xref: /dragonfly/contrib/grep/lib/regex.h (revision e0b1d537)
1 /* Definitions for data structures and routines for the regular
2    expression library.
3    Copyright (C) 1985, 1989-1993, 1995-1998, 2000-2003, 2005-2012
4    Free Software Foundation, Inc.
5    This file is part of the GNU C Library.
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 3, or (at your option)
10    any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License along
18    with this program; if not, see <http://www.gnu.org/licenses/>.  */
19 
20 #ifndef _REGEX_H
21 #define _REGEX_H 1
22 
23 #include <sys/types.h>
24 
25 /* Allow the use in C++ code.  */
26 #ifdef __cplusplus
27 extern "C" {
28 #endif
29 
30 /* Define __USE_GNU to declare GNU extensions that violate the
31    POSIX name space rules.  */
32 #ifdef _GNU_SOURCE
33 # define __USE_GNU 1
34 #endif
35 
36 #ifdef _REGEX_LARGE_OFFSETS
37 
38 /* Use types and values that are wide enough to represent signed and
39    unsigned byte offsets in memory.  This currently works only when
40    the regex code is used outside of the GNU C library; it is not yet
41    supported within glibc itself, and glibc users should not define
42    _REGEX_LARGE_OFFSETS.  */
43 
44 /* The type of nonnegative object indexes.  Traditionally, GNU regex
45    uses 'int' for these.  Code that uses __re_idx_t should work
46    regardless of whether the type is signed.  */
47 typedef size_t __re_idx_t;
48 
49 /* The type of object sizes.  */
50 typedef size_t __re_size_t;
51 
52 /* The type of object sizes, in places where the traditional code
53    uses unsigned long int.  */
54 typedef size_t __re_long_size_t;
55 
56 #else
57 
58 /* The traditional GNU regex implementation mishandles strings longer
59    than INT_MAX.  */
60 typedef int __re_idx_t;
61 typedef unsigned int __re_size_t;
62 typedef unsigned long int __re_long_size_t;
63 
64 #endif
65 
66 /* The following two types have to be signed and unsigned integer type
67    wide enough to hold a value of a pointer.  For most ANSI compilers
68    ptrdiff_t and size_t should be likely OK.  Still size of these two
69    types is 2 for Microsoft C.  Ugh... */
70 typedef long int s_reg_t;
71 typedef unsigned long int active_reg_t;
72 
73 /* The following bits are used to determine the regexp syntax we
74    recognize.  The set/not-set meanings are chosen so that Emacs syntax
75    remains the value 0.  The bits are given in alphabetical order, and
76    the definitions shifted by one from the previous bit; thus, when we
77    add or remove a bit, only one other definition need change.  */
78 typedef unsigned long int reg_syntax_t;
79 
80 #ifdef __USE_GNU
81 /* If this bit is not set, then \ inside a bracket expression is literal.
82    If set, then such a \ quotes the following character.  */
83 # define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
84 
85 /* If this bit is not set, then + and ? are operators, and \+ and \? are
86      literals.
87    If set, then \+ and \? are operators and + and ? are literals.  */
88 # define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
89 
90 /* If this bit is set, then character classes are supported.  They are:
91      [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
92      [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
93    If not set, then character classes are not supported.  */
94 # define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
95 
96 /* If this bit is set, then ^ and $ are always anchors (outside bracket
97      expressions, of course).
98    If this bit is not set, then it depends:
99 	^  is an anchor if it is at the beginning of a regular
100 	   expression or after an open-group or an alternation operator;
101 	$  is an anchor if it is at the end of a regular expression, or
102 	   before a close-group or an alternation operator.
103 
104    This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
105    POSIX draft 11.2 says that * etc. in leading positions is undefined.
106    We already implemented a previous draft which made those constructs
107    invalid, though, so we haven't changed the code back.  */
108 # define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
109 
110 /* If this bit is set, then special characters are always special
111      regardless of where they are in the pattern.
112    If this bit is not set, then special characters are special only in
113      some contexts; otherwise they are ordinary.  Specifically,
114      * + ? and intervals are only special when not after the beginning,
115      open-group, or alternation operator.  */
116 # define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
117 
118 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
119      immediately after an alternation or begin-group operator.  */
120 # define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
121 
122 /* If this bit is set, then . matches newline.
123    If not set, then it doesn't.  */
124 # define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
125 
126 /* If this bit is set, then . doesn't match NUL.
127    If not set, then it does.  */
128 # define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
129 
130 /* If this bit is set, nonmatching lists [^...] do not match newline.
131    If not set, they do.  */
132 # define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
133 
134 /* If this bit is set, either \{...\} or {...} defines an
135      interval, depending on RE_NO_BK_BRACES.
136    If not set, \{, \}, {, and } are literals.  */
137 # define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
138 
139 /* If this bit is set, +, ? and | aren't recognized as operators.
140    If not set, they are.  */
141 # define RE_LIMITED_OPS (RE_INTERVALS << 1)
142 
143 /* If this bit is set, newline is an alternation operator.
144    If not set, newline is literal.  */
145 # define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
146 
147 /* If this bit is set, then '{...}' defines an interval, and \{ and \}
148      are literals.
149   If not set, then '\{...\}' defines an interval.  */
150 # define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
151 
152 /* If this bit is set, (...) defines a group, and \( and \) are literals.
153    If not set, \(...\) defines a group, and ( and ) are literals.  */
154 # define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
155 
156 /* If this bit is set, then \<digit> matches <digit>.
157    If not set, then \<digit> is a back-reference.  */
158 # define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
159 
160 /* If this bit is set, then | is an alternation operator, and \| is literal.
161    If not set, then \| is an alternation operator, and | is literal.  */
162 # define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
163 
164 /* If this bit is set, then an ending range point collating higher
165      than the starting range point, as in [z-a], is invalid.
166    If not set, then when ending range point collates higher than the
167      starting range point, the range is ignored.  */
168 # define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
169 
170 /* If this bit is set, then an unmatched ) is ordinary.
171    If not set, then an unmatched ) is invalid.  */
172 # define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
173 
174 /* If this bit is set, succeed as soon as we match the whole pattern,
175    without further backtracking.  */
176 # define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
177 
178 /* If this bit is set, do not process the GNU regex operators.
179    If not set, then the GNU regex operators are recognized. */
180 # define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
181 
182 /* If this bit is set, turn on internal regex debugging.
183    If not set, and debugging was on, turn it off.
184    This only works if regex.c is compiled -DDEBUG.
185    We define this bit always, so that all that's needed to turn on
186    debugging is to recompile regex.c; the calling code can always have
187    this bit set, and it won't affect anything in the normal case. */
188 # define RE_DEBUG (RE_NO_GNU_OPS << 1)
189 
190 /* If this bit is set, a syntactically invalid interval is treated as
191    a string of ordinary characters.  For example, the ERE 'a{1' is
192    treated as 'a\{1'.  */
193 # define RE_INVALID_INTERVAL_ORD (RE_DEBUG << 1)
194 
195 /* If this bit is set, then ignore case when matching.
196    If not set, then case is significant.  */
197 # define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
198 
199 /* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
200    for ^, because it is difficult to scan the regex backwards to find
201    whether ^ should be special.  */
202 # define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
203 
204 /* If this bit is set, then \{ cannot be first in a regex or
205    immediately after an alternation, open-group or \} operator.  */
206 # define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
207 
208 /* If this bit is set, then no_sub will be set to 1 during
209    re_compile_pattern.  */
210 # define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
211 #endif
212 
213 /* This global variable defines the particular regexp syntax to use (for
214    some interfaces).  When a regexp is compiled, the syntax used is
215    stored in the pattern buffer, so changing this does not affect
216    already-compiled regexps.  */
217 extern reg_syntax_t re_syntax_options;
218 
219 #ifdef __USE_GNU
220 /* Define combinations of the above bits for the standard possibilities.
221    (The [[[ comments delimit what gets put into the Texinfo file, so
222    don't delete them!)  */
223 /* [[[begin syntaxes]]] */
224 # define RE_SYNTAX_EMACS 0
225 
226 # define RE_SYNTAX_AWK							\
227   (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL			\
228    | RE_NO_BK_PARENS              | RE_NO_BK_REFS			\
229    | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES			\
230    | RE_DOT_NEWLINE		  | RE_CONTEXT_INDEP_ANCHORS		\
231    | RE_CHAR_CLASSES							\
232    | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
233 
234 # define RE_SYNTAX_GNU_AWK						\
235   ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
236     | RE_INVALID_INTERVAL_ORD)						\
237    & ~(RE_DOT_NOT_NULL | RE_CONTEXT_INDEP_OPS				\
238       | RE_CONTEXT_INVALID_OPS ))
239 
240 # define RE_SYNTAX_POSIX_AWK						\
241   (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
242    | RE_INTERVALS	    | RE_NO_GNU_OPS				\
243    | RE_INVALID_INTERVAL_ORD)
244 
245 # define RE_SYNTAX_GREP							\
246   (RE_BK_PLUS_QM              | RE_CHAR_CLASSES				\
247    | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS				\
248    | RE_NEWLINE_ALT)
249 
250 # define RE_SYNTAX_EGREP						\
251   (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS			\
252    | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE			\
253    | RE_NEWLINE_ALT       | RE_NO_BK_PARENS				\
254    | RE_NO_BK_VBAR)
255 
256 # define RE_SYNTAX_POSIX_EGREP						\
257   (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES			\
258    | RE_INVALID_INTERVAL_ORD)
259 
260 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
261 # define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
262 
263 # define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
264 
265 /* Syntax bits common to both basic and extended POSIX regex syntax.  */
266 # define _RE_SYNTAX_POSIX_COMMON					\
267   (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL		\
268    | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
269 
270 # define RE_SYNTAX_POSIX_BASIC						\
271   (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
272 
273 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
274    RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
275    isn't minimal, since other operators, such as \`, aren't disabled.  */
276 # define RE_SYNTAX_POSIX_MINIMAL_BASIC					\
277   (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
278 
279 # define RE_SYNTAX_POSIX_EXTENDED					\
280   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
281    | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES				\
282    | RE_NO_BK_PARENS        | RE_NO_BK_VBAR				\
283    | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
284 
285 /* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
286    removed and RE_NO_BK_REFS is added.  */
287 # define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
288   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
289    | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
290    | RE_NO_BK_PARENS        | RE_NO_BK_REFS				\
291    | RE_NO_BK_VBAR	    | RE_UNMATCHED_RIGHT_PAREN_ORD)
292 /* [[[end syntaxes]]] */
293 
294 /* Maximum number of duplicates an interval can allow.  POSIX-conforming
295    systems might define this in <limits.h>, but we want our
296    value, so remove any previous define.  */
297 # ifdef _REGEX_INCLUDE_LIMITS_H
298 #  include <limits.h>
299 # endif
300 # ifdef RE_DUP_MAX
301 #  undef RE_DUP_MAX
302 # endif
303 
304 /* RE_DUP_MAX is 2**15 - 1 because an earlier implementation stored
305    the counter as a 2-byte signed integer.  This is no longer true, so
306    RE_DUP_MAX could be increased to (INT_MAX / 10 - 1), or to
307    ((SIZE_MAX - 9) / 10) if _REGEX_LARGE_OFFSETS is defined.
308    However, there would be a huge performance problem if someone
309    actually used a pattern like a\{214748363\}, so RE_DUP_MAX retains
310    its historical value.  */
311 # define RE_DUP_MAX (0x7fff)
312 #endif
313 
314 
315 /* POSIX 'cflags' bits (i.e., information for 'regcomp').  */
316 
317 /* If this bit is set, then use extended regular expression syntax.
318    If not set, then use basic regular expression syntax.  */
319 #define REG_EXTENDED 1
320 
321 /* If this bit is set, then ignore case when matching.
322    If not set, then case is significant.  */
323 #define REG_ICASE (1 << 1)
324 
325 /* If this bit is set, then anchors do not match at newline
326      characters in the string.
327    If not set, then anchors do match at newlines.  */
328 #define REG_NEWLINE (1 << 2)
329 
330 /* If this bit is set, then report only success or fail in regexec.
331    If not set, then returns differ between not matching and errors.  */
332 #define REG_NOSUB (1 << 3)
333 
334 
335 /* POSIX 'eflags' bits (i.e., information for regexec).  */
336 
337 /* If this bit is set, then the beginning-of-line operator doesn't match
338      the beginning of the string (presumably because it's not the
339      beginning of a line).
340    If not set, then the beginning-of-line operator does match the
341      beginning of the string.  */
342 #define REG_NOTBOL 1
343 
344 /* Like REG_NOTBOL, except for the end-of-line.  */
345 #define REG_NOTEOL (1 << 1)
346 
347 /* Use PMATCH[0] to delimit the start and end of the search in the
348    buffer.  */
349 #define REG_STARTEND (1 << 2)
350 
351 
352 /* If any error codes are removed, changed, or added, update the
353    '__re_error_msgid' table in regcomp.c.  */
354 
355 typedef enum
356 {
357   _REG_ENOSYS = -1,	/* This will never happen for this implementation.  */
358   _REG_NOERROR = 0,	/* Success.  */
359   _REG_NOMATCH,		/* Didn't find a match (for regexec).  */
360 
361   /* POSIX regcomp return error codes.  (In the order listed in the
362      standard.)  */
363   _REG_BADPAT,		/* Invalid pattern.  */
364   _REG_ECOLLATE,	/* Invalid collating element.  */
365   _REG_ECTYPE,		/* Invalid character class name.  */
366   _REG_EESCAPE,		/* Trailing backslash.  */
367   _REG_ESUBREG,		/* Invalid back reference.  */
368   _REG_EBRACK,		/* Unmatched left bracket.  */
369   _REG_EPAREN,		/* Parenthesis imbalance.  */
370   _REG_EBRACE,		/* Unmatched \{.  */
371   _REG_BADBR,		/* Invalid contents of \{\}.  */
372   _REG_ERANGE,		/* Invalid range end.  */
373   _REG_ESPACE,		/* Ran out of memory.  */
374   _REG_BADRPT,		/* No preceding re for repetition op.  */
375 
376   /* Error codes we've added.  */
377   _REG_EEND,		/* Premature end.  */
378   _REG_ESIZE,		/* Too large (e.g., repeat count too large).  */
379   _REG_ERPAREN		/* Unmatched ) or \); not returned from regcomp.  */
380 } reg_errcode_t;
381 
382 #if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
383 # define REG_ENOSYS	_REG_ENOSYS
384 #endif
385 #define REG_NOERROR	_REG_NOERROR
386 #define REG_NOMATCH	_REG_NOMATCH
387 #define REG_BADPAT	_REG_BADPAT
388 #define REG_ECOLLATE	_REG_ECOLLATE
389 #define REG_ECTYPE	_REG_ECTYPE
390 #define REG_EESCAPE	_REG_EESCAPE
391 #define REG_ESUBREG	_REG_ESUBREG
392 #define REG_EBRACK	_REG_EBRACK
393 #define REG_EPAREN	_REG_EPAREN
394 #define REG_EBRACE	_REG_EBRACE
395 #define REG_BADBR	_REG_BADBR
396 #define REG_ERANGE	_REG_ERANGE
397 #define REG_ESPACE	_REG_ESPACE
398 #define REG_BADRPT	_REG_BADRPT
399 #define REG_EEND	_REG_EEND
400 #define REG_ESIZE	_REG_ESIZE
401 #define REG_ERPAREN	_REG_ERPAREN
402 
403 /* This data structure represents a compiled pattern.  Before calling
404    the pattern compiler, the fields 'buffer', 'allocated', 'fastmap',
405    and 'translate' can be set.  After the pattern has been compiled,
406    the fields 're_nsub', 'not_bol' and 'not_eol' are available.  All
407    other fields are private to the regex routines.  */
408 
409 #ifndef RE_TRANSLATE_TYPE
410 # define __RE_TRANSLATE_TYPE unsigned char *
411 # ifdef __USE_GNU
412 #  define RE_TRANSLATE_TYPE __RE_TRANSLATE_TYPE
413 # endif
414 #endif
415 
416 #ifdef __USE_GNU
417 # define __REPB_PREFIX(name) name
418 #else
419 # define __REPB_PREFIX(name) __##name
420 #endif
421 
422 struct re_pattern_buffer
423 {
424   /* Space that holds the compiled pattern.  The type
425      'struct re_dfa_t' is private and is not declared here.  */
426   struct re_dfa_t *__REPB_PREFIX(buffer);
427 
428   /* Number of bytes to which 'buffer' points.  */
429   __re_long_size_t __REPB_PREFIX(allocated);
430 
431   /* Number of bytes actually used in 'buffer'.  */
432   __re_long_size_t __REPB_PREFIX(used);
433 
434   /* Syntax setting with which the pattern was compiled.  */
435   reg_syntax_t __REPB_PREFIX(syntax);
436 
437   /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
438      fastmap, if there is one, to skip over impossible starting points
439      for matches.  */
440   char *__REPB_PREFIX(fastmap);
441 
442   /* Either a translate table to apply to all characters before
443      comparing them, or zero for no translation.  The translation is
444      applied to a pattern when it is compiled and to a string when it
445      is matched.  */
446   __RE_TRANSLATE_TYPE __REPB_PREFIX(translate);
447 
448   /* Number of subexpressions found by the compiler.  */
449   size_t re_nsub;
450 
451   /* Zero if this pattern cannot match the empty string, one else.
452      Well, in truth it's used only in 're_search_2', to see whether or
453      not we should use the fastmap, so we don't set this absolutely
454      perfectly; see 're_compile_fastmap' (the "duplicate" case).  */
455   unsigned __REPB_PREFIX(can_be_null) : 1;
456 
457   /* If REGS_UNALLOCATED, allocate space in the 'regs' structure
458      for 'max (RE_NREGS, re_nsub + 1)' groups.
459      If REGS_REALLOCATE, reallocate space if necessary.
460      If REGS_FIXED, use what's there.  */
461 #ifdef __USE_GNU
462 # define REGS_UNALLOCATED 0
463 # define REGS_REALLOCATE 1
464 # define REGS_FIXED 2
465 #endif
466   unsigned __REPB_PREFIX(regs_allocated) : 2;
467 
468   /* Set to zero when 're_compile_pattern' compiles a pattern; set to
469      one by 're_compile_fastmap' if it updates the fastmap.  */
470   unsigned __REPB_PREFIX(fastmap_accurate) : 1;
471 
472   /* If set, 're_match_2' does not return information about
473      subexpressions.  */
474   unsigned __REPB_PREFIX(no_sub) : 1;
475 
476   /* If set, a beginning-of-line anchor doesn't match at the beginning
477      of the string.  */
478   unsigned __REPB_PREFIX(not_bol) : 1;
479 
480   /* Similarly for an end-of-line anchor.  */
481   unsigned __REPB_PREFIX(not_eol) : 1;
482 
483   /* If true, an anchor at a newline matches.  */
484   unsigned __REPB_PREFIX(newline_anchor) : 1;
485 };
486 
487 typedef struct re_pattern_buffer regex_t;
488 
489 /* Type for byte offsets within the string.  POSIX mandates this.  */
490 #ifdef _REGEX_LARGE_OFFSETS
491 /* POSIX 1003.1-2008 requires that regoff_t be at least as wide as
492    ptrdiff_t and ssize_t.  We don't know of any hosts where ptrdiff_t
493    is wider than ssize_t, so ssize_t is safe.  */
494 typedef ssize_t regoff_t;
495 #else
496 /* The traditional GNU regex implementation mishandles strings longer
497    than INT_MAX.  */
498 typedef int regoff_t;
499 #endif
500 
501 
502 #ifdef __USE_GNU
503 /* This is the structure we store register match data in.  See
504    regex.texinfo for a full description of what registers match.  */
505 struct re_registers
506 {
507   __re_size_t num_regs;
508   regoff_t *start;
509   regoff_t *end;
510 };
511 
512 
513 /* If 'regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
514    're_match_2' returns information about at least this many registers
515    the first time a 'regs' structure is passed.  */
516 # ifndef RE_NREGS
517 #  define RE_NREGS 30
518 # endif
519 #endif
520 
521 
522 /* POSIX specification for registers.  Aside from the different names than
523    're_registers', POSIX uses an array of structures, instead of a
524    structure of arrays.  */
525 typedef struct
526 {
527   regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
528   regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
529 } regmatch_t;
530 
531 /* Declarations for routines.  */
532 
533 #ifdef __USE_GNU
534 /* Sets the current default syntax to SYNTAX, and return the old syntax.
535    You can also simply assign to the 're_syntax_options' variable.  */
536 extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
537 
538 /* Compile the regular expression PATTERN, with length LENGTH
539    and syntax given by the global 're_syntax_options', into the buffer
540    BUFFER.  Return NULL if successful, and an error string if not.
541 
542    To free the allocated storage, you must call 'regfree' on BUFFER.
543    Note that the translate table must either have been initialised by
544    'regcomp', with a malloc'ed value, or set to NULL before calling
545    'regfree'.  */
546 extern const char *re_compile_pattern (const char *__pattern, size_t __length,
547 				       struct re_pattern_buffer *__buffer);
548 
549 
550 /* Compile a fastmap for the compiled pattern in BUFFER; used to
551    accelerate searches.  Return 0 if successful and -2 if was an
552    internal error.  */
553 extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
554 
555 
556 /* Search in the string STRING (with length LENGTH) for the pattern
557    compiled into BUFFER.  Start searching at position START, for RANGE
558    characters.  Return the starting position of the match, -1 for no
559    match, or -2 for an internal error.  Also return register
560    information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
561 extern regoff_t re_search (struct re_pattern_buffer *__buffer,
562 			   const char *__string, __re_idx_t __length,
563 			   __re_idx_t __start, regoff_t __range,
564 			   struct re_registers *__regs);
565 
566 
567 /* Like 're_search', but search in the concatenation of STRING1 and
568    STRING2.  Also, stop searching at index START + STOP.  */
569 extern regoff_t re_search_2 (struct re_pattern_buffer *__buffer,
570 			     const char *__string1, __re_idx_t __length1,
571 			     const char *__string2, __re_idx_t __length2,
572 			     __re_idx_t __start, regoff_t __range,
573 			     struct re_registers *__regs,
574 			     __re_idx_t __stop);
575 
576 
577 /* Like 're_search', but return how many characters in STRING the regexp
578    in BUFFER matched, starting at position START.  */
579 extern regoff_t re_match (struct re_pattern_buffer *__buffer,
580 			  const char *__string, __re_idx_t __length,
581 			  __re_idx_t __start, struct re_registers *__regs);
582 
583 
584 /* Relates to 're_match' as 're_search_2' relates to 're_search'.  */
585 extern regoff_t re_match_2 (struct re_pattern_buffer *__buffer,
586 			    const char *__string1, __re_idx_t __length1,
587 			    const char *__string2, __re_idx_t __length2,
588 			    __re_idx_t __start, struct re_registers *__regs,
589 			    __re_idx_t __stop);
590 
591 
592 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
593    ENDS.  Subsequent matches using BUFFER and REGS will use this memory
594    for recording register information.  STARTS and ENDS must be
595    allocated with malloc, and must each be at least 'NUM_REGS * sizeof
596    (regoff_t)' bytes long.
597 
598    If NUM_REGS == 0, then subsequent matches should allocate their own
599    register data.
600 
601    Unless this function is called, the first search or match using
602    BUFFER will allocate its own register data, without
603    freeing the old data.  */
604 extern void re_set_registers (struct re_pattern_buffer *__buffer,
605 			      struct re_registers *__regs,
606 			      __re_size_t __num_regs,
607 			      regoff_t *__starts, regoff_t *__ends);
608 #endif	/* Use GNU */
609 
610 #if defined _REGEX_RE_COMP || (defined _LIBC && defined __USE_BSD)
611 # ifndef _CRAY
612 /* 4.2 bsd compatibility.  */
613 extern char *re_comp (const char *);
614 extern int re_exec (const char *);
615 # endif
616 #endif
617 
618 /* GCC 2.95 and later have "__restrict"; C99 compilers have
619    "restrict", and "configure" may have defined "restrict".
620    Other compilers use __restrict, __restrict__, and _Restrict, and
621    'configure' might #define 'restrict' to those words, so pick a
622    different name.  */
623 #ifndef _Restrict_
624 # if 199901L <= __STDC_VERSION__
625 #  define _Restrict_ restrict
626 # elif 2 < __GNUC__ || (2 == __GNUC__ && 95 <= __GNUC_MINOR__)
627 #  define _Restrict_ __restrict
628 # else
629 #  define _Restrict_
630 # endif
631 #endif
632 /* gcc 3.1 and up support the [restrict] syntax.  Don't trust
633    sys/cdefs.h's definition of __restrict_arr, though, as it
634    mishandles gcc -ansi -pedantic.  */
635 #ifndef _Restrict_arr_
636 # if ((199901L <= __STDC_VERSION__					\
637        || ((3 < __GNUC__ || (3 == __GNUC__ && 1 <= __GNUC_MINOR__))	\
638 	   && !defined __STRICT_ANSI__))					\
639       && !defined __GNUG__)
640 #  define _Restrict_arr_ _Restrict_
641 # else
642 #  define _Restrict_arr_
643 # endif
644 #endif
645 
646 /* POSIX compatibility.  */
647 extern int regcomp (regex_t *_Restrict_ __preg,
648 		    const char *_Restrict_ __pattern,
649 		    int __cflags);
650 
651 extern int regexec (const regex_t *_Restrict_ __preg,
652 		    const char *_Restrict_ __string, size_t __nmatch,
653 		    regmatch_t __pmatch[_Restrict_arr_],
654 		    int __eflags);
655 
656 extern size_t regerror (int __errcode, const regex_t *_Restrict_ __preg,
657 			char *_Restrict_ __errbuf, size_t __errbuf_size);
658 
659 extern void regfree (regex_t *__preg);
660 
661 
662 #ifdef __cplusplus
663 }
664 #endif	/* C++ */
665 
666 #endif /* regex.h */
667