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