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re.c revision 1.13 
      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 static char *rcsid = "@(#)re.c,v 1.6 1994/02/01 00:34:43 alm Exp";
     31 #endif /* not lint */
     32 
     33 #include "ed.h"
     34 
     35 
     36 extern int patlock;
     37 
     38 char errmsg[MAXPATHLEN + 40] = "";
     39 
     40 /* get_compiled_pattern: return pointer to compiled pattern from command
     41    buffer */
     42 pattern_t *
     43 get_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 */
     79 char *
     80 extract_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 */
    116 char *
    117 parse_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