PostgreSQL Source Code  git master
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros
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) 1996-2017, 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(char *t, int tlen, 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(char *t, int tlen, 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(char *t, int tlen, char *p, int plen,
43  pg_locale_t locale, bool locale_is_c);
44 
45 static int SB_IMatchText(char *t, int tlen, char *p, int plen,
46  pg_locale_t locale, bool locale_is_c);
47 
48 static int GenericMatchText(char *s, int slen, char *p, int plen);
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(char *p1, 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(char *s, int slen, char *p, int plen)
152 {
154  return SB_MatchText(s, slen, p, plen, 0, true);
155  else if (GetDatabaseEncoding() == PG_UTF8)
156  return UTF8_MatchText(s, slen, p, plen, 0, true);
157  else
158  return MB_MatchText(s, slen, p, plen, 0, true);
159 }
160 
161 static inline int
162 Generic_Text_IC_like(text *str, text *pat, Oid collation)
163 {
164  char *s,
165  *p;
166  int slen,
167  plen;
168  pg_locale_t locale = 0;
169  bool locale_is_c = false;
170 
171  if (lc_ctype_is_c(collation))
172  locale_is_c = true;
173  else if (collation != DEFAULT_COLLATION_OID)
174  {
175  if (!OidIsValid(collation))
176  {
177  /*
178  * This typically means that the parser could not resolve a
179  * conflict of implicit collations, so report it that way.
180  */
181  ereport(ERROR,
182  (errcode(ERRCODE_INDETERMINATE_COLLATION),
183  errmsg("could not determine which collation to use for ILIKE"),
184  errhint("Use the COLLATE clause to set the collation explicitly.")));
185  }
186  locale = pg_newlocale_from_collation(collation);
187  }
188 
189  /*
190  * For efficiency reasons, in the single byte case we don't call lower()
191  * on the pattern and text, but instead call SB_lower_char on each
192  * character. In the multi-byte case we don't have much choice :-(. Also,
193  * ICU does not support single-character case folding, so we go the long
194  * way.
195  */
196 
197  if (pg_database_encoding_max_length() > 1 || (locale && locale->provider == COLLPROVIDER_ICU))
198  {
199  /* lower's result is never packed, so OK to use old macros here */
201  PointerGetDatum(pat)));
202  p = VARDATA_ANY(pat);
203  plen = VARSIZE_ANY_EXHDR(pat);
205  PointerGetDatum(str)));
206  s = VARDATA_ANY(str);
207  slen = VARSIZE_ANY_EXHDR(str);
208  if (GetDatabaseEncoding() == PG_UTF8)
209  return UTF8_MatchText(s, slen, p, plen, 0, true);
210  else
211  return MB_MatchText(s, slen, p, plen, 0, true);
212  }
213  else
214  {
215  p = VARDATA_ANY(pat);
216  plen = VARSIZE_ANY_EXHDR(pat);
217  s = VARDATA_ANY(str);
218  slen = VARSIZE_ANY_EXHDR(str);
219  return SB_IMatchText(s, slen, p, plen, locale, locale_is_c);
220  }
221 }
222 
223 /*
224  * interface routines called by the function manager
225  */
226 
227 Datum
229 {
230  Name str = PG_GETARG_NAME(0);
231  text *pat = PG_GETARG_TEXT_PP(1);
232  bool result;
233  char *s,
234  *p;
235  int slen,
236  plen;
237 
238  s = NameStr(*str);
239  slen = strlen(s);
240  p = VARDATA_ANY(pat);
241  plen = VARSIZE_ANY_EXHDR(pat);
242 
243  result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
244 
245  PG_RETURN_BOOL(result);
246 }
247 
248 Datum
250 {
251  Name str = PG_GETARG_NAME(0);
252  text *pat = PG_GETARG_TEXT_PP(1);
253  bool result;
254  char *s,
255  *p;
256  int slen,
257  plen;
258 
259  s = NameStr(*str);
260  slen = strlen(s);
261  p = VARDATA_ANY(pat);
262  plen = VARSIZE_ANY_EXHDR(pat);
263 
264  result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
265 
266  PG_RETURN_BOOL(result);
267 }
268 
269 Datum
271 {
272  text *str = PG_GETARG_TEXT_PP(0);
273  text *pat = PG_GETARG_TEXT_PP(1);
274  bool result;
275  char *s,
276  *p;
277  int slen,
278  plen;
279 
280  s = VARDATA_ANY(str);
281  slen = VARSIZE_ANY_EXHDR(str);
282  p = VARDATA_ANY(pat);
283  plen = VARSIZE_ANY_EXHDR(pat);
284 
285  result = (GenericMatchText(s, slen, p, plen) == LIKE_TRUE);
286 
287  PG_RETURN_BOOL(result);
288 }
289 
290 Datum
292 {
293  text *str = PG_GETARG_TEXT_PP(0);
294  text *pat = PG_GETARG_TEXT_PP(1);
295  bool result;
296  char *s,
297  *p;
298  int slen,
299  plen;
300 
301  s = VARDATA_ANY(str);
302  slen = VARSIZE_ANY_EXHDR(str);
303  p = VARDATA_ANY(pat);
304  plen = VARSIZE_ANY_EXHDR(pat);
305 
306  result = (GenericMatchText(s, slen, p, plen) != LIKE_TRUE);
307 
308  PG_RETURN_BOOL(result);
309 }
310 
311 Datum
313 {
314  bytea *str = PG_GETARG_BYTEA_PP(0);
315  bytea *pat = PG_GETARG_BYTEA_PP(1);
316  bool result;
317  char *s,
318  *p;
319  int slen,
320  plen;
321 
322  s = VARDATA_ANY(str);
323  slen = VARSIZE_ANY_EXHDR(str);
324  p = VARDATA_ANY(pat);
325  plen = VARSIZE_ANY_EXHDR(pat);
326 
327  result = (SB_MatchText(s, slen, p, plen, 0, true) == LIKE_TRUE);
328 
329  PG_RETURN_BOOL(result);
330 }
331 
332 Datum
334 {
335  bytea *str = PG_GETARG_BYTEA_PP(0);
336  bytea *pat = PG_GETARG_BYTEA_PP(1);
337  bool result;
338  char *s,
339  *p;
340  int slen,
341  plen;
342 
343  s = VARDATA_ANY(str);
344  slen = VARSIZE_ANY_EXHDR(str);
345  p = VARDATA_ANY(pat);
346  plen = VARSIZE_ANY_EXHDR(pat);
347 
348  result = (SB_MatchText(s, slen, p, plen, 0, true) != LIKE_TRUE);
349 
350  PG_RETURN_BOOL(result);
351 }
352 
353 /*
354  * Case-insensitive versions
355  */
356 
357 Datum
359 {
360  Name str = PG_GETARG_NAME(0);
361  text *pat = PG_GETARG_TEXT_PP(1);
362  bool result;
363  text *strtext;
364 
366  NameGetDatum(str)));
367  result = (Generic_Text_IC_like(strtext, pat, PG_GET_COLLATION()) == LIKE_TRUE);
368 
369  PG_RETURN_BOOL(result);
370 }
371 
372 Datum
374 {
375  Name str = PG_GETARG_NAME(0);
376  text *pat = PG_GETARG_TEXT_PP(1);
377  bool result;
378  text *strtext;
379 
381  NameGetDatum(str)));
382  result = (Generic_Text_IC_like(strtext, pat, PG_GET_COLLATION()) != LIKE_TRUE);
383 
384  PG_RETURN_BOOL(result);
385 }
386 
387 Datum
389 {
390  text *str = PG_GETARG_TEXT_PP(0);
391  text *pat = PG_GETARG_TEXT_PP(1);
392  bool result;
393 
394  result = (Generic_Text_IC_like(str, pat, PG_GET_COLLATION()) == LIKE_TRUE);
395 
396  PG_RETURN_BOOL(result);
397 }
398 
399 Datum
401 {
402  text *str = PG_GETARG_TEXT_PP(0);
403  text *pat = PG_GETARG_TEXT_PP(1);
404  bool result;
405 
406  result = (Generic_Text_IC_like(str, pat, PG_GET_COLLATION()) != LIKE_TRUE);
407 
408  PG_RETURN_BOOL(result);
409 }
410 
411 /*
412  * like_escape() --- given a pattern and an ESCAPE string,
413  * convert the pattern to use Postgres' standard backslash escape convention.
414  */
415 Datum
417 {
418  text *pat = PG_GETARG_TEXT_PP(0);
419  text *esc = PG_GETARG_TEXT_PP(1);
420  text *result;
421 
423  result = SB_do_like_escape(pat, esc);
424  else
425  result = MB_do_like_escape(pat, esc);
426 
427  PG_RETURN_TEXT_P(result);
428 }
429 
430 /*
431  * like_escape_bytea() --- given a pattern and an ESCAPE string,
432  * convert the pattern to use Postgres' standard backslash escape convention.
433  */
434 Datum
436 {
437  bytea *pat = PG_GETARG_BYTEA_PP(0);
438  bytea *esc = PG_GETARG_BYTEA_PP(1);
439  bytea *result = SB_do_like_escape((text *) pat, (text *) esc);
440 
441  PG_RETURN_BYTEA_P((bytea *) result);
442 }
Datum textnlike(PG_FUNCTION_ARGS)
Definition: like.c:291
Datum namelike(PG_FUNCTION_ARGS)
Definition: like.c:228
#define COLLPROVIDER_ICU
Definition: pg_collation.h:85
Datum nameiclike(PG_FUNCTION_ARGS)
Definition: like.c:358
#define NameGetDatum(X)
Definition: postgres.h:601
static int wchareq(char *p1, char *p2)
Definition: like.c:57
int errhint(const char *fmt,...)
Definition: elog.c:987
Datum like_escape_bytea(PG_FUNCTION_ARGS)
Definition: like.c:435
#define VARDATA_ANY(PTR)
Definition: postgres.h:347
Datum lower(PG_FUNCTION_ARGS)
Definition: oracle_compat.c:43
static text * SB_do_like_escape(text *, text *)
#define PointerGetDatum(X)
Definition: postgres.h:562
Datum bytealike(PG_FUNCTION_ARGS)
Definition: like.c:312
unsigned char pg_ascii_tolower(unsigned char ch)
Definition: pgstrcasecmp.c:146
#define DatumGetTextPP(X)
Definition: fmgr.h:256
union pg_locale_struct::@120 info
#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:575
Datum textlike(PG_FUNCTION_ARGS)
Definition: like.c:270
#define DirectFunctionCall1(func, arg1)
Definition: fmgr.h:585
#define PG_RETURN_BYTEA_P(x)
Definition: fmgr.h:330
unsigned int Oid
Definition: postgres_ext.h:31
#define OidIsValid(objectId)
Definition: c.h:532
#define PG_GET_COLLATION()
Definition: fmgr.h:163
#define PG_GETARG_TEXT_PP(n)
Definition: fmgr.h:273
static int SB_MatchText(char *t, int tlen, char *p, int plen, pg_locale_t locale, bool locale_is_c)
static int UTF8_MatchText(char *t, int tlen, char *p, int plen, pg_locale_t locale, bool locale_is_c)
Datum nameicnlike(PG_FUNCTION_ARGS)
Definition: like.c:373
#define ERROR
Definition: elog.h:43
static int MB_MatchText(char *t, int tlen, char *p, int plen, pg_locale_t locale, bool locale_is_c)
static int GenericMatchText(char *s, int slen, char *p, int plen)
Definition: like.c:151
Definition: c.h:487
char * c
static char SB_lower_char(unsigned char c, pg_locale_t locale, bool locale_is_c)
Definition: like.c:93
#define DEFAULT_COLLATION_OID
Definition: pg_collation.h:75
int pg_database_encoding_max_length(void)
Definition: wchar.c:1833
Datum namenlike(PG_FUNCTION_ARGS)
Definition: like.c:249
static text * MB_do_like_escape(text *, text *)
Datum texticnlike(PG_FUNCTION_ARGS)
Definition: like.c:400
Datum DirectFunctionCall1Coll(PGFunction func, Oid collation, Datum arg1)
Definition: fmgr.c:702
#define ereport(elevel, rest)
Definition: elog.h:122
Datum name_text(PG_FUNCTION_ARGS)
Definition: varlena.c:3189
pg_locale_t pg_newlocale_from_collation(Oid collid)
Definition: pg_locale.c:1275
Datum texticlike(PG_FUNCTION_ARGS)
Definition: like.c:388
#define PG_RETURN_BOOL(x)
Definition: fmgr.h:319
uintptr_t Datum
Definition: postgres.h:372
int GetDatabaseEncoding(void)
Definition: mbutils.c:1004
#define PG_RETURN_TEXT_P(x)
Definition: fmgr.h:331
Datum byteanlike(PG_FUNCTION_ARGS)
Definition: like.c:333
Datum like_escape(PG_FUNCTION_ARGS)
Definition: like.c:416
#define PG_GETARG_BYTEA_PP(n)
Definition: fmgr.h:272
static int Generic_Text_IC_like(text *str, text *pat, Oid collation)
Definition: like.c:162
int pg_mblen(const char *mbstr)
Definition: mbutils.c:760
#define tolower_l
Definition: win32.h:324
#define VARSIZE_ANY_EXHDR(PTR)
Definition: postgres.h:340
int errmsg(const char *fmt,...)
Definition: elog.c:797
#define NameStr(name)
Definition: c.h:493
static char * locale
Definition: initdb.c:124
Definition: c.h:433
#define PG_FUNCTION_ARGS
Definition: fmgr.h:158
static int SB_IMatchText(char *t, int tlen, char *p, int plen, pg_locale_t locale, bool locale_is_c)
bool lc_ctype_is_c(Oid collation)
Definition: pg_locale.c:1178
#define PG_GETARG_NAME(n)
Definition: fmgr.h:243