text_cmds/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
  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 }