libguile/regex-posix.c

   1 /*      Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   2  *
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
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   6  * any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this software; see the file COPYING.  If not, write to
  15  * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  16  * Boston, MA 02111-1307 USA
  17  *
  18  * As a special exception, the Free Software Foundation gives permission
  19  * for additional uses of the text contained in its release of GUILE.
  20  *
  21  * The exception is that, if you link the GUILE library with other files
  22  * to produce an executable, this does not by itself cause the
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  30  * This exception applies only to the code released by the
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  41  */
  42
  43
  44 \f
  45
  46 /* regex-posix.c -- POSIX regular expression support.
  47
  48    This code was written against Henry Spencer's famous regex package.
  49    The principal reference for POSIX behavior was the man page for this
  50    library, not the 1003.2 document itself.  Ergo, other `POSIX'
  51    libraries which do not agree with the Spencer implementation may
  52    produce varying behavior.  Sigh. */
  53
  54 #include <sys/types.h>
  55
  56 #include "libguile/_scm.h"
  57
  58 /* Supposedly, this file is never compiled unless we know we have
  59    POSIX regular expressions.  But we still put this in an #ifdef so
  60    the file is CPP'able (for dependency scanning) even on systems that
  61    don't have a <regex.h> header.  */
  62 #ifdef HAVE_REGCOMP
  63 #ifdef HAVE_REGEX_H
  64 #include <regex.h>
  65 #else
  66 #ifdef HAVE_RXPOSIX_H
  67 #include <rxposix.h>            /* GNU Rx library */
  68 #else
  69 #ifdef HAVE_RX_RXPOSIX_H
  70 #include <rx/rxposix.h>         /* GNU Rx library on Linux */
  71 #endif
  72 #endif
  73 #endif
  74 #endif
  75
  76 #include "libguile/smob.h"
  77 #include "libguile/symbols.h"
  78 #include "libguile/vectors.h"
  79 #include "libguile/strports.h"
  80 #include "libguile/ports.h"
  81 #include "libguile/feature.h"
  82 #include "libguile/strings.h"
  83
  84 #include "libguile/validate.h"
  85 #include "libguile/regex-posix.h"
  86
  87 /* This is defined by some regex libraries and omitted by others. */
  88 #ifndef REG_BASIC
  89 #define REG_BASIC 0
  90 #endif
  91
  92 scm_t_bits scm_tc16_regex;
  93
  94 static size_t
  95 regex_free (SCM obj)
  96 {
  97   regfree (SCM_RGX (obj));
  98   free (SCM_RGX (obj));
  99   return sizeof(regex_t);
 100 }
 101
 102 \f
 103
 104 SCM_SYMBOL (scm_regexp_error_key, "regular-expression-syntax");
 105
 106 static char *
 107 scm_regexp_error_msg (int regerrno, regex_t *rx)
 108 {
 109   SCM errmsg;
 110   int l;
 111
 112   /* FIXME: must we wrap any external calls in SCM_DEFER_INTS...SCM_ALLOW_INTS?
 113      Or are these only necessary when a SCM object may be left in an
 114      undetermined state (half-formed)?  If the latter then I believe we
 115      may do without the critical section code. -twp */
 116
 117   /* We could simply make errmsg a char pointer, and allocate space with
 118      malloc.  But since we are about to pass the pointer to scm_error, which
 119      never returns, we would never have the opportunity to free it.  Creating
 120      it as a SCM object means that the system will GC it at some point. */
 121
 122   errmsg = scm_make_string (SCM_MAKINUM (80), SCM_UNDEFINED);
 123   SCM_DEFER_INTS;
 124   l = regerror (regerrno, rx, SCM_STRING_CHARS (errmsg), 80);
 125   if (l > 80)
 126     {
 127       errmsg = scm_make_string (SCM_MAKINUM (l), SCM_UNDEFINED);
 128       regerror (regerrno, rx, SCM_STRING_CHARS (errmsg), l);
 129     }
 130   SCM_ALLOW_INTS;
 131   return SCM_STRING_CHARS (errmsg);
 132 }
 133
 134 SCM_DEFINE (scm_regexp_p, "regexp?", 1, 0, 0,
 135             (SCM obj),
 136             "Return @code{#t} if @var{obj} is a compiled regular expression,\n"
 137             "or @code{#f} otherwise.")
 138 #define FUNC_NAME s_scm_regexp_p
 139 {
 140   return SCM_BOOL(SCM_RGXP (obj));
 141 }
 142 #undef FUNC_NAME
 143
 144 SCM_DEFINE (scm_make_regexp, "make-regexp", 1, 0, 1,
 145             (SCM pat, SCM flags),
 146             "Compile the regular expression described by @var{pat}, and\n"
 147             "return the compiled regexp structure.  If @var{pat} does not\n"
 148             "describe a legal regular expression, @code{make-regexp} throws\n"
 149             "a @code{regular-expression-syntax} error.\n"
 150             "\n"
 151             "The @var{flags} arguments change the behavior of the compiled\n"
 152             "regular expression.  The following flags may be supplied:\n"
 153             "\n"
 154             "@table @code\n"
 155             "@item regexp/icase\n"
 156             "Consider uppercase and lowercase letters to be the same when\n"
 157             "matching.\n"
 158             "@item regexp/newline\n"
 159             "If a newline appears in the target string, then permit the\n"
 160             "@samp{^} and @samp{$} operators to match immediately after or\n"
 161             "immediately before the newline, respectively.  Also, the\n"
 162             "@samp{.} and @samp{[^...]} operators will never match a newline\n"
 163             "character.  The intent of this flag is to treat the target\n"
 164             "string as a buffer containing many lines of text, and the\n"
 165             "regular expression as a pattern that may match a single one of\n"
 166             "those lines.\n"
 167             "@item regexp/basic\n"
 168             "Compile a basic (``obsolete'') regexp instead of the extended\n"
 169             "(``modern'') regexps that are the default.  Basic regexps do\n"
 170             "not consider @samp{|}, @samp{+} or @samp{?} to be special\n"
 171             "characters, and require the @samp{@{...@}} and @samp{(...)}\n"
 172             "metacharacters to be backslash-escaped (@pxref{Backslash\n"
 173             "Escapes}).  There are several other differences between basic\n"
 174             "and extended regular expressions, but these are the most\n"
 175             "significant.\n"
 176             "@item regexp/extended\n"
 177             "Compile an extended regular expression rather than a basic\n"
 178             "regexp.  This is the default behavior; this flag will not\n"
 179             "usually be needed.  If a call to @code{make-regexp} includes\n"
 180             "both @code{regexp/basic} and @code{regexp/extended} flags, the\n"
 181             "one which comes last will override the earlier one.\n"
 182             "@end table")
 183 #define FUNC_NAME s_scm_make_regexp
 184 {
 185   SCM flag;
 186   regex_t *rx;
 187   int status, cflags;
 188
 189   SCM_VALIDATE_STRING (1, pat);
 190   SCM_VALIDATE_REST_ARGUMENT (flags);
 191
 192   /* Examine list of regexp flags.  If REG_BASIC is supplied, then
 193      turn off REG_EXTENDED flag (on by default). */
 194   cflags = REG_EXTENDED;
 195   flag = flags;
 196   while (!SCM_NULLP (flag))
 197     {
 198       if (SCM_INUM (SCM_CAR (flag)) == REG_BASIC)
 199         cflags &= ~REG_EXTENDED;
 200       else
 201         cflags |= SCM_INUM (SCM_CAR (flag));
 202       flag = SCM_CDR (flag);
 203     }
 204
 205   rx = SCM_MUST_MALLOC_TYPE (regex_t);
 206   status = regcomp (rx, SCM_STRING_CHARS (pat),
 207                     /* Make sure they're not passing REG_NOSUB;
 208                        regexp-exec assumes we're getting match data.  */
 209                     cflags & ~REG_NOSUB);
 210   if (status != 0)
 211     {
 212       scm_error (scm_regexp_error_key,
 213                  FUNC_NAME,
 214                  scm_regexp_error_msg (status, rx),
 215                  SCM_BOOL_F,
 216                  SCM_BOOL_F);
 217       /* never returns */
 218     }
 219   SCM_RETURN_NEWSMOB (scm_tc16_regex, rx);
 220 }
 221 #undef FUNC_NAME
 222
 223 SCM_DEFINE (scm_regexp_exec, "regexp-exec", 2, 2, 0,
 224             (SCM rx, SCM str, SCM start, SCM flags),
 225             "Match the compiled regular expression @var{rx} against\n"
 226             "@code{str}.  If the optional integer @var{start} argument is\n"
 227             "provided, begin matching from that position in the string.\n"
 228             "Return a match structure describing the results of the match,\n"
 229             "or @code{#f} if no match could be found.\n"
 230             "\n"
 231             "The @var{flags} arguments change the matching behavior.\n"
 232             "The following flags may be supplied:\n"
 233             "\n"
 234             "@table @code\n"
 235             "@item regexp/notbol\n"
 236             "Operator @samp{^} always fails (unless @code{regexp/newline}\n"
 237             "is used).  Use this when the beginning of the string should\n"
 238             "not be considered the beginning of a line.\n"
 239             "@item regexp/noteol\n"
 240             "Operator @samp{$} always fails (unless @code{regexp/newline}\n"
 241             "is used).  Use this when the end of the string should not be\n"
 242             "considered the end of a line.\n"
 243             "@end table")
 244 #define FUNC_NAME s_scm_regexp_exec
 245 {
 246   int status, nmatches, offset;
 247   regmatch_t *matches;
 248   SCM mvec = SCM_BOOL_F;
 249
 250   SCM_VALIDATE_RGXP (1,rx);
 251   SCM_VALIDATE_STRING (2, str);
 252   SCM_VALIDATE_INUM_DEF_COPY (3,start,0,offset);
 253   SCM_ASSERT_RANGE (3,start, offset >= 0 && offset <= SCM_STRING_LENGTH (str));
 254   if (SCM_UNBNDP (flags))
 255     flags = SCM_INUM0;
 256   SCM_VALIDATE_INUM (4,flags);
 257
 258   /* re_nsub doesn't account for the `subexpression' representing the
 259      whole regexp, so add 1 to nmatches. */
 260
 261   nmatches = SCM_RGX(rx)->re_nsub + 1;
 262   SCM_DEFER_INTS;
 263   matches = SCM_MUST_MALLOC_TYPE_NUM (regmatch_t,nmatches);
 264   status = regexec (SCM_RGX (rx), SCM_STRING_CHARS (str) + offset,
 265                     nmatches, matches,
 266                     SCM_INUM (flags));
 267   if (!status)
 268     {
 269       int i;
 270       /* The match vector must include a cell for the string that was matched,
 271          so add 1. */
 272       mvec = scm_c_make_vector (nmatches + 1, SCM_UNSPECIFIED);
 273       SCM_VELTS(mvec)[0] = str;
 274       for (i = 0; i < nmatches; ++i)
 275         if (matches[i].rm_so == -1)
 276           SCM_VELTS(mvec)[i+1] = scm_cons (SCM_MAKINUM (-1), SCM_MAKINUM (-1));
 277         else
 278           SCM_VELTS(mvec)[i+1]
 279             = scm_cons (scm_long2num (matches[i].rm_so + offset),
 280                         scm_long2num (matches[i].rm_eo + offset));
 281     }
 282   scm_must_free ((char *) matches);
 283   SCM_ALLOW_INTS;
 284
 285   if (status != 0 && status != REG_NOMATCH)
 286     scm_error (scm_regexp_error_key,
 287                FUNC_NAME,
 288                scm_regexp_error_msg (status, SCM_RGX (rx)),
 289                SCM_BOOL_F,
 290                SCM_BOOL_F);
 291   return mvec;
 292 }
 293 #undef FUNC_NAME
 294
 295 void
 296 scm_init_regex_posix ()
 297 {
 298   scm_tc16_regex = scm_make_smob_type ("regexp", sizeof (regex_t));
 299   scm_set_smob_free (scm_tc16_regex, regex_free);
 300
 301   /* Compilation flags.  */
 302   scm_c_define ("regexp/basic", scm_long2num (REG_BASIC));
 303   scm_c_define ("regexp/extended", scm_long2num (REG_EXTENDED));
 304   scm_c_define ("regexp/icase", scm_long2num (REG_ICASE));
 305   scm_c_define ("regexp/newline", scm_long2num (REG_NEWLINE));
 306
 307   /* Execution flags.  */
 308   scm_c_define ("regexp/notbol", scm_long2num (REG_NOTBOL));
 309   scm_c_define ("regexp/noteol", scm_long2num (REG_NOTEOL));
 310
 311 #ifndef SCM_MAGIC_SNARFER
 312 #include "libguile/regex-posix.x"
 313 #endif
 314
 315   scm_add_feature ("regex");
 316 }
 317
 318 /*
 319   Local Variables:
 320   c-file-style: "gnu"
 321   End:
 322 */