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#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: src/bin/ed/re.c,v 1.20 2003/07/20 10:24:09 ru Exp $");
31
32#include "ed.h"
33
34
35extern int patlock;
36
37const char *errmsg = "";
38
39/* get_compiled_pattern: return pointer to compiled pattern from command
40   buffer */
41pattern_t *
42get_compiled_pattern(void)
43{
44	static pattern_t *expr = NULL;
45	static char error[1024];
46
47	char *exprs;
48	char delimiter;
49	int n;
50
51	if ((delimiter = *ibufp) == ' ') {
52		errmsg = "invalid pattern delimiter";
53		return NULL;
54	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
55		if (!expr)
56			errmsg = "no previous pattern";
57		return expr;
58	} else if ((exprs = extract_pattern(delimiter)) == NULL)
59		return NULL;
60	/* buffer alloc'd && not reserved */
61	if (expr && !patlock)
62		regfree(expr);
63	else if ((expr = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
64		fprintf(stderr, "%s\n", strerror(errno));
65		errmsg = "out of memory";
66		return NULL;
67	}
68	patlock = 0;
69	if ((n = regcomp(expr, exprs, 0))) {
70		regerror(n, expr, error, sizeof error);
71		errmsg = error;
72		free(expr);
73		return expr = NULL;
74	}
75	return expr;
76}
77
78
79/* extract_pattern: copy a pattern string from the command buffer; return
80   pointer to the copy */
81char *
82extract_pattern(int delimiter)
83{
84	static char *lhbuf = NULL;	/* buffer */
85	static int lhbufsz = 0;		/* buffer size */
86
87	char *nd;
88	int len;
89
90	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
91		switch (*nd) {
92		default:
93			break;
94		case '[':
95			if ((nd = parse_char_class(++nd)) == NULL) {
96				errmsg = "unbalanced brackets ([])";
97				return NULL;
98			}
99			break;
100		case '\\':
101			if (*++nd == '\n') {
102				errmsg = "trailing backslash (\\)";
103				return NULL;
104			}
105			break;
106		}
107	len = nd - ibufp;
108	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
109	memcpy(lhbuf, ibufp, len);
110	lhbuf[len] = '\0';
111	ibufp = nd;
112	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
113}
114
115
116/* parse_char_class: expand a POSIX character class */
117char *
118parse_char_class(char *s)
119{
120	int c, d;
121
122	if (*s == '^')
123		s++;
124	if (*s == ']')
125		s++;
126	for (; *s != ']' && *s != '\n'; s++)
127		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
128			for (s++, c = *++s; *s != ']' || c != d; s++)
129				if ((c = *s) == '\n')
130					return NULL;
131	return  (*s == ']') ? s : NULL;
132}
133