re.c revision 27963 
1/* re.c: This file contains the regular expression interface routines for
2   the ed line editor. */
3/*-
4 * Copyright (c) 1993 Andrew Moore, Talke Studio.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef lint
30#if 0
31static char * const rcsid = "@(#)re.c,v 1.6 1994/02/01 00:34:43 alm Exp";
32#else
33static char * const rcsid =
34	"$Id: re.c,v 1.13 1997/02/22 14:03:18 peter Exp $";
35#endif
36#endif /* not lint */
37
38#include "ed.h"
39
40
41extern int patlock;
42
43char errmsg[MAXPATHLEN + 40] = "";
44
45/* get_compiled_pattern: return pointer to compiled pattern from command
46   buffer */
47pattern_t *
48get_compiled_pattern()
49{
50	static pattern_t *exp = NULL;
51
52	char *exps;
53	char delimiter;
54	int n;
55
56	if ((delimiter = *ibufp) == ' ') {
57		sprintf(errmsg, "invalid pattern delimiter");
58		return NULL;
59	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
60		if (!exp) sprintf(errmsg, "no previous pattern");
61		return exp;
62	} else if ((exps = extract_pattern(delimiter)) == NULL)
63		return NULL;
64	/* buffer alloc'd && not reserved */
65	if (exp && !patlock)
66		regfree(exp);
67	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
68		fprintf(stderr, "%s\n", strerror(errno));
69		sprintf(errmsg, "out of memory");
70		return NULL;
71	}
72	patlock = 0;
73	if ((n = regcomp(exp, exps, 0))) {
74		regerror(n, exp, errmsg, sizeof errmsg);
75		free(exp);
76		return exp = NULL;
77	}
78	return exp;
79}
80
81
82/* extract_pattern: copy a pattern string from the command buffer; return
83   pointer to the copy */
84char *
85extract_pattern(delimiter)
86	int delimiter;
87{
88	static char *lhbuf = NULL;	/* buffer */
89	static int lhbufsz = 0;		/* buffer size */
90
91	char *nd;
92	int len;
93
94	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
95		switch (*nd) {
96		default:
97			break;
98		case '[':
99			if ((nd = parse_char_class(++nd)) == NULL) {
100				sprintf(errmsg, "unbalanced brackets ([])");
101				return NULL;
102			}
103			break;
104		case '\\':
105			if (*++nd == '\n') {
106				sprintf(errmsg, "trailing backslash (\\)");
107				return NULL;
108			}
109			break;
110		}
111	len = nd - ibufp;
112	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
113	memcpy(lhbuf, ibufp, len);
114	lhbuf[len] = '\0';
115	ibufp = nd;
116	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
117}
118
119
120/* parse_char_class: expand a POSIX character class */
121char *
122parse_char_class(s)
123	char *s;
124{
125	int c, d;
126
127	if (*s == '^')
128		s++;
129	if (*s == ']')
130		s++;
131	for (; *s != ']' && *s != '\n'; s++)
132		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
133			for (s++, c = *++s; *s != ']' || c != d; s++)
134				if ((c = *s) == '\n')
135					return NULL;
136	return  (*s == ']') ? s : NULL;
137}
138