lib/libcompat/regexp/regsub.c

   1 /*
   2  * regsub
   3  *
   4  *      Copyright (c) 1986 by University of Toronto.
   5  *      Written by Henry Spencer.  Not derived from licensed software.
   6  *
   7  *      Permission is granted to anyone to use this software for any
   8  *      purpose on any computer system, and to redistribute it freely,
   9  *      subject to the following restrictions:
  10  *
  11  *      1. The author is not responsible for the consequences of use of
  12  *              this software, no matter how awful, even if they arise
  13  *              from defects in it.
  14  *
  15  *      2. The origin of this software must not be misrepresented, either
  16  *              by explicit claim or by omission.
  17  *
  18  *      3. Altered versions must be plainly marked as such, and must not
  19  *              be misrepresented as being the original software.
  20  */
  21
  22 #include <sys/cdefs.h>
  23 #if defined(LIBC_SCCS) && !defined(lint)
  24 __RCSID("$NetBSD: regsub.c,v 1.8 1999/05/06 17:09:31 christos Exp $");
  25 #endif /* LIBC_SCCS and not lint */
  26
  27 #include <regexp.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include "regmagic.h"
  31
  32 #ifndef CHARBITS
  33 #define UCHARAT(p)      ((int)*(unsigned char *)(p))
  34 #else
  35 #define UCHARAT(p)      ((int)*(p)&CHARBITS)
  36 #endif
  37
  38 /*
  39  - regsub - perform substitutions after a regexp match
  40  */
  41 void
  42 __compat_regsub(prog, source, dest)
  43 const regexp *prog;
  44 const char *source;
  45 char *dest;
  46 {
  47         char *src;
  48         char *dst;
  49         char c;
  50         int no;
  51         int len;
  52
  53         if (prog == NULL || source == NULL || dest == 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
  62         /* LINTED const castaway */
  63         src = (char *)source;
  64         dst = dest;
  65         while ((c = *src++) != '\0') {
  66                 if (c == '&')
  67                         no = 0;
  68                 else if (c == '\\' && '0' <= *src && *src <= '9')
  69                         no = *src++ - '0';
  70                 else
  71                         no = -1;
  72                 if (no < 0) {   /* Ordinary character. */
  73                         if (c == '\\' && (*src == '\\' || *src == '&'))
  74                                 c = *src++;
  75                         *dst++ = c;
  76                 } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
  77                         len = prog->endp[no] - prog->startp[no];
  78                         (void) strncpy(dst, prog->startp[no], (size_t)len);
  79                         dst += len;
  80                         if (len != 0 && *(dst-1) == '\0') {     /* strncpy hit NUL. */
  81                                 regerror("damaged match string");
  82                                 return;
  83                         }
  84                 }
  85         }
  86         *dst++ = '\0';
  87 }