re.c revision 22988 
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 *	$Id$
29 */
30
31#ifndef lint
32static char * const rcsid = "@(#)re.c,v 1.6 1994/02/01 00:34:43 alm Exp";
33#endif /* not lint */
34
35#include "ed.h"
36
37
38extern int patlock;
39
40char errmsg[MAXPATHLEN + 40] = "";
41
42/* get_compiled_pattern: return pointer to compiled pattern from command
43   buffer */
44pattern_t *
45get_compiled_pattern()
46{
47	static pattern_t *exp = NULL;
48
49	char *exps;
50	char delimiter;
51	int n;
52
53	if ((delimiter = *ibufp) == ' ') {
54		sprintf(errmsg, "invalid pattern delimiter");
55		return NULL;
56	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
57		if (!exp) sprintf(errmsg, "no previous pattern");
58		return exp;
59	} else if ((exps = extract_pattern(delimiter)) == NULL)
60		return NULL;
61	/* buffer alloc'd && not reserved */
62	if (exp && !patlock)
63		regfree(exp);
64	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
65		fprintf(stderr, "%s\n", strerror(errno));
66		sprintf(errmsg, "out of memory");
67		return NULL;
68	}
69	patlock = 0;
70	if ((n = regcomp(exp, exps, 0))) {
71		regerror(n, exp, errmsg, sizeof errmsg);
72		free(exp);
73		return exp = NULL;
74	}
75	return exp;
76}
77
78
79/* extract_pattern: copy a pattern string from the command buffer; return
80   pointer to the copy */
81char *
82extract_pattern(delimiter)
83	int delimiter;
84{
85	static char *lhbuf = NULL;	/* buffer */
86	static int lhbufsz = 0;		/* buffer size */
87
88	char *nd;
89	int len;
90
91	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
92		switch (*nd) {
93		default:
94			break;
95		case '[':
96			if ((nd = parse_char_class(++nd)) == NULL) {
97				sprintf(errmsg, "unbalanced brackets ([])");
98				return NULL;
99			}
100			break;
101		case '\\':
102			if (*++nd == '\n') {
103				sprintf(errmsg, "trailing backslash (\\)");
104				return NULL;
105			}
106			break;
107		}
108	len = nd - ibufp;
109	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
110	memcpy(lhbuf, ibufp, len);
111	lhbuf[len] = '\0';
112	ibufp = nd;
113	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
114}
115
116
117/* parse_char_class: expand a POSIX character class */
118char *
119parse_char_class(s)
120	char *s;
121{
122	int c, d;
123
124	if (*s == '^')
125		s++;
126	if (*s == ']')
127		s++;
128	for (; *s != ']' && *s != '\n'; s++)
129		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
130			for (s++, c = *++s; *s != ']' || c != d; s++)
131				if ((c = *s) == '\n')
132					return NULL;
133	return  (*s == ']') ? s : NULL;
134}
135