PostgreSQL Source Code  git master
like.c
Go to the documentation of this file.
1 /*-------------------------------------------------------------------------
2  *
3  * like.c
4  * like expression handling code.
5  *
6  * NOTES
7  * A big hack of the regexp.c code!! Contributed by
8  * Keith Parks <emkxp01@mtcc.demon.co.uk> (7/95).
9  *
10  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
11  * Portions Copyright (c) 1994, Regents of the University of California
12  *
13  * IDENTIFICATION
14  * src/backend/utils/adt/like.c
15  *
16  *-------------------------------------------------------------------------
17  */
18 #include "postgres.h"
19 
20 #include <ctype.h>
21 
22 #include "catalog/pg_collation.h"
23 #include "mb/pg_wchar.h"
24 #include "miscadmin.h"
25 #include "utils/builtins.h"
26 #include "utils/pg_locale.h"
27 
28 
29 #define LIKE_TRUE 1
30 #define LIKE_FALSE 0
31 #define LIKE_ABORT (-1)
32 
33 
34 static int SB_MatchText(const char *t, int tlen, const char *p, int plen,
35  pg_locale_t locale, bool locale_is_c);
36 static text *SB_do_like_escape(text *, text *);
37 
38 static int MB_MatchText(const char *t, int tlen, const char *p, int plen,
39  pg_locale_t locale, bool locale_is_c);
40 static text *MB_do_like_escape(text *, text *);
41 
42 static int UTF8_MatchText(const char *t, int tlen, const char *p, int plen,
43  pg_locale_t locale, bool locale_is_c);
44 
45 static int SB_IMatchText(const char *t, int tlen, const char *p, int plen,
46  pg_locale_t locale, bool locale_is_c);
47 
48 static int GenericMatchText(const char *s, int slen, const char *p, int plen, Oid collation);
49 static int Generic_Text_IC_like(text *str, text *pat, Oid collation);
50 
51 /*--------------------
52  * Support routine for MatchText. Compares given multibyte streams
53  * as wide characters. If they match, returns 1 otherwise returns 0.
54  *--------------------
55  */
56 static inline int
57 wchareq(const char *p1, const char *p2)
58 {
59  int p1_len;
60 
61  /* Optimization: quickly compare the first byte. */
62  if (*p1 != *p2)
63  return 0;
64 
65  p1_len = pg_mblen(p1);
66  if (pg_mblen(p2) != p1_len)
67  return 0;
68 
69  /* They are the same length */
70  while (p1_len--)
71  {
72  if (*p1++ != *p2++)
73  return 0;
74  }
75  return 1;
76 }
77 
78 /*
79  * Formerly we had a routine iwchareq() here that tried to do case-insensitive
80  * comparison of multibyte characters. It did not work at all, however,
81  * because it relied on tolower() which has a single-byte API ... and
82  * towlower() wouldn't be much better since we have no suitably cheap way
83  * of getting a single character transformed to the system's wchar_t format.
84  * So now, we just downcase the strings using lower() and apply regular LIKE
85  * comparison. This should be revisited when we install better locale support.
86  */
87 
88 /*
89  * We do handle case-insensitive matching for single-byte encodings using
90  * fold-on-the-fly processing, however.
91  */
92 static char
93 SB_lower_char(unsigned char c, pg_locale_t locale, bool locale_is_c)
94 {
95  if (locale_is_c)
96  return pg_ascii_tolower(c);
97 #ifdef HAVE_LOCALE_T
98  else if (locale)
99  return tolower_l(c, locale->info.lt);
100 #endif
101  else
102  return pg_tolower(c);
103 }
104 
105 
106 #define NextByte(p, plen) ((p)++, (plen)--)
107 
108 /* Set up to compile like_match.c for multibyte characters */
109 #define CHAREQ(p1, p2) wchareq((p1), (p2))
110 #define NextChar(p, plen) \
111  do { int __l = pg_mblen(p); (p) +=__l; (plen) -=__l; } while (0)
112 #define CopyAdvChar(dst, src, srclen) \
113  do { int __l = pg_mblen(src); \
114  (srclen) -= __l; \
115  while (__l-- > 0) \
116  *(dst)++ = *(src)++; \
117  } while (0)
118 
119 #define MatchText MB_MatchText
120 #define do_like_escape MB_do_like_escape
121 
122 #include "like_match.c"
123 
124 /* Set up to compile like_match.c for single-byte characters */
125 #define CHAREQ(p1, p2) (*(p1) == *(p2))
126 #define NextChar(p, plen) NextByte((p), (plen))
127 #define CopyAdvChar(dst, src, srclen) (*(dst)++ = *(src)++, (srclen)--)
128 
129 #define MatchText SB_MatchText
130 #define do_like_escape SB_do_like_escape
131 
132 #include "like_match.c"
133 
134 /* setup to compile like_match.c for single byte case insensitive matches */
135 #define MATCH_LOWER(t) SB_lower_char((unsigned char) (t), locale, locale_is_c)
136 #define NextChar(p, plen) NextByte((p), (plen))
137 #define MatchText SB_IMatchText
138 
139 #include "like_match.c"
140 
141 /* setup to compile like_match.c for UTF8 encoding, using fast NextChar */
142 
143 #define NextChar(p, plen) \
144  do { (p)++; (plen)--; } while ((plen) > 0 && (*(p) & 0xC0) == 0x80 )
145 #define MatchText UTF8_MatchText
146 
147 #include "like_match.c"
148 
149 /* Generic for all cases not requiring inline case-folding */
150 static inline int
151 GenericMatchText(const char *s, int slen, const char *p, int plen, Oid collation)
152 {
153  if (collation && !lc_ctype_is_c(collation) && collation != DEFAULT_COLLATION_OID)
154  {
156 
157  if (locale && !locale->deterministic)
158  ereport(ERROR,
159  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
160  errmsg("nondeterministic collations are not supported for LIKE")));
161  }
162 
164  return SB_MatchText(s, slen, p, plen, 0, true);
165  else if (GetDatabaseEncoding() == PG_UTF8)
166  return UTF8_MatchText(s, slen, p, plen, 0, true);
167  else
168  return MB_MatchText(s, slen, p, plen, 0, true);
169 }
170 
171 static inline int
173 {
174  char *s,
175  *p;
176  int slen,
177  plen;
178  pg_locale_t locale = 0;
179  bool locale_is_c = false;
180 
181  if (lc_ctype_is_c(collation))
182  locale_is_c = true;
183  else if (collation != DEFAULT_COLLATION_OID)
184  {
185  if (!OidIsValid(collation))
186  {
187  /*
188  * This typically means that the parser could not resolve a
189  * conflict of implicit collations, so report it that way.
190  */
191  ereport(ERROR,
192  (errcode(ERRCODE_INDETERMINATE_COLLATION),
193  errmsg("could not determine which collation to use for ILIKE"),
194  errhint("Use the COLLATE clause to set the collation explicitly.")));
195  }
196  locale = pg_newlocale_from_collation(collation);
197 
198  if (locale && !locale->deterministic)
199  ereport(ERROR,
200  (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
201  errmsg("nondeterministic collations are not supported for ILIKE")));
202  }
203 
204  /*
205  * For efficiency reasons, in the single byte case we don't call lower()
206  * on the pattern and text, but instead call SB_lower_char on each
207  * character. In the multi-byte case we don't have much choice :-(. Also,
208  * ICU does not support single-character case folding, so we go the long
209  * way.
210  */
211 
212  if (pg_database_encoding_max_length() > 1 || (locale && locale->provider == COLLPROVIDER_ICU))
213  {
215  PointerGetDatum(pat)));
216  p = VARDATA_ANY(pat);
217  plen = VARSIZE_ANY_EXHDR(pat);
219  PointerGetDatum(str)));
220  s = VARDATA_ANY(str);
221  slen = VARSIZE_ANY_EXHDR(str);
222  if (GetDatabaseEncoding() == PG_UTF8)
223  return UTF8_MatchText(s, slen, p, plen, 0, true);
224  else
225  return MB_MatchText(s, slen, p, plen, 0, true);
226  }
227  else
228  {
229  p = VARDATA_ANY(pat);
230  plen = VARSIZE_ANY_EXHDR(pat);
231  s = VARDATA_ANY(str);
232  slen = VARSIZE_ANY_EXHDR(str);
233  return SB_IMatchText(s, slen, p, plen, locale, locale_is_c);
234  }
235 }
236 
237 /*
238  * interface routines called by the function manager
239  */
240 
241 Datum
243 {
244  Name str = PG_GETARG_NAME(0);
245  text *pat = PG_GETARG_TEXT_PP(1);
246  bool result;
247  char *s,
248  *p;
249  int slen,
250  plen;
251 
252  s = NameStr(*str);
253  slen = strlen(s);
254  p = VARDATA_ANY(pat);
255  plen = VARSIZE_ANY_EXHDR(pat);
256 
257  result = (GenericMatchText(s, slen, p, plen, PG_GET_COLLATION()) == LIKE_TRUE);
258 
259  PG_RETURN_BOOL(result);
260 }
261 
262 Datum
264 {
265  Name str = PG_GETARG_NAME(0);
266  text *pat = PG_GETARG_TEXT_PP(1);
267  bool result;
268  char *s,
269  *p;
270  int slen,
271  plen;
272 
273  s = NameStr(*str);
274  slen = strlen(s);
275  p = VARDATA_ANY(pat);
276  plen = VARSIZE_ANY_EXHDR(pat);
277 
278  result = (GenericMatchText(s, slen, p, plen, PG_GET_COLLATION()) != LIKE_TRUE);
279 
280  PG_RETURN_BOOL(result);
281 }
282 
283 Datum
285 {
286  text *str = PG_GETARG_TEXT_PP(0);
287  text *pat = PG_GETARG_TEXT_PP(1);
288  bool result;
289  char *s,
290  *p;
291  int slen,
292  plen;
293 
294  s = VARDATA_ANY(str);
295  slen = VARSIZE_ANY_EXHDR(str);
296  p = VARDATA_ANY(pat);
297  plen = VARSIZE_ANY_EXHDR(pat);
298 
299  result = (GenericMatchText(s, slen, p, plen, PG_GET_COLLATION()) == LIKE_TRUE);
300 
301  PG_RETURN_BOOL(result);
302 }
303 
304 Datum
306 {
307  text *str = PG_GETARG_TEXT_PP(0);
308  text *pat = PG_GETARG_TEXT_PP(1);
309  bool result;
310  char *s,
311  *p;
312  int slen,
313  plen;
314 
315  s = VARDATA_ANY(str);
316  slen = VARSIZE_ANY_EXHDR(str);
317  p = VARDATA_ANY(pat);
318  plen = VARSIZE_ANY_EXHDR(pat);
319 
320  result = (GenericMatchText(s, slen, p, plen, PG_GET_COLLATION()) != LIKE_TRUE);
321 
322  PG_RETURN_BOOL(result);
323 }
324 
325 Datum
327 {
329  bytea *pat = PG_GETARG_BYTEA_PP(1);
330  bool result;
331  char *s,
332  *p;
333  int slen,
334  plen;
335 
336  s = VARDATA_ANY(str);
337  slen = VARSIZE_ANY_EXHDR(str);
338  p = VARDATA_ANY(pat);
339  plen = VARSIZE_ANY_EXHDR(pat);
340 
341  result = (SB_MatchText(s, slen, p, plen, 0, true) == LIKE_TRUE);
342 
343  PG_RETURN_BOOL(result);
344 }
345 
346 Datum
348 {
350  bytea *pat = PG_GETARG_BYTEA_PP(1);
351  bool result;
352  char *s,
353  *p;
354  int slen,
355  plen;
356 
357  s = VARDATA_ANY(str);
358  slen = VARSIZE_ANY_EXHDR(str);
359  p = VARDATA_ANY(pat);
360  plen = VARSIZE_ANY_EXHDR(pat);
361 
362  result = (SB_MatchText(s, slen, p, plen, 0, true) != LIKE_TRUE);
363 
364  PG_RETURN_BOOL(result);
365 }
366 
367 /*
368  * Case-insensitive versions
369  */
370 
371 Datum
373 {
374  Name str = PG_GETARG_NAME(0);
375  text *pat = PG_GETARG_TEXT_PP(1);
376  bool result;
377  text *strtext;
378 
380  NameGetDatum(str)));
381  result = (Generic_Text_IC_like(strtext, pat, PG_GET_COLLATION()) == LIKE_TRUE);
382 
383  PG_RETURN_BOOL(result);
384 }
385 
386 Datum
388 {
389  Name str = PG_GETARG_NAME(0);
390  text *pat = PG_GETARG_TEXT_PP(1);
391  bool result;
392  text *strtext;
393 
395  NameGetDatum(str)));
396  result = (Generic_Text_IC_like(strtext, pat, PG_GET_COLLATION()) != LIKE_TRUE);
397 
398  PG_RETURN_BOOL(result);
399 }
400 
401 Datum
403 {
404  text *str = PG_GETARG_TEXT_PP(0);
405  text *pat = PG_GETARG_TEXT_PP(1);
406  bool result;
407 
408  result = (Generic_Text_IC_like(str, pat, PG_GET_COLLATION()) == LIKE_TRUE);
409 
410  PG_RETURN_BOOL(result);
411 }
412 
413 Datum
415 {
416  text *str = PG_GETARG_TEXT_PP(0);
417  text *pat = PG_GETARG_TEXT_PP(1);
418  bool result;
419 
420  result = (Generic_Text_IC_like(str, pat, PG_GET_COLLATION()) != LIKE_TRUE);
421 
422  PG_RETURN_BOOL(result);
423 }
424 
425 /*
426  * like_escape() --- given a pattern and an ESCAPE string,
427  * convert the pattern to use Postgres' standard backslash escape convention.
428  */
429 Datum
431 {
432  text *pat = PG_GETARG_TEXT_PP(0);
433  text *esc = PG_GETARG_TEXT_PP(1);
434  text *result;
435 
437  result = SB_do_like_escape(pat, esc);
438  else
439  result = MB_do_like_escape(pat, esc);
440 
441  PG_RETURN_TEXT_P(result);
442 }
443 
444 /*
445  * like_escape_bytea() --- given a pattern and an ESCAPE string,
446  * convert the pattern to use Postgres' standard backslash escape convention.
447  */
448 Datum
450 {
451  bytea *pat = PG_GETARG_BYTEA_PP(0);
452  bytea *esc = PG_GETARG_BYTEA_PP(1);
453  bytea *result = SB_do_like_escape((text *) pat, (text *) esc);
454 
455  PG_RETURN_BYTEA_P((bytea *) result);
456 }
Datum textnlike(PG_FUNCTION_ARGS)
Definition: like.c:305
static int SB_IMatchText(const char *t, int tlen, const char *p, int plen, pg_locale_t locale, bool locale_is_c)
Datum namelike(PG_FUNCTION_ARGS)
Definition: like.c:242
union pg_locale_struct::@144 info
Datum nameiclike(PG_FUNCTION_ARGS)
Definition: like.c:372
#define NameGetDatum(X)
Definition: postgres.h:595
int errhint(const char *fmt,...)
Definition: elog.c:1069
Datum like_escape_bytea(PG_FUNCTION_ARGS)
Definition: like.c:449
#define VARDATA_ANY(PTR)
Definition: postgres.h:348
Datum lower(PG_FUNCTION_ARGS)
Definition: oracle_compat.c:43
static text * SB_do_like_escape(text *, text *)
#define PointerGetDatum(X)
Definition: postgres.h:556
Datum bytealike(PG_FUNCTION_ARGS)
Definition: like.c:326
unsigned char pg_ascii_tolower(unsigned char ch)
Definition: pgstrcasecmp.c:146
#define DatumGetTextPP(X)
Definition: fmgr.h:286
#define LIKE_TRUE
Definition: like.c:29
unsigned char pg_tolower(unsigned char ch)
Definition: pgstrcasecmp.c:122
int errcode(int sqlerrcode)
Definition: elog.c:608
Datum textlike(PG_FUNCTION_ARGS)
Definition: like.c:284
#define tolower_l
Definition: win32_port.h:364
#define DirectFunctionCall1(func, arg1)
Definition: fmgr.h:615
#define PG_RETURN_BYTEA_P(x)
Definition: fmgr.h:360
unsigned int Oid
Definition: postgres_ext.h:31
#define OidIsValid(objectId)
Definition: c.h:645
#define PG_GET_COLLATION()
Definition: fmgr.h:193
#define PG_GETARG_TEXT_PP(n)
Definition: fmgr.h:303
Datum nameicnlike(PG_FUNCTION_ARGS)
Definition: like.c:387
static int MB_MatchText(const char *t, int tlen, const char *p, int plen, pg_locale_t locale, bool locale_is_c)
#define ERROR
Definition: elog.h:43
Definition: c.h:610
char * c
static char SB_lower_char(unsigned char c, pg_locale_t locale, bool locale_is_c)
Definition: like.c:93
int pg_database_encoding_max_length(void)
Definition: wchar.c:1881
Datum namenlike(PG_FUNCTION_ARGS)
Definition: like.c:263
static text * MB_do_like_escape(text *, text *)
Datum texticnlike(PG_FUNCTION_ARGS)
Definition: like.c:414
static int GenericMatchText(const char *s, int slen, const char *p, int plen, Oid collation)
Definition: like.c:151
Datum DirectFunctionCall1Coll(PGFunction func, Oid collation, Datum arg1)
Definition: fmgr.c:793
#define ereport(elevel, rest)
Definition: elog.h:141
Datum name_text(PG_FUNCTION_ARGS)
Definition: varlena.c:3577
pg_locale_t pg_newlocale_from_collation(Oid collid)
Definition: pg_locale.c:1323
Datum texticlike(PG_FUNCTION_ARGS)
Definition: like.c:402
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:349
uintptr_t Datum
Definition: postgres.h:367
int GetDatabaseEncoding(void)
Definition: mbutils.c:1046
bool deterministic
Definition: pg_locale.h:85
static int UTF8_MatchText(const char *t, int tlen, const char *p, int plen, pg_locale_t locale, bool locale_is_c)
#define PG_RETURN_TEXT_P(x)
Definition: fmgr.h:361
Datum byteanlike(PG_FUNCTION_ARGS)
Definition: like.c:347
static int SB_MatchText(const char *t, int tlen, const char *p, int plen, pg_locale_t locale, bool locale_is_c)
Datum like_escape(PG_FUNCTION_ARGS)
Definition: like.c:430
#define PG_GETARG_BYTEA_PP(n)
Definition: fmgr.h:302
static int Generic_Text_IC_like(text *str, text *pat, Oid collation)
Definition: like.c:172
int pg_mblen(const char *mbstr)
Definition: mbutils.c:802
#define VARSIZE_ANY_EXHDR(PTR)
Definition: postgres.h:341
int errmsg(const char *fmt,...)
Definition: elog.c:822
#define NameStr(name)
Definition: c.h:616
static char * locale
Definition: initdb.c:125
Definition: c.h:556
#define PG_FUNCTION_ARGS
Definition: fmgr.h:188
static int wchareq(const char *p1, const char *p2)
Definition: like.c:57
bool lc_ctype_is_c(Oid collation)
Definition: pg_locale.c:1226
#define PG_GETARG_NAME(n)
Definition: fmgr.h:273