xref: /freebsd/lib/libc/regex/regexec.c (revision adeb92a24c57f97d5cd3c3c45be239cbb23aed68)
1 /*-
2  * Copyright (c) 1992, 1993, 1994 Henry Spencer.
3  * Copyright (c) 1992, 1993, 1994
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * This code is derived from software contributed to Berkeley by
7  * Henry Spencer.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  *	@(#)regexec.c	8.3 (Berkeley) 3/20/94
38  */
39 
40 #if defined(LIBC_SCCS) && !defined(lint)
41 static char sccsid[] = "@(#)regexec.c	8.3 (Berkeley) 3/20/94";
42 #endif /* LIBC_SCCS and not lint */
43 
44 /*
45  * the outer shell of regexec()
46  *
47  * This file includes engine.c *twice*, after muchos fiddling with the
48  * macros that code uses.  This lets the same code operate on two different
49  * representations for state sets.
50  */
51 #include <sys/types.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <limits.h>
56 #include <ctype.h>
57 #include <regex.h>
58 
59 #include "utils.h"
60 #include "regex2.h"
61 
62 static int nope = 0;		/* for use in asserts; shuts lint up */
63 
64 /* macros for manipulating states, small version */
65 #define	states	long
66 #define	states1	states		/* for later use in regexec() decision */
67 #define	CLEAR(v)	((v) = 0)
68 #define	SET0(v, n)	((v) &= ~((unsigned long)1 << (n)))
69 #define	SET1(v, n)	((v) |= (unsigned long)1 << (n))
70 #define	ISSET(v, n)	(((v) & ((unsigned long)1 << (n))) != 0)
71 #define	ASSIGN(d, s)	((d) = (s))
72 #define	EQ(a, b)	((a) == (b))
73 #define	STATEVARS	long dummy	/* dummy version */
74 #define	STATESETUP(m, n)	/* nothing */
75 #define	STATETEARDOWN(m)	/* nothing */
76 #define	SETUP(v)	((v) = 0)
77 #define	onestate	long
78 #define	INIT(o, n)	((o) = (unsigned long)1 << (n))
79 #define	INC(o)	((o) <<= 1)
80 #define	ISSTATEIN(v, o)	(((v) & (o)) != 0)
81 /* some abbreviations; note that some of these know variable names! */
82 /* do "if I'm here, I can also be there" etc without branches */
83 #define	FWD(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) << (n))
84 #define	BACK(dst, src, n)	((dst) |= ((unsigned long)(src)&(here)) >> (n))
85 #define	ISSETBACK(v, n)	(((v) & ((unsigned long)here >> (n))) != 0)
86 /* function names */
87 #define SNAMES			/* engine.c looks after details */
88 
89 #include "engine.c"
90 
91 /* now undo things */
92 #undef	states
93 #undef	CLEAR
94 #undef	SET0
95 #undef	SET1
96 #undef	ISSET
97 #undef	ASSIGN
98 #undef	EQ
99 #undef	STATEVARS
100 #undef	STATESETUP
101 #undef	STATETEARDOWN
102 #undef	SETUP
103 #undef	onestate
104 #undef	INIT
105 #undef	INC
106 #undef	ISSTATEIN
107 #undef	FWD
108 #undef	BACK
109 #undef	ISSETBACK
110 #undef	SNAMES
111 
112 /* macros for manipulating states, large version */
113 #define	states	char *
114 #define	CLEAR(v)	memset(v, 0, m->g->nstates)
115 #define	SET0(v, n)	((v)[n] = 0)
116 #define	SET1(v, n)	((v)[n] = 1)
117 #define	ISSET(v, n)	((v)[n])
118 #define	ASSIGN(d, s)	memcpy(d, s, m->g->nstates)
119 #define	EQ(a, b)	(memcmp(a, b, m->g->nstates) == 0)
120 #define	STATEVARS	long vn; char *space
121 #define	STATESETUP(m, nv)	{ (m)->space = malloc((nv)*(m)->g->nstates); \
122 				if ((m)->space == NULL) return(REG_ESPACE); \
123 				(m)->vn = 0; }
124 #define	STATETEARDOWN(m)	{ free((m)->space); }
125 #define	SETUP(v)	((v) = &m->space[m->vn++ * m->g->nstates])
126 #define	onestate	long
127 #define	INIT(o, n)	((o) = (n))
128 #define	INC(o)	((o)++)
129 #define	ISSTATEIN(v, o)	((v)[o])
130 /* some abbreviations; note that some of these know variable names! */
131 /* do "if I'm here, I can also be there" etc without branches */
132 #define	FWD(dst, src, n)	((dst)[here+(n)] |= (src)[here])
133 #define	BACK(dst, src, n)	((dst)[here-(n)] |= (src)[here])
134 #define	ISSETBACK(v, n)	((v)[here - (n)])
135 /* function names */
136 #define	LNAMES			/* flag */
137 
138 #include "engine.c"
139 
140 /*
141  - regexec - interface for matching
142  = extern int regexec(const regex_t *, const char *, size_t, \
143  =					regmatch_t [], int);
144  = #define	REG_NOTBOL	00001
145  = #define	REG_NOTEOL	00002
146  = #define	REG_STARTEND	00004
147  = #define	REG_TRACE	00400	// tracing of execution
148  = #define	REG_LARGE	01000	// force large representation
149  = #define	REG_BACKR	02000	// force use of backref code
150  *
151  * We put this here so we can exploit knowledge of the state representation
152  * when choosing which matcher to call.  Also, by this point the matchers
153  * have been prototyped.
154  */
155 int				/* 0 success, REG_NOMATCH failure */
156 regexec(preg, string, nmatch, pmatch, eflags)
157 const regex_t *preg;
158 const char *string;
159 size_t nmatch;
160 regmatch_t pmatch[];
161 int eflags;
162 {
163 	register struct re_guts *g = preg->re_g;
164 #ifdef REDEBUG
165 #	define	GOODFLAGS(f)	(f)
166 #else
167 #	define	GOODFLAGS(f)	((f)&(REG_NOTBOL|REG_NOTEOL|REG_STARTEND))
168 #endif
169 
170 	if (preg->re_magic != MAGIC1 || g->magic != MAGIC2)
171 		return(REG_BADPAT);
172 	assert(!(g->iflags&BAD));
173 	if (g->iflags&BAD)		/* backstop for no-debug case */
174 		return(REG_BADPAT);
175 	eflags = GOODFLAGS(eflags);
176 
177 	if (g->nstates <= CHAR_BIT*sizeof(states1) && !(eflags&REG_LARGE))
178 		return(smatcher(g, (char *)string, nmatch, pmatch, eflags));
179 	else
180 		return(lmatcher(g, (char *)string, nmatch, pmatch, eflags));
181 }
182