re.c revision 339 
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) == ' ') {
68		sprintf(errmsg, "invalid pattern delimiter");
69		return NULL;
70	} else if (delim == '\n' || *++ibufp == '\n' || *ibufp == delim) {
71		if (!exp) sprintf(errmsg, "no previous pattern");
72		return exp;
73	} else if ((exps = getlhs(delim)) == NULL)
74		return NULL;
75	/* buffer alloc'd && not reserved */
76	if (exp && !patlock)
77		regfree(exp);
78	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
79		fprintf(stderr, "%s\n", strerror(errno));
80		sprintf(errmsg, "out of memory");
81		return NULL;
82	}
83	patlock = 0;
84	if (n = regcomp(exp, exps, 0)) {
85		regerror(n, exp, errmsg, sizeof errmsg);
86		free(exp);
87		return exp = NULL;
88	}
89	return exp;
90}
91
92
93extern int isbinary;
94
95/* getlhs: copy a pattern string from the command buffer; return pointer
96   to the copy */
97char *
98getlhs(delim)
99	int delim;
100{
101	char *nd;
102	int len;
103
104	for (nd = ibufp; *nd != delim && *nd != '\n'; nd++)
105		switch (*nd) {
106		default:
107			break;
108		case '[':
109			if ((nd = ccl(++nd)) == NULL) {
110				sprintf(errmsg, "unbalanced brackets ([])");
111				return NULL;
112			}
113			break;
114		case '\\':
115			if (*++nd == '\n') {
116				sprintf(errmsg, "trailing backslash (\\)");
117				return NULL;
118			}
119			break;
120		}
121	len = nd - ibufp;
122	CKBUF(lhbuf, lhbufsz, len + 1, NULL);
123	memcpy(lhbuf, ibufp, len);
124	lhbuf[len] = '\0';
125	ibufp = nd;
126	return (isbinary) ? nultonl(lhbuf, len) : lhbuf;
127}
128
129
130/* ccl: expand a POSIX character class */
131char *
132ccl(s)
133	char *s;
134{
135	int c, d;
136
137	if (*s == '^')
138		s++;
139	if (*s == ']')
140		s++;
141	for (; *s != ']' && *s != '\n'; s++)
142		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
143			for (s++, c = *++s; *s != ']' || c != d; s++)
144				if ((c = *s) == '\n')
145					return NULL;
146	return  (*s == ']') ? s : NULL;
147}
148