re.c revision 17 
1/* re.c: This file contains the regular expression interface routines for
2   the ed line editor. */
3/*-
4 * Copyright (c) 1993 The Regents of the University of California.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley
8 * by Andrew Moore, Talke Studio.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *	This product includes software developed by the University of
21 *	California, Berkeley and its contributors.
22 * 4. Neither the name of the University nor the names of its contributors
23 *    may be used to endorse or promote products derived from this software
24 *    without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39#ifndef lint
40static char sccsid[] = "@(#)re.c	5.5 (Berkeley) 3/28/93";
41#endif /* not lint */
42
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46
47#include "ed.h"
48
49extern char *lhbuf;
50extern int lhbufsz;
51extern char *ibufp;
52extern int ibufsz;
53extern int patlock;
54
55char errmsg[MAXFNAME + 40] = "";
56
57/* optpat: return pointer to compiled pattern from command buffer */
58pattern_t *
59optpat()
60{
61	static pattern_t *exp = NULL;
62
63	char *exps;
64	char delim;
65	int n;
66
67	if ((delim = *ibufp) == '\n') {
68		if (!exp) sprintf(errmsg, "no previous pattern");
69		return exp;
70	} else if (delim == ' ' || *++ibufp == '\n') {
71		sprintf(errmsg, "invalid pattern delimiter");
72		return NULL;
73	} else if (*ibufp == delim) {
74		sprintf(errmsg, "no previous pattern");
75		return exp;
76	} else if ((exps = getlhs(delim)) == NULL)
77		return NULL;
78	/* buffer alloc'd && not reserved */
79	if (exp && !patlock)
80		regfree(exp);
81	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
82		fprintf(stderr, "%s\n", strerror(errno));
83		sprintf(errmsg, "out of memory");
84		return NULL;
85	}
86	patlock = 0;
87#ifdef GNU_REGEX
88	/* initialize pattern buffer */
89	exp->buffer = NULL;
90	exp->allocated = 0L;
91	exp->fastmap = 0;		/* not used by GNU regex after 0.12 */
92	exp->translate = 0;
93#endif
94	if (n = regcomp(exp, exps, 0)) {
95		regerror(n, exp, errmsg, sizeof errmsg);
96		return NULL;
97	}
98	return exp;
99}
100
101
102extern int isbinary;
103
104/* getlhs: copy a pattern string from the command buffer; return pointer
105   to the copy */
106char *
107getlhs(delim)
108	int delim;
109{
110	char *nd;
111	int len;
112
113	for (nd = ibufp; *nd != delim && *nd != '\n'; nd++)
114		switch (*nd) {
115		default:
116			break;
117		case '[':
118			if ((nd = ccl(++nd)) == NULL) {
119				sprintf(errmsg, "unbalanced brackets ([])");
120				return NULL;
121			}
122			break;
123		case '\\':
124			if (*++nd == '\n') {
125				sprintf(errmsg, "trailing backslash (\\)");
126				return NULL;
127			}
128			break;
129		}
130	len = nd - ibufp;
131	CKBUF(lhbuf, lhbufsz, len + 1, NULL);
132	memcpy(lhbuf, ibufp, len);
133	lhbuf[len] = '\0';
134	ibufp = nd;
135	return (isbinary) ? nultonl(lhbuf, len) : lhbuf;
136}
137
138
139/* ccl: expand a POSIX character class */
140char *
141ccl(s)
142	char *s;
143{
144	int c, d;
145
146	if (*s == '^')
147		s++;
148	if (*s == ']')
149		s++;
150	for (; *s != ']' && *s != '\n'; s++)
151		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
152			for (s++, c = *++s; *s != ']' || c != d; s++)
153				if ((c = *s) == '\n')
154					return NULL;
155	return  (*s == ']') ? s : NULL;
156}
157