xref: /freebsd/lib/libc/regex/regexec.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993, 1994 Henry Spencer.
5  * Copyright (c) 1992, 1993, 1994
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * This code is derived from software contributed to Berkeley by
9  * Henry Spencer.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  *
35  *	@(#)regexec.c	8.3 (Berkeley) 3/20/94
36  */
37 
38 #if defined(LIBC_SCCS) && !defined(lint)
39 static char sccsid[] = "@(#)regexec.c	8.3 (Berkeley) 3/20/94";
40 #endif /* LIBC_SCCS and not lint */
41 /*
42  * the outer shell of regexec()
43  *
44  * This file includes engine.c three times, after muchos fiddling with the
45  * macros that code uses.  This lets the same code operate on two different
46  * representations for state sets and characters.
47  */
48 #include <sys/types.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51 #include <string.h>
52 #include <limits.h>
53 #include <ctype.h>
54 #include <regex.h>
55 #include <wchar.h>
56 #include <wctype.h>
57 
58 #include "utils.h"
59 #include "regex2.h"
60 
61 static int nope __unused = 0;	/* for use in asserts; shuts lint up */
62 
63 static __inline size_t
64 xmbrtowc(wint_t *wi, const char *s, size_t n, mbstate_t *mbs, wint_t dummy)
65 {
66 	size_t nr;
67 	wchar_t wc;
68 
69 	nr = mbrtowc(&wc, s, n, mbs);
70 	if (wi != NULL)
71 		*wi = wc;
72 	if (nr == 0)
73 		return (1);
74 	else if (nr == (size_t)-1 || nr == (size_t)-2) {
75 		memset(mbs, 0, sizeof(*mbs));
76 		if (wi != NULL)
77 			*wi = dummy;
78 		return (1);
79 	} else
80                 return (nr);
81 }
82 
83 static __inline size_t
84 xmbrtowc_dummy(wint_t *wi,
85 		const char *s,
86 		size_t n __unused,
87 		mbstate_t *mbs __unused,
88 		wint_t dummy __unused)
89 {
90 
91 	if (wi != NULL)
92 		*wi = (unsigned char)*s;
93 	return (1);
94 }
95 
96 /* macros for manipulating states, small version */
97 #define	states1	long		/* for later use in regexec() decision */
98 #define	states	states1
99 #define	CLEAR(v)	((v) = 0)
100 #define	SET0(v, n)	((v) &= ~((unsigned long)1 << (n)))
101 #define	SET1(v, n)	((v) |= (unsigned long)1 << (n))
102 #define	ISSET(v, n)	(((v) & ((unsigned long)1 << (n))) != 0)
103 #define	ASSIGN(d, s)	((d) = (s))
104 #define	EQ(a, b)	((a) == (b))
105 #define	STATEVARS	long dummy	/* dummy version */
106 #define	STATESETUP(m, n)	/* nothing */
107 #define	STATETEARDOWN(m)	/* nothing */
108 #define	SETUP(v)	((v) = 0)
109 #define	onestate	long
110 #define	INIT(o, n)	((o) = (unsigned long)1 << (n))
111 #define	INC(o)	((o) <<= 1)
112 #define	ISSTATEIN(v, o)	(((v) & (o)) != 0)
113 /* some abbreviations; note that some of these know variable names! */
114 /* do "if I'm here, I can also be there" etc without branches */
115 #define	FWD(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) << (n))
116 #define	BACK(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) >> (n))
117 #define	ISSETBACK(v, n)	(((v) & ((unsigned long)here >> (n))) != 0)
118 /* no multibyte support */
119 #define	XMBRTOWC	xmbrtowc_dummy
120 #define	ZAPSTATE(mbs)	((void)(mbs))
121 /* function names */
122 #define SNAMES			/* engine.c looks after details */
123 
124 #include "engine.c"
125 
126 /* now undo things */
127 #undef	states
128 #undef	CLEAR
129 #undef	SET0
130 #undef	SET1
131 #undef	ISSET
132 #undef	ASSIGN
133 #undef	EQ
134 #undef	STATEVARS
135 #undef	STATESETUP
136 #undef	STATETEARDOWN
137 #undef	SETUP
138 #undef	onestate
139 #undef	INIT
140 #undef	INC
141 #undef	ISSTATEIN
142 #undef	FWD
143 #undef	BACK
144 #undef	ISSETBACK
145 #undef	SNAMES
146 #undef	XMBRTOWC
147 #undef	ZAPSTATE
148 
149 /* macros for manipulating states, large version */
150 #define	states	char *
151 #define	CLEAR(v)	memset(v, 0, m->g->nstates)
152 #define	SET0(v, n)	((v)[n] = 0)
153 #define	SET1(v, n)	((v)[n] = 1)
154 #define	ISSET(v, n)	((v)[n])
155 #define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
156 #define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
157 #define	STATEVARS	long vn; char *space
158 #define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
159 				if ((m)->space == NULL) return(REG_ESPACE); \
160 				(m)->vn = 0; }
161 #define	STATETEARDOWN(m)	{ free((m)->space); }
162 #define	SETUP(v)	((v) = &m->space[m->vn++ * m->g->nstates])
163 #define	onestate	long
164 #define	INIT(o, n)	((o) = (n))
165 #define	INC(o)	((o)++)
166 #define	ISSTATEIN(v, o)	((v)[o])
167 /* some abbreviations; note that some of these know variable names! */
168 /* do "if I'm here, I can also be there" etc without branches */
169 #define	FWD(dst, src, n)	((dst)[here+(n)] |= (src)[here])
170 #define	BACK(dst, src, n)	((dst)[here-(n)] |= (src)[here])
171 #define	ISSETBACK(v, n)	((v)[here - (n)])
172 /* no multibyte support */
173 #define	XMBRTOWC	xmbrtowc_dummy
174 #define	ZAPSTATE(mbs)	((void)(mbs))
175 /* function names */
176 #define	LNAMES			/* flag */
177 
178 #include "engine.c"
179 
180 /* multibyte character & large states version */
181 #undef	LNAMES
182 #undef	XMBRTOWC
183 #undef	ZAPSTATE
184 #define	XMBRTOWC	xmbrtowc
185 #define	ZAPSTATE(mbs)	memset((mbs), 0, sizeof(*(mbs)))
186 #define	MNAMES
187 
188 #include "engine.c"
189 
190 /*
191  - regexec - interface for matching
192  = extern int regexec(const regex_t *, const char *, size_t, \
193  =					regmatch_t [], int);
194  = #define	REG_NOTBOL	00001
195  = #define	REG_NOTEOL	00002
196  = #define	REG_STARTEND	00004
197  = #define	REG_TRACE	00400	// tracing of execution
198  = #define	REG_LARGE	01000	// force large representation
199  = #define	REG_BACKR	02000	// force use of backref code
200  *
201  * We put this here so we can exploit knowledge of the state representation
202  * when choosing which matcher to call.  Also, by this point the matchers
203  * have been prototyped.
204  */
205 int				/* 0 success, REG_NOMATCH failure */
206 regexec(const regex_t * __restrict preg,
207 	const char * __restrict string,
208 	size_t nmatch,
209 	regmatch_t pmatch[__restrict],
210 	int eflags)
211 {
212 	struct re_guts *g = preg->re_g;
213 #ifdef REDEBUG
214 #	define	GOODFLAGS(f)	(f)
215 #else
216 #	define	GOODFLAGS(f)	((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
217 #endif
218 
219 	if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
220 		return(REG_BADPAT);
221 	assert(!(g->iflags&BAD));
222 	if (g->iflags&BAD)		/* backstop for no-debug case */
223 		return(REG_BADPAT);
224 	eflags = GOODFLAGS(eflags);
225 
226 	if (MB_CUR_MAX > 1)
227 		return(mmatcher(g, string, nmatch, pmatch, eflags));
228 	else if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
229 		return(smatcher(g, string, nmatch, pmatch, eflags));
230 	else
231 		return(lmatcher(g, string, nmatch, pmatch, eflags));
232 }
233