lib/regex.h

   1 /* Definitions for data structures and routines for the regular
   2    expression library.
   3    Copyright (C) 1985, 1989-2020 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library 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 GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://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 object sizes.  */
  45 typedef size_t __re_size_t;
  46
  47 /* The type of object sizes, in places where the traditional code
  48    uses unsigned long int.  */
  49 typedef size_t __re_long_size_t;
  50
  51 #else
  52
  53 /* The traditional GNU regex implementation mishandles strings longer
  54    than INT_MAX.  */
  55 typedef unsigned int __re_size_t;
  56 typedef unsigned long int __re_long_size_t;
  57
  58 #endif
  59
  60 /* The following two types have to be signed and unsigned integer type
  61    wide enough to hold a value of a pointer.  For most ANSI compilers
  62    ptrdiff_t and size_t should be likely OK.  Still size of these two
  63    types is 2 for Microsoft C.  Ugh... */
  64 typedef long int s_reg_t;
  65 typedef unsigned long int active_reg_t;
  66
  67 /* The following bits are used to determine the regexp syntax we
  68    recognize.  The set/not-set meanings are chosen so that Emacs syntax
  69    remains the value 0.  The bits are given in alphabetical order, and
  70    the definitions shifted by one from the previous bit; thus, when we
  71    add or remove a bit, only one other definition need change.  */
  72 typedef unsigned long int reg_syntax_t;
  73
  74 #ifdef __USE_GNU
  75 /* If this bit is not set, then \ inside a bracket expression is literal.
  76    If set, then such a \ quotes the following character.  */
  77 # define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
  78
  79 /* If this bit is not set, then + and ? are operators, and \+ and \? are
  80      literals.
  81    If set, then \+ and \? are operators and + and ? are literals.  */
  82 # define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
  83
  84 /* If this bit is set, then character classes are supported.  They are:
  85      [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
  86      [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
  87    If not set, then character classes are not supported.  */
  88 # define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
  89
  90 /* If this bit is set, then ^ and $ are always anchors (outside bracket
  91      expressions, of course).
  92    If this bit is not set, then it depends:
  93         ^  is an anchor if it is at the beginning of a regular
  94            expression or after an open-group or an alternation operator;
  95         $  is an anchor if it is at the end of a regular expression, or
  96            before a close-group or an alternation operator.
  97
  98    This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
  99    POSIX draft 11.2 says that * etc. in leading positions is undefined.
 100    We already implemented a previous draft which made those constructs
 101    invalid, though, so we haven't changed the code back.  */
 102 # define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
 103
 104 /* If this bit is set, then special characters are always special
 105      regardless of where they are in the pattern.
 106    If this bit is not set, then special characters are special only in
 107      some contexts; otherwise they are ordinary.  Specifically,
 108      * + ? and intervals are only special when not after the beginning,
 109      open-group, or alternation operator.  */
 110 # define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
 111
 112 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
 113      immediately after an alternation or begin-group operator.  */
 114 # define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
 115
 116 /* If this bit is set, then . matches newline.
 117    If not set, then it doesn't.  */
 118 # define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
 119
 120 /* If this bit is set, then . doesn't match NUL.
 121    If not set, then it does.  */
 122 # define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
 123
 124 /* If this bit is set, nonmatching lists [^...] do not match newline.
 125    If not set, they do.  */
 126 # define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
 127
 128 /* If this bit is set, either \{...\} or {...} defines an
 129      interval, depending on RE_NO_BK_BRACES.
 130    If not set, \{, \}, {, and } are literals.  */
 131 # define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
 132
 133 /* If this bit is set, +, ? and | aren't recognized as operators.
 134    If not set, they are.  */
 135 # define RE_LIMITED_OPS (RE_INTERVALS << 1)
 136
 137 /* If this bit is set, newline is an alternation operator.
 138    If not set, newline is literal.  */
 139 # define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
 140
 141 /* If this bit is set, then '{...}' defines an interval, and \{ and \}
 142      are literals.
 143   If not set, then '\{...\}' defines an interval.  */
 144 # define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
 145
 146 /* If this bit is set, (...) defines a group, and \( and \) are literals.
 147    If not set, \(...\) defines a group, and ( and ) are literals.  */
 148 # define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
 149
 150 /* If this bit is set, then \<digit> matches <digit>.
 151    If not set, then \<digit> is a back-reference.  */
 152 # define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
 153
 154 /* If this bit is set, then | is an alternation operator, and \| is literal.
 155    If not set, then \| is an alternation operator, and | is literal.  */
 156 # define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
 157
 158 /* If this bit is set, then an ending range point collating higher
 159      than the starting range point, as in [z-a], is invalid.
 160    If not set, then when ending range point collates higher than the
 161      starting range point, the range is ignored.  */
 162 # define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
 163
 164 /* If this bit is set, then an unmatched ) is ordinary.
 165    If not set, then an unmatched ) is invalid.  */
 166 # define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
 167
 168 /* If this bit is set, succeed as soon as we match the whole pattern,
 169    without further backtracking.  */
 170 # define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
 171
 172 /* If this bit is set, do not process the GNU regex operators.
 173    If not set, then the GNU regex operators are recognized. */
 174 # define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
 175
 176 /* If this bit is set, turn on internal regex debugging.
 177    If not set, and debugging was on, turn it off.
 178    This only works if regex.c is compiled -DDEBUG.
 179    We define this bit always, so that all that's needed to turn on
 180    debugging is to recompile regex.c; the calling code can always have
 181    this bit set, and it won't affect anything in the normal case. */
 182 # define RE_DEBUG (RE_NO_GNU_OPS << 1)
 183
 184 /* If this bit is set, a syntactically invalid interval is treated as
 185    a string of ordinary characters.  For example, the ERE 'a{1' is
 186    treated as 'a\{1'.  */
 187 # define RE_INVALID_INTERVAL_ORD (RE_DEBUG << 1)
 188
 189 /* If this bit is set, then ignore case when matching.
 190    If not set, then case is significant.  */
 191 # define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
 192
 193 /* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
 194    for ^, because it is difficult to scan the regex backwards to find
 195    whether ^ should be special.  */
 196 # define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
 197
 198 /* If this bit is set, then \{ cannot be first in a regex or
 199    immediately after an alternation, open-group or \} operator.  */
 200 # define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
 201
 202 /* If this bit is set, then no_sub will be set to 1 during
 203    re_compile_pattern.  */
 204 # define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
 205 #endif
 206
 207 /* This global variable defines the particular regexp syntax to use (for
 208    some interfaces).  When a regexp is compiled, the syntax used is
 209    stored in the pattern buffer, so changing this does not affect
 210    already-compiled regexps.  */
 211 extern reg_syntax_t re_syntax_options;
 212 \f
 213 #ifdef __USE_GNU
 214 /* Define combinations of the above bits for the standard possibilities.
 215    (The [[[ comments delimit what gets put into the Texinfo file, so
 216    don't delete them!)  */
 217 /* [[[begin syntaxes]]] */
 218 # define RE_SYNTAX_EMACS 0
 219
 220 # define RE_SYNTAX_AWK                                                  \
 221   (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL                     \
 222    | RE_NO_BK_PARENS              | RE_NO_BK_REFS                       \
 223    | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES                  \
 224    | RE_DOT_NEWLINE               | RE_CONTEXT_INDEP_ANCHORS            \
 225    | RE_CHAR_CLASSES                                                    \
 226    | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
 227
 228 # define RE_SYNTAX_GNU_AWK                                              \
 229   ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS             \
 230     | RE_INVALID_INTERVAL_ORD)                                          \
 231    & ~(RE_DOT_NOT_NULL | RE_CONTEXT_INDEP_OPS                           \
 232       | RE_CONTEXT_INVALID_OPS ))
 233
 234 # define RE_SYNTAX_POSIX_AWK                                            \
 235   (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS              \
 236    | RE_INTERVALS           | RE_NO_GNU_OPS                             \
 237    | RE_INVALID_INTERVAL_ORD)
 238
 239 # define RE_SYNTAX_GREP                                                 \
 240   ((RE_SYNTAX_POSIX_BASIC | RE_NEWLINE_ALT)                             \
 241    & ~(RE_CONTEXT_INVALID_DUP | RE_DOT_NOT_NULL))
 242
 243 # define RE_SYNTAX_EGREP                                                \
 244   ((RE_SYNTAX_POSIX_EXTENDED | RE_INVALID_INTERVAL_ORD | RE_NEWLINE_ALT) \
 245    & ~(RE_CONTEXT_INVALID_OPS | RE_DOT_NOT_NULL))
 246
 247 /* POSIX grep -E behavior is no longer incompatible with GNU.  */
 248 # define RE_SYNTAX_POSIX_EGREP                                          \
 249   RE_SYNTAX_EGREP
 250
 251 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
 252 # define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
 253
 254 # define RE_SYNTAX_SED RE_SYNTAX_POSIX_BASIC
 255
 256 /* Syntax bits common to both basic and extended POSIX regex syntax.  */
 257 # define _RE_SYNTAX_POSIX_COMMON                                        \
 258   (RE_CHAR_CLASSES | RE_DOT_NEWLINE      | RE_DOT_NOT_NULL              \
 259    | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
 260
 261 # define RE_SYNTAX_POSIX_BASIC                                          \
 262   (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
 263
 264 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
 265    RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
 266    isn't minimal, since other operators, such as \`, aren't disabled.  */
 267 # define RE_SYNTAX_POSIX_MINIMAL_BASIC                                  \
 268   (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
 269
 270 # define RE_SYNTAX_POSIX_EXTENDED                                       \
 271   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 272    | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES                           \
 273    | RE_NO_BK_PARENS        | RE_NO_BK_VBAR                             \
 274    | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
 275
 276 /* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
 277    removed and RE_NO_BK_REFS is added.  */
 278 # define RE_SYNTAX_POSIX_MINIMAL_EXTENDED                               \
 279   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS                  \
 280    | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES                           \
 281    | RE_NO_BK_PARENS        | RE_NO_BK_REFS                             \
 282    | RE_NO_BK_VBAR          | RE_UNMATCHED_RIGHT_PAREN_ORD)
 283 /* [[[end syntaxes]]] */
 284
 285 /* Maximum number of duplicates an interval can allow.  POSIX-conforming
 286    systems might define this in <limits.h>, but we want our
 287    value, so remove any previous define.  */
 288 # ifdef _REGEX_INCLUDE_LIMITS_H
 289 #  include <limits.h>
 290 # endif
 291 # ifdef RE_DUP_MAX
 292 #  undef RE_DUP_MAX
 293 # endif
 294
 295 /* RE_DUP_MAX is 2**15 - 1 because an earlier implementation stored
 296    the counter as a 2-byte signed integer.  This is no longer true, so
 297    RE_DUP_MAX could be increased to (INT_MAX / 10 - 1), or to
 298    ((SIZE_MAX - 9) / 10) if _REGEX_LARGE_OFFSETS is defined.
 299    However, there would be a huge performance problem if someone
 300    actually used a pattern like a\{214748363\}, so RE_DUP_MAX retains
 301    its historical value.  */
 302 # define RE_DUP_MAX (0x7fff)
 303 #endif
 304
 305
 306 /* POSIX 'cflags' bits (i.e., information for 'regcomp').  */
 307
 308 /* If this bit is set, then use extended regular expression syntax.
 309    If not set, then use basic regular expression syntax.  */
 310 #define REG_EXTENDED 1
 311
 312 /* If this bit is set, then ignore case when matching.
 313    If not set, then case is significant.  */
 314 #define REG_ICASE (1 << 1)
 315
 316 /* If this bit is set, then anchors do not match at newline
 317      characters in the string.
 318    If not set, then anchors do match at newlines.  */
 319 #define REG_NEWLINE (1 << 2)
 320
 321 /* If this bit is set, then report only success or fail in regexec.
 322    If not set, then returns differ between not matching and errors.  */
 323 #define REG_NOSUB (1 << 3)
 324
 325
 326 /* POSIX 'eflags' bits (i.e., information for regexec).  */
 327
 328 /* If this bit is set, then the beginning-of-line operator doesn't match
 329      the beginning of the string (presumably because it's not the
 330      beginning of a line).
 331    If not set, then the beginning-of-line operator does match the
 332      beginning of the string.  */
 333 #define REG_NOTBOL 1
 334
 335 /* Like REG_NOTBOL, except for the end-of-line.  */
 336 #define REG_NOTEOL (1 << 1)
 337
 338 /* Use PMATCH[0] to delimit the start and end of the search in the
 339    buffer.  */
 340 #define REG_STARTEND (1 << 2)
 341
 342
 343 /* If any error codes are removed, changed, or added, update the
 344    '__re_error_msgid' table in regcomp.c.  */
 345
 346 typedef enum
 347 {
 348   _REG_ENOSYS = -1,     /* This will never happen for this implementation.  */
 349   _REG_NOERROR = 0,     /* Success.  */
 350   _REG_NOMATCH,         /* Didn't find a match (for regexec).  */
 351
 352   /* POSIX regcomp return error codes.  (In the order listed in the
 353      standard.)  */
 354   _REG_BADPAT,          /* Invalid pattern.  */
 355   _REG_ECOLLATE,        /* Invalid collating element.  */
 356   _REG_ECTYPE,          /* Invalid character class name.  */
 357   _REG_EESCAPE,         /* Trailing backslash.  */
 358   _REG_ESUBREG,         /* Invalid back reference.  */
 359   _REG_EBRACK,          /* Unmatched left bracket.  */
 360   _REG_EPAREN,          /* Parenthesis imbalance.  */
 361   _REG_EBRACE,          /* Unmatched \{.  */
 362   _REG_BADBR,           /* Invalid contents of \{\}.  */
 363   _REG_ERANGE,          /* Invalid range end.  */
 364   _REG_ESPACE,          /* Ran out of memory.  */
 365   _REG_BADRPT,          /* No preceding re for repetition op.  */
 366
 367   /* Error codes we've added.  */
 368   _REG_EEND,            /* Premature end.  */
 369   _REG_ESIZE,           /* Too large (e.g., repeat count too large).  */
 370   _REG_ERPAREN          /* Unmatched ) or \); not returned from regcomp.  */
 371 } reg_errcode_t;
 372
 373 #if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
 374 # define REG_ENOSYS     _REG_ENOSYS
 375 #endif
 376 #define REG_NOERROR     _REG_NOERROR
 377 #define REG_NOMATCH     _REG_NOMATCH
 378 #define REG_BADPAT      _REG_BADPAT
 379 #define REG_ECOLLATE    _REG_ECOLLATE
 380 #define REG_ECTYPE      _REG_ECTYPE
 381 #define REG_EESCAPE     _REG_EESCAPE
 382 #define REG_ESUBREG     _REG_ESUBREG
 383 #define REG_EBRACK      _REG_EBRACK
 384 #define REG_EPAREN      _REG_EPAREN
 385 #define REG_EBRACE      _REG_EBRACE
 386 #define REG_BADBR       _REG_BADBR
 387 #define REG_ERANGE      _REG_ERANGE
 388 #define REG_ESPACE      _REG_ESPACE
 389 #define REG_BADRPT      _REG_BADRPT
 390 #define REG_EEND        _REG_EEND
 391 #define REG_ESIZE       _REG_ESIZE
 392 #define REG_ERPAREN     _REG_ERPAREN
 393 \f
 394 /* This data structure represents a compiled pattern.  Before calling
 395    the pattern compiler, the fields 'buffer', 'allocated', 'fastmap',
 396    and 'translate' can be set.  After the pattern has been compiled,
 397    the fields 're_nsub', 'not_bol' and 'not_eol' are available.  All
 398    other fields are private to the regex routines.  */
 399
 400 #ifndef RE_TRANSLATE_TYPE
 401 # define __RE_TRANSLATE_TYPE unsigned char *
 402 # ifdef __USE_GNU
 403 #  define RE_TRANSLATE_TYPE __RE_TRANSLATE_TYPE
 404 # endif
 405 #endif
 406
 407 #ifdef __USE_GNU
 408 # define __REPB_PREFIX(name) name
 409 #else
 410 # define __REPB_PREFIX(name) __##name
 411 #endif
 412
 413 struct re_pattern_buffer
 414 {
 415   /* Space that holds the compiled pattern.  The type
 416      'struct re_dfa_t' is private and is not declared here.  */
 417   struct re_dfa_t *__REPB_PREFIX(buffer);
 418
 419   /* Number of bytes to which 'buffer' points.  */
 420   __re_long_size_t __REPB_PREFIX(allocated);
 421
 422   /* Number of bytes actually used in 'buffer'.  */
 423   __re_long_size_t __REPB_PREFIX(used);
 424
 425   /* Syntax setting with which the pattern was compiled.  */
 426   reg_syntax_t __REPB_PREFIX(syntax);
 427
 428   /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
 429      fastmap, if there is one, to skip over impossible starting points
 430      for matches.  */
 431   char *__REPB_PREFIX(fastmap);
 432
 433   /* Either a translate table to apply to all characters before
 434      comparing them, or zero for no translation.  The translation is
 435      applied to a pattern when it is compiled and to a string when it
 436      is matched.  */
 437   __RE_TRANSLATE_TYPE __REPB_PREFIX(translate);
 438
 439   /* Number of subexpressions found by the compiler.  */
 440   size_t re_nsub;
 441
 442   /* Zero if this pattern cannot match the empty string, one else.
 443      Well, in truth it's used only in 're_search_2', to see whether or
 444      not we should use the fastmap, so we don't set this absolutely
 445      perfectly; see 're_compile_fastmap' (the "duplicate" case).  */
 446   unsigned __REPB_PREFIX(can_be_null) : 1;
 447
 448   /* If REGS_UNALLOCATED, allocate space in the 'regs' structure
 449      for 'max (RE_NREGS, re_nsub + 1)' groups.
 450      If REGS_REALLOCATE, reallocate space if necessary.
 451      If REGS_FIXED, use what's there.  */
 452 #ifdef __USE_GNU
 453 # define REGS_UNALLOCATED 0
 454 # define REGS_REALLOCATE 1
 455 # define REGS_FIXED 2
 456 #endif
 457   unsigned __REPB_PREFIX(regs_allocated) : 2;
 458
 459   /* Set to zero when 're_compile_pattern' compiles a pattern; set to
 460      one by 're_compile_fastmap' if it updates the fastmap.  */
 461   unsigned __REPB_PREFIX(fastmap_accurate) : 1;
 462
 463   /* If set, 're_match_2' does not return information about
 464      subexpressions.  */
 465   unsigned __REPB_PREFIX(no_sub) : 1;
 466
 467   /* If set, a beginning-of-line anchor doesn't match at the beginning
 468      of the string.  */
 469   unsigned __REPB_PREFIX(not_bol) : 1;
 470
 471   /* Similarly for an end-of-line anchor.  */
 472   unsigned __REPB_PREFIX(not_eol) : 1;
 473
 474   /* If true, an anchor at a newline matches.  */
 475   unsigned __REPB_PREFIX(newline_anchor) : 1;
 476 };
 477
 478 typedef struct re_pattern_buffer regex_t;
 479 \f
 480 /* Type for byte offsets within the string.  POSIX mandates this.  */
 481 #ifdef _REGEX_LARGE_OFFSETS
 482 /* POSIX 1003.1-2008 requires that regoff_t be at least as wide as
 483    ptrdiff_t and ssize_t.  We don't know of any hosts where ptrdiff_t
 484    is wider than ssize_t, so ssize_t is safe.  ptrdiff_t is not
 485    visible here, so use ssize_t.  */
 486 typedef ssize_t regoff_t;
 487 #else
 488 /* The traditional GNU regex implementation mishandles strings longer
 489    than INT_MAX.  */
 490 typedef int regoff_t;
 491 #endif
 492
 493
 494 #ifdef __USE_GNU
 495 /* This is the structure we store register match data in.  See
 496    regex.texinfo for a full description of what registers match.  */
 497 struct re_registers
 498 {
 499   __re_size_t num_regs;
 500   regoff_t *start;
 501   regoff_t *end;
 502 };
 503
 504
 505 /* If 'regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
 506    're_match_2' returns information about at least this many registers
 507    the first time a 'regs' structure is passed.  */
 508 # ifndef RE_NREGS
 509 #  define RE_NREGS 30
 510 # endif
 511 #endif
 512
 513
 514 /* POSIX specification for registers.  Aside from the different names than
 515    're_registers', POSIX uses an array of structures, instead of a
 516    structure of arrays.  */
 517 typedef struct
 518 {
 519   regoff_t rm_so;  /* Byte offset from string's start to substring's start.  */
 520   regoff_t rm_eo;  /* Byte offset from string's start to substring's end.  */
 521 } regmatch_t;
 522 \f
 523 /* Declarations for routines.  */
 524
 525 #ifdef __USE_GNU
 526 /* Sets the current default syntax to SYNTAX, and return the old syntax.
 527    You can also simply assign to the 're_syntax_options' variable.  */
 528 extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
 529
 530 /* Compile the regular expression PATTERN, with length LENGTH
 531    and syntax given by the global 're_syntax_options', into the buffer
 532    BUFFER.  Return NULL if successful, and an error string if not.
 533
 534    To free the allocated storage, you must call 'regfree' on BUFFER.
 535    Note that the translate table must either have been initialized by
 536    'regcomp', with a malloc'ed value, or set to NULL before calling
 537    'regfree'.  */
 538 extern const char *re_compile_pattern (const char *__pattern, size_t __length,
 539                                        struct re_pattern_buffer *__buffer);
 540
 541
 542 /* Compile a fastmap for the compiled pattern in BUFFER; used to
 543    accelerate searches.  Return 0 if successful and -2 if was an
 544    internal error.  */
 545 extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
 546
 547
 548 /* Search in the string STRING (with length LENGTH) for the pattern
 549    compiled into BUFFER.  Start searching at position START, for RANGE
 550    characters.  Return the starting position of the match, -1 for no
 551    match, or -2 for an internal error.  Also return register
 552    information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
 553 extern regoff_t re_search (struct re_pattern_buffer *__buffer,
 554                            const char *__String, regoff_t __length,
 555                            regoff_t __start, regoff_t __range,
 556                            struct re_registers *__regs);
 557
 558
 559 /* Like 're_search', but search in the concatenation of STRING1 and
 560    STRING2.  Also, stop searching at index START + STOP.  */
 561 extern regoff_t re_search_2 (struct re_pattern_buffer *__buffer,
 562                              const char *__string1, regoff_t __length1,
 563                              const char *__string2, regoff_t __length2,
 564                              regoff_t __start, regoff_t __range,
 565                              struct re_registers *__regs,
 566                              regoff_t __stop);
 567
 568
 569 /* Like 're_search', but return how many characters in STRING the regexp
 570    in BUFFER matched, starting at position START.  */
 571 extern regoff_t re_match (struct re_pattern_buffer *__buffer,
 572                           const char *__String, regoff_t __length,
 573                           regoff_t __start, struct re_registers *__regs);
 574
 575
 576 /* Relates to 're_match' as 're_search_2' relates to 're_search'.  */
 577 extern regoff_t re_match_2 (struct re_pattern_buffer *__buffer,
 578                             const char *__string1, regoff_t __length1,
 579                             const char *__string2, regoff_t __length2,
 580                             regoff_t __start, struct re_registers *__regs,
 581                             regoff_t __stop);
 582
 583
 584 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
 585    ENDS.  Subsequent matches using BUFFER and REGS will use this memory
 586    for recording register information.  STARTS and ENDS must be
 587    allocated with malloc, and must each be at least 'NUM_REGS * sizeof
 588    (regoff_t)' bytes long.
 589
 590    If NUM_REGS == 0, then subsequent matches should allocate their own
 591    register data.
 592
 593    Unless this function is called, the first search or match using
 594    BUFFER will allocate its own register data, without
 595    freeing the old data.  */
 596 extern void re_set_registers (struct re_pattern_buffer *__buffer,
 597                               struct re_registers *__regs,
 598                               __re_size_t __num_regs,
 599                               regoff_t *__starts, regoff_t *__ends);
 600 #endif  /* Use GNU */
 601
 602 #if defined _REGEX_RE_COMP || (defined _LIBC && defined __USE_MISC)
 603 /* 4.2 bsd compatibility.  */
 604 extern char *re_comp (const char *);
 605 extern int re_exec (const char *);
 606 #endif
 607
 608 /* For plain 'restrict', use glibc's __restrict if defined.
 609    Otherwise, GCC 2.95 and later have "__restrict"; C99 compilers have
 610    "restrict", and "configure" may have defined "restrict".
 611    Other compilers use __restrict, __restrict__, and _Restrict, and
 612    'configure' might #define 'restrict' to those words, so pick a
 613    different name.  */
 614 #ifndef _Restrict_
 615 # if defined __restrict \
 616      || 2 < __GNUC__ + (95 <= __GNUC_MINOR__) \
 617      || __clang_major__ >= 3
 618 #  define _Restrict_ __restrict
 619 # elif 199901L <= __STDC_VERSION__ || defined restrict
 620 #  define _Restrict_ restrict
 621 # else
 622 #  define _Restrict_
 623 # endif
 624 #endif
 625 /* For the ISO C99 syntax
 626      array_name[restrict]
 627    use glibc's __restrict_arr if available.
 628    Otherwise, GCC 3.1 and clang support this syntax (but not in C++ mode).
 629    Other ISO C99 compilers support it as well.  */
 630 #ifndef _Restrict_arr_
 631 # ifdef __restrict_arr
 632 #  define _Restrict_arr_ __restrict_arr
 633 # elif ((199901L <= __STDC_VERSION__ \
 634          || 3 < __GNUC__ + (1 <= __GNUC_MINOR__) \
 635          || __clang_major__ >= 3) \
 636         && !defined __cplusplus)
 637 #  define _Restrict_arr_ _Restrict_
 638 # else
 639 #  define _Restrict_arr_
 640 # endif
 641 #endif
 642
 643 /* POSIX compatibility.  */
 644 extern int regcomp (regex_t *_Restrict_ __preg,
 645                     const char *_Restrict_ __pattern,
 646                     int __cflags);
 647
 648 extern int regexec (const regex_t *_Restrict_ __preg,
 649                     const char *_Restrict_ __String, size_t __nmatch,
 650                     regmatch_t __pmatch[_Restrict_arr_],
 651                     int __eflags);
 652
 653 extern size_t regerror (int __errcode, const regex_t *_Restrict_ __preg,
 654                         char *_Restrict_ __errbuf, size_t __errbuf_size);
 655
 656 extern void regfree (regex_t *__preg);
 657
 658
 659 #ifdef __cplusplus
 660 }
 661 #endif  /* C++ */
 662
 663 #endif /* regex.h */