1 /*-------------------------------------------------------------------------
2 *
3 * regexp.c
4 * Postgres' interface to the regular expression package.
5 *
6 * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/utils/adt/regexp.c
12 *
13 * Alistair Crooks added the code for the regex caching
14 * agc - cached the regular expressions used - there's a good chance
15 * that we'll get a hit, so this saves a compile step for every
16 * attempted match. I haven't actually measured the speed improvement,
17 * but it `looks' a lot quicker visually when watching regression
18 * test output.
19 *
20 * agc - incorporated Keith Bostic's Berkeley regex code into
21 * the tree for all ports. To distinguish this regex code from any that
22 * is existent on a platform, I've prepended the string "pg_" to
23 * the functions regcomp, regerror, regexec and regfree.
24 * Fixed a bug that was originally a typo by me, where `i' was used
25 * instead of `oldest' when compiling regular expressions - benign
26 * results mostly, although occasionally it bit you...
27 *
28 *-------------------------------------------------------------------------
29 */
30 #include "postgres.h"
31
32 #include "catalog/pg_type.h"
33 #include "funcapi.h"
34 #include "miscadmin.h"
35 #include "regex/regex.h"
36 #include "utils/array.h"
37 #include "utils/builtins.h"
38 #include "utils/memutils.h"
39 #include "utils/varlena.h"
40
41 #define PG_GETARG_TEXT_PP_IF_EXISTS(_n) \
42 (PG_NARGS() > (_n) ? PG_GETARG_TEXT_PP(_n) : NULL)
43
44
45 /* all the options of interest for regex functions */
46 typedef struct pg_re_flags
47 {
48 int cflags; /* compile flags for Spencer's regex code */
49 bool glob; /* do it globally (for each occurrence) */
50 } pg_re_flags;
51
52 /* cross-call state for regexp_match and regexp_split functions */
53 typedef struct regexp_matches_ctx
54 {
55 text *orig_str; /* data string in original TEXT form */
56 int nmatches; /* number of places where pattern matched */
57 int npatterns; /* number of capturing subpatterns */
58 /* We store start char index and end+1 char index for each match */
59 /* so the number of entries in match_locs is nmatches * npatterns * 2 */
60 int *match_locs; /* 0-based character indexes */
61 int next_match; /* 0-based index of next match to process */
62 /* workspace for build_regexp_match_result() */
63 Datum *elems; /* has npatterns elements */
64 bool *nulls; /* has npatterns elements */
65 pg_wchar *wide_str; /* wide-char version of original string */
66 char *conv_buf; /* conversion buffer, if needed */
67 int conv_bufsiz; /* size thereof */
68 } regexp_matches_ctx;
69
70 /*
71 * We cache precompiled regular expressions using a "self organizing list"
72 * structure, in which recently-used items tend to be near the front.
73 * Whenever we use an entry, it's moved up to the front of the list.
74 * Over time, an item's average position corresponds to its frequency of use.
75 *
76 * When we first create an entry, it's inserted at the front of
77 * the array, dropping the entry at the end of the array if necessary to
78 * make room. (This might seem to be weighting the new entry too heavily,
79 * but if we insert new entries further back, we'll be unable to adjust to
80 * a sudden shift in the query mix where we are presented with MAX_CACHED_RES
81 * never-before-seen items used circularly. We ought to be able to handle
82 * that case, so we have to insert at the front.)
83 *
84 * Knuth mentions a variant strategy in which a used item is moved up just
85 * one place in the list. Although he says this uses fewer comparisons on
86 * average, it seems not to adapt very well to the situation where you have
87 * both some reusable patterns and a steady stream of non-reusable patterns.
88 * A reusable pattern that isn't used at least as often as non-reusable
89 * patterns are seen will "fail to keep up" and will drop off the end of the
90 * cache. With move-to-front, a reusable pattern is guaranteed to stay in
91 * the cache as long as it's used at least once in every MAX_CACHED_RES uses.
92 */
93
94 /* this is the maximum number of cached regular expressions */
95 #ifndef MAX_CACHED_RES
96 #define MAX_CACHED_RES 32
97 #endif
98
99 /* this structure describes one cached regular expression */
100 typedef struct cached_re_str
101 {
102 char *cre_pat; /* original RE (not null terminated!) */
103 int cre_pat_len; /* length of original RE, in bytes */
104 int cre_flags; /* compile flags: extended,icase etc */
105 Oid cre_collation; /* collation to use */
106 regex_t cre_re; /* the compiled regular expression */
107 } cached_re_str;
108
109 static int num_res = 0; /* # of cached re's */
110 static cached_re_str re_array[MAX_CACHED_RES]; /* cached re's */
111
112
113 /* Local functions */
114 static regexp_matches_ctx *setup_regexp_matches(text *orig_str, text *pattern,
115 pg_re_flags *flags,
116 Oid collation,
117 bool use_subpatterns,
118 bool ignore_degenerate,
119 bool fetching_unmatched);
120 static ArrayType *build_regexp_match_result(regexp_matches_ctx *matchctx);
121 static Datum build_regexp_split_result(regexp_matches_ctx *splitctx);
122
123
124 /*
125 * RE_compile_and_cache - compile a RE, caching if possible
126 *
127 * Returns regex_t *
128 *
129 * text_re --- the pattern, expressed as a TEXT object
130 * cflags --- compile options for the pattern
131 * collation --- collation to use for LC_CTYPE-dependent behavior
132 *
133 * Pattern is given in the database encoding. We internally convert to
134 * an array of pg_wchar, which is what Spencer's regex package wants.
135 */
136 regex_t *
RE_compile_and_cache(text * text_re,int cflags,Oid collation)137 RE_compile_and_cache(text *text_re, int cflags, Oid collation)
138 {
139 int text_re_len = VARSIZE_ANY_EXHDR(text_re);
140 char *text_re_val = VARDATA_ANY(text_re);
141 pg_wchar *pattern;
142 int pattern_len;
143 int i;
144 int regcomp_result;
145 cached_re_str re_temp;
146 char errMsg[100];
147
148 /*
149 * Look for a match among previously compiled REs. Since the data
150 * structure is self-organizing with most-used entries at the front, our
151 * search strategy can just be to scan from the front.
152 */
153 for (i = 0; i < num_res; i++)
154 {
155 if (re_array[i].cre_pat_len == text_re_len &&
156 re_array[i].cre_flags == cflags &&
157 re_array[i].cre_collation == collation &&
158 memcmp(re_array[i].cre_pat, text_re_val, text_re_len) == 0)
159 {
160 /*
161 * Found a match; move it to front if not there already.
162 */
163 if (i > 0)
164 {
165 re_temp = re_array[i];
166 memmove(&re_array[1], &re_array[0], i * sizeof(cached_re_str));
167 re_array[0] = re_temp;
168 }
169
170 return &re_array[0].cre_re;
171 }
172 }
173
174 /*
175 * Couldn't find it, so try to compile the new RE. To avoid leaking
176 * resources on failure, we build into the re_temp local.
177 */
178
179 /* Convert pattern string to wide characters */
180 pattern = (pg_wchar *) palloc((text_re_len + 1) * sizeof(pg_wchar));
181 pattern_len = pg_mb2wchar_with_len(text_re_val,
182 pattern,
183 text_re_len);
184
185 regcomp_result = pg_regcomp(&re_temp.cre_re,
186 pattern,
187 pattern_len,
188 cflags,
189 collation);
190
191 pfree(pattern);
192
193 if (regcomp_result != REG_OKAY)
194 {
195 /* re didn't compile (no need for pg_regfree, if so) */
196
197 /*
198 * Here and in other places in this file, do CHECK_FOR_INTERRUPTS
199 * before reporting a regex error. This is so that if the regex
200 * library aborts and returns REG_CANCEL, we don't print an error
201 * message that implies the regex was invalid.
202 */
203 CHECK_FOR_INTERRUPTS();
204
205 pg_regerror(regcomp_result, &re_temp.cre_re, errMsg, sizeof(errMsg));
206 ereport(ERROR,
207 (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
208 errmsg("invalid regular expression: %s", errMsg)));
209 }
210
211 /*
212 * We use malloc/free for the cre_pat field because the storage has to
213 * persist across transactions, and because we want to get control back on
214 * out-of-memory. The Max() is because some malloc implementations return
215 * NULL for malloc(0).
216 */
217 re_temp.cre_pat = malloc(Max(text_re_len, 1));
218 if (re_temp.cre_pat == NULL)
219 {
220 pg_regfree(&re_temp.cre_re);
221 ereport(ERROR,
222 (errcode(ERRCODE_OUT_OF_MEMORY),
223 errmsg("out of memory")));
224 }
225 memcpy(re_temp.cre_pat, text_re_val, text_re_len);
226 re_temp.cre_pat_len = text_re_len;
227 re_temp.cre_flags = cflags;
228 re_temp.cre_collation = collation;
229
230 /*
231 * Okay, we have a valid new item in re_temp; insert it into the storage
232 * array. Discard last entry if needed.
233 */
234 if (num_res >= MAX_CACHED_RES)
235 {
236 --num_res;
237 Assert(num_res < MAX_CACHED_RES);
238 pg_regfree(&re_array[num_res].cre_re);
239 free(re_array[num_res].cre_pat);
240 }
241
242 if (num_res > 0)
243 memmove(&re_array[1], &re_array[0], num_res * sizeof(cached_re_str));
244
245 re_array[0] = re_temp;
246 num_res++;
247
248 return &re_array[0].cre_re;
249 }
250
251 /*
252 * RE_wchar_execute - execute a RE on pg_wchar data
253 *
254 * Returns true on match, false on no match
255 *
256 * re --- the compiled pattern as returned by RE_compile_and_cache
257 * data --- the data to match against (need not be null-terminated)
258 * data_len --- the length of the data string
259 * start_search -- the offset in the data to start searching
260 * nmatch, pmatch --- optional return area for match details
261 *
262 * Data is given as array of pg_wchar which is what Spencer's regex package
263 * wants.
264 */
265 static bool
RE_wchar_execute(regex_t * re,pg_wchar * data,int data_len,int start_search,int nmatch,regmatch_t * pmatch)266 RE_wchar_execute(regex_t *re, pg_wchar *data, int data_len,
267 int start_search, int nmatch, regmatch_t *pmatch)
268 {
269 int regexec_result;
270 char errMsg[100];
271
272 /* Perform RE match and return result */
273 regexec_result = pg_regexec(re,
274 data,
275 data_len,
276 start_search,
277 NULL, /* no details */
278 nmatch,
279 pmatch,
280 0);
281
282 if (regexec_result != REG_OKAY && regexec_result != REG_NOMATCH)
283 {
284 /* re failed??? */
285 CHECK_FOR_INTERRUPTS();
286 pg_regerror(regexec_result, re, errMsg, sizeof(errMsg));
287 ereport(ERROR,
288 (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
289 errmsg("regular expression failed: %s", errMsg)));
290 }
291
292 return (regexec_result == REG_OKAY);
293 }
294
295 /*
296 * RE_execute - execute a RE
297 *
298 * Returns true on match, false on no match
299 *
300 * re --- the compiled pattern as returned by RE_compile_and_cache
301 * dat --- the data to match against (need not be null-terminated)
302 * dat_len --- the length of the data string
303 * nmatch, pmatch --- optional return area for match details
304 *
305 * Data is given in the database encoding. We internally
306 * convert to array of pg_wchar which is what Spencer's regex package wants.
307 */
308 static bool
RE_execute(regex_t * re,char * dat,int dat_len,int nmatch,regmatch_t * pmatch)309 RE_execute(regex_t *re, char *dat, int dat_len,
310 int nmatch, regmatch_t *pmatch)
311 {
312 pg_wchar *data;
313 int data_len;
314 bool match;
315
316 /* Convert data string to wide characters */
317 data = (pg_wchar *) palloc((dat_len + 1) * sizeof(pg_wchar));
318 data_len = pg_mb2wchar_with_len(dat, data, dat_len);
319
320 /* Perform RE match and return result */
321 match = RE_wchar_execute(re, data, data_len, 0, nmatch, pmatch);
322
323 pfree(data);
324 return match;
325 }
326
327 /*
328 * RE_compile_and_execute - compile and execute a RE
329 *
330 * Returns true on match, false on no match
331 *
332 * text_re --- the pattern, expressed as a TEXT object
333 * dat --- the data to match against (need not be null-terminated)
334 * dat_len --- the length of the data string
335 * cflags --- compile options for the pattern
336 * collation --- collation to use for LC_CTYPE-dependent behavior
337 * nmatch, pmatch --- optional return area for match details
338 *
339 * Both pattern and data are given in the database encoding. We internally
340 * convert to array of pg_wchar which is what Spencer's regex package wants.
341 */
342 bool
RE_compile_and_execute(text * text_re,char * dat,int dat_len,int cflags,Oid collation,int nmatch,regmatch_t * pmatch)343 RE_compile_and_execute(text *text_re, char *dat, int dat_len,
344 int cflags, Oid collation,
345 int nmatch, regmatch_t *pmatch)
346 {
347 regex_t *re;
348
349 /* Compile RE */
350 re = RE_compile_and_cache(text_re, cflags, collation);
351
352 return RE_execute(re, dat, dat_len, nmatch, pmatch);
353 }
354
355
356 /*
357 * parse_re_flags - parse the options argument of regexp_match and friends
358 *
359 * flags --- output argument, filled with desired options
360 * opts --- TEXT object, or NULL for defaults
361 *
362 * This accepts all the options allowed by any of the callers; callers that
363 * don't want some have to reject them after the fact.
364 */
365 static void
parse_re_flags(pg_re_flags * flags,text * opts)366 parse_re_flags(pg_re_flags *flags, text *opts)
367 {
368 /* regex flavor is always folded into the compile flags */
369 flags->cflags = REG_ADVANCED;
370 flags->glob = false;
371
372 if (opts)
373 {
374 char *opt_p = VARDATA_ANY(opts);
375 int opt_len = VARSIZE_ANY_EXHDR(opts);
376 int i;
377
378 for (i = 0; i < opt_len; i++)
379 {
380 switch (opt_p[i])
381 {
382 case 'g':
383 flags->glob = true;
384 break;
385 case 'b': /* BREs (but why???) */
386 flags->cflags &= ~(REG_ADVANCED | REG_EXTENDED | REG_QUOTE);
387 break;
388 case 'c': /* case sensitive */
389 flags->cflags &= ~REG_ICASE;
390 break;
391 case 'e': /* plain EREs */
392 flags->cflags |= REG_EXTENDED;
393 flags->cflags &= ~(REG_ADVANCED | REG_QUOTE);
394 break;
395 case 'i': /* case insensitive */
396 flags->cflags |= REG_ICASE;
397 break;
398 case 'm': /* Perloid synonym for n */
399 case 'n': /* \n affects ^ $ . [^ */
400 flags->cflags |= REG_NEWLINE;
401 break;
402 case 'p': /* ~Perl, \n affects . [^ */
403 flags->cflags |= REG_NLSTOP;
404 flags->cflags &= ~REG_NLANCH;
405 break;
406 case 'q': /* literal string */
407 flags->cflags |= REG_QUOTE;
408 flags->cflags &= ~(REG_ADVANCED | REG_EXTENDED);
409 break;
410 case 's': /* single line, \n ordinary */
411 flags->cflags &= ~REG_NEWLINE;
412 break;
413 case 't': /* tight syntax */
414 flags->cflags &= ~REG_EXPANDED;
415 break;
416 case 'w': /* weird, \n affects ^ $ only */
417 flags->cflags &= ~REG_NLSTOP;
418 flags->cflags |= REG_NLANCH;
419 break;
420 case 'x': /* expanded syntax */
421 flags->cflags |= REG_EXPANDED;
422 break;
423 default:
424 ereport(ERROR,
425 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
426 errmsg("invalid regular expression option: \"%c\"",
427 opt_p[i])));
428 break;
429 }
430 }
431 }
432 }
433
434
435 /*
436 * interface routines called by the function manager
437 */
438
439 Datum
nameregexeq(PG_FUNCTION_ARGS)440 nameregexeq(PG_FUNCTION_ARGS)
441 {
442 Name n = PG_GETARG_NAME(0);
443 text *p = PG_GETARG_TEXT_PP(1);
444
445 PG_RETURN_BOOL(RE_compile_and_execute(p,
446 NameStr(*n),
447 strlen(NameStr(*n)),
448 REG_ADVANCED,
449 PG_GET_COLLATION(),
450 0, NULL));
451 }
452
453 Datum
nameregexne(PG_FUNCTION_ARGS)454 nameregexne(PG_FUNCTION_ARGS)
455 {
456 Name n = PG_GETARG_NAME(0);
457 text *p = PG_GETARG_TEXT_PP(1);
458
459 PG_RETURN_BOOL(!RE_compile_and_execute(p,
460 NameStr(*n),
461 strlen(NameStr(*n)),
462 REG_ADVANCED,
463 PG_GET_COLLATION(),
464 0, NULL));
465 }
466
467 Datum
textregexeq(PG_FUNCTION_ARGS)468 textregexeq(PG_FUNCTION_ARGS)
469 {
470 text *s = PG_GETARG_TEXT_PP(0);
471 text *p = PG_GETARG_TEXT_PP(1);
472
473 PG_RETURN_BOOL(RE_compile_and_execute(p,
474 VARDATA_ANY(s),
475 VARSIZE_ANY_EXHDR(s),
476 REG_ADVANCED,
477 PG_GET_COLLATION(),
478 0, NULL));
479 }
480
481 Datum
textregexne(PG_FUNCTION_ARGS)482 textregexne(PG_FUNCTION_ARGS)
483 {
484 text *s = PG_GETARG_TEXT_PP(0);
485 text *p = PG_GETARG_TEXT_PP(1);
486
487 PG_RETURN_BOOL(!RE_compile_and_execute(p,
488 VARDATA_ANY(s),
489 VARSIZE_ANY_EXHDR(s),
490 REG_ADVANCED,
491 PG_GET_COLLATION(),
492 0, NULL));
493 }
494
495
496 /*
497 * routines that use the regexp stuff, but ignore the case.
498 * for this, we use the REG_ICASE flag to pg_regcomp
499 */
500
501
502 Datum
nameicregexeq(PG_FUNCTION_ARGS)503 nameicregexeq(PG_FUNCTION_ARGS)
504 {
505 Name n = PG_GETARG_NAME(0);
506 text *p = PG_GETARG_TEXT_PP(1);
507
508 PG_RETURN_BOOL(RE_compile_and_execute(p,
509 NameStr(*n),
510 strlen(NameStr(*n)),
511 REG_ADVANCED | REG_ICASE,
512 PG_GET_COLLATION(),
513 0, NULL));
514 }
515
516 Datum
nameicregexne(PG_FUNCTION_ARGS)517 nameicregexne(PG_FUNCTION_ARGS)
518 {
519 Name n = PG_GETARG_NAME(0);
520 text *p = PG_GETARG_TEXT_PP(1);
521
522 PG_RETURN_BOOL(!RE_compile_and_execute(p,
523 NameStr(*n),
524 strlen(NameStr(*n)),
525 REG_ADVANCED | REG_ICASE,
526 PG_GET_COLLATION(),
527 0, NULL));
528 }
529
530 Datum
texticregexeq(PG_FUNCTION_ARGS)531 texticregexeq(PG_FUNCTION_ARGS)
532 {
533 text *s = PG_GETARG_TEXT_PP(0);
534 text *p = PG_GETARG_TEXT_PP(1);
535
536 PG_RETURN_BOOL(RE_compile_and_execute(p,
537 VARDATA_ANY(s),
538 VARSIZE_ANY_EXHDR(s),
539 REG_ADVANCED | REG_ICASE,
540 PG_GET_COLLATION(),
541 0, NULL));
542 }
543
544 Datum
texticregexne(PG_FUNCTION_ARGS)545 texticregexne(PG_FUNCTION_ARGS)
546 {
547 text *s = PG_GETARG_TEXT_PP(0);
548 text *p = PG_GETARG_TEXT_PP(1);
549
550 PG_RETURN_BOOL(!RE_compile_and_execute(p,
551 VARDATA_ANY(s),
552 VARSIZE_ANY_EXHDR(s),
553 REG_ADVANCED | REG_ICASE,
554 PG_GET_COLLATION(),
555 0, NULL));
556 }
557
558
559 /*
560 * textregexsubstr()
561 * Return a substring matched by a regular expression.
562 */
563 Datum
textregexsubstr(PG_FUNCTION_ARGS)564 textregexsubstr(PG_FUNCTION_ARGS)
565 {
566 text *s = PG_GETARG_TEXT_PP(0);
567 text *p = PG_GETARG_TEXT_PP(1);
568 regex_t *re;
569 regmatch_t pmatch[2];
570 int so,
571 eo;
572
573 /* Compile RE */
574 re = RE_compile_and_cache(p, REG_ADVANCED, PG_GET_COLLATION());
575
576 /*
577 * We pass two regmatch_t structs to get info about the overall match and
578 * the match for the first parenthesized subexpression (if any). If there
579 * is a parenthesized subexpression, we return what it matched; else
580 * return what the whole regexp matched.
581 */
582 if (!RE_execute(re,
583 VARDATA_ANY(s), VARSIZE_ANY_EXHDR(s),
584 2, pmatch))
585 PG_RETURN_NULL(); /* definitely no match */
586
587 if (re->re_nsub > 0)
588 {
589 /* has parenthesized subexpressions, use the first one */
590 so = pmatch[1].rm_so;
591 eo = pmatch[1].rm_eo;
592 }
593 else
594 {
595 /* no parenthesized subexpression, use whole match */
596 so = pmatch[0].rm_so;
597 eo = pmatch[0].rm_eo;
598 }
599
600 /*
601 * It is possible to have a match to the whole pattern but no match for a
602 * subexpression; for example 'foo(bar)?' is considered to match 'foo' but
603 * there is no subexpression match. So this extra test for match failure
604 * is not redundant.
605 */
606 if (so < 0 || eo < 0)
607 PG_RETURN_NULL();
608
609 return DirectFunctionCall3(text_substr,
610 PointerGetDatum(s),
611 Int32GetDatum(so + 1),
612 Int32GetDatum(eo - so));
613 }
614
615 /*
616 * textregexreplace_noopt()
617 * Return a string matched by a regular expression, with replacement.
618 *
619 * This version doesn't have an option argument: we default to case
620 * sensitive match, replace the first instance only.
621 */
622 Datum
textregexreplace_noopt(PG_FUNCTION_ARGS)623 textregexreplace_noopt(PG_FUNCTION_ARGS)
624 {
625 text *s = PG_GETARG_TEXT_PP(0);
626 text *p = PG_GETARG_TEXT_PP(1);
627 text *r = PG_GETARG_TEXT_PP(2);
628 regex_t *re;
629
630 re = RE_compile_and_cache(p, REG_ADVANCED, PG_GET_COLLATION());
631
632 PG_RETURN_TEXT_P(replace_text_regexp(s, (void *) re, r, false));
633 }
634
635 /*
636 * textregexreplace()
637 * Return a string matched by a regular expression, with replacement.
638 */
639 Datum
textregexreplace(PG_FUNCTION_ARGS)640 textregexreplace(PG_FUNCTION_ARGS)
641 {
642 text *s = PG_GETARG_TEXT_PP(0);
643 text *p = PG_GETARG_TEXT_PP(1);
644 text *r = PG_GETARG_TEXT_PP(2);
645 text *opt = PG_GETARG_TEXT_PP(3);
646 regex_t *re;
647 pg_re_flags flags;
648
649 parse_re_flags(&flags, opt);
650
651 re = RE_compile_and_cache(p, flags.cflags, PG_GET_COLLATION());
652
653 PG_RETURN_TEXT_P(replace_text_regexp(s, (void *) re, r, flags.glob));
654 }
655
656 /*
657 * similar_to_escape(), similar_escape()
658 *
659 * Convert a SQL "SIMILAR TO" regexp pattern to POSIX style, so it can be
660 * used by our regexp engine.
661 *
662 * similar_escape_internal() is the common workhorse for three SQL-exposed
663 * functions. esc_text can be passed as NULL to select the default escape
664 * (which is '\'), or as an empty string to select no escape character.
665 */
666 static text *
similar_escape_internal(text * pat_text,text * esc_text)667 similar_escape_internal(text *pat_text, text *esc_text)
668 {
669 text *result;
670 char *p,
671 *e,
672 *r;
673 int plen,
674 elen;
675 bool afterescape = false;
676 bool incharclass = false;
677 int nquotes = 0;
678
679 p = VARDATA_ANY(pat_text);
680 plen = VARSIZE_ANY_EXHDR(pat_text);
681 if (esc_text == NULL)
682 {
683 /* No ESCAPE clause provided; default to backslash as escape */
684 e = "\\";
685 elen = 1;
686 }
687 else
688 {
689 e = VARDATA_ANY(esc_text);
690 elen = VARSIZE_ANY_EXHDR(esc_text);
691 if (elen == 0)
692 e = NULL; /* no escape character */
693 else if (elen > 1)
694 {
695 int escape_mblen = pg_mbstrlen_with_len(e, elen);
696
697 if (escape_mblen > 1)
698 ereport(ERROR,
699 (errcode(ERRCODE_INVALID_ESCAPE_SEQUENCE),
700 errmsg("invalid escape string"),
701 errhint("Escape string must be empty or one character.")));
702 }
703 }
704
705 /*----------
706 * We surround the transformed input string with
707 * ^(?: ... )$
708 * which requires some explanation. We need "^" and "$" to force
709 * the pattern to match the entire input string as per the SQL spec.
710 * The "(?:" and ")" are a non-capturing set of parens; we have to have
711 * parens in case the string contains "|", else the "^" and "$" will
712 * be bound into the first and last alternatives which is not what we
713 * want, and the parens must be non capturing because we don't want them
714 * to count when selecting output for SUBSTRING.
715 *
716 * When the pattern is divided into three parts by escape-double-quotes,
717 * what we emit is
718 * ^(?:part1){1,1}?(part2){1,1}(?:part3)$
719 * which requires even more explanation. The "{1,1}?" on part1 makes it
720 * non-greedy so that it will match the smallest possible amount of text
721 * not the largest, as required by SQL. The plain parens around part2
722 * are capturing parens so that that part is what controls the result of
723 * SUBSTRING. The "{1,1}" forces part2 to be greedy, so that it matches
724 * the largest possible amount of text; hence part3 must match the
725 * smallest amount of text, as required by SQL. We don't need an explicit
726 * greediness marker on part3. Note that this also confines the effects
727 * of any "|" characters to the respective part, which is what we want.
728 *
729 * The SQL spec says that SUBSTRING's pattern must contain exactly two
730 * escape-double-quotes, but we only complain if there's more than two.
731 * With none, we act as though part1 and part3 are empty; with one, we
732 * act as though part3 is empty. Both behaviors fall out of omitting
733 * the relevant part separators in the above expansion. If the result
734 * of this function is used in a plain regexp match (SIMILAR TO), the
735 * escape-double-quotes have no effect on the match behavior.
736 *----------
737 */
738
739 /*
740 * We need room for the prefix/postfix and part separators, plus as many
741 * as 3 output bytes per input byte; since the input is at most 1GB this
742 * can't overflow size_t.
743 */
744 result = (text *) palloc(VARHDRSZ + 23 + 3 * (size_t) plen);
745 r = VARDATA(result);
746
747 *r++ = '^';
748 *r++ = '(';
749 *r++ = '?';
750 *r++ = ':';
751
752 while (plen > 0)
753 {
754 char pchar = *p;
755
756 /*
757 * If both the escape character and the current character from the
758 * pattern are multi-byte, we need to take the slow path.
759 *
760 * But if one of them is single-byte, we can process the pattern one
761 * byte at a time, ignoring multi-byte characters. (This works
762 * because all server-encodings have the property that a valid
763 * multi-byte character representation cannot contain the
764 * representation of a valid single-byte character.)
765 */
766
767 if (elen > 1)
768 {
769 int mblen = pg_mblen(p);
770
771 if (mblen > 1)
772 {
773 /* slow, multi-byte path */
774 if (afterescape)
775 {
776 *r++ = '\\';
777 memcpy(r, p, mblen);
778 r += mblen;
779 afterescape = false;
780 }
781 else if (e && elen == mblen && memcmp(e, p, mblen) == 0)
782 {
783 /* SQL escape character; do not send to output */
784 afterescape = true;
785 }
786 else
787 {
788 /*
789 * We know it's a multi-byte character, so we don't need
790 * to do all the comparisons to single-byte characters
791 * that we do below.
792 */
793 memcpy(r, p, mblen);
794 r += mblen;
795 }
796
797 p += mblen;
798 plen -= mblen;
799
800 continue;
801 }
802 }
803
804 /* fast path */
805 if (afterescape)
806 {
807 if (pchar == '"' && !incharclass) /* escape-double-quote? */
808 {
809 /* emit appropriate part separator, per notes above */
810 if (nquotes == 0)
811 {
812 *r++ = ')';
813 *r++ = '{';
814 *r++ = '1';
815 *r++ = ',';
816 *r++ = '1';
817 *r++ = '}';
818 *r++ = '?';
819 *r++ = '(';
820 }
821 else if (nquotes == 1)
822 {
823 *r++ = ')';
824 *r++ = '{';
825 *r++ = '1';
826 *r++ = ',';
827 *r++ = '1';
828 *r++ = '}';
829 *r++ = '(';
830 *r++ = '?';
831 *r++ = ':';
832 }
833 else
834 ereport(ERROR,
835 (errcode(ERRCODE_INVALID_USE_OF_ESCAPE_CHARACTER),
836 errmsg("SQL regular expression may not contain more than two escape-double-quote separators")));
837 nquotes++;
838 }
839 else
840 {
841 /*
842 * We allow any character at all to be escaped; notably, this
843 * allows access to POSIX character-class escapes such as
844 * "\d". The SQL spec is considerably more restrictive.
845 */
846 *r++ = '\\';
847 *r++ = pchar;
848 }
849 afterescape = false;
850 }
851 else if (e && pchar == *e)
852 {
853 /* SQL escape character; do not send to output */
854 afterescape = true;
855 }
856 else if (incharclass)
857 {
858 if (pchar == '\\')
859 *r++ = '\\';
860 *r++ = pchar;
861 if (pchar == ']')
862 incharclass = false;
863 }
864 else if (pchar == '[')
865 {
866 *r++ = pchar;
867 incharclass = true;
868 }
869 else if (pchar == '%')
870 {
871 *r++ = '.';
872 *r++ = '*';
873 }
874 else if (pchar == '_')
875 *r++ = '.';
876 else if (pchar == '(')
877 {
878 /* convert to non-capturing parenthesis */
879 *r++ = '(';
880 *r++ = '?';
881 *r++ = ':';
882 }
883 else if (pchar == '\\' || pchar == '.' ||
884 pchar == '^' || pchar == '$')
885 {
886 *r++ = '\\';
887 *r++ = pchar;
888 }
889 else
890 *r++ = pchar;
891 p++, plen--;
892 }
893
894 *r++ = ')';
895 *r++ = '$';
896
897 SET_VARSIZE(result, r - ((char *) result));
898
899 return result;
900 }
901
902 /*
903 * similar_to_escape(pattern, escape)
904 */
905 Datum
similar_to_escape_2(PG_FUNCTION_ARGS)906 similar_to_escape_2(PG_FUNCTION_ARGS)
907 {
908 text *pat_text = PG_GETARG_TEXT_PP(0);
909 text *esc_text = PG_GETARG_TEXT_PP(1);
910 text *result;
911
912 result = similar_escape_internal(pat_text, esc_text);
913
914 PG_RETURN_TEXT_P(result);
915 }
916
917 /*
918 * similar_to_escape(pattern)
919 * Inserts a default escape character.
920 */
921 Datum
similar_to_escape_1(PG_FUNCTION_ARGS)922 similar_to_escape_1(PG_FUNCTION_ARGS)
923 {
924 text *pat_text = PG_GETARG_TEXT_PP(0);
925 text *result;
926
927 result = similar_escape_internal(pat_text, NULL);
928
929 PG_RETURN_TEXT_P(result);
930 }
931
932 /*
933 * similar_escape(pattern, escape)
934 *
935 * Legacy function for compatibility with views stored using the
936 * pre-v13 expansion of SIMILAR TO. Unlike the above functions, this
937 * is non-strict, which leads to not-per-spec handling of "ESCAPE NULL".
938 */
939 Datum
similar_escape(PG_FUNCTION_ARGS)940 similar_escape(PG_FUNCTION_ARGS)
941 {
942 text *pat_text;
943 text *esc_text;
944 text *result;
945
946 /* This function is not strict, so must test explicitly */
947 if (PG_ARGISNULL(0))
948 PG_RETURN_NULL();
949 pat_text = PG_GETARG_TEXT_PP(0);
950
951 if (PG_ARGISNULL(1))
952 esc_text = NULL; /* use default escape character */
953 else
954 esc_text = PG_GETARG_TEXT_PP(1);
955
956 result = similar_escape_internal(pat_text, esc_text);
957
958 PG_RETURN_TEXT_P(result);
959 }
960
961 /*
962 * regexp_match()
963 * Return the first substring(s) matching a pattern within a string.
964 */
965 Datum
regexp_match(PG_FUNCTION_ARGS)966 regexp_match(PG_FUNCTION_ARGS)
967 {
968 text *orig_str = PG_GETARG_TEXT_PP(0);
969 text *pattern = PG_GETARG_TEXT_PP(1);
970 text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
971 pg_re_flags re_flags;
972 regexp_matches_ctx *matchctx;
973
974 /* Determine options */
975 parse_re_flags(&re_flags, flags);
976 /* User mustn't specify 'g' */
977 if (re_flags.glob)
978 ereport(ERROR,
979 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
980 /* translator: %s is a SQL function name */
981 errmsg("%s does not support the \"global\" option",
982 "regexp_match()"),
983 errhint("Use the regexp_matches function instead.")));
984
985 matchctx = setup_regexp_matches(orig_str, pattern, &re_flags,
986 PG_GET_COLLATION(), true, false, false);
987
988 if (matchctx->nmatches == 0)
989 PG_RETURN_NULL();
990
991 Assert(matchctx->nmatches == 1);
992
993 /* Create workspace that build_regexp_match_result needs */
994 matchctx->elems = (Datum *) palloc(sizeof(Datum) * matchctx->npatterns);
995 matchctx->nulls = (bool *) palloc(sizeof(bool) * matchctx->npatterns);
996
997 PG_RETURN_DATUM(PointerGetDatum(build_regexp_match_result(matchctx)));
998 }
999
1000 /* This is separate to keep the opr_sanity regression test from complaining */
1001 Datum
regexp_match_no_flags(PG_FUNCTION_ARGS)1002 regexp_match_no_flags(PG_FUNCTION_ARGS)
1003 {
1004 return regexp_match(fcinfo);
1005 }
1006
1007 /*
1008 * regexp_matches()
1009 * Return a table of all matches of a pattern within a string.
1010 */
1011 Datum
regexp_matches(PG_FUNCTION_ARGS)1012 regexp_matches(PG_FUNCTION_ARGS)
1013 {
1014 FuncCallContext *funcctx;
1015 regexp_matches_ctx *matchctx;
1016
1017 if (SRF_IS_FIRSTCALL())
1018 {
1019 text *pattern = PG_GETARG_TEXT_PP(1);
1020 text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
1021 pg_re_flags re_flags;
1022 MemoryContext oldcontext;
1023
1024 funcctx = SRF_FIRSTCALL_INIT();
1025 oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
1026
1027 /* Determine options */
1028 parse_re_flags(&re_flags, flags);
1029
1030 /* be sure to copy the input string into the multi-call ctx */
1031 matchctx = setup_regexp_matches(PG_GETARG_TEXT_P_COPY(0), pattern,
1032 &re_flags,
1033 PG_GET_COLLATION(),
1034 true, false, false);
1035
1036 /* Pre-create workspace that build_regexp_match_result needs */
1037 matchctx->elems = (Datum *) palloc(sizeof(Datum) * matchctx->npatterns);
1038 matchctx->nulls = (bool *) palloc(sizeof(bool) * matchctx->npatterns);
1039
1040 MemoryContextSwitchTo(oldcontext);
1041 funcctx->user_fctx = (void *) matchctx;
1042 }
1043
1044 funcctx = SRF_PERCALL_SETUP();
1045 matchctx = (regexp_matches_ctx *) funcctx->user_fctx;
1046
1047 if (matchctx->next_match < matchctx->nmatches)
1048 {
1049 ArrayType *result_ary;
1050
1051 result_ary = build_regexp_match_result(matchctx);
1052 matchctx->next_match++;
1053 SRF_RETURN_NEXT(funcctx, PointerGetDatum(result_ary));
1054 }
1055
1056 SRF_RETURN_DONE(funcctx);
1057 }
1058
1059 /* This is separate to keep the opr_sanity regression test from complaining */
1060 Datum
regexp_matches_no_flags(PG_FUNCTION_ARGS)1061 regexp_matches_no_flags(PG_FUNCTION_ARGS)
1062 {
1063 return regexp_matches(fcinfo);
1064 }
1065
1066 /*
1067 * setup_regexp_matches --- do the initial matching for regexp_match
1068 * and regexp_split functions
1069 *
1070 * To avoid having to re-find the compiled pattern on each call, we do
1071 * all the matching in one swoop. The returned regexp_matches_ctx contains
1072 * the locations of all the substrings matching the pattern.
1073 *
1074 * The three bool parameters have only two patterns (one for matching, one for
1075 * splitting) but it seems clearer to distinguish the functionality this way
1076 * than to key it all off one "is_split" flag. We don't currently assume that
1077 * fetching_unmatched is exclusive of fetching the matched text too; if it's
1078 * set, the conversion buffer is large enough to fetch any single matched or
1079 * unmatched string, but not any larger substring. (In practice, when splitting
1080 * the matches are usually small anyway, and it didn't seem worth complicating
1081 * the code further.)
1082 */
1083 static regexp_matches_ctx *
setup_regexp_matches(text * orig_str,text * pattern,pg_re_flags * re_flags,Oid collation,bool use_subpatterns,bool ignore_degenerate,bool fetching_unmatched)1084 setup_regexp_matches(text *orig_str, text *pattern, pg_re_flags *re_flags,
1085 Oid collation,
1086 bool use_subpatterns,
1087 bool ignore_degenerate,
1088 bool fetching_unmatched)
1089 {
1090 regexp_matches_ctx *matchctx = palloc0(sizeof(regexp_matches_ctx));
1091 int eml = pg_database_encoding_max_length();
1092 int orig_len;
1093 pg_wchar *wide_str;
1094 int wide_len;
1095 regex_t *cpattern;
1096 regmatch_t *pmatch;
1097 int pmatch_len;
1098 int array_len;
1099 int array_idx;
1100 int prev_match_end;
1101 int prev_valid_match_end;
1102 int start_search;
1103 int maxlen = 0; /* largest fetch length in characters */
1104
1105 /* save original string --- we'll extract result substrings from it */
1106 matchctx->orig_str = orig_str;
1107
1108 /* convert string to pg_wchar form for matching */
1109 orig_len = VARSIZE_ANY_EXHDR(orig_str);
1110 wide_str = (pg_wchar *) palloc(sizeof(pg_wchar) * (orig_len + 1));
1111 wide_len = pg_mb2wchar_with_len(VARDATA_ANY(orig_str), wide_str, orig_len);
1112
1113 /* set up the compiled pattern */
1114 cpattern = RE_compile_and_cache(pattern, re_flags->cflags, collation);
1115
1116 /* do we want to remember subpatterns? */
1117 if (use_subpatterns && cpattern->re_nsub > 0)
1118 {
1119 matchctx->npatterns = cpattern->re_nsub;
1120 pmatch_len = cpattern->re_nsub + 1;
1121 }
1122 else
1123 {
1124 use_subpatterns = false;
1125 matchctx->npatterns = 1;
1126 pmatch_len = 1;
1127 }
1128
1129 /* temporary output space for RE package */
1130 pmatch = palloc(sizeof(regmatch_t) * pmatch_len);
1131
1132 /*
1133 * the real output space (grown dynamically if needed)
1134 *
1135 * use values 2^n-1, not 2^n, so that we hit the limit at 2^28-1 rather
1136 * than at 2^27
1137 */
1138 array_len = re_flags->glob ? 255 : 31;
1139 matchctx->match_locs = (int *) palloc(sizeof(int) * array_len);
1140 array_idx = 0;
1141
1142 /* search for the pattern, perhaps repeatedly */
1143 prev_match_end = 0;
1144 prev_valid_match_end = 0;
1145 start_search = 0;
1146 while (RE_wchar_execute(cpattern, wide_str, wide_len, start_search,
1147 pmatch_len, pmatch))
1148 {
1149 /*
1150 * If requested, ignore degenerate matches, which are zero-length
1151 * matches occurring at the start or end of a string or just after a
1152 * previous match.
1153 */
1154 if (!ignore_degenerate ||
1155 (pmatch[0].rm_so < wide_len &&
1156 pmatch[0].rm_eo > prev_match_end))
1157 {
1158 /* enlarge output space if needed */
1159 while (array_idx + matchctx->npatterns * 2 + 1 > array_len)
1160 {
1161 array_len += array_len + 1; /* 2^n-1 => 2^(n+1)-1 */
1162 if (array_len > MaxAllocSize / sizeof(int))
1163 ereport(ERROR,
1164 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1165 errmsg("too many regular expression matches")));
1166 matchctx->match_locs = (int *) repalloc(matchctx->match_locs,
1167 sizeof(int) * array_len);
1168 }
1169
1170 /* save this match's locations */
1171 if (use_subpatterns)
1172 {
1173 int i;
1174
1175 for (i = 1; i <= matchctx->npatterns; i++)
1176 {
1177 int so = pmatch[i].rm_so;
1178 int eo = pmatch[i].rm_eo;
1179
1180 matchctx->match_locs[array_idx++] = so;
1181 matchctx->match_locs[array_idx++] = eo;
1182 if (so >= 0 && eo >= 0 && (eo - so) > maxlen)
1183 maxlen = (eo - so);
1184 }
1185 }
1186 else
1187 {
1188 int so = pmatch[0].rm_so;
1189 int eo = pmatch[0].rm_eo;
1190
1191 matchctx->match_locs[array_idx++] = so;
1192 matchctx->match_locs[array_idx++] = eo;
1193 if (so >= 0 && eo >= 0 && (eo - so) > maxlen)
1194 maxlen = (eo - so);
1195 }
1196 matchctx->nmatches++;
1197
1198 /*
1199 * check length of unmatched portion between end of previous valid
1200 * (nondegenerate, or degenerate but not ignored) match and start
1201 * of current one
1202 */
1203 if (fetching_unmatched &&
1204 pmatch[0].rm_so >= 0 &&
1205 (pmatch[0].rm_so - prev_valid_match_end) > maxlen)
1206 maxlen = (pmatch[0].rm_so - prev_valid_match_end);
1207 prev_valid_match_end = pmatch[0].rm_eo;
1208 }
1209 prev_match_end = pmatch[0].rm_eo;
1210
1211 /* if not glob, stop after one match */
1212 if (!re_flags->glob)
1213 break;
1214
1215 /*
1216 * Advance search position. Normally we start the next search at the
1217 * end of the previous match; but if the match was of zero length, we
1218 * have to advance by one character, or we'd just find the same match
1219 * again.
1220 */
1221 start_search = prev_match_end;
1222 if (pmatch[0].rm_so == pmatch[0].rm_eo)
1223 start_search++;
1224 if (start_search > wide_len)
1225 break;
1226 }
1227
1228 /*
1229 * check length of unmatched portion between end of last match and end of
1230 * input string
1231 */
1232 if (fetching_unmatched &&
1233 (wide_len - prev_valid_match_end) > maxlen)
1234 maxlen = (wide_len - prev_valid_match_end);
1235
1236 /*
1237 * Keep a note of the end position of the string for the benefit of
1238 * splitting code.
1239 */
1240 matchctx->match_locs[array_idx] = wide_len;
1241
1242 if (eml > 1)
1243 {
1244 int64 maxsiz = eml * (int64) maxlen;
1245 int conv_bufsiz;
1246
1247 /*
1248 * Make the conversion buffer large enough for any substring of
1249 * interest.
1250 *
1251 * Worst case: assume we need the maximum size (maxlen*eml), but take
1252 * advantage of the fact that the original string length in bytes is
1253 * an upper bound on the byte length of any fetched substring (and we
1254 * know that len+1 is safe to allocate because the varlena header is
1255 * longer than 1 byte).
1256 */
1257 if (maxsiz > orig_len)
1258 conv_bufsiz = orig_len + 1;
1259 else
1260 conv_bufsiz = maxsiz + 1; /* safe since maxsiz < 2^30 */
1261
1262 matchctx->conv_buf = palloc(conv_bufsiz);
1263 matchctx->conv_bufsiz = conv_bufsiz;
1264 matchctx->wide_str = wide_str;
1265 }
1266 else
1267 {
1268 /* No need to keep the wide string if we're in a single-byte charset. */
1269 pfree(wide_str);
1270 matchctx->wide_str = NULL;
1271 matchctx->conv_buf = NULL;
1272 matchctx->conv_bufsiz = 0;
1273 }
1274
1275 /* Clean up temp storage */
1276 pfree(pmatch);
1277
1278 return matchctx;
1279 }
1280
1281 /*
1282 * build_regexp_match_result - build output array for current match
1283 */
1284 static ArrayType *
build_regexp_match_result(regexp_matches_ctx * matchctx)1285 build_regexp_match_result(regexp_matches_ctx *matchctx)
1286 {
1287 char *buf = matchctx->conv_buf;
1288 Datum *elems = matchctx->elems;
1289 bool *nulls = matchctx->nulls;
1290 int dims[1];
1291 int lbs[1];
1292 int loc;
1293 int i;
1294
1295 /* Extract matching substrings from the original string */
1296 loc = matchctx->next_match * matchctx->npatterns * 2;
1297 for (i = 0; i < matchctx->npatterns; i++)
1298 {
1299 int so = matchctx->match_locs[loc++];
1300 int eo = matchctx->match_locs[loc++];
1301
1302 if (so < 0 || eo < 0)
1303 {
1304 elems[i] = (Datum) 0;
1305 nulls[i] = true;
1306 }
1307 else if (buf)
1308 {
1309 int len = pg_wchar2mb_with_len(matchctx->wide_str + so,
1310 buf,
1311 eo - so);
1312
1313 Assert(len < matchctx->conv_bufsiz);
1314 elems[i] = PointerGetDatum(cstring_to_text_with_len(buf, len));
1315 nulls[i] = false;
1316 }
1317 else
1318 {
1319 elems[i] = DirectFunctionCall3(text_substr,
1320 PointerGetDatum(matchctx->orig_str),
1321 Int32GetDatum(so + 1),
1322 Int32GetDatum(eo - so));
1323 nulls[i] = false;
1324 }
1325 }
1326
1327 /* And form an array */
1328 dims[0] = matchctx->npatterns;
1329 lbs[0] = 1;
1330 /* XXX: this hardcodes assumptions about the text type */
1331 return construct_md_array(elems, nulls, 1, dims, lbs,
1332 TEXTOID, -1, false, TYPALIGN_INT);
1333 }
1334
1335 /*
1336 * regexp_split_to_table()
1337 * Split the string at matches of the pattern, returning the
1338 * split-out substrings as a table.
1339 */
1340 Datum
regexp_split_to_table(PG_FUNCTION_ARGS)1341 regexp_split_to_table(PG_FUNCTION_ARGS)
1342 {
1343 FuncCallContext *funcctx;
1344 regexp_matches_ctx *splitctx;
1345
1346 if (SRF_IS_FIRSTCALL())
1347 {
1348 text *pattern = PG_GETARG_TEXT_PP(1);
1349 text *flags = PG_GETARG_TEXT_PP_IF_EXISTS(2);
1350 pg_re_flags re_flags;
1351 MemoryContext oldcontext;
1352
1353 funcctx = SRF_FIRSTCALL_INIT();
1354 oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
1355
1356 /* Determine options */
1357 parse_re_flags(&re_flags, flags);
1358 /* User mustn't specify 'g' */
1359 if (re_flags.glob)
1360 ereport(ERROR,
1361 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1362 /* translator: %s is a SQL function name */
1363 errmsg("%s does not support the \"global\" option",
1364 "regexp_split_to_table()")));
1365 /* But we find all the matches anyway */
1366 re_flags.glob = true;
1367
1368 /* be sure to copy the input string into the multi-call ctx */
1369 splitctx = setup_regexp_matches(PG_GETARG_TEXT_P_COPY(0), pattern,
1370 &re_flags,
1371 PG_GET_COLLATION(),
1372 false, true, true);
1373
1374 MemoryContextSwitchTo(oldcontext);
1375 funcctx->user_fctx = (void *) splitctx;
1376 }
1377
1378 funcctx = SRF_PERCALL_SETUP();
1379 splitctx = (regexp_matches_ctx *) funcctx->user_fctx;
1380
1381 if (splitctx->next_match <= splitctx->nmatches)
1382 {
1383 Datum result = build_regexp_split_result(splitctx);
1384
1385 splitctx->next_match++;
1386 SRF_RETURN_NEXT(funcctx, result);
1387 }
1388
1389 SRF_RETURN_DONE(funcctx);
1390 }
1391
1392 /* This is separate to keep the opr_sanity regression test from complaining */
1393 Datum
regexp_split_to_table_no_flags(PG_FUNCTION_ARGS)1394 regexp_split_to_table_no_flags(PG_FUNCTION_ARGS)
1395 {
1396 return regexp_split_to_table(fcinfo);
1397 }
1398
1399 /*
1400 * regexp_split_to_array()
1401 * Split the string at matches of the pattern, returning the
1402 * split-out substrings as an array.
1403 */
1404 Datum
regexp_split_to_array(PG_FUNCTION_ARGS)1405 regexp_split_to_array(PG_FUNCTION_ARGS)
1406 {
1407 ArrayBuildState *astate = NULL;
1408 pg_re_flags re_flags;
1409 regexp_matches_ctx *splitctx;
1410
1411 /* Determine options */
1412 parse_re_flags(&re_flags, PG_GETARG_TEXT_PP_IF_EXISTS(2));
1413 /* User mustn't specify 'g' */
1414 if (re_flags.glob)
1415 ereport(ERROR,
1416 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
1417 /* translator: %s is a SQL function name */
1418 errmsg("%s does not support the \"global\" option",
1419 "regexp_split_to_array()")));
1420 /* But we find all the matches anyway */
1421 re_flags.glob = true;
1422
1423 splitctx = setup_regexp_matches(PG_GETARG_TEXT_PP(0),
1424 PG_GETARG_TEXT_PP(1),
1425 &re_flags,
1426 PG_GET_COLLATION(),
1427 false, true, true);
1428
1429 while (splitctx->next_match <= splitctx->nmatches)
1430 {
1431 astate = accumArrayResult(astate,
1432 build_regexp_split_result(splitctx),
1433 false,
1434 TEXTOID,
1435 CurrentMemoryContext);
1436 splitctx->next_match++;
1437 }
1438
1439 PG_RETURN_ARRAYTYPE_P(makeArrayResult(astate, CurrentMemoryContext));
1440 }
1441
1442 /* This is separate to keep the opr_sanity regression test from complaining */
1443 Datum
regexp_split_to_array_no_flags(PG_FUNCTION_ARGS)1444 regexp_split_to_array_no_flags(PG_FUNCTION_ARGS)
1445 {
1446 return regexp_split_to_array(fcinfo);
1447 }
1448
1449 /*
1450 * build_regexp_split_result - build output string for current match
1451 *
1452 * We return the string between the current match and the previous one,
1453 * or the string after the last match when next_match == nmatches.
1454 */
1455 static Datum
build_regexp_split_result(regexp_matches_ctx * splitctx)1456 build_regexp_split_result(regexp_matches_ctx *splitctx)
1457 {
1458 char *buf = splitctx->conv_buf;
1459 int startpos;
1460 int endpos;
1461
1462 if (splitctx->next_match > 0)
1463 startpos = splitctx->match_locs[splitctx->next_match * 2 - 1];
1464 else
1465 startpos = 0;
1466 if (startpos < 0)
1467 elog(ERROR, "invalid match ending position");
1468
1469 endpos = splitctx->match_locs[splitctx->next_match * 2];
1470 if (endpos < startpos)
1471 elog(ERROR, "invalid match starting position");
1472
1473 if (buf)
1474 {
1475 int len;
1476
1477 len = pg_wchar2mb_with_len(splitctx->wide_str + startpos,
1478 buf,
1479 endpos - startpos);
1480 Assert(len < splitctx->conv_bufsiz);
1481 return PointerGetDatum(cstring_to_text_with_len(buf, len));
1482 }
1483 else
1484 {
1485 return DirectFunctionCall3(text_substr,
1486 PointerGetDatum(splitctx->orig_str),
1487 Int32GetDatum(startpos + 1),
1488 Int32GetDatum(endpos - startpos));
1489 }
1490 }
1491
1492 /*
1493 * regexp_fixed_prefix - extract fixed prefix, if any, for a regexp
1494 *
1495 * The result is NULL if there is no fixed prefix, else a palloc'd string.
1496 * If it is an exact match, not just a prefix, *exact is returned as true.
1497 */
1498 char *
regexp_fixed_prefix(text * text_re,bool case_insensitive,Oid collation,bool * exact)1499 regexp_fixed_prefix(text *text_re, bool case_insensitive, Oid collation,
1500 bool *exact)
1501 {
1502 char *result;
1503 regex_t *re;
1504 int cflags;
1505 int re_result;
1506 pg_wchar *str;
1507 size_t slen;
1508 size_t maxlen;
1509 char errMsg[100];
1510
1511 *exact = false; /* default result */
1512
1513 /* Compile RE */
1514 cflags = REG_ADVANCED;
1515 if (case_insensitive)
1516 cflags |= REG_ICASE;
1517
1518 re = RE_compile_and_cache(text_re, cflags, collation);
1519
1520 /* Examine it to see if there's a fixed prefix */
1521 re_result = pg_regprefix(re, &str, &slen);
1522
1523 switch (re_result)
1524 {
1525 case REG_NOMATCH:
1526 return NULL;
1527
1528 case REG_PREFIX:
1529 /* continue with wchar conversion */
1530 break;
1531
1532 case REG_EXACT:
1533 *exact = true;
1534 /* continue with wchar conversion */
1535 break;
1536
1537 default:
1538 /* re failed??? */
1539 CHECK_FOR_INTERRUPTS();
1540 pg_regerror(re_result, re, errMsg, sizeof(errMsg));
1541 ereport(ERROR,
1542 (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
1543 errmsg("regular expression failed: %s", errMsg)));
1544 break;
1545 }
1546
1547 /* Convert pg_wchar result back to database encoding */
1548 maxlen = pg_database_encoding_max_length() * slen + 1;
1549 result = (char *) palloc(maxlen);
1550 slen = pg_wchar2mb_with_len(str, result, slen);
1551 Assert(slen < maxlen);
1552
1553 free(str);
1554
1555 return result;
1556 }
1557