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: head/bin/ed/re.c 252374 2013-06-29 15:49:26Z kientzle $
  30  */
  31
  32 #include "ed.h"
  33
  34 const char *errmsg = "";
  35
  36 /* get_compiled_pattern: return pointer to compiled pattern from command
  37    buffer */
  38 pattern_t *
  39 get_compiled_pattern(void)
  40 {
  41         static pattern_t *expr = NULL;
  42         static char error[1024];
  43
  44         char *exprs;
  45         char delimiter;
  46         int n;
  47
  48         if ((delimiter = *ibufp) == ' ') {
  49                 errmsg = "invalid pattern delimiter";
  50                 return NULL;
  51         } else if (delimiter == '\n' || *++ibufp == '\n' || *ibufp == delimiter) {
  52                 if (!expr)
  53                         errmsg = "no previous pattern";
  54                 return expr;
  55         } else if ((exprs = extract_pattern(delimiter)) == NULL)
  56                 return NULL;
  57         /* buffer alloc'd && not reserved */
  58         if (expr && !patlock)
  59                 regfree(expr);
  60         else if ((expr = (pattern_t *) malloc(sizeof(pattern_t))) == NULL) {
  61                 fprintf(stderr, "%s\n", strerror(errno));
  62                 errmsg = "out of memory";
  63                 return NULL;
  64         }
  65         patlock = 0;
  66         if ((n = regcomp(expr, exprs, 0))) {
  67                 regerror(n, expr, error, sizeof error);
  68                 errmsg = error;
  69                 free(expr);
  70                 return expr = NULL;
  71         }
  72         return expr;
  73 }
  74
  75
  76 /* extract_pattern: copy a pattern string from the command buffer; return
  77    pointer to the copy */
  78 char *
  79 extract_pattern(int delimiter)
  80 {
  81         static char *lhbuf = NULL;      /* buffer */
  82         static int lhbufsz = 0;         /* buffer size */
  83
  84         char *nd;
  85         int len;
  86
  87         for (nd = ibufp; *nd != delimiter && *nd != '\n'; nd++)
  88                 switch (*nd) {
  89                 default:
  90                         break;
  91                 case '[':
  92                         if ((nd = parse_char_class(nd + 1)) == NULL) {
  93                                 errmsg = "unbalanced brackets ([])";
  94                                 return NULL;
  95                         }
  96                         break;
  97                 case '\\':
  98                         if (*++nd == '\n') {
  99                                 errmsg = "trailing backslash (\\)";
 100                                 return NULL;
 101                         }
 102                         break;
 103                 }
 104         len = nd - ibufp;
 105         REALLOC(lhbuf, lhbufsz, len + 1, NULL);
 106         memcpy(lhbuf, ibufp, len);
 107         lhbuf[len] = '\0';
 108         ibufp = nd;
 109         return (isbinary) ? NUL_TO_NEWLINE(lhbuf, len) : lhbuf;
 110 }
 111
 112
 113 /* parse_char_class: expand a POSIX character class */
 114 char *
 115 parse_char_class(char *s)
 116 {
 117         int c, d;
 118
 119         if (*s == '^')
 120                 s++;
 121         if (*s == ']')
 122                 s++;
 123         for (; *s != ']' && *s != '\n'; s++)
 124                 if (*s == '[' && ((d = *(s+1)) == '.' || d == ':' || d == '='))
 125                         for (s++, c = *++s; *s != ']' || c != d; s++)
 126                                 if ((c = *s) == '\n')
 127                                         return NULL;
 128         return  (*s == ']') ? s : NULL;
 129 }