type, 407 MemoryContext rcontext, bool subcontext); 408 extern ArrayBuildState *accumArrayResult(ArrayBuildState *astate, 409 Datum dvalue, bool disnull, 410 Oid element_type, 411 MemoryContext rcontext); 412 extern Datum makeArrayResult(ArrayBuildState *astate, 413 MemoryContext rcontext); 414 extern Datum makeMdArrayResult(ArrayBuildState *astate, int ndims, 415 int *dims, int *lbs, MemoryContext rcontext, bool release); 416 417 extern ArrayBuildStateArr *initArrayResultArr(Oid array_type, Oid element_type, 418 MemoryContext rcontext, bool subcontext); 419 extern ArrayBuildStateArr *accumArrayResultArr(ArrayBuildStateArr *astate, 420 Datum dvalue, bool disnull, 421 Oid array_type, 422 MemoryContext rcontext); 423 extern Datum makeArrayResultArr(ArrayBuildStateArr *astate, 424 MemoryContext rcontext, bool release); 425 426 extern ArrayBuildStateAny *initArrayResultAny(Oid input_type, 427 MemoryContext rcontext, bool subcontext); 428 extern ArrayBuildStateAny *accumArrayResultAny(ArrayBuildStateAny *astate, 429 Datum dvalue, bool disnull, 430 Oid input_type, 431 MemoryContext rcontext); 432 extern Datum makeArrayResultAny(ArrayBuildStateAny *astate, 433 MemoryContext rcontext, bool release); 434 435 extern ArrayIterator array_create_iterator(ArrayType *arr, int slice_ndim, ArrayMetaState *mstate); 436 extern bool array_iterate(ArrayIterator iterator, Datum *value, bool *isnull); 437 extern void array_free_iterator(ArrayIterator iterator); 438 439 /* 440 * prototypes for functions defined in arrayutils.c 441 */ 442 443 extern int ArrayGetOffset(int n, const int *dim, const int *lb, const int *indx); 444 extern int ArrayGetOffset0(int n, const int *tup, const int *scale); 445 extern int ArrayGetNItems(int ndim, const int *dims); 446 extern void ArrayCheckBounds(int ndim, const int *dims, const int *lb); 447 extern void mda_get_range(int n, int *span, const int *st, const int *endp); 448 extern void mda_get_prod(int n, const int *range, int *prod); 449 extern void mda_get_offset_values(int n, int *dist, const int *prod, const int *span); 450 extern int mda_next_tuple(int n, int *curr, const int *span); 451 extern int32 *ArrayGetIntegerTypmods(ArrayType *arr, int *n); 452 453 /* 454 * prototypes for functions defined in array_expanded.c 455 */ 456 extern Datum expand_array(Datum arraydatum, MemoryContext parentcontext, 457 ArrayMetaState *metacache); 458 extern ExpandedArrayHeader *DatumGetExpandedArray(Datum d); 459 extern ExpandedArrayHeader *DatumGetExpandedArrayX(Datum d, 460 ArrayMetaState *metacache); 461 extern AnyArrayType *DatumGetAnyArrayP(Datum d); 462 extern void deconstruct_expanded_array(ExpandedArrayHeader *eah); 463 464 #endif /* ARRAY_H */ 465