re.c revision 1057 
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 char *rcsid = "@(#)$Id: re.c,v 1.2 1993/12/14 16:19:56 alm Exp $";
31#endif /* not lint */
32
33#include "ed.h"
34
35
36extern int patlock;
37
38char errmsg[MAXPATHLEN + 40] = "";
39
40/* get_compiled_pattern: return pointer to compiled pattern from command
41   buffer */
42pattern_t *
43get_compiled_pattern()
44{
45	static pattern_t *exp = NULL;
46
47	char *exps;
48	char delimiter;
49	int n;
50
51	if ((delimiter = *ibufp) == ' ') {
52		sprintf(errmsg, "invalid pattern delimiter");
53		return NULL;
54	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
55		if (!exp) sprintf(errmsg, "no previous pattern");
56		return exp;
57	} else if ((exps = extract_pattern(delimiter)) == NULL)
58		return NULL;
59	/* buffer alloc'd && not reserved */
60	if (exp && !patlock)
61		regfree(exp);
62	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
63		fprintf(stderr, "%s\n", strerror(errno));
64		sprintf(errmsg, "out of memory");
65		return NULL;
66	}
67	patlock = 0;
68	if (n = regcomp(exp, exps, 0)) {
69		regerror(n, exp, errmsg, sizeof errmsg);
70		free(exp);
71		return exp = NULL;
72	}
73	return exp;
74}
75
76
77/* extract_pattern: copy a pattern string from the command buffer; return
78   pointer to the copy */
79char *
80extract_pattern(delimiter)
81	int delimiter;
82{
83	static char *lhbuf = NULL;	/* buffer */
84	static int lhbufsz = 0;		/* buffer size */
85
86	char *nd;
87	int len;
88
89	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
90		switch (*nd) {
91		default:
92			break;
93		case '[':
94			if ((nd = parse_char_class(++nd)) == NULL) {
95				sprintf(errmsg, "unbalanced brackets ([])");
96				return NULL;
97			}
98			break;
99		case '\\':
100			if (*++nd == '\n') {
101				sprintf(errmsg, "trailing backslash (\\)");
102				return NULL;
103			}
104			break;
105		}
106	len = nd - ibufp;
107	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
108	memcpy(lhbuf, ibufp, len);
109	lhbuf[len] = '\0';
110	ibufp = nd;
111	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
112}
113
114
115/* parse_char_class: expand a POSIX character class */
116char *
117parse_char_class(s)
118	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