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[emacs.git] / src / regex.h
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1 /* Definitions for data structures and routines for the regular
2 expression library, version 0.12.
4 Copyright (C) 1985,89,90,91,92,93,95,2000 Free Software Foundation, Inc.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
19 USA. */
21 #ifndef __REGEXP_LIBRARY_H__
22 #define __REGEXP_LIBRARY_H__
24 /* POSIX says that <sys/types.h> must be included (by the caller) before
25 <regex.h>. */
27 #if !defined (_POSIX_C_SOURCE) && !defined (_POSIX_SOURCE) && defined (VMS)
28 /* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
29 should be there. */
30 #include <stddef.h>
31 #endif
34 /* The following bits are used to determine the regexp syntax we
35 recognize. The set/not-set meanings where historically chosen so
36 that Emacs syntax had the value 0.
37 The bits are given in alphabetical order, and
38 the definitions shifted by one from the previous bit; thus, when we
39 add or remove a bit, only one other definition need change. */
40 typedef unsigned reg_syntax_t;
42 /* If this bit is set, then even *?, +? and ?? match greedily. */
43 #define RE_ALL_GREEDY (1)
45 /* If this bit is not set, then \ inside a bracket expression is literal.
46 If set, then such a \ quotes the following character. */
47 #define RE_BACKSLASH_ESCAPE_IN_LISTS (RE_ALL_GREEDY << 1)
49 /* If this bit is not set, then + and ? are operators, and \+ and \? are
50 literals.
51 If set, then \+ and \? are operators and + and ? are literals. */
52 #define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
54 /* If this bit is set, then character classes are supported. They are:
55 [:alpha:], [:upper:], [:lower:], [:digit:], [:alnum:], [:xdigit:],
56 [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
57 If not set, then character classes are not supported. */
58 #define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
60 /* If this bit is set, then ^ and $ are always anchors (outside bracket
61 expressions, of course).
62 If this bit is not set, then it depends:
63 ^ is an anchor if it is at the beginning of a regular
64 expression or after an open-group or an alternation operator;
65 $ is an anchor if it is at the end of a regular expression, or
66 before a close-group or an alternation operator.
68 This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
69 POSIX draft 11.2 says that * etc. in leading positions is undefined.
70 We already implemented a previous draft which made those constructs
71 invalid, though, so we haven't changed the code back. */
72 #define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
74 /* If this bit is set, then special characters are always special
75 regardless of where they are in the pattern.
76 If this bit is not set, then special characters are special only in
77 some contexts; otherwise they are ordinary. Specifically,
78 * + ? and intervals are only special when not after the beginning,
79 open-group, or alternation operator. */
80 #define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
82 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
83 immediately after an alternation or begin-group operator. */
84 #define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
86 /* If this bit is set, then . matches newline.
87 If not set, then it doesn't. */
88 #define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
90 /* If this bit is set, then . doesn't match NUL.
91 If not set, then it does. */
92 #define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
94 /* If this bit is set, nonmatching lists [^...] do not match newline.
95 If not set, they do. */
96 #define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
98 /* If this bit is set, either \{...\} or {...} defines an
99 interval, depending on RE_NO_BK_BRACES.
100 If not set, \{, \}, {, and } are literals. */
101 #define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
103 /* If this bit is set, +, ? and | aren't recognized as operators.
104 If not set, they are. */
105 #define RE_LIMITED_OPS (RE_INTERVALS << 1)
107 /* If this bit is set, newline is an alternation operator.
108 If not set, newline is literal. */
109 #define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
111 /* If this bit is set, then `{...}' defines an interval, and \{ and \}
112 are literals.
113 If not set, then `\{...\}' defines an interval. */
114 #define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
116 /* If this bit is set, (...) defines a group, and \( and \) are literals.
117 If not set, \(...\) defines a group, and ( and ) are literals. */
118 #define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
120 /* If this bit is set, then \<digit> matches <digit>.
121 If not set, then \<digit> is a back-reference. */
122 #define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
124 /* If this bit is set, then | is an alternation operator, and \| is literal.
125 If not set, then \| is an alternation operator, and | is literal. */
126 #define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
128 /* If this bit is set, then an ending range point collating higher
129 than the starting range point, as in [z-a], is invalid.
130 If not set, then when ending range point collates higher than the
131 starting range point, the range is ignored. */
132 #define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
134 /* If this bit is set, succeed as soon as we match the whole pattern,
135 without further backtracking. */
136 #define RE_NO_POSIX_BACKTRACKING (RE_NO_EMPTY_RANGES << 1)
138 /* If this bit is set, then (?:...) is treated as a shy group. */
139 #define RE_SHY_GROUPS (RE_NO_POSIX_BACKTRACKING << 1)
141 /* If this bit is set, then an unmatched ) is ordinary.
142 If not set, then an unmatched ) is invalid. */
143 #define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_SHY_GROUPS << 1)
145 /* This global variable defines the particular regexp syntax to use (for
146 some interfaces). When a regexp is compiled, the syntax used is
147 stored in the pattern buffer, so changing this does not affect
148 already-compiled regexps. */
149 extern reg_syntax_t re_syntax_options;
151 #ifdef emacs
152 /* In Emacs, this is the string or buffer in which we
153 are matching. It is used for looking up syntax properties. */
154 extern Lisp_Object re_match_object;
155 #endif
158 /* Define combinations of the above bits for the standard possibilities.
159 (The [[[ comments delimit what gets put into the Texinfo file, so
160 don't delete them!) */
161 /* [[[begin syntaxes]]] */
162 #define RE_SYNTAX_EMACS (RE_CHAR_CLASSES | RE_INTERVALS | RE_SHY_GROUPS)
164 #define RE_SYNTAX_AWK \
165 (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL \
166 | RE_NO_BK_PARENS | RE_NO_BK_REFS \
167 | RE_NO_BK_VBAR | RE_NO_EMPTY_RANGES \
168 | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_ALL_GREEDY)
170 #define RE_SYNTAX_POSIX_AWK \
171 (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)
173 #define RE_SYNTAX_GREP \
174 (RE_BK_PLUS_QM | RE_CHAR_CLASSES \
175 | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS \
176 | RE_NEWLINE_ALT | RE_ALL_GREEDY)
178 #define RE_SYNTAX_EGREP \
179 (RE_CHAR_CLASSES | RE_CONTEXT_INDEP_ANCHORS \
180 | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE \
181 | RE_NEWLINE_ALT | RE_NO_BK_PARENS \
182 | RE_NO_BK_VBAR | RE_ALL_GREEDY)
184 #define RE_SYNTAX_POSIX_EGREP \
185 (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
187 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff. */
188 #define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
190 #define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
192 /* Syntax bits common to both basic and extended POSIX regex syntax. */
193 #define _RE_SYNTAX_POSIX_COMMON \
194 (RE_CHAR_CLASSES | RE_DOT_NEWLINE | RE_DOT_NOT_NULL \
195 | RE_INTERVALS | RE_NO_EMPTY_RANGES | RE_ALL_GREEDY)
197 #define RE_SYNTAX_POSIX_BASIC \
198 (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)
200 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
201 RE_LIMITED_OPS, i.e., \? \+ \| are not recognized. Actually, this
202 isn't minimal, since other operators, such as \`, aren't disabled. */
203 #define RE_SYNTAX_POSIX_MINIMAL_BASIC \
204 (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
206 #define RE_SYNTAX_POSIX_EXTENDED \
207 (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS \
208 | RE_CONTEXT_INDEP_OPS | RE_NO_BK_BRACES \
209 | RE_NO_BK_PARENS | RE_NO_BK_VBAR \
210 | RE_UNMATCHED_RIGHT_PAREN_ORD)
212 /* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
213 replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added. */
214 #define RE_SYNTAX_POSIX_MINIMAL_EXTENDED \
215 (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS \
216 | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES \
217 | RE_NO_BK_PARENS | RE_NO_BK_REFS \
218 | RE_NO_BK_VBAR | RE_UNMATCHED_RIGHT_PAREN_ORD)
219 /* [[[end syntaxes]]] */
221 /* Maximum number of duplicates an interval can allow. Some systems
222 (erroneously) define this in other header files, but we want our
223 value, so remove any previous define. */
224 #ifdef RE_DUP_MAX
225 #undef RE_DUP_MAX
226 #endif
227 #define RE_DUP_MAX ((1 << 15) - 1)
230 /* POSIX `cflags' bits (i.e., information for `regcomp'). */
232 /* If this bit is set, then use extended regular expression syntax.
233 If not set, then use basic regular expression syntax. */
234 #define REG_EXTENDED 1
236 /* If this bit is set, then ignore case when matching.
237 If not set, then case is significant. */
238 #define REG_ICASE (REG_EXTENDED << 1)
240 /* If this bit is set, then anchors do not match at newline
241 characters in the string.
242 If not set, then anchors do match at newlines. */
243 #define REG_NEWLINE (REG_ICASE << 1)
245 /* If this bit is set, then report only success or fail in regexec.
246 If not set, then returns differ between not matching and errors. */
247 #define REG_NOSUB (REG_NEWLINE << 1)
250 /* POSIX `eflags' bits (i.e., information for regexec). */
252 /* If this bit is set, then the beginning-of-line operator doesn't match
253 the beginning of the string (presumably because it's not the
254 beginning of a line).
255 If not set, then the beginning-of-line operator does match the
256 beginning of the string. */
257 #define REG_NOTBOL 1
259 /* Like REG_NOTBOL, except for the end-of-line. */
260 #define REG_NOTEOL (1 << 1)
263 /* If any error codes are removed, changed, or added, update the
264 `re_error_msg' table in regex.c. */
265 typedef enum
267 REG_NOERROR = 0, /* Success. */
268 REG_NOMATCH, /* Didn't find a match (for regexec). */
270 /* POSIX regcomp return error codes. (In the order listed in the
271 standard.) */
272 REG_BADPAT, /* Invalid pattern. */
273 REG_ECOLLATE, /* Not implemented. */
274 REG_ECTYPE, /* Invalid character class name. */
275 REG_EESCAPE, /* Trailing backslash. */
276 REG_ESUBREG, /* Invalid back reference. */
277 REG_EBRACK, /* Unmatched left bracket. */
278 REG_EPAREN, /* Parenthesis imbalance. */
279 REG_EBRACE, /* Unmatched \{. */
280 REG_BADBR, /* Invalid contents of \{\}. */
281 REG_ERANGE, /* Invalid range end. */
282 REG_ESPACE, /* Ran out of memory. */
283 REG_BADRPT, /* No preceding re for repetition op. */
285 /* Error codes we've added. */
286 REG_EEND, /* Premature end. */
287 REG_ESIZE, /* Compiled pattern bigger than 2^16 bytes. */
288 REG_ERPAREN /* Unmatched ) or \); not returned from regcomp. */
289 } reg_errcode_t;
291 /* This data structure represents a compiled pattern. Before calling
292 the pattern compiler, the fields `buffer', `allocated', `fastmap',
293 `translate', and `no_sub' can be set. After the pattern has been
294 compiled, the `re_nsub' field is available. All other fields are
295 private to the regex routines. */
297 #ifndef RE_TRANSLATE_TYPE
298 #define RE_TRANSLATE_TYPE char *
299 #define RE_TRANSLATE(TBL, C) ((TBL)[C])
300 #define RE_TRANSLATE_P(TBL) (TBL)
301 #endif
303 struct re_pattern_buffer
305 /* [[[begin pattern_buffer]]] */
306 /* Space that holds the compiled pattern. It is declared as
307 `unsigned char *' because its elements are
308 sometimes used as array indexes. */
309 unsigned char *buffer;
311 /* Number of bytes to which `buffer' points. */
312 unsigned long allocated;
314 /* Number of bytes actually used in `buffer'. */
315 unsigned long used;
317 /* Syntax setting with which the pattern was compiled. */
318 reg_syntax_t syntax;
320 /* Pointer to a fastmap, if any, otherwise zero. re_search uses
321 the fastmap, if there is one, to skip over impossible
322 starting points for matches. */
323 char *fastmap;
325 /* Either a translate table to apply to all characters before
326 comparing them, or zero for no translation. The translation
327 is applied to a pattern when it is compiled and to a string
328 when it is matched. */
329 RE_TRANSLATE_TYPE translate;
331 /* Number of subexpressions found by the compiler. */
332 size_t re_nsub;
334 /* Zero if this pattern cannot match the empty string, one else.
335 Well, in truth it's used only in `re_search_2', to see
336 whether or not we should use the fastmap, so we don't set
337 this absolutely perfectly; see `re_compile_fastmap'. */
338 unsigned can_be_null : 1;
340 /* If REGS_UNALLOCATED, allocate space in the `regs' structure
341 for `max (RE_NREGS, re_nsub + 1)' groups.
342 If REGS_REALLOCATE, reallocate space if necessary.
343 If REGS_FIXED, use what's there. */
344 #define REGS_UNALLOCATED 0
345 #define REGS_REALLOCATE 1
346 #define REGS_FIXED 2
347 unsigned regs_allocated : 2;
349 /* Set to zero when `regex_compile' compiles a pattern; set to one
350 by `re_compile_fastmap' if it updates the fastmap. */
351 unsigned fastmap_accurate : 1;
353 /* If set, `re_match_2' does not return information about
354 subexpressions. */
355 unsigned no_sub : 1;
357 /* If set, a beginning-of-line anchor doesn't match at the
358 beginning of the string. */
359 unsigned not_bol : 1;
361 /* Similarly for an end-of-line anchor. */
362 unsigned not_eol : 1;
364 /* If true, an anchor at a newline matches. */
365 unsigned newline_anchor : 1;
367 /* If true, multi-byte form in the `buffer' should be recognized as a
368 multibyte character. */
369 unsigned multibyte : 1;
371 /* [[[end pattern_buffer]]] */
374 typedef struct re_pattern_buffer regex_t;
376 /* Type for byte offsets within the string. POSIX mandates this. */
377 typedef int regoff_t;
380 /* This is the structure we store register match data in. See
381 regex.texinfo for a full description of what registers match. */
382 struct re_registers
384 unsigned num_regs;
385 regoff_t *start;
386 regoff_t *end;
390 /* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
391 `re_match_2' returns information about at least this many registers
392 the first time a `regs' structure is passed. */
393 #ifndef RE_NREGS
394 #define RE_NREGS 30
395 #endif
398 /* POSIX specification for registers. Aside from the different names than
399 `re_registers', POSIX uses an array of structures, instead of a
400 structure of arrays. */
401 typedef struct
403 regoff_t rm_so; /* Byte offset from string's start to substring's start. */
404 regoff_t rm_eo; /* Byte offset from string's start to substring's end. */
405 } regmatch_t;
407 /* Declarations for routines. */
409 /* To avoid duplicating every routine declaration -- once with a
410 prototype (if we are ANSI), and once without (if we aren't) -- we
411 use the following macro to declare argument types. This
412 unfortunately clutters up the declarations a bit, but I think it's
413 worth it. */
415 #if __STDC__
417 #define _RE_ARGS(args) args
419 #else /* not __STDC__ */
421 #define _RE_ARGS(args) ()
423 #endif /* not __STDC__ */
425 /* Sets the current default syntax to SYNTAX, and return the old syntax.
426 You can also simply assign to the `re_syntax_options' variable. */
427 extern reg_syntax_t re_set_syntax _RE_ARGS ((reg_syntax_t syntax));
429 /* Compile the regular expression PATTERN, with length LENGTH
430 and syntax given by the global `re_syntax_options', into the buffer
431 BUFFER. Return NULL if successful, and an error string if not. */
432 extern const char *re_compile_pattern
433 _RE_ARGS ((const char *pattern, int length,
434 struct re_pattern_buffer *buffer));
437 /* Compile a fastmap for the compiled pattern in BUFFER; used to
438 accelerate searches. Return 0 if successful and -2 if was an
439 internal error. */
440 extern int re_compile_fastmap _RE_ARGS ((struct re_pattern_buffer *buffer));
443 /* Search in the string STRING (with length LENGTH) for the pattern
444 compiled into BUFFER. Start searching at position START, for RANGE
445 characters. Return the starting position of the match, -1 for no
446 match, or -2 for an internal error. Also return register
447 information in REGS (if REGS and BUFFER->no_sub are nonzero). */
448 extern int re_search
449 _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
450 int length, int start, int range, struct re_registers *regs));
453 /* Like `re_search', but search in the concatenation of STRING1 and
454 STRING2. Also, stop searching at index START + STOP. */
455 extern int re_search_2
456 _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
457 int length1, const char *string2, int length2,
458 int start, int range, struct re_registers *regs, int stop));
461 /* Like `re_search', but return how many characters in STRING the regexp
462 in BUFFER matched, starting at position START. */
463 extern int re_match
464 _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
465 int length, int start, struct re_registers *regs));
468 /* Relates to `re_match' as `re_search_2' relates to `re_search'. */
469 extern int re_match_2
470 _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
471 int length1, const char *string2, int length2,
472 int start, struct re_registers *regs, int stop));
475 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
476 ENDS. Subsequent matches using BUFFER and REGS will use this memory
477 for recording register information. STARTS and ENDS must be
478 allocated with malloc, and must each be at least `NUM_REGS * sizeof
479 (regoff_t)' bytes long.
481 If NUM_REGS == 0, then subsequent matches should allocate their own
482 register data.
484 Unless this function is called, the first search or match using
485 PATTERN_BUFFER will allocate its own register data, without
486 freeing the old data. */
487 extern void re_set_registers
488 _RE_ARGS ((struct re_pattern_buffer *buffer, struct re_registers *regs,
489 unsigned num_regs, regoff_t *starts, regoff_t *ends));
491 #ifdef _REGEX_RE_COMP
492 /* 4.2 bsd compatibility. */
493 extern char *re_comp _RE_ARGS ((const char *));
494 extern int re_exec _RE_ARGS ((const char *));
495 #endif
497 /* POSIX compatibility. */
498 extern int regcomp _RE_ARGS ((regex_t *preg, const char *pattern, int cflags));
499 extern int regexec
500 _RE_ARGS ((const regex_t *preg, const char *string, size_t nmatch,
501 regmatch_t pmatch[], int eflags));
502 extern size_t regerror
503 _RE_ARGS ((int errcode, const regex_t *preg, char *errbuf,
504 size_t errbuf_size));
505 extern void regfree _RE_ARGS ((regex_t *preg));
507 #endif /* not __REGEXP_LIBRARY_H__ */
510 Local variables:
511 make-backup-files: t
512 version-control: t
513 trim-versions-without-asking: nil
514 End: