1 /* Copyright (C) 1997, 1998, 1999, 2000, 2001, 2004, 2006, 2007, 2010, 2011, 2012 Free Software Foundation, Inc.
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public License
5 * as published by the Free Software Foundation; either version 3 of
6 * the License, or (at your option) any later version.
8 * This library is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 /* regex-posix.c -- POSIX regular expression support.
24 This code was written against Henry Spencer's famous regex package.
25 The principal reference for POSIX behavior was the man page for this
26 library, not the 1003.2 document itself. Ergo, other `POSIX'
27 libraries which do not agree with the Spencer implementation may
28 produce varying behavior. Sigh. */
34 #include <sys/types.h>
36 #include "libguile/_scm.h"
44 #include "libguile/async.h"
45 #include "libguile/smob.h"
46 #include "libguile/symbols.h"
47 #include "libguile/vectors.h"
48 #include "libguile/strports.h"
49 #include "libguile/ports.h"
50 #include "libguile/feature.h"
51 #include "libguile/strings.h"
53 #include "libguile/validate.h"
54 #include "libguile/regex-posix.h"
56 /* This is defined by some regex libraries and omitted by others. */
61 scm_t_bits scm_tc16_regex
;
66 regfree (SCM_RGX (obj
));
67 scm_gc_free (SCM_RGX (obj
), sizeof(regex_t
), "regex");
73 SCM_SYMBOL (scm_regexp_error_key
, "regular-expression-syntax");
76 scm_regexp_error_msg (int regerrno
, regex_t
*rx
)
81 errmsg
= scm_malloc (80);
82 l
= regerror (regerrno
, rx
, errmsg
, 80);
86 errmsg
= scm_malloc (l
);
87 regerror (regerrno
, rx
, errmsg
, l
);
89 return scm_take_locale_string (errmsg
);
92 SCM_DEFINE (scm_regexp_p
, "regexp?", 1, 0, 0,
94 "Return @code{#t} if @var{obj} is a compiled regular expression,\n"
95 "or @code{#f} otherwise.")
96 #define FUNC_NAME s_scm_regexp_p
98 return scm_from_bool(SCM_RGXP (obj
));
102 SCM_DEFINE (scm_make_regexp
, "make-regexp", 1, 0, 1,
103 (SCM pat
, SCM flags
),
104 "Compile the regular expression described by @var{pat}, and\n"
105 "return the compiled regexp structure. If @var{pat} does not\n"
106 "describe a legal regular expression, @code{make-regexp} throws\n"
107 "a @code{regular-expression-syntax} error.\n"
109 "The @var{flags} arguments change the behavior of the compiled\n"
110 "regular expression. The following flags may be supplied:\n"
113 "@item regexp/icase\n"
114 "Consider uppercase and lowercase letters to be the same when\n"
116 "@item regexp/newline\n"
117 "If a newline appears in the target string, then permit the\n"
118 "@samp{^} and @samp{$} operators to match immediately after or\n"
119 "immediately before the newline, respectively. Also, the\n"
120 "@samp{.} and @samp{[^...]} operators will never match a newline\n"
121 "character. The intent of this flag is to treat the target\n"
122 "string as a buffer containing many lines of text, and the\n"
123 "regular expression as a pattern that may match a single one of\n"
125 "@item regexp/basic\n"
126 "Compile a basic (``obsolete'') regexp instead of the extended\n"
127 "(``modern'') regexps that are the default. Basic regexps do\n"
128 "not consider @samp{|}, @samp{+} or @samp{?} to be special\n"
129 "characters, and require the @samp{@{...@}} and @samp{(...)}\n"
130 "metacharacters to be backslash-escaped (@pxref{Backslash\n"
131 "Escapes}). There are several other differences between basic\n"
132 "and extended regular expressions, but these are the most\n"
134 "@item regexp/extended\n"
135 "Compile an extended regular expression rather than a basic\n"
136 "regexp. This is the default behavior; this flag will not\n"
137 "usually be needed. If a call to @code{make-regexp} includes\n"
138 "both @code{regexp/basic} and @code{regexp/extended} flags, the\n"
139 "one which comes last will override the earlier one.\n"
141 #define FUNC_NAME s_scm_make_regexp
148 SCM_VALIDATE_STRING (1, pat
);
149 SCM_VALIDATE_REST_ARGUMENT (flags
);
151 /* Examine list of regexp flags. If REG_BASIC is supplied, then
152 turn off REG_EXTENDED flag (on by default). */
153 cflags
= REG_EXTENDED
;
155 while (!scm_is_null (flag
))
157 if (scm_to_int (SCM_CAR (flag
)) == REG_BASIC
)
158 cflags
&= ~REG_EXTENDED
;
160 cflags
|= scm_to_int (SCM_CAR (flag
));
161 flag
= SCM_CDR (flag
);
164 rx
= scm_gc_malloc_pointerless (sizeof (regex_t
), "regex");
165 c_pat
= scm_to_locale_string (pat
);
166 status
= regcomp (rx
, c_pat
,
167 /* Make sure they're not passing REG_NOSUB;
168 regexp-exec assumes we're getting match data. */
169 cflags
& ~REG_NOSUB
);
173 SCM errmsg
= scm_regexp_error_msg (status
, rx
);
174 scm_gc_free (rx
, sizeof(regex_t
), "regex");
175 scm_error_scm (scm_regexp_error_key
,
176 scm_from_locale_string (FUNC_NAME
),
183 SCM_RETURN_NEWSMOB (scm_tc16_regex
, rx
);
189 * While regexec does respect the current locale, it returns byte
190 * offsets instead of character offsets. This routine fixes up the
191 * regmatch_t structures to refer to characters instead. See "Converting
192 * a Character" in the libc manual, for more details.
195 fixup_multibyte_match (regmatch_t
*matches
, int nmatches
, char *str
)
199 size_t char_idx
, byte_idx
;
200 size_t nbytes
= 1; /* just to kick off the for loop */
202 memset (&state
, '\0', sizeof (state
));
204 for (char_idx
= byte_idx
= 0; nbytes
> 0; char_idx
++, byte_idx
+= nbytes
)
206 for (i
= 0; i
< nmatches
; ++i
)
208 if (matches
[i
].rm_so
== byte_idx
)
209 matches
[i
].rm_so
= char_idx
;
210 if (matches
[i
].rm_eo
== byte_idx
)
211 matches
[i
].rm_eo
= char_idx
;
214 nbytes
= mbrlen (str
+ byte_idx
, MB_LEN_MAX
, &state
);
215 if (nbytes
== (size_t) -2 || nbytes
== (size_t) -1)
216 /* Something is wrong. Shouldn't be possible, as the regex match
224 SCM_DEFINE (scm_regexp_exec
, "regexp-exec", 2, 2, 0,
225 (SCM rx
, SCM str
, SCM start
, SCM flags
),
226 "Match the compiled regular expression @var{rx} against\n"
227 "@code{str}. If the optional integer @var{start} argument is\n"
228 "provided, begin matching from that position in the string.\n"
229 "Return a match structure describing the results of the match,\n"
230 "or @code{#f} if no match could be found.\n"
232 "The @var{flags} arguments change the matching behavior.\n"
233 "The following flags may be supplied:\n"
236 "@item regexp/notbol\n"
237 "Operator @samp{^} always fails (unless @code{regexp/newline}\n"
238 "is used). Use this when the beginning of the string should\n"
239 "not be considered the beginning of a line.\n"
240 "@item regexp/noteol\n"
241 "Operator @samp{$} always fails (unless @code{regexp/newline}\n"
242 "is used). Use this when the end of the string should not be\n"
243 "considered the end of a line.\n"
245 #define FUNC_NAME s_scm_regexp_exec
247 /* We used to have an SCM_DEFER_INTS, and then later an
248 SCM_CRITICAL_SECTION_START, around the regexec() call. Can't quite
249 remember what defer ints was for, but a critical section would only be
250 wanted now if we think regexec() is not thread-safe. The posix spec
252 http://www.opengroup.org/onlinepubs/009695399/functions/regcomp.html
254 reads like regexec is meant to be both thread safe and reentrant
255 (mentioning simultaneous use in threads, and in signal handlers). So
256 for now believe no protection needed. */
258 int status
, nmatches
, offset
;
261 SCM mvec
= SCM_BOOL_F
;
264 SCM_VALIDATE_RGXP (1, rx
);
265 SCM_VALIDATE_STRING (2, str
);
267 if (SCM_UNBNDP (start
))
274 substr
= scm_substring (str
, start
, SCM_UNDEFINED
);
275 offset
= scm_to_int (start
);
278 if (SCM_UNBNDP (flags
))
281 /* re_nsub doesn't account for the `subexpression' representing the
282 whole regexp, so add 1 to nmatches. */
284 c_str
= scm_to_locale_string (substr
);
286 nmatches
= SCM_RGX(rx
)->re_nsub
+ 1;
287 matches
= scm_malloc (sizeof (regmatch_t
) * nmatches
);
288 status
= regexec (SCM_RGX (rx
), c_str
, nmatches
, matches
,
293 fixup_multibyte_match (matches
, nmatches
, c_str
);
301 /* The match vector must include a cell for the string that was matched,
303 mvec
= scm_c_make_vector (nmatches
+ 1, SCM_UNSPECIFIED
);
304 SCM_SIMPLE_VECTOR_SET(mvec
,0, str
);
305 for (i
= 0; i
< nmatches
; ++i
)
306 if (matches
[i
].rm_so
== -1)
307 SCM_SIMPLE_VECTOR_SET(mvec
, i
+1,
308 scm_cons (scm_from_int (-1), scm_from_int (-1)));
310 SCM_SIMPLE_VECTOR_SET(mvec
, i
+1,
311 scm_cons (scm_from_long (matches
[i
].rm_so
+ offset
),
312 scm_from_long (matches
[i
].rm_eo
+ offset
)));
316 if (status
!= 0 && status
!= REG_NOMATCH
)
317 scm_error_scm (scm_regexp_error_key
,
318 scm_from_locale_string (FUNC_NAME
),
319 scm_regexp_error_msg (status
, SCM_RGX (rx
)),
320 SCM_BOOL_F
, SCM_BOOL_F
);
326 scm_init_regex_posix ()
328 scm_tc16_regex
= scm_make_smob_type ("regexp", sizeof (regex_t
));
329 scm_set_smob_free (scm_tc16_regex
, regex_free
);
331 /* Compilation flags. */
332 scm_c_define ("regexp/basic", scm_from_int (REG_BASIC
));
333 scm_c_define ("regexp/extended", scm_from_int (REG_EXTENDED
));
334 scm_c_define ("regexp/icase", scm_from_int (REG_ICASE
));
335 scm_c_define ("regexp/newline", scm_from_int (REG_NEWLINE
));
337 /* Execution flags. */
338 scm_c_define ("regexp/notbol", scm_from_int (REG_NOTBOL
));
339 scm_c_define ("regexp/noteol", scm_from_int (REG_NOTEOL
));
341 #include "libguile/regex-posix.x"
343 scm_add_feature ("regex");