lib/other/v8regsub.c

   1 /* regsub
   2  *
   3  *      Copyright (c) 1986 by University of Toronto.
   4  *      Written by Henry Spencer.  Not derived from licensed software.
   5  *
   6  *      Permission is granted to anyone to use this software for any
   7  *      purpose on any computer system, and to redistribute it freely,
   8  *      subject to the following restrictions:
   9  *
  10  *      1. The author is not responsible for the consequences of use of
  11  *              this software, no matter how awful, even if they arise
  12  *              from defects in it.
  13  *
  14  *      2. The origin of this software must not be misrepresented, either
  15  *              by explicit claim or by omission.
  16  *
  17  *      3. Altered versions must be plainly marked as such, and must not
  18  *              be misrepresented as being the original software.
  19  */
  20
  21 #include <string.h>
  22 #include <stdio.h>
  23 #define const           /* avoid "const poisoning" */
  24 #include <regexp.h>
  25 #undef const
  26
  27 /* The first byte of the regexp internal "program" is actually this magic
  28  * number; the start node begins in the second byte.
  29  */
  30 #define MAGIC   0234
  31
  32 #define CHARBITS 0377
  33 #ifndef CHARBITS
  34 #define UCHARAT(p)      ((int)*(unsigned char *)(p))
  35 #else
  36 #define UCHARAT(p)      ((int)*(p)&CHARBITS)
  37 #endif
  38
  39 /*
  40  - regsub - perform substitutions after a regexp match
  41  */
  42 void regsub(prog, source, dest)
  43 regexp *prog;
  44 char *source;
  45 char *dest;
  46 {
  47   register char *src;
  48   register char *dst;
  49   register char c;
  50   register int no;
  51   register int len;
  52
  53   if (prog == (regexp *)NULL || source == (char *)NULL || dest == (char *)NULL) {
  54         regerror("NULL parm to regsub");
  55         return;
  56   }
  57   if (UCHARAT(prog->program) != MAGIC) {
  58         regerror("damaged regexp fed to regsub");
  59         return;
  60   }
  61   src = source;
  62   dst = dest;
  63   while ((c = *src++) != '\0') {
  64         if (c == '&')
  65                 no = 0;
  66         else if (c == '\\' && '0' <= *src && *src <= '9')
  67                 no = *src++ - '0';
  68         else
  69                 no = -1;
  70
  71         if (no < 0) {           /* Ordinary character. */
  72                 if (c == '\\' && (*src == '\\' || *src == '&')) c = *src++;
  73                 *dst++ = c;
  74         } else
  75         if (prog->startp[no] != (char *)NULL && prog->endp[no] != (char *)NULL) {
  76                 len = (int) (prog->endp[no] - prog->startp[no]);
  77                 strncpy(dst, prog->startp[no], len);
  78                 dst += len;
  79                 if (len != 0 && *(dst - 1) == '\0') {   /* strncpy hit NUL. */
  80                         regerror("damaged match string");
  81                         return;
  82                 }
  83         }
  84   }
  85   *dst++ = '\0';
  86 }
  87
  88 /*
  89  * $PchId: regsub.c,v 1.3 1995/11/27 20:18:16 philip Exp $
  90  */