re.c

     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	#include <sys/cdefs.h>
    30	__FBSDID("$FreeBSD: src/bin/ed/re.c,v 1.20 2003/07/20 10:24:09 ru Exp $");
    31	
    32	#include "ed.h"
    33	
    34	
    35	extern int patlock;
    36	
    37	const char *errmsg = "";
    38	
    39	/* get_compiled_pattern: return pointer to compiled pattern from command
    40	   buffer */
    41	pattern_t *
    42	get_compiled_pattern(void)
    43	{
    44		static pattern_t *expr = NULL;
    45		static char error[1024];
    46	
    47		char *exprs;
    48		char delimiter;
    49		int n;
    50	
    51		if ((delimiter = *ibufp) == ' ') {
    52			errmsg = "invalid pattern delimiter";
    53			return NULL;
    54		} else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
    55			if (!expr)
    56				errmsg = "no previous pattern";
    57			return expr;
    58		} else if ((exprs = extract_pattern(delimiter)) == NULL)
    59			return NULL;
    60		/* buffer alloc'd && not reserved */
    61		if (expr && !patlock)
    62			regfree(expr);
    63		else if ((expr = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
    64			fprintf(stderr, "%s\n", strerror(errno));
    65			errmsg = "out of memory";
    66			return NULL;
    67		}
    68		patlock = 0;
    69		if ((n = regcomp(expr, exprs, 0))) {
    70			regerror(n, expr, error, sizeof error);
    71			errmsg = error;
    72			free(expr);
    73			return expr = NULL;
    74		}
    75		return expr;
    76	}
    77	
    78	
    79	/* extract_pattern: copy a pattern string from the command buffer; return
    80	   pointer to the copy */
    81	char *
    82	extract_pattern(int delimiter)
    83	{
    84		static char *lhbuf = NULL;	/* buffer */
    85		static int lhbufsz = 0;		/* buffer size */
    86	
    87		char *nd;
    88		int len;
    89	
    90		for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
    91			switch (*nd) {
    92			default:
    93				break;
    94			case '[':
    95				if ((nd = parse_char_class(++nd)) == NULL) {
    96					errmsg = "unbalanced brackets ([])";
    97					return NULL;
    98				}
    99				break;
   100			case '\\':
   101				if (*++nd == '\n') {
   102					errmsg = "trailing backslash (\\)";
   103					return NULL;
   104				}
   105				break;
   106			}
   107		len = nd - ibufp;
   108		REALLOC(lhbuf, lhbufsz, len + 1, NULL);
   109		memcpy(lhbuf, ibufp, len);
   110		lhbuf[len] = '\0';
   111		ibufp = nd;
   112		return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
   113	}
   114	
   115	
   116	/* parse_char_class: expand a POSIX character class */
   117	char *
   118	parse_char_class(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	}