gl/regex.h

   1 /* Definitions for data structures and routines for the regular
   2    expression library.
   3    Copyright (C) 1985,1989-93,1995-98,2000,2001,2002,2003,2005,2006
   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, write to the Free Software Foundation,
  19    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
  20
  21 #ifndef _REGEX_H
  22 #define _REGEX_H 1
  23
  24 #include <sys/types.h>
  25
  26 /* Allow the use in C++ code.  */
  27 #ifdef __cplusplus
  28 extern "C" {
  29 #endif
  30
  31 /* Define __USE_GNU_REGEX to declare GNU extensions that violate the
  32    POSIX name space rules.  */
  33 #undef __USE_GNU_REGEX
  34 #if (defined _GNU_SOURCE                                        \
  35      || (!defined _POSIX_C_SOURCE && !defined _POSIX_SOURCE     \
  36          && !defined _XOPEN_SOURCE))
  37 # define __USE_GNU_REGEX 1
  38 #endif
  39
  40 #ifdef _REGEX_LARGE_OFFSETS
  41
  42 /* Use types and values that are wide enough to represent signed and
  43    unsigned byte offsets in memory.  This currently works only when
  44    the regex code is used outside of the GNU C library; it is not yet
  45    supported within glibc itself, and glibc users should not define
  46    _REGEX_LARGE_OFFSETS.  */
  47
  48 /* The type of the offset of a byte within a string.
  49    For historical reasons POSIX 1003.1-2004 requires that regoff_t be
  50    at least as wide as off_t.  However, many common POSIX platforms set
  51    regoff_t to the more-sensible ssize_t and the Open Group has
  52    signalled its intention to change the requirement to be that
  53    regoff_t be at least as wide as ptrdiff_t and ssize_t; see XBD ERN
  54    60 (2005-08-25).  We don't know of any hosts where ssize_t or
  55    ptrdiff_t is wider than ssize_t, so ssize_t is safe.  */
  56 typedef ssize_t regoff_t;
  57
  58 /* The type of nonnegative object indexes.  Traditionally, GNU regex
  59    uses 'int' for these.  Code that uses __re_idx_t should work
  60    regardless of whether the type is signed.  */
  61 typedef size_t __re_idx_t;
  62
  63 /* The type of object sizes.  */
  64 typedef size_t __re_size_t;
  65
  66 /* The type of object sizes, in places where the traditional code
  67    uses unsigned long int.  */
  68 typedef size_t __re_long_size_t;
  69
  70 #else
  71
  72 /* Use types that are binary-compatible with the traditional GNU regex
  73    implementation, which mishandles strings longer than INT_MAX.  */
  74
  75 typedef int regoff_t;
  76 typedef int __re_idx_t;
  77 typedef unsigned int __re_size_t;
  78 typedef unsigned long int __re_long_size_t;
  79
  80 #endif
  81
  82 /* The following two types have to be signed and unsigned integer type
  83    wide enough to hold a value of a pointer.  For most ANSI compilers
  84    ptrdiff_t and size_t should be likely OK.  Still size of these two
  85    types is 2 for Microsoft C.  Ugh... */
  86 typedef long int s_reg_t;
  87 typedef unsigned long int active_reg_t;
  88
  89 /* The following bits are used to determine the regexp syntax we
  90    recognize.  The set/not-set meanings are chosen so that Emacs syntax
  91    remains the value 0.  The bits are given in alphabetical order, and
  92    the definitions shifted by one from the previous bit; thus, when we
  93    add or remove a bit, only one other definition need change.  */
  94 typedef unsigned long int reg_syntax_t;
  95
  96 #ifdef __USE_GNU_REGEX
  97
  98 /* If this bit is not set, then \ inside a bracket expression is literal.
  99    If set, then such a \ quotes the following character.  */
 100 # define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
 101
 102 /* If this bit is not set, then + and ? are operators, and \+ and \? are
 103      literals.
 104    If set, then \+ and \? are operators and + and ? are literals.  */
 105 # define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
 106
 107 /* If this bit is set, then character classes are supported.  They are:
 108      [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
 109      [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
 110    If not set, then character classes are not supported.  */
 111 # define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
 112
 113 /* If this bit is set, then ^ and $ are always anchors (outside bracket
 114      expressions, of course).
 115    If this bit is not set, then it depends:
 116         ^  is an anchor if it is at the beginning of a regular
 117            expression or after an open-group or an alternation operator;
 118         $  is an anchor if it is at the end of a regular expression, or
 119            before a close-group or an alternation operator.
 120
 121    This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
 122    POSIX draft 11.2 says that * etc. in leading positions is undefined.
 123    We already implemented a previous draft which made those constructs
 124    invalid, though, so we haven't changed the code back.  */
 125 # define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
 126
 127 /* If this bit is set, then special characters are always special
 128      regardless of where they are in the pattern.
 129    If this bit is not set, then special characters are special only in
 130      some contexts; otherwise they are ordinary.  Specifically,
 131      * + ? and intervals are only special when not after the beginning,
 132      open-group, or alternation operator.  */
 133 # define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
 134
 135 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
 136      immediately after an alternation or begin-group operator.  */
 137 # define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
 138
 139 /* If this bit is set, then . matches newline.
 140    If not set, then it doesn't.  */
 141 # define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
 142
 143 /* If this bit is set, then . doesn't match NUL.
 144    If not set, then it does.  */
 145 # define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
 146
 147 /* If this bit is set, nonmatching lists [^...] do not match newline.
 148    If not set, they do.  */
 149 # define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
 150
 151 /* If this bit is set, either \{...\} or {...} defines an
 152      interval, depending on RE_NO_BK_BRACES.
 153    If not set, \{, \}, {, and } are literals.  */
 154 # define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
 155
 156 /* If this bit is set, +, ? and | aren't recognized as operators.
 157    If not set, they are.  */
 158 # define RE_LIMITED_OPS (RE_INTERVALS << 1)
 159
 160 /* If this bit is set, newline is an alternation operator.
 161    If not set, newline is literal.  */
 162 # define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
 163
 164 /* If this bit is set, then `{...}' defines an interval, and \{ and \}
 165      are literals.
 166   If not set, then `\{...\}' defines an interval.  */
 167 # define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
 168
 169 /* If this bit is set, (...) defines a group, and \( and \) are literals.
 170    If not set, \(...\) defines a group, and ( and ) are literals.  */
 171 # define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
 172
 173 /* If this bit is set, then \<digit> matches <digit>.
 174    If not set, then \<digit> is a back-reference.  */
 175 # define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
 176
 177 /* If this bit is set, then | is an alternation operator, and \| is literal.
 178    If not set, then \| is an alternation operator, and | is literal.  */
 179 # define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
 180
 181 /* If this bit is set, then an ending range point collating higher
 182      than the starting range point, as in [z-a], is invalid.
 183    If not set, then when ending range point collates higher than the
 184      starting range point, the range is ignored.  */
 185 # define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
 186
 187 /* If this bit is set, then an unmatched ) is ordinary.
 188    If not set, then an unmatched ) is invalid.  */
 189 # define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
 190
 191 /* If this bit is set, succeed as soon as we match the whole pattern,
 192    without further backtracking.  */
 193 # define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
 194
 195 /* If this bit is set, do not process the GNU regex operators.
 196    If not set, then the GNU regex operators are recognized. */
 197 # define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
 198
 199 /* If this bit is set, turn on internal regex debugging.
 200    If not set, and debugging was on, turn it off.
 201    This only works if regex.c is compiled -DDEBUG.
 202    We define this bit always, so that all that's needed to turn on
 203    debugging is to recompile regex.c; the calling code can always have
 204    this bit set, and it won't affect anything in the normal case. */
 205 # define RE_DEBUG (RE_NO_GNU_OPS << 1)
 206
 207 /* If this bit is set, a syntactically invalid interval is treated as
 208    a string of ordinary characters.  For example, the ERE 'a{1' is
 209    treated as 'a\{1'.  */
 210 # define RE_INVALID_INTERVAL_ORD (RE_DEBUG << 1)
 211
 212 /* If this bit is set, then ignore case when matching.
 213    If not set, then case is significant.  */
 214 # define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
 215
 216 /* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
 217    for ^, because it is difficult to scan the regex backwards to find
 218    whether ^ should be special.  */
 219 # define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
 220
 221 /* If this bit is set, then \{ cannot be first in an bre or
 222    immediately after an alternation or begin-group operator.  */
 223 # define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
 224
 225 /* If this bit is set, then no_sub will be set to 1 during
 226    re_compile_pattern.  */
 227 # define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
 228
 229 #endif /* defined __USE_GNU_REGEX */
 230
 231 /* This global variable defines the particular regexp syntax to use (for
 232    some interfaces).  When a regexp is compiled, the syntax used is
 233    stored in the pattern buffer, so changing this does not affect
 234    already-compiled regexps.  */
 235 extern reg_syntax_t re_syntax_options;
 236 \f
 237 #ifdef __USE_GNU_REGEX
 238 /* Define combinations of the above bits for the standard possibilities.
 239    (The [[[ comments delimit what gets put into the Texinfo file, so
 240    don't delete them!)  */
 241 /* [[[begin syntaxes]]] */
 242 # define RE_SYNTAX_EMACS 0
 243
 244 # define RE_SYNTAX_AWK                                                  \
 245   (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL                     \
 246    | RE_NO_BK_PARENS              | RE_NO_BK_REFS                       \
 247    | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES                  \
 248    | RE_DOT_NEWLINE               | RE_CONTEXT_INDEP_ANCHORS            \
 249    | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
 250
 251 # define RE_SYNTAX_GNU_AWK                                              \
 252   ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DEBUG) \
 253    & ~(RE_DOT_NOT_NULL | RE_INTERVALS | RE_CONTEXT_INDEP_OPS            \
 254        | RE_CONTEXT_INVALID_OPS ))
 255
 256 # define RE_SYNTAX_POSIX_AWK                                            \
 257   (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS              \
 258    | RE_INTERVALS           | RE_NO_GNU_OPS)
 259
 260 # define RE_SYNTAX_GREP                                                 \
 261   (RE_BK_PLUS_QM              | RE_CHAR_CLASSES                         \
 262    | RE_HAT_LISTS_NOT_NEWLINE | RE_INTERVALS                            \
 263    | RE_NEWLINE_ALT)
 264
 265 # define RE_SYNTAX_EGREP                                                \
 266   (RE_CHAR_CLASSES        | RE_CONTEXT_INDEP_ANCHORS                    \
 267    | RE_CONTEXT_INDEP_OPS | RE_HAT_LISTS_NOT_NEWLINE                    \
 268    | RE_NEWLINE_ALT       | RE_NO_BK_PARENS                             \
 269    | RE_NO_BK_VBAR)
 270
 271 # define RE_SYNTAX_POSIX_EGREP                                          \
 272   (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES                     \
 273    | RE_INVALID_INTERVAL_ORD)
 274
 275 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
 276 # define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
 277
 278 # define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
 279
 280 /* Syntax bits common to both basic and extended POSIX regex syntax.  */
 281 # define _RE_SYNTAX_POSIX_COMMON                                        \
 282   (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL              \
 283    | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
 284
 285 # define RE_SYNTAX_POSIX_BASIC                                          \
 286   (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
 287
 288 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
 289    RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
 290    isn't minimal, since other operators, such as \`, aren't disabled.  */
 291 # define RE_SYNTAX_POSIX_MINIMAL_BASIC                                  \
 292   (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
 293
 294 # define RE_SYNTAX_POSIX_EXTENDED                                       \
 295   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 296    | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES                           \
 297    | RE_NO_BK_PARENS        | RE_NO_BK_VBAR                             \
 298    | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
 299
 300 /* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
 301    removed and RE_NO_BK_REFS is added.  */
 302 # define RE_SYNTAX_POSIX_MINIMAL_EXTENDED                               \
 303   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 304    | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES                           \
 305    | RE_NO_BK_PARENS        | RE_NO_BK_REFS                             \
 306    | RE_NO_BK_VBAR          | RE_UNMATCHED_RIGHT_PAREN_ORD)
 307 /* [[[end syntaxes]]] */
 308
 309 #endif /* defined __USE_GNU_REGEX */
 310 \f
 311 #ifdef __USE_GNU_REGEX
 312
 313 /* Maximum number of duplicates an interval can allow.  POSIX-conforming
 314    systems might define this in <limits.h>, but we want our
 315    value, so remove any previous define.  */
 316 # ifdef RE_DUP_MAX
 317 #  undef RE_DUP_MAX
 318 # endif
 319
 320 /* RE_DUP_MAX is 2**15 - 1 because an earlier implementation stored
 321    the counter as a 2-byte signed integer.  This is no longer true, so
 322    RE_DUP_MAX could be increased to (INT_MAX / 10 - 1), or to
 323    ((SIZE_MAX - 2) / 10 - 1) if _REGEX_LARGE_OFFSETS is defined.
 324    However, there would be a huge performance problem if someone
 325    actually used a pattern like a\{214748363\}, so RE_DUP_MAX retains
 326    its historical value.  */
 327 # define RE_DUP_MAX (0x7fff)
 328
 329 #endif /* defined __USE_GNU_REGEX */
 330
 331
 332 /* POSIX `cflags' bits (i.e., information for `regcomp').  */
 333
 334 /* If this bit is set, then use extended regular expression syntax.
 335    If not set, then use basic regular expression syntax.  */
 336 #define REG_EXTENDED 1
 337
 338 /* If this bit is set, then ignore case when matching.
 339    If not set, then case is significant.  */
 340 #define REG_ICASE (1 << 1)
 341
 342 /* If this bit is set, then anchors do not match at newline
 343      characters in the string.
 344    If not set, then anchors do match at newlines.  */
 345 #define REG_NEWLINE (1 << 2)
 346
 347 /* If this bit is set, then report only success or fail in regexec.
 348    If not set, then returns differ between not matching and errors.  */
 349 #define REG_NOSUB (1 << 3)
 350
 351
 352 /* POSIX `eflags' bits (i.e., information for regexec).  */
 353
 354 /* If this bit is set, then the beginning-of-line operator doesn't match
 355      the beginning of the string (presumably because it's not the
 356      beginning of a line).
 357    If not set, then the beginning-of-line operator does match the
 358      beginning of the string.  */
 359 #define REG_NOTBOL 1
 360
 361 /* Like REG_NOTBOL, except for the end-of-line.  */
 362 #define REG_NOTEOL (1 << 1)
 363
 364 /* Use PMATCH[0] to delimit the start and end of the search in the
 365    buffer.  */
 366 #define REG_STARTEND (1 << 2)
 367
 368
 369 /* If any error codes are removed, changed, or added, update the
 370    `__re_error_msgid' table in regcomp.c.  */
 371
 372 typedef enum
 373 {
 374   _REG_ENOSYS = -1,     /* This will never happen for this implementation.  */
 375   _REG_NOERROR = 0,     /* Success.  */
 376   _REG_NOMATCH,         /* Didn't find a match (for regexec).  */
 377
 378   /* POSIX regcomp return error codes.  (In the order listed in the
 379      standard.)  */
 380   _REG_BADPAT,          /* Invalid pattern.  */
 381   _REG_ECOLLATE,        /* Invalid collating element.  */
 382   _REG_ECTYPE,          /* Invalid character class name.  */
 383   _REG_EESCAPE,         /* Trailing backslash.  */
 384   _REG_ESUBREG,         /* Invalid back reference.  */
 385   _REG_EBRACK,          /* Unmatched left bracket.  */
 386   _REG_EPAREN,          /* Parenthesis imbalance.  */
 387   _REG_EBRACE,          /* Unmatched \{.  */
 388   _REG_BADBR,           /* Invalid contents of \{\}.  */
 389   _REG_ERANGE,          /* Invalid range end.  */
 390   _REG_ESPACE,          /* Ran out of memory.  */
 391   _REG_BADRPT,          /* No preceding re for repetition op.  */
 392
 393   /* Error codes we've added.  */
 394   _REG_EEND,            /* Premature end.  */
 395   _REG_ESIZE,           /* Compiled pattern bigger than 2^16 bytes.  */
 396   _REG_ERPAREN          /* Unmatched ) or \); not returned from regcomp.  */
 397 } reg_errcode_t;
 398
 399 #ifdef _XOPEN_SOURCE
 400 # define REG_ENOSYS     _REG_ENOSYS
 401 #endif
 402 #define REG_NOERROR     _REG_NOERROR
 403 #define REG_NOMATCH     _REG_NOMATCH
 404 #define REG_BADPAT      _REG_BADPAT
 405 #define REG_ECOLLATE    _REG_ECOLLATE
 406 #define REG_ECTYPE      _REG_ECTYPE
 407 #define REG_EESCAPE     _REG_EESCAPE
 408 #define REG_ESUBREG     _REG_ESUBREG
 409 #define REG_EBRACK      _REG_EBRACK
 410 #define REG_EPAREN      _REG_EPAREN
 411 #define REG_EBRACE      _REG_EBRACE
 412 #define REG_BADBR       _REG_BADBR
 413 #define REG_ERANGE      _REG_ERANGE
 414 #define REG_ESPACE      _REG_ESPACE
 415 #define REG_BADRPT      _REG_BADRPT
 416 #define REG_EEND        _REG_EEND
 417 #define REG_ESIZE       _REG_ESIZE
 418 #define REG_ERPAREN     _REG_ERPAREN
 419 \f
 420 /* struct re_pattern_buffer normally uses member names like `buffer'
 421    that POSIX does not allow.  In POSIX mode these members have names
 422    with leading `re_' (e.g., `re_buffer').  */
 423 #ifdef __USE_GNU_REGEX
 424 # define _REG_RE_NAME(id) id
 425 # define _REG_RM_NAME(id) id
 426 #else
 427 # define _REG_RE_NAME(id) re_##id
 428 # define _REG_RM_NAME(id) rm_##id
 429 #endif
 430
 431 /* The user can specify the type of the re_translate member by
 432    defining the macro RE_TRANSLATE_TYPE, which defaults to unsigned
 433    char *.  This pollutes the POSIX name space, so in POSIX mode just
 434    use unsigned char *.  */
 435 #ifdef __USE_GNU_REGEX
 436 # ifndef RE_TRANSLATE_TYPE
 437 #  define RE_TRANSLATE_TYPE unsigned char *
 438 # endif
 439 # define REG_TRANSLATE_TYPE RE_TRANSLATE_TYPE
 440 #else
 441 # define REG_TRANSLATE_TYPE unsigned char *
 442 #endif
 443
 444 /* This data structure represents a compiled pattern.  Before calling
 445    the pattern compiler, the fields `buffer', `allocated', `fastmap',
 446    `translate', and `no_sub' can be set.  After the pattern has been
 447    compiled, the `re_nsub' field is available.  All other fields are
 448    private to the regex routines.  */
 449
 450 struct re_pattern_buffer
 451 {
 452   /* Space that holds the compiled pattern.  It is declared as
 453      `unsigned char *' because its elements are sometimes used as
 454      array indexes.  */
 455   unsigned char *_REG_RE_NAME (buffer);
 456
 457   /* Number of bytes to which `buffer' points.  */
 458   __re_long_size_t _REG_RE_NAME (allocated);
 459
 460   /* Number of bytes actually used in `buffer'.  */
 461   __re_long_size_t _REG_RE_NAME (used);
 462
 463   /* Syntax setting with which the pattern was compiled.  */
 464   reg_syntax_t _REG_RE_NAME (syntax);
 465
 466   /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
 467      fastmap, if there is one, to skip over impossible starting points
 468      for matches.  */
 469   char *_REG_RE_NAME (fastmap);
 470
 471   /* Either a translate table to apply to all characters before
 472      comparing them, or zero for no translation.  The translation is
 473      applied to a pattern when it is compiled and to a string when it
 474      is matched.  */
 475   REG_TRANSLATE_TYPE _REG_RE_NAME (translate);
 476
 477   /* Number of subexpressions found by the compiler.  */
 478   size_t re_nsub;
 479
 480   /* Zero if this pattern cannot match the empty string, one else.
 481      Well, in truth it's used only in `re_search_2', to see whether or
 482      not we should use the fastmap, so we don't set this absolutely
 483      perfectly; see `re_compile_fastmap' (the `duplicate' case).  */
 484   unsigned int _REG_RE_NAME (can_be_null) : 1;
 485
 486   /* If REGS_UNALLOCATED, allocate space in the `regs' structure
 487      for `max (RE_NREGS, re_nsub + 1)' groups.
 488      If REGS_REALLOCATE, reallocate space if necessary.
 489      If REGS_FIXED, use what's there.  */
 490 #ifdef __USE_GNU_REGEX
 491 # define REGS_UNALLOCATED 0
 492 # define REGS_REALLOCATE 1
 493 # define REGS_FIXED 2
 494 #endif
 495   unsigned int _REG_RE_NAME (regs_allocated) : 2;
 496
 497   /* Set to zero when `regex_compile' compiles a pattern; set to one
 498      by `re_compile_fastmap' if it updates the fastmap.  */
 499   unsigned int _REG_RE_NAME (fastmap_accurate) : 1;
 500
 501   /* If set, `re_match_2' does not return information about
 502      subexpressions.  */
 503   unsigned int _REG_RE_NAME (no_sub) : 1;
 504
 505   /* If set, a beginning-of-line anchor doesn't match at the beginning
 506      of the string.  */
 507   unsigned int _REG_RE_NAME (not_bol) : 1;
 508
 509   /* Similarly for an end-of-line anchor.  */
 510   unsigned int _REG_RE_NAME (not_eol) : 1;
 511
 512   /* If true, an anchor at a newline matches.  */
 513   unsigned int _REG_RE_NAME (newline_anchor) : 1;
 514
 515 /* [[[end pattern_buffer]]] */
 516 };
 517
 518 typedef struct re_pattern_buffer regex_t;
 519 \f
 520 /* This is the structure we store register match data in.  See
 521    regex.texinfo for a full description of what registers match.  */
 522 struct re_registers
 523 {
 524   __re_size_t _REG_RM_NAME (num_regs);
 525   regoff_t *_REG_RM_NAME (start);
 526   regoff_t *_REG_RM_NAME (end);
 527 };
 528
 529
 530 /* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
 531    `re_match_2' returns information about at least this many registers
 532    the first time a `regs' structure is passed.  */
 533 #if !defined RE_NREGS && defined __USE_GNU_REGEX
 534 # define RE_NREGS 30
 535 #endif
 536
 537
 538 /* POSIX specification for registers.  Aside from the different names than
 539    `re_registers', POSIX uses an array of structures, instead of a
 540    structure of arrays.  */
 541 typedef struct
 542 {
 543   regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
 544   regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
 545 } regmatch_t;
 546 \f
 547 /* Declarations for routines.  */
 548
 549 /* Sets the current default syntax to SYNTAX, and return the old syntax.
 550    You can also simply assign to the `re_syntax_options' variable.  */
 551 extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
 552
 553 /* Compile the regular expression PATTERN, with length LENGTH
 554    and syntax given by the global `re_syntax_options', into the buffer
 555    BUFFER.  Return NULL if successful, and an error string if not.  */
 556 extern const char *re_compile_pattern (const char *__pattern, size_t __length,
 557                                        struct re_pattern_buffer *__buffer);
 558
 559
 560 /* Compile a fastmap for the compiled pattern in BUFFER; used to
 561    accelerate searches.  Return 0 if successful and -2 if was an
 562    internal error.  */
 563 extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
 564
 565
 566 /* Search in the string STRING (with length LENGTH) for the pattern
 567    compiled into BUFFER.  Start searching at position START, for RANGE
 568    characters.  Return the starting position of the match, -1 for no
 569    match, or -2 for an internal error.  Also return register
 570    information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
 571 extern regoff_t re_search (struct re_pattern_buffer *__buffer,
 572                            const char *__string, __re_idx_t __length,
 573                            __re_idx_t __start, regoff_t __range,
 574                            struct re_registers *__regs);
 575
 576
 577 /* Like `re_search', but search in the concatenation of STRING1 and
 578    STRING2.  Also, stop searching at index START + STOP.  */
 579 extern regoff_t re_search_2 (struct re_pattern_buffer *__buffer,
 580                              const char *__string1, __re_idx_t __length1,
 581                              const char *__string2, __re_idx_t __length2,
 582                              __re_idx_t __start, regoff_t __range,
 583                              struct re_registers *__regs,
 584                              __re_idx_t __stop);
 585
 586
 587 /* Like `re_search', but return how many characters in STRING the regexp
 588    in BUFFER matched, starting at position START.  */
 589 extern regoff_t re_match (struct re_pattern_buffer *__buffer,
 590                           const char *__string, __re_idx_t __length,
 591                           __re_idx_t __start, struct re_registers *__regs);
 592
 593
 594 /* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
 595 extern regoff_t re_match_2 (struct re_pattern_buffer *__buffer,
 596                             const char *__string1, __re_idx_t __length1,
 597                             const char *__string2, __re_idx_t __length2,
 598                             __re_idx_t __start, struct re_registers *__regs,
 599                             __re_idx_t __stop);
 600
 601
 602 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
 603    ENDS.  Subsequent matches using BUFFER and REGS will use this memory
 604    for recording register information.  STARTS and ENDS must be
 605    allocated with malloc, and must each be at least `NUM_REGS * sizeof
 606    (regoff_t)' bytes long.
 607
 608    If NUM_REGS == 0, then subsequent matches should allocate their own
 609    register data.
 610
 611    Unless this function is called, the first search or match using
 612    PATTERN_BUFFER will allocate its own register data, without
 613    freeing the old data.  */
 614 extern void re_set_registers (struct re_pattern_buffer *__buffer,
 615                               struct re_registers *__regs,
 616                               __re_size_t __num_regs,
 617                               regoff_t *__starts, regoff_t *__ends);
 618
 619 #if defined _REGEX_RE_COMP || defined _LIBC
 620 # ifndef _CRAY
 621 /* 4.2 bsd compatibility.  */
 622 extern char *re_comp (const char *);
 623 extern int re_exec (const char *);
 624 # endif
 625 #endif
 626
 627 /* GCC 2.95 and later have "__restrict"; C99 compilers have
 628    "restrict", and "configure" may have defined "restrict".
 629    Other compilers use __restrict, __restrict__, and _Restrict, and
 630    'configure' might #define 'restrict' to those words, so pick a
 631    different name.  */
 632 #ifndef _Restrict_
 633 # if 199901L <= __STDC_VERSION__
 634 #  define _Restrict_ restrict
 635 # elif 2 < __GNUC__ || (2 == __GNUC__ && 95 <= __GNUC_MINOR__)
 636 #  define _Restrict_ __restrict
 637 # else
 638 #  define _Restrict_
 639 # endif
 640 #endif
 641 /* gcc 3.1 and up support the [restrict] syntax.  Don't trust
 642    sys/cdefs.h's definition of __restrict_arr, though, as it
 643    mishandles gcc -ansi -pedantic.  */
 644 #ifndef _Restrict_arr_
 645 # if ((199901L <= __STDC_VERSION__                                      \
 646        || ((3 < __GNUC__ || (3 == __GNUC__ && 1 <= __GNUC_MINOR__))     \
 647            && !__STRICT_ANSI__))                                        \
 648       && !defined __GNUG__)
 649 #  define _Restrict_arr_ _Restrict_
 650 # else
 651 #  define _Restrict_arr_
 652 # endif
 653 #endif
 654
 655 /* POSIX compatibility.  */
 656 extern int regcomp (regex_t *_Restrict_ __preg,
 657                     const char *_Restrict_ __pattern,
 658                     int __cflags);
 659
 660 extern int regexec (const regex_t *_Restrict_ __preg,
 661                     const char *_Restrict_ __string, size_t __nmatch,
 662                     regmatch_t __pmatch[_Restrict_arr_],
 663                     int __eflags);
 664
 665 extern size_t regerror (int __errcode, const regex_t *_Restrict_ __preg,
 666                         char *_Restrict_ __errbuf, size_t __errbuf_size);
 667
 668 extern void regfree (regex_t *__preg);
 669
 670
 671 #ifdef __cplusplus
 672 }
 673 #endif  /* C++ */
 674
 675 #endif /* regex.h */