xref: /freebsd/bin/ed/re.c (revision 7f3dea244c40159a41ab22da77a434d7c5b5e85a)
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
30 #if 0
31 static char * const rcsid = "@(#)re.c,v 1.6 1994/02/01 00:34:43 alm Exp";
32 #else
33 static char * const rcsid =
34   "$FreeBSD$";
35 #endif
36 #endif /* not lint */
37 
38 #include "ed.h"
39 
40 
41 extern int patlock;
42 
43 char errmsg[MAXPATHLEN + 40] = "";
44 
45 /* get_compiled_pattern: return pointer to compiled pattern from command
46    buffer */
47 pattern_t *
48 get_compiled_pattern()
49 {
50 	static pattern_t *exp = NULL;
51 
52 	char *exps;
53 	char delimiter;
54 	int n;
55 
56 	if ((delimiter = *ibufp) == ' ') {
57 		sprintf(errmsg, "invalid pattern delimiter");
58 		return NULL;
59 	} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
60 		if (!exp) sprintf(errmsg, "no previous pattern");
61 		return exp;
62 	} else if ((exps = extract_pattern(delimiter)) == NULL)
63 		return NULL;
64 	/* buffer alloc'd && not reserved */
65 	if (exp && !patlock)
66 		regfree(exp);
67 	else if ((exp = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
68 		fprintf(stderr, "%s\n", strerror(errno));
69 		sprintf(errmsg, "out of memory");
70 		return NULL;
71 	}
72 	patlock = 0;
73 	if ((n = regcomp(exp, exps, 0))) {
74 		regerror(n, exp, errmsg, sizeof errmsg);
75 		free(exp);
76 		return exp = NULL;
77 	}
78 	return exp;
79 }
80 
81 
82 /* extract_pattern: copy a pattern string from the command buffer; return
83    pointer to the copy */
84 char *
85 extract_pattern(delimiter)
86 	int delimiter;
87 {
88 	static char *lhbuf = NULL;	/* buffer */
89 	static int lhbufsz = 0;		/* buffer size */
90 
91 	char *nd;
92 	int len;
93 
94 	for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
95 		switch (*nd) {
96 		default:
97 			break;
98 		case '[':
99 			if ((nd = parse_char_class(++nd)) == NULL) {
100 				sprintf(errmsg, "unbalanced brackets ([])");
101 				return NULL;
102 			}
103 			break;
104 		case '\\':
105 			if (*++nd == '\n') {
106 				sprintf(errmsg, "trailing backslash (\\)");
107 				return NULL;
108 			}
109 			break;
110 		}
111 	len = nd - ibufp;
112 	REALLOC(lhbuf, lhbufsz, len + 1, NULL);
113 	memcpy(lhbuf, ibufp, len);
114 	lhbuf[len] = '\0';
115 	ibufp = nd;
116 	return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
117 }
118 
119 
120 /* parse_char_class: expand a POSIX character class */
121 char *
122 parse_char_class(s)
123 	char *s;
124 {
125 	int c, d;
126 
127 	if (*s == '^')
128 		s++;
129 	if (*s == ']')
130 		s++;
131 	for (; *s != ']' && *s != '\n'; s++)
132 		if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
133 			for (s++, c = *++s; *s != ']' || c != d; s++)
134 				if ((c = *s) == '\n')
135 					return NULL;
136 	return  (*s == ']') ? s : NULL;
137 }
138