bin/ed/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  * @(#)re.c,v 1.6 1994/02/01 00:34:43 alm Exp
  29  * $FreeBSD: src/bin/ed/re.c,v 1.20 2003/07/20 10:24:09 ru Exp $
  30  * $DragonFly: src/bin/ed/re.c,v 1.4 2007/04/06 23:36:54 pavalos Exp $
  31  */
  32
  33 #include "ed.h"
  34
  35
  36 extern int patlock;
  37
  38 const char *errmsg = "";
  39
  40 /* get_compiled_pattern: return pointer to compiled pattern from command
  41    buffer */
  42 pattern_t *
  43 get_compiled_pattern(void)
  44 {
  45         static pattern_t *expr = NULL;
  46         static char error[1024];
  47
  48         char *exprs;
  49         char delimiter;
  50         int n;
  51
  52         if ((delimiter = *ibufp) == ' ') {
  53                 errmsg = "invalid pattern delimiter";
  54                 return NULL;
  55         } else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
  56                 if (!expr)
  57                         errmsg = "no previous pattern";
  58                 return expr;
  59         } else if ((exprs = extract_pattern(delimiter)) == NULL)
  60                 return NULL;
  61         /* buffer alloc'd && not reserved */
  62         if (expr && !patlock)
  63                 regfree(expr);
  64         else if ((expr = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
  65                 fprintf(stderr, "%s\n", strerror(errno));
  66                 errmsg = "out of memory";
  67                 return NULL;
  68         }
  69         patlock = 0;
  70         if ((n = regcomp(expr, exprs, 0))) {
  71                 regerror(n, expr, error, sizeof error);
  72                 errmsg = error;
  73                 free(expr);
  74                 return expr = NULL;
  75         }
  76         return expr;
  77 }
  78
  79
  80 /* extract_pattern: copy a pattern string from the command buffer; return
  81    pointer to the copy */
  82 char *
  83 extract_pattern(int delimiter)
  84 {
  85         static char *lhbuf = NULL;      /* buffer */
  86         static int lhbufsz = 0;         /* buffer size */
  87
  88         char *nd;
  89         int len;
  90
  91         for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
  92                 switch (*nd) {
  93                 default:
  94                         break;
  95                 case '[':
  96                         if ((nd = parse_char_class(++nd)) == NULL) {
  97                                 errmsg = "unbalanced brackets ([])";
  98                                 return NULL;
  99                         }
 100                         break;
 101                 case '\\':
 102                         if (*++nd == '\n') {
 103                                 errmsg = "trailing backslash (\\)";
 104                                 return NULL;
 105                         }
 106                         break;
 107                 }
 108         len = nd - ibufp;
 109         REALLOC(lhbuf, lhbufsz, len + 1, NULL);
 110         memcpy(lhbuf, ibufp, len);
 111         lhbuf[len] = '\0';
 112         ibufp = nd;
 113         return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
 114 }
 115
 116
 117 /* parse_char_class: expand a POSIX character class */
 118 char *
 119 parse_char_class(char *s)
 120 {
 121         int c, d;
 122
 123         if (*s == '^')
 124                 s++;
 125         if (*s == ']')
 126                 s++;
 127         for (; *s != ']' && *s != '\n'; s++)
 128                 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
 129                         for (s++, c = *++s; *s != ']' || c != d; s++)
 130                                 if ((c = *s) == '\n')
 131                                         return NULL;
 132         return  (*s == ']') ? s : NULL;
 133 }