libguile/regex-posix.c

   1 /*      Copyright (C) 1997, 1998, 1999, 2000 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
   5  * the Free Software Foundation; either version 2, or (at your option)
   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
  23  * resulting executable to be covered by the GNU General Public License.
  24  * Your use of that executable is in no way restricted on account of
  25  * linking the GUILE library code into it.
  26  *
  27  * This exception does not however invalidate any other reasons why
  28  * the executable file might be covered by the GNU General Public License.
  29  *
  30  * This exception applies only to the code released by the
  31  * Free Software Foundation under the name GUILE.  If you copy
  32  * code from other Free Software Foundation releases into a copy of
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  36  * this exception notice from them.
  37  *
  38  * If you write modifications of your own for GUILE, it is your choice
  39  * whether to permit this exception to apply to your modifications.
  40  * If you do not wish that, delete this exception notice.
  41  */
  42
  43 /* Software engineering face-lift by Greg J. Badros, 11-Dec-1999,
  44    gjb@cs.washington.edu, http://www.cs.washington.edu/homes/gjb */
  45
  46 \f
  47
  48 /* regex-posix.c -- POSIX regular expression support.
  49
  50    This code was written against Henry Spencer's famous regex package.
  51    The principal reference for POSIX behavior was the man page for this
  52    library, not the 1003.2 document itself.  Ergo, other `POSIX'
  53    libraries which do not agree with the Spencer implementation may
  54    produce varying behavior.  Sigh. */
  55
  56 #include <stdio.h>
  57 #include <sys/types.h>
  58
  59 #include "libguile/_scm.h"
  60
  61 /* Supposedly, this file is never compiled unless we know we have
  62    POSIX regular expressions.  But we still put this in an #ifdef so
  63    the file is CPP'able (for dependency scanning) even on systems that
  64    don't have a <regex.h> header.  */
  65 #ifdef HAVE_REGCOMP
  66 #ifdef HAVE_REGEX_H
  67 #include <regex.h>
  68 #else
  69 #ifdef HAVE_RXPOSIX_H
  70 #include <rxposix.h>            /* GNU Rx library */
  71 #else
  72 #ifdef HAVE_RX_RXPOSIX_H
  73 #include <rx/rxposix.h>         /* GNU Rx library on Linux */
  74 #endif
  75 #endif
  76 #endif
  77 #endif
  78
  79 #include "libguile/smob.h"
  80 #include "libguile/symbols.h"
  81 #include "libguile/vectors.h"
  82 #include "libguile/strports.h"
  83 #include "libguile/ports.h"
  84 #include "libguile/feature.h"
  85 #include "libguile/strings.h"
  86
  87 #include "libguile/validate.h"
  88 #include "libguile/regex-posix.h"
  89
  90 /* This is defined by some regex libraries and omitted by others. */
  91 #ifndef REG_BASIC
  92 #define REG_BASIC 0
  93 #endif
  94
  95 long scm_tc16_regex;
  96
  97 static scm_sizet
  98 free_regex (SCM obj)
  99 {
 100   regfree (SCM_RGX (obj));
 101   free (SCM_RGX (obj));
 102   return sizeof(regex_t);
 103 }
 104
 105 \f
 106
 107 SCM_SYMBOL (scm_regexp_error_key, "regular-expression-syntax");
 108
 109 static char *
 110 scm_regexp_error_msg (int regerrno, regex_t *rx)
 111 {
 112   SCM errmsg;
 113   int l;
 114
 115   /* FIXME: must we wrap any external calls in SCM_DEFER_INTS...SCM_ALLOW_INTS?
 116      Or are these only necessary when a SCM object may be left in an
 117      undetermined state (half-formed)?  If the latter then I believe we
 118      may do without the critical section code. -twp */
 119
 120   /* We could simply make errmsg a char pointer, and allocate space with
 121      malloc.  But since we are about to pass the pointer to scm_error, which
 122      never returns, we would never have the opportunity to free it.  Creating
 123      it as a SCM object means that the system will GC it at some point. */
 124
 125   errmsg = scm_make_string (SCM_MAKINUM (80), SCM_UNDEFINED);
 126   SCM_DEFER_INTS;
 127   l = regerror (regerrno, rx, SCM_CHARS (errmsg), 80);
 128   if (l > 80)
 129     {
 130       errmsg = scm_make_string (SCM_MAKINUM (l), SCM_UNDEFINED);
 131       regerror (regerrno, rx, SCM_CHARS (errmsg), l);
 132     }
 133   SCM_ALLOW_INTS;
 134   return SCM_CHARS (errmsg);
 135 }
 136
 137 SCM_DEFINE (scm_regexp_p, "regexp?", 1, 0, 0,
 138             (SCM x),
 139             "Return @code{#t} if @var{obj} is a compiled regular expression, or\n"
 140             "@code{#f} otherwise.")
 141 #define FUNC_NAME s_scm_regexp_p
 142 {
 143   return SCM_BOOL(SCM_RGXP (x));
 144 }
 145 #undef FUNC_NAME
 146
 147 SCM_DEFINE (scm_make_regexp, "make-regexp", 1, 0, 1,
 148             (SCM pat, SCM flags),
 149             "Compile the regular expression described by @var{str}, and return the\n"
 150             "compiled regexp structure.  If @var{str} does not describe a legal\n"
 151             "regular expression, @code{make-regexp} throws a\n"
 152             "@code{regular-expression-syntax} error.\n\n"
 153             "The @var{flag} arguments change the behavior of the compiled regexp.\n"
 154             "The following flags may be supplied:\n\n"
 155             "@table @code\n"
 156             "@item regexp/icase\n"
 157             "Consider uppercase and lowercase letters to be the same when matching.\n\n"
 158             "@item regexp/newline\n"
 159             "If a newline appears in the target string, then permit the @samp{^} and\n"
 160             "@samp{$} operators to match immediately after or immediately before the\n"
 161             "newline, respectively.  Also, the @samp{.} and @samp{[^...]} operators\n"
 162             "will never match a newline character.  The intent of this flag is to\n"
 163             "treat the target string as a buffer containing many lines of text, and\n"
 164             "the regular expression as a pattern that may match a single one of those\n"
 165             "lines.\n\n"
 166             "@item regexp/basic\n"
 167             "Compile a basic (``obsolete'') regexp instead of the extended\n"
 168             "(``modern'') regexps that are the default.  Basic regexps do not\n"
 169             "consider @samp{|}, @samp{+} or @samp{?} to be special characters, and\n"
 170             "require the @samp{@{...@}} and @samp{(...)} metacharacters to be\n"
 171             "backslash-escaped (@pxref{Backslash Escapes}).  There are several other\n"
 172             "differences between basic and extended regular expressions, but these\n"
 173             "are the most significant.\n\n"
 174             "@item regexp/extended\n"
 175             "Compile an extended regular expression rather than a basic regexp.  This\n"
 176             "is the default behavior; this flag will not usually be needed.  If a\n"
 177             "call to @code{make-regexp} includes both @code{regexp/basic} and\n"
 178             "@code{regexp/extended} flags, the one which comes last will override\n"
 179             "the earlier one.\n"
 180             "@end table\n")
 181 #define FUNC_NAME s_scm_make_regexp
 182 {
 183   SCM flag;
 184   regex_t *rx;
 185   int status, cflags;
 186
 187   SCM_VALIDATE_ROSTRING (1,pat);
 188   SCM_VALIDATE_REST_ARGUMENT (flags);
 189   SCM_COERCE_SUBSTR (pat);
 190
 191   /* Examine list of regexp flags.  If REG_BASIC is supplied, then
 192      turn off REG_EXTENDED flag (on by default). */
 193   cflags = REG_EXTENDED;
 194   flag = flags;
 195   while (!SCM_NULLP (flag))
 196     {
 197       if (SCM_INUM (SCM_CAR (flag)) == REG_BASIC)
 198         cflags &= ~REG_EXTENDED;
 199       else
 200         cflags |= SCM_INUM (SCM_CAR (flag));
 201       flag = SCM_CDR (flag);
 202     }
 203
 204   rx = SCM_MUST_MALLOC_TYPE (regex_t);
 205   status = regcomp (rx, SCM_ROCHARS (pat),
 206                     /* Make sure they're not passing REG_NOSUB;
 207                        regexp-exec assumes we're getting match data.  */
 208                     cflags & ~REG_NOSUB);
 209   if (status != 0)
 210     {
 211       scm_error (scm_regexp_error_key,
 212                  FUNC_NAME,
 213                  scm_regexp_error_msg (status, rx),
 214                  SCM_BOOL_F,
 215                  SCM_BOOL_F);
 216       /* never returns */
 217     }
 218   SCM_RETURN_NEWSMOB (scm_tc16_regex, rx);
 219 }
 220 #undef FUNC_NAME
 221
 222 SCM_DEFINE (scm_regexp_exec, "regexp-exec", 2, 2, 0,
 223             (SCM rx, SCM str, SCM start, SCM flags),
 224             "Match the compiled regular expression @var{regexp} against @code{str}.\n"
 225             "If the optional integer @var{start} argument is provided, begin matching\n"
 226             "from that position in the string.  Return a match structure describing\n"
 227             "the results of the match, or @code{#f} if no match could be found.")
 228 #define FUNC_NAME s_scm_regexp_exec
 229 {
 230   int status, nmatches, offset;
 231   regmatch_t *matches;
 232   SCM mvec = SCM_BOOL_F;
 233
 234   SCM_VALIDATE_RGXP (1,rx);
 235   SCM_VALIDATE_ROSTRING (2,str);
 236   SCM_VALIDATE_INUM_DEF_COPY (3,start,0,offset);
 237   SCM_ASSERT_RANGE (3,start,offset >= 0 && (unsigned) offset <= SCM_LENGTH (str));
 238   if (SCM_UNBNDP (flags))
 239     flags = SCM_INUM0;
 240   SCM_VALIDATE_INUM (4,flags);
 241   SCM_COERCE_SUBSTR (str);
 242
 243   /* re_nsub doesn't account for the `subexpression' representing the
 244      whole regexp, so add 1 to nmatches. */
 245
 246   nmatches = SCM_RGX(rx)->re_nsub + 1;
 247   SCM_DEFER_INTS;
 248   matches = SCM_MUST_MALLOC_TYPE_NUM (regmatch_t,nmatches);
 249   status = regexec (SCM_RGX (rx), SCM_ROCHARS (str) + offset,
 250                     nmatches, matches,
 251                     SCM_INUM (flags));
 252   if (!status)
 253     {
 254       int i;
 255       /* The match vector must include a cell for the string that was matched,
 256          so add 1. */
 257       mvec = scm_make_vector (SCM_MAKINUM (nmatches + 1), SCM_UNSPECIFIED);
 258       SCM_VELTS(mvec)[0] = str;
 259       for (i = 0; i < nmatches; ++i)
 260         if (matches[i].rm_so == -1)
 261           SCM_VELTS(mvec)[i+1] = scm_cons (SCM_MAKINUM (-1), SCM_MAKINUM (-1));
 262         else
 263           SCM_VELTS(mvec)[i+1]
 264             = scm_cons(SCM_MAKINUM(matches[i].rm_so + offset),
 265                        SCM_MAKINUM(matches[i].rm_eo + offset));
 266     }
 267   scm_must_free ((char *) matches);
 268   SCM_ALLOW_INTS;
 269
 270   if (status != 0 && status != REG_NOMATCH)
 271     scm_error (scm_regexp_error_key,
 272                FUNC_NAME,
 273                scm_regexp_error_msg (status, SCM_RGX (rx)),
 274                SCM_BOOL_F,
 275                SCM_BOOL_F);
 276   return mvec;
 277 }
 278 #undef FUNC_NAME
 279
 280 void
 281 scm_init_regex_posix ()
 282 {
 283   scm_tc16_regex = scm_make_smob_type_mfpe ("regexp", sizeof (regex_t),
 284                                             NULL, free_regex, NULL, NULL);
 285
 286   /* Compilation flags.  */
 287   scm_sysintern ("regexp/basic", scm_long2num (REG_BASIC));
 288   scm_sysintern ("regexp/extended", scm_long2num (REG_EXTENDED));
 289   scm_sysintern ("regexp/icase", scm_long2num (REG_ICASE));
 290   scm_sysintern ("regexp/newline", scm_long2num (REG_NEWLINE));
 291
 292   /* Execution flags.  */
 293   scm_sysintern ("regexp/notbol", scm_long2num (REG_NOTBOL));
 294   scm_sysintern ("regexp/noteol", scm_long2num (REG_NOTEOL));
 295
 296 #include "libguile/regex-posix.x"
 297
 298   scm_add_feature ("regex");
 299 }
 300
 301 /*
 302   Local Variables:
 303   c-file-style: "gnu"
 304   End:
 305 */