re.c revision 81220 
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
30static const char rcsid[] =
31  "$FreeBSD: head/bin/ed/re.c 81220 2001-08-06 22:01:31Z mike $";
32#endif /* not lint */
33
34#include "ed.h"
35
36
37extern int patlock;
38
39const char *errmsg = "";
40
41/* get_compiled_pattern: return pointer to compiled pattern from command
42   buffer */
43pattern_t *
44get_compiled_pattern()
45{
46	static pattern_t *exp = NULL;
47	static char error[1024];
48
49	char *exps;
50	char delimiter;
51	int n;
52
53	if ((delimiter = *ibufp) == ' ') {
54		errmsg = "invalid pattern delimiter";
55		return NULL;
56	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
57		if (!exp)
58			errmsg = "no previous pattern";
59		return exp;
60	} else if ((exps = extract_pattern(delimiter)) == NULL)
61		return NULL;
62	/* buffer alloc'd && not reserved */
63	if (exp && !patlock)
64		regfree(exp);
65	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
66		fprintf(stderr, "%s\n", strerror(errno));
67		errmsg = "out of memory";
68		return NULL;
69	}
70	patlock = 0;
71	if ((n = regcomp(exp, exps, 0))) {
72		regerror(n, exp, error, sizeof error);
73		errmsg = error;
74		free(exp);
75		return exp = NULL;
76	}
77	return exp;
78}
79
80
81/* extract_pattern: copy a pattern string from the command buffer; return
82   pointer to the copy */
83char *
84extract_pattern(delimiter)
85	int delimiter;
86{
87	static char *lhbuf = NULL;	/* buffer */
88	static int lhbufsz = 0;		/* buffer size */
89
90	char *nd;
91	int len;
92
93	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
94		switch (*nd) {
95		default:
96			break;
97		case '[':
98			if ((nd = parse_char_class(++nd)) == NULL) {
99				errmsg = "unbalanced brackets ([])";
100				return NULL;
101			}
102			break;
103		case '\\':
104			if (*++nd == '\n') {
105				errmsg = "trailing backslash (\\)";
106				return NULL;
107			}
108			break;
109		}
110	len = nd - ibufp;
111	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
112	memcpy(lhbuf, ibufp, len);
113	lhbuf[len] = '\0';
114	ibufp = nd;
115	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
116}
117
118
119/* parse_char_class: expand a POSIX character class */
120char *
121parse_char_class(s)
122	char *s;
123{
124	int c, d;
125
126	if (*s == '^')
127		s++;
128	if (*s == ']')
129		s++;
130	for (; *s != ']' && *s != '\n'; s++)
131		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
132			for (s++, c = *++s; *s != ']' || c != d; s++)
133				if ((c = *s) == '\n')
134					return NULL;
135	return  (*s == ']') ? s : NULL;
136}
137