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trgm_op.c
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1 /*
2  * contrib/pg_trgm/trgm_op.c
3  */
4 #include "postgres.h"
5 
6 #include <ctype.h>
7 
8 #include "trgm.h"
9 
10 #include "catalog/pg_type.h"
11 #include "tsearch/ts_locale.h"
12 #include "utils/lsyscache.h"
13 #include "utils/memutils.h"
14 #include "utils/pg_crc.h"
15 
17 
18 /* GUC variables */
19 double similarity_threshold = 0.3f;
21 
22 void _PG_init(void);
23 
35 
36 /* Trigram with position */
37 typedef struct
38 {
40  int index;
41 } pos_trgm;
42 
43 /*
44  * Module load callback
45  */
46 void
47 _PG_init(void)
48 {
49  /* Define custom GUC variables. */
50  DefineCustomRealVariable("pg_trgm.similarity_threshold",
51  "Sets the threshold used by the %% operator.",
52  "Valid range is 0.0 .. 1.0.",
54  0.3,
55  0.0,
56  1.0,
58  0,
59  NULL,
60  NULL,
61  NULL);
62  DefineCustomRealVariable("pg_trgm.word_similarity_threshold",
63  "Sets the threshold used by the <%% operator.",
64  "Valid range is 0.0 .. 1.0.",
66  0.6,
67  0.0,
68  1.0,
70  0,
71  NULL,
72  NULL,
73  NULL);
74 }
75 
76 /*
77  * Deprecated function.
78  * Use "pg_trgm.similarity_threshold" GUC variable instead of this function.
79  */
80 Datum
82 {
83  float4 nlimit = PG_GETARG_FLOAT4(0);
84  char *nlimit_str;
85  Oid func_out_oid;
86  bool is_varlena;
87 
88  getTypeOutputInfo(FLOAT4OID, &func_out_oid, &is_varlena);
89 
90  nlimit_str = OidOutputFunctionCall(func_out_oid, Float4GetDatum(nlimit));
91 
92  SetConfigOption("pg_trgm.similarity_threshold", nlimit_str,
94 
96 }
97 
98 /*
99  * Deprecated function.
100  * Use "pg_trgm.similarity_threshold" GUC variable instead of this function.
101  */
102 Datum
104 {
106 }
107 
108 static int
109 comp_trgm(const void *a, const void *b)
110 {
111  return CMPTRGM(a, b);
112 }
113 
114 static int
115 unique_array(trgm *a, int len)
116 {
117  trgm *curend,
118  *tmp;
119 
120  curend = tmp = a;
121  while (tmp - a < len)
122  if (CMPTRGM(tmp, curend))
123  {
124  curend++;
125  CPTRGM(curend, tmp);
126  tmp++;
127  }
128  else
129  tmp++;
130 
131  return curend + 1 - a;
132 }
133 
134 /*
135  * Finds first word in string, returns pointer to the word,
136  * endword points to the character after word
137  */
138 static char *
139 find_word(char *str, int lenstr, char **endword, int *charlen)
140 {
141  char *beginword = str;
142 
143  while (beginword - str < lenstr && !ISWORDCHR(beginword))
144  beginword += pg_mblen(beginword);
145 
146  if (beginword - str >= lenstr)
147  return NULL;
148 
149  *endword = beginword;
150  *charlen = 0;
151  while (*endword - str < lenstr && ISWORDCHR(*endword))
152  {
153  *endword += pg_mblen(*endword);
154  (*charlen)++;
155  }
156 
157  return beginword;
158 }
159 
160 /*
161  * Reduce a trigram (three possibly multi-byte characters) to a trgm,
162  * which is always exactly three bytes. If we have three single-byte
163  * characters, we just use them as-is; otherwise we form a hash value.
164  */
165 void
166 compact_trigram(trgm *tptr, char *str, int bytelen)
167 {
168  if (bytelen == 3)
169  {
170  CPTRGM(tptr, str);
171  }
172  else
173  {
174  pg_crc32 crc;
175 
176  INIT_LEGACY_CRC32(crc);
177  COMP_LEGACY_CRC32(crc, str, bytelen);
178  FIN_LEGACY_CRC32(crc);
179 
180  /*
181  * use only 3 upper bytes from crc, hope, it's good enough hashing
182  */
183  CPTRGM(tptr, &crc);
184  }
185 }
186 
187 /*
188  * Adds trigrams from words (already padded).
189  */
190 static trgm *
191 make_trigrams(trgm *tptr, char *str, int bytelen, int charlen)
192 {
193  char *ptr = str;
194 
195  if (charlen < 3)
196  return tptr;
197 
198  if (bytelen > charlen)
199  {
200  /* Find multibyte character boundaries and apply compact_trigram */
201  int lenfirst = pg_mblen(str),
202  lenmiddle = pg_mblen(str + lenfirst),
203  lenlast = pg_mblen(str + lenfirst + lenmiddle);
204 
205  while ((ptr - str) + lenfirst + lenmiddle + lenlast <= bytelen)
206  {
207  compact_trigram(tptr, ptr, lenfirst + lenmiddle + lenlast);
208 
209  ptr += lenfirst;
210  tptr++;
211 
212  lenfirst = lenmiddle;
213  lenmiddle = lenlast;
214  lenlast = pg_mblen(ptr + lenfirst + lenmiddle);
215  }
216  }
217  else
218  {
219  /* Fast path when there are no multibyte characters */
220  Assert(bytelen == charlen);
221 
222  while (ptr - str < bytelen - 2 /* number of trigrams = strlen - 2 */ )
223  {
224  CPTRGM(tptr, ptr);
225  ptr++;
226  tptr++;
227  }
228  }
229 
230  return tptr;
231 }
232 
233 /*
234  * Make array of trigrams without sorting and removing duplicate items.
235  *
236  * trg: where to return the array of trigrams.
237  * str: source string, of length slen bytes.
238  *
239  * Returns length of the generated array.
240  */
241 static int
242 generate_trgm_only(trgm *trg, char *str, int slen)
243 {
244  trgm *tptr;
245  char *buf;
246  int charlen,
247  bytelen;
248  char *bword,
249  *eword;
250 
251  if (slen + LPADDING + RPADDING < 3 || slen == 0)
252  return 0;
253 
254  tptr = trg;
255 
256  /* Allocate a buffer for case-folded, blank-padded words */
257  buf = (char *) palloc(slen * pg_database_encoding_max_length() + 4);
258 
259  if (LPADDING > 0)
260  {
261  *buf = ' ';
262  if (LPADDING > 1)
263  *(buf + 1) = ' ';
264  }
265 
266  eword = str;
267  while ((bword = find_word(eword, slen - (eword - str), &eword, &charlen)) != NULL)
268  {
269 #ifdef IGNORECASE
270  bword = lowerstr_with_len(bword, eword - bword);
271  bytelen = strlen(bword);
272 #else
273  bytelen = eword - bword;
274 #endif
275 
276  memcpy(buf + LPADDING, bword, bytelen);
277 
278 #ifdef IGNORECASE
279  pfree(bword);
280 #endif
281 
282  buf[LPADDING + bytelen] = ' ';
283  buf[LPADDING + bytelen + 1] = ' ';
284 
285  /*
286  * count trigrams
287  */
288  tptr = make_trigrams(tptr, buf, bytelen + LPADDING + RPADDING,
289  charlen + LPADDING + RPADDING);
290  }
291 
292  pfree(buf);
293 
294  return tptr - trg;
295 }
296 
297 /*
298  * Guard against possible overflow in the palloc requests below. (We
299  * don't worry about the additive constants, since palloc can detect
300  * requests that are a little above MaxAllocSize --- we just need to
301  * prevent integer overflow in the multiplications.)
302  */
303 static void
305 {
306  if ((Size) (slen / 2) >= (MaxAllocSize / (sizeof(trgm) * 3)) ||
308  ereport(ERROR,
309  (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
310  errmsg("out of memory")));
311 }
312 
313 /*
314  * Make array of trigrams with sorting and removing duplicate items.
315  *
316  * str: source string, of length slen bytes.
317  *
318  * Returns the sorted array of unique trigrams.
319  */
320 TRGM *
321 generate_trgm(char *str, int slen)
322 {
323  TRGM *trg;
324  int len;
325 
326  protect_out_of_mem(slen);
327 
328  trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) *3);
329  trg->flag = ARRKEY;
330 
331  len = generate_trgm_only(GETARR(trg), str, slen);
332  SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));
333 
334  if (len == 0)
335  return trg;
336 
337  /*
338  * Make trigrams unique.
339  */
340  if (len > 1)
341  {
342  qsort((void *) GETARR(trg), len, sizeof(trgm), comp_trgm);
343  len = unique_array(GETARR(trg), len);
344  }
345 
346  SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));
347 
348  return trg;
349 }
350 
351 /*
352  * Make array of positional trigrams from two trigram arrays trg1 and trg2.
353  *
354  * trg1: trigram array of search pattern, of length len1. trg1 is required
355  * word which positions don't matter and replaced with -1.
356  * trg2: trigram array of text, of length len2. trg2 is haystack where we
357  * search and have to store its positions.
358  *
359  * Returns concatenated trigram array.
360  */
361 static pos_trgm *
362 make_positional_trgm(trgm *trg1, int len1, trgm *trg2, int len2)
363 {
364  pos_trgm *result;
365  int i,
366  len = len1 + len2;
367 
368  result = (pos_trgm *) palloc(sizeof(pos_trgm) * len);
369 
370  for (i = 0; i < len1; i++)
371  {
372  memcpy(&result[i].trg, &trg1[i], sizeof(trgm));
373  result[i].index = -1;
374  }
375 
376  for (i = 0; i < len2; i++)
377  {
378  memcpy(&result[i + len1].trg, &trg2[i], sizeof(trgm));
379  result[i + len1].index = i;
380  }
381 
382  return result;
383 }
384 
385 /*
386  * Compare position trigrams: compare trigrams first and position second.
387  */
388 static int
389 comp_ptrgm(const void *v1, const void *v2)
390 {
391  const pos_trgm *p1 = (const pos_trgm *) v1;
392  const pos_trgm *p2 = (const pos_trgm *) v2;
393  int cmp;
394 
395  cmp = CMPTRGM(p1->trg, p2->trg);
396  if (cmp != 0)
397  return cmp;
398 
399  if (p1->index < p2->index)
400  return -1;
401  else if (p1->index == p2->index)
402  return 0;
403  else
404  return 1;
405 }
406 
407 /*
408  * Iterative search function which calculates maximum similarity with word in
409  * the string. But maximum similarity is calculated only if check_only == false.
410  *
411  * trg2indexes: array which stores indexes of the array "found".
412  * found: array which stores true of false values.
413  * ulen1: count of unique trigrams of array "trg1".
414  * len2: length of array "trg2" and array "trg2indexes".
415  * len: length of the array "found".
416  * check_only: if true then only check existence of similar search pattern in
417  * text.
418  *
419  * Returns word similarity.
420  */
421 static float4
422 iterate_word_similarity(int *trg2indexes,
423  bool *found,
424  int ulen1,
425  int len2,
426  int len,
427  bool check_only)
428 {
429  int *lastpos,
430  i,
431  ulen2 = 0,
432  count = 0,
433  upper = -1,
434  lower = -1;
435  float4 smlr_cur,
436  smlr_max = 0.0f;
437 
438  /* Memorise last position of each trigram */
439  lastpos = (int *) palloc(sizeof(int) * len);
440  memset(lastpos, -1, sizeof(int) * len);
441 
442  for (i = 0; i < len2; i++)
443  {
444  /* Get index of next trigram */
445  int trgindex = trg2indexes[i];
446 
447  /* Update last position of this trigram */
448  if (lower >= 0 || found[trgindex])
449  {
450  if (lastpos[trgindex] < 0)
451  {
452  ulen2++;
453  if (found[trgindex])
454  count++;
455  }
456  lastpos[trgindex] = i;
457  }
458 
459  /* Adjust lower bound if this trigram is present in required substring */
460  if (found[trgindex])
461  {
462  int prev_lower,
463  tmp_ulen2,
464  tmp_lower,
465  tmp_count;
466 
467  upper = i;
468  if (lower == -1)
469  {
470  lower = i;
471  ulen2 = 1;
472  }
473 
474  smlr_cur = CALCSML(count, ulen1, ulen2);
475 
476  /* Also try to adjust upper bound for greater similarity */
477  tmp_count = count;
478  tmp_ulen2 = ulen2;
479  prev_lower = lower;
480  for (tmp_lower = lower; tmp_lower <= upper; tmp_lower++)
481  {
482  float smlr_tmp = CALCSML(tmp_count, ulen1, tmp_ulen2);
483  int tmp_trgindex;
484 
485  if (smlr_tmp > smlr_cur)
486  {
487  smlr_cur = smlr_tmp;
488  ulen2 = tmp_ulen2;
489  lower = tmp_lower;
490  count = tmp_count;
491  }
492 
493  /*
494  * if we only check that word similarity is greater than
495  * pg_trgm.word_similarity_threshold we do not need to
496  * calculate a maximum similarity.
497  */
498  if (check_only && smlr_cur >= word_similarity_threshold)
499  break;
500 
501  tmp_trgindex = trg2indexes[tmp_lower];
502  if (lastpos[tmp_trgindex] == tmp_lower)
503  {
504  tmp_ulen2--;
505  if (found[tmp_trgindex])
506  tmp_count--;
507  }
508  }
509 
510  smlr_max = Max(smlr_max, smlr_cur);
511 
512  /*
513  * if we only check that word similarity is greater than
514  * pg_trgm.word_similarity_threshold we do not need to calculate a
515  * maximum similarity
516  */
517  if (check_only && smlr_max >= word_similarity_threshold)
518  break;
519 
520  for (tmp_lower = prev_lower; tmp_lower < lower; tmp_lower++)
521  {
522  int tmp_trgindex;
523 
524  tmp_trgindex = trg2indexes[tmp_lower];
525  if (lastpos[tmp_trgindex] == tmp_lower)
526  lastpos[tmp_trgindex] = -1;
527  }
528  }
529  }
530 
531  pfree(lastpos);
532 
533  return smlr_max;
534 }
535 
536 /*
537  * Calculate word similarity.
538  * This function prepare two arrays: "trg2indexes" and "found". Then this arrays
539  * are used to calculate word similarity using iterate_word_similarity().
540  *
541  * "trg2indexes" is array which stores indexes of the array "found".
542  * In other words:
543  * trg2indexes[j] = i;
544  * found[i] = true (or false);
545  * If found[i] == true then there is trigram trg2[j] in array "trg1".
546  * If found[i] == false then there is not trigram trg2[j] in array "trg1".
547  *
548  * str1: search pattern string, of length slen1 bytes.
549  * str2: text in which we are looking for a word, of length slen2 bytes.
550  * check_only: if true then only check existence of similar search pattern in
551  * text.
552  *
553  * Returns word similarity.
554  */
555 static float4
556 calc_word_similarity(char *str1, int slen1, char *str2, int slen2,
557  bool check_only)
558 {
559  bool *found;
560  pos_trgm *ptrg;
561  trgm *trg1;
562  trgm *trg2;
563  int len1,
564  len2,
565  len,
566  i,
567  j,
568  ulen1;
569  int *trg2indexes;
570  float4 result;
571 
572  protect_out_of_mem(slen1 + slen2);
573 
574  /* Make positional trigrams */
575  trg1 = (trgm *) palloc(sizeof(trgm) * (slen1 / 2 + 1) *3);
576  trg2 = (trgm *) palloc(sizeof(trgm) * (slen2 / 2 + 1) *3);
577 
578  len1 = generate_trgm_only(trg1, str1, slen1);
579  len2 = generate_trgm_only(trg2, str2, slen2);
580 
581  ptrg = make_positional_trgm(trg1, len1, trg2, len2);
582  len = len1 + len2;
583  qsort(ptrg, len, sizeof(pos_trgm), comp_ptrgm);
584 
585  pfree(trg1);
586  pfree(trg2);
587 
588  /*
589  * Merge positional trigrams array: enumerate each trigram and find its
590  * presence in required word.
591  */
592  trg2indexes = (int *) palloc(sizeof(int) * len2);
593  found = (bool *) palloc0(sizeof(bool) * len);
594 
595  ulen1 = 0;
596  j = 0;
597  for (i = 0; i < len; i++)
598  {
599  if (i > 0)
600  {
601  int cmp = CMPTRGM(ptrg[i - 1].trg, ptrg[i].trg);
602 
603  if (cmp != 0)
604  {
605  if (found[j])
606  ulen1++;
607  j++;
608  }
609  }
610 
611  if (ptrg[i].index >= 0)
612  {
613  trg2indexes[ptrg[i].index] = j;
614  }
615  else
616  {
617  found[j] = true;
618  }
619  }
620  if (found[j])
621  ulen1++;
622 
623  /* Run iterative procedure to find maximum similarity with word */
624  result = iterate_word_similarity(trg2indexes, found, ulen1, len2, len,
625  check_only);
626 
627  pfree(trg2indexes);
628  pfree(found);
629  pfree(ptrg);
630 
631  return result;
632 }
633 
634 
635 /*
636  * Extract the next non-wildcard part of a search string, i.e. a word bounded
637  * by '_' or '%' meta-characters, non-word characters or string end.
638  *
639  * str: source string, of length lenstr bytes (need not be null-terminated)
640  * buf: where to return the substring (must be long enough)
641  * *bytelen: receives byte length of the found substring
642  * *charlen: receives character length of the found substring
643  *
644  * Returns pointer to end+1 of the found substring in the source string.
645  * Returns NULL if no word found (in which case buf, bytelen, charlen not set)
646  *
647  * If the found word is bounded by non-word characters or string boundaries
648  * then this function will include corresponding padding spaces into buf.
649  */
650 static const char *
651 get_wildcard_part(const char *str, int lenstr,
652  char *buf, int *bytelen, int *charlen)
653 {
654  const char *beginword = str;
655  const char *endword;
656  char *s = buf;
657  bool in_leading_wildcard_meta = false;
658  bool in_trailing_wildcard_meta = false;
659  bool in_escape = false;
660  int clen;
661 
662  /*
663  * Find the first word character, remembering whether preceding character
664  * was wildcard meta-character. Note that the in_escape state persists
665  * from this loop to the next one, since we may exit at a word character
666  * that is in_escape.
667  */
668  while (beginword - str < lenstr)
669  {
670  if (in_escape)
671  {
672  if (ISWORDCHR(beginword))
673  break;
674  in_escape = false;
675  in_leading_wildcard_meta = false;
676  }
677  else
678  {
679  if (ISESCAPECHAR(beginword))
680  in_escape = true;
681  else if (ISWILDCARDCHAR(beginword))
682  in_leading_wildcard_meta = true;
683  else if (ISWORDCHR(beginword))
684  break;
685  else
686  in_leading_wildcard_meta = false;
687  }
688  beginword += pg_mblen(beginword);
689  }
690 
691  /*
692  * Handle string end.
693  */
694  if (beginword - str >= lenstr)
695  return NULL;
696 
697  /*
698  * Add left padding spaces if preceding character wasn't wildcard
699  * meta-character.
700  */
701  *charlen = 0;
702  if (!in_leading_wildcard_meta)
703  {
704  if (LPADDING > 0)
705  {
706  *s++ = ' ';
707  (*charlen)++;
708  if (LPADDING > 1)
709  {
710  *s++ = ' ';
711  (*charlen)++;
712  }
713  }
714  }
715 
716  /*
717  * Copy data into buf until wildcard meta-character, non-word character or
718  * string boundary. Strip escapes during copy.
719  */
720  endword = beginword;
721  while (endword - str < lenstr)
722  {
723  clen = pg_mblen(endword);
724  if (in_escape)
725  {
726  if (ISWORDCHR(endword))
727  {
728  memcpy(s, endword, clen);
729  (*charlen)++;
730  s += clen;
731  }
732  else
733  {
734  /*
735  * Back up endword to the escape character when stopping at an
736  * escaped char, so that subsequent get_wildcard_part will
737  * restart from the escape character. We assume here that
738  * escape chars are single-byte.
739  */
740  endword--;
741  break;
742  }
743  in_escape = false;
744  }
745  else
746  {
747  if (ISESCAPECHAR(endword))
748  in_escape = true;
749  else if (ISWILDCARDCHAR(endword))
750  {
751  in_trailing_wildcard_meta = true;
752  break;
753  }
754  else if (ISWORDCHR(endword))
755  {
756  memcpy(s, endword, clen);
757  (*charlen)++;
758  s += clen;
759  }
760  else
761  break;
762  }
763  endword += clen;
764  }
765 
766  /*
767  * Add right padding spaces if next character isn't wildcard
768  * meta-character.
769  */
770  if (!in_trailing_wildcard_meta)
771  {
772  if (RPADDING > 0)
773  {
774  *s++ = ' ';
775  (*charlen)++;
776  if (RPADDING > 1)
777  {
778  *s++ = ' ';
779  (*charlen)++;
780  }
781  }
782  }
783 
784  *bytelen = s - buf;
785  return endword;
786 }
787 
788 /*
789  * Generates trigrams for wildcard search string.
790  *
791  * Returns array of trigrams that must occur in any string that matches the
792  * wildcard string. For example, given pattern "a%bcd%" the trigrams
793  * " a", "bcd" would be extracted.
794  */
795 TRGM *
796 generate_wildcard_trgm(const char *str, int slen)
797 {
798  TRGM *trg;
799  char *buf,
800  *buf2;
801  trgm *tptr;
802  int len,
803  charlen,
804  bytelen;
805  const char *eword;
806 
807  protect_out_of_mem(slen);
808 
809  trg = (TRGM *) palloc(TRGMHDRSIZE + sizeof(trgm) * (slen / 2 + 1) *3);
810  trg->flag = ARRKEY;
811  SET_VARSIZE(trg, TRGMHDRSIZE);
812 
813  if (slen + LPADDING + RPADDING < 3 || slen == 0)
814  return trg;
815 
816  tptr = GETARR(trg);
817 
818  /* Allocate a buffer for blank-padded, but not yet case-folded, words */
819  buf = palloc(sizeof(char) * (slen + 4));
820 
821  /*
822  * Extract trigrams from each substring extracted by get_wildcard_part.
823  */
824  eword = str;
825  while ((eword = get_wildcard_part(eword, slen - (eword - str),
826  buf, &bytelen, &charlen)) != NULL)
827  {
828 #ifdef IGNORECASE
829  buf2 = lowerstr_with_len(buf, bytelen);
830  bytelen = strlen(buf2);
831 #else
832  buf2 = buf;
833 #endif
834 
835  /*
836  * count trigrams
837  */
838  tptr = make_trigrams(tptr, buf2, bytelen, charlen);
839 
840 #ifdef IGNORECASE
841  pfree(buf2);
842 #endif
843  }
844 
845  pfree(buf);
846 
847  if ((len = tptr - GETARR(trg)) == 0)
848  return trg;
849 
850  /*
851  * Make trigrams unique.
852  */
853  if (len > 1)
854  {
855  qsort((void *) GETARR(trg), len, sizeof(trgm), comp_trgm);
856  len = unique_array(GETARR(trg), len);
857  }
858 
859  SET_VARSIZE(trg, CALCGTSIZE(ARRKEY, len));
860 
861  return trg;
862 }
863 
864 uint32
866 {
867  uint32 val = 0;
868 
869  val |= *(((unsigned char *) ptr));
870  val <<= 8;
871  val |= *(((unsigned char *) ptr) + 1);
872  val <<= 8;
873  val |= *(((unsigned char *) ptr) + 2);
874 
875  return val;
876 }
877 
878 Datum
880 {
881  text *in = PG_GETARG_TEXT_P(0);
882  TRGM *trg;
883  Datum *d;
884  ArrayType *a;
885  trgm *ptr;
886  int i;
887 
888  trg = generate_trgm(VARDATA(in), VARSIZE(in) - VARHDRSZ);
889  d = (Datum *) palloc(sizeof(Datum) * (1 + ARRNELEM(trg)));
890 
891  for (i = 0, ptr = GETARR(trg); i < ARRNELEM(trg); i++, ptr++)
892  {
893  text *item = (text *) palloc(VARHDRSZ + Max(12, pg_database_encoding_max_length() * 3));
894 
896  {
897  snprintf(VARDATA(item), 12, "0x%06x", trgm2int(ptr));
898  SET_VARSIZE(item, VARHDRSZ + strlen(VARDATA(item)));
899  }
900  else
901  {
902  SET_VARSIZE(item, VARHDRSZ + 3);
903  CPTRGM(VARDATA(item), ptr);
904  }
905  d[i] = PointerGetDatum(item);
906  }
907 
908  a = construct_array(
909  d,
910  ARRNELEM(trg),
911  TEXTOID,
912  -1,
913  false,
914  'i'
915  );
916 
917  for (i = 0; i < ARRNELEM(trg); i++)
918  pfree(DatumGetPointer(d[i]));
919 
920  pfree(d);
921  pfree(trg);
922  PG_FREE_IF_COPY(in, 0);
923 
925 }
926 
927 float4
928 cnt_sml(TRGM *trg1, TRGM *trg2, bool inexact)
929 {
930  trgm *ptr1,
931  *ptr2;
932  int count = 0;
933  int len1,
934  len2;
935 
936  ptr1 = GETARR(trg1);
937  ptr2 = GETARR(trg2);
938 
939  len1 = ARRNELEM(trg1);
940  len2 = ARRNELEM(trg2);
941 
942  /* explicit test is needed to avoid 0/0 division when both lengths are 0 */
943  if (len1 <= 0 || len2 <= 0)
944  return (float4) 0.0;
945 
946  while (ptr1 - GETARR(trg1) < len1 && ptr2 - GETARR(trg2) < len2)
947  {
948  int res = CMPTRGM(ptr1, ptr2);
949 
950  if (res < 0)
951  ptr1++;
952  else if (res > 0)
953  ptr2++;
954  else
955  {
956  ptr1++;
957  ptr2++;
958  count++;
959  }
960  }
961 
962  /*
963  * If inexact then len2 is equal to count, because we don't know actual
964  * length of second string in inexact search and we can assume that count
965  * is a lower bound of len2.
966  */
967  return CALCSML(count, len1, inexact ? count : len2);
968 }
969 
970 
971 /*
972  * Returns whether trg2 contains all trigrams in trg1.
973  * This relies on the trigram arrays being sorted.
974  */
975 bool
977 {
978  trgm *ptr1,
979  *ptr2;
980  int len1,
981  len2;
982 
983  ptr1 = GETARR(trg1);
984  ptr2 = GETARR(trg2);
985 
986  len1 = ARRNELEM(trg1);
987  len2 = ARRNELEM(trg2);
988 
989  while (ptr1 - GETARR(trg1) < len1 && ptr2 - GETARR(trg2) < len2)
990  {
991  int res = CMPTRGM(ptr1, ptr2);
992 
993  if (res < 0)
994  return false;
995  else if (res > 0)
996  ptr2++;
997  else
998  {
999  ptr1++;
1000  ptr2++;
1001  }
1002  }
1003  if (ptr1 - GETARR(trg1) < len1)
1004  return false;
1005  else
1006  return true;
1007 }
1008 
1009 /*
1010  * Return a palloc'd boolean array showing, for each trigram in "query",
1011  * whether it is present in the trigram array "key".
1012  * This relies on the "key" array being sorted, but "query" need not be.
1013  */
1014 bool *
1016 {
1017  bool *result;
1018  trgm *ptrq = GETARR(query),
1019  *ptrk = GETARR(key);
1020  int lenq = ARRNELEM(query),
1021  lenk = ARRNELEM(key),
1022  i;
1023 
1024  result = (bool *) palloc0(lenq * sizeof(bool));
1025 
1026  /* for each query trigram, do a binary search in the key array */
1027  for (i = 0; i < lenq; i++)
1028  {
1029  int lo = 0;
1030  int hi = lenk;
1031 
1032  while (lo < hi)
1033  {
1034  int mid = (lo + hi) / 2;
1035  int res = CMPTRGM(ptrq, ptrk + mid);
1036 
1037  if (res < 0)
1038  hi = mid;
1039  else if (res > 0)
1040  lo = mid + 1;
1041  else
1042  {
1043  result[i] = true;
1044  break;
1045  }
1046  }
1047  ptrq++;
1048  }
1049 
1050  return result;
1051 }
1052 
1053 Datum
1055 {
1056  text *in1 = PG_GETARG_TEXT_P(0);
1057  text *in2 = PG_GETARG_TEXT_P(1);
1058  TRGM *trg1,
1059  *trg2;
1060  float4 res;
1061 
1062  trg1 = generate_trgm(VARDATA(in1), VARSIZE(in1) - VARHDRSZ);
1063  trg2 = generate_trgm(VARDATA(in2), VARSIZE(in2) - VARHDRSZ);
1064 
1065  res = cnt_sml(trg1, trg2, false);
1066 
1067  pfree(trg1);
1068  pfree(trg2);
1069  PG_FREE_IF_COPY(in1, 0);
1070  PG_FREE_IF_COPY(in2, 1);
1071 
1072  PG_RETURN_FLOAT4(res);
1073 }
1074 
1075 Datum
1077 {
1078  text *in1 = PG_GETARG_TEXT_PP(0);
1079  text *in2 = PG_GETARG_TEXT_PP(1);
1080  float4 res;
1081 
1083  VARDATA_ANY(in2), VARSIZE_ANY_EXHDR(in2),
1084  false);
1085 
1086  PG_FREE_IF_COPY(in1, 0);
1087  PG_FREE_IF_COPY(in2, 1);
1088  PG_RETURN_FLOAT4(res);
1089 }
1090 
1091 Datum
1093 {
1095  PG_GETARG_DATUM(0),
1096  PG_GETARG_DATUM(1)));
1097 
1098  PG_RETURN_FLOAT4(1.0 - res);
1099 }
1100 
1101 Datum
1103 {
1105  PG_GETARG_DATUM(0),
1106  PG_GETARG_DATUM(1)));
1107 
1109 }
1110 
1111 Datum
1113 {
1114  text *in1 = PG_GETARG_TEXT_PP(0);
1115  text *in2 = PG_GETARG_TEXT_PP(1);
1116  float4 res;
1117 
1119  VARDATA_ANY(in2), VARSIZE_ANY_EXHDR(in2),
1120  true);
1121 
1122  PG_FREE_IF_COPY(in1, 0);
1123  PG_FREE_IF_COPY(in2, 1);
1125 }
1126 
1127 Datum
1129 {
1130  text *in1 = PG_GETARG_TEXT_PP(0);
1131  text *in2 = PG_GETARG_TEXT_PP(1);
1132  float4 res;
1133 
1135  VARDATA_ANY(in1), VARSIZE_ANY_EXHDR(in1),
1136  true);
1137 
1138  PG_FREE_IF_COPY(in1, 0);
1139  PG_FREE_IF_COPY(in2, 1);
1141 }
1142 
1143 Datum
1145 {
1146  text *in1 = PG_GETARG_TEXT_PP(0);
1147  text *in2 = PG_GETARG_TEXT_PP(1);
1148  float4 res;
1149 
1151  VARDATA_ANY(in2), VARSIZE_ANY_EXHDR(in2),
1152  false);
1153 
1154  PG_FREE_IF_COPY(in1, 0);
1155  PG_FREE_IF_COPY(in2, 1);
1156  PG_RETURN_FLOAT4(1.0 - res);
1157 }
1158 
1159 Datum
1161 {
1162  text *in1 = PG_GETARG_TEXT_PP(0);
1163  text *in2 = PG_GETARG_TEXT_PP(1);
1164  float4 res;
1165 
1167  VARDATA_ANY(in1), VARSIZE_ANY_EXHDR(in1),
1168  false);
1169 
1170  PG_FREE_IF_COPY(in1, 0);
1171  PG_FREE_IF_COPY(in2, 1);
1172  PG_RETURN_FLOAT4(1.0 - res);
1173 }
#define PG_RETURN_POINTER(x)
Definition: fmgr.h:305
uint32 trgm2int(trgm *ptr)
Definition: trgm_op.c:865
#define INIT_LEGACY_CRC32(crc)
Definition: pg_crc.h:79
#define ISWILDCARDCHAR(x)
Definition: trgm.h:60
#define PG_RETURN_FLOAT4(x)
Definition: fmgr.h:309
#define CMPTRGM(a, b)
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void getTypeOutputInfo(Oid type, Oid *typOutput, bool *typIsVarlena)
Definition: lsyscache.c:2600
#define VARDATA_ANY(PTR)
Definition: postgres.h:349
#define VARDATA(PTR)
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PG_FUNCTION_INFO_V1(set_limit)
Datum lower(PG_FUNCTION_ARGS)
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Datum word_similarity_dist_commutator_op(PG_FUNCTION_ARGS)
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#define TEXTOID
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int index
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#define VARSIZE(PTR)
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#define PointerGetDatum(X)
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#define PG_GETARG_DATUM(n)
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#define VARHDRSZ
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char * lowerstr_with_len(const char *str, int len)
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ArrayType * construct_array(Datum *elems, int nelems, Oid elmtype, int elmlen, bool elmbyval, char elmalign)
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#define ISWORDCHR(c)
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#define ARRKEY
Definition: trgm.h:94
int errcode(int sqlerrcode)
Definition: elog.c:575
Datum similarity_op(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1102
static void protect_out_of_mem(int slen)
Definition: trgm_op.c:304
static trgm * make_trigrams(trgm *tptr, char *str, int bytelen, int charlen)
Definition: trgm_op.c:191
void _PG_init(void)
Definition: trgm_op.c:47
int snprintf(char *str, size_t count, const char *fmt,...) pg_attribute_printf(3
#define ARRNELEM(x)
Definition: trgm.h:105
TRGM * generate_trgm(char *str, int slen)
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Datum upper(PG_FUNCTION_ARGS)
Definition: oracle_compat.c:74
unsigned int Oid
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static char * find_word(char *str, int lenstr, char **endword, int *charlen)
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void DefineCustomRealVariable(const char *name, const char *short_desc, const char *long_desc, double *valueAddr, double bootValue, double minValue, double maxValue, GucContext context, int flags, GucRealCheckHook check_hook, GucRealAssignHook assign_hook, GucShowHook show_hook)
Definition: guc.c:7739
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Definition: pg_crc.h:80
#define PG_GETARG_TEXT_PP(n)
Definition: fmgr.h:270
Definition: type.h:90
#define GETARR(x)
Definition: trgm.h:104
bool * trgm_presence_map(TRGM *query, TRGM *key)
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Definition: mcxt.c:992
#define ERROR
Definition: elog.h:43
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static int comp_ptrgm(const void *v1, const void *v2)
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#define ISPRINTABLETRGM(t)
Definition: trgm.h:57
Datum Float4GetDatum(float4 X)
Definition: fmgr.c:2114
void SetConfigOption(const char *name, const char *value, GucContext context, GucSource source)
Definition: guc.c:6629
static char * buf
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int pg_database_encoding_max_length(void)
Definition: wchar.c:1833
Datum show_trgm(PG_FUNCTION_ARGS)
Definition: trgm_op.c:879
unsigned int uint32
Definition: c.h:265
Datum word_similarity(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1076
#define TRGMHDRSIZE
Definition: trgm.h:70
#define PG_GETARG_FLOAT4(n)
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#define ereport(elevel, rest)
Definition: elog.h:122
TRGM * generate_wildcard_trgm(const char *str, int slen)
Definition: trgm_op.c:796
static float4 calc_word_similarity(char *str1, int slen1, char *str2, int slen2, bool check_only)
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PG_MODULE_MAGIC
Definition: trgm_op.c:16
static float4 iterate_word_similarity(int *trg2indexes, bool *found, int ulen1, int len2, int len, bool check_only)
Definition: trgm_op.c:422
#define MaxAllocSize
Definition: memutils.h:40
float float4
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#define FLOAT4OID
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void * palloc0(Size size)
Definition: mcxt.c:920
#define PG_RETURN_BOOL(x)
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uintptr_t Datum
Definition: postgres.h:374
uint8 flag
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Definition: trgm_op.c:81
char trgm[3]
Definition: trgm.h:38
#define Max(x, y)
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#define CALCGTSIZE(flag)
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#define NULL
Definition: c.h:226
#define Assert(condition)
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Datum similarity(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1054
Datum similarity_dist(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1092
#define DatumGetFloat4(X)
Definition: postgres.h:688
#define ISESCAPECHAR(x)
Definition: trgm.h:59
Datum word_similarity_op(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1112
size_t Size
Definition: c.h:353
Datum show_limit(PG_FUNCTION_ARGS)
Definition: trgm_op.c:103
Datum word_similarity_dist_op(PG_FUNCTION_ARGS)
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Definition: fmgr.h:216
#define RPADDING
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Datum word_similarity_commutator_op(PG_FUNCTION_ARGS)
Definition: trgm_op.c:1128
float4 cnt_sml(TRGM *trg1, TRGM *trg2, bool inexact)
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#define DatumGetPointer(X)
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trgm trg
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char * OidOutputFunctionCall(Oid functionId, Datum val)
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#define VARSIZE_ANY_EXHDR(PTR)
Definition: postgres.h:342
void * palloc(Size size)
Definition: mcxt.c:891
#define LPADDING
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int errmsg(const char *fmt,...)
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Definition: pg_crc.h:81
int i
static const char * get_wildcard_part(const char *str, int lenstr, char *buf, int *bytelen, int *charlen)
Definition: trgm_op.c:651
Definition: c.h:435
#define PG_FUNCTION_ARGS
Definition: fmgr.h:150
#define SET_VARSIZE(PTR, len)
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static int generate_trgm_only(trgm *trg, char *str, int slen)
Definition: trgm_op.c:242
long val
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#define DirectFunctionCall2(func, arg1, arg2)
Definition: fmgr.h:557
static pos_trgm * make_positional_trgm(trgm *trg1, int len1, trgm *trg2, int len2)
Definition: trgm_op.c:362
#define CPTRGM(a, b)
Definition: trgm.h:44
static int cmp(const chr *x, const chr *y, size_t len)
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Definition: trgm_op.c:166
#define CALCSML(count, len1, len2)
Definition: trgm.h:114
static int comp_trgm(const void *a, const void *b)
Definition: trgm_op.c:109