sys/src/libregexp/regsub.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include "regexp.h"
   4
   5 /* substitute into one string using the matches from the last regexec() */
   6 extern  void
   7 regsub(char *sp,        /* source string */
   8         char *dp,       /* destination string */
   9         int dlen,
  10         Resub *mp,      /* subexpression elements */
  11         int ms)         /* number of elements pointed to by mp */
  12 {
  13         char *ssp, *ep;
  14         int i;
  15
  16         ep = dp+dlen-1;
  17         while(*sp != '\0'){
  18                 if(*sp == '\\'){
  19                         switch(*++sp){
  20                         case '0':
  21                         case '1':
  22                         case '2':
  23                         case '3':
  24                         case '4':
  25                         case '5':
  26                         case '6':
  27                         case '7':
  28                         case '8':
  29                         case '9':
  30                                 i = *sp-'0';
  31                                 if(mp!=0 && mp[i].sp != 0 && ms>i)
  32                                         for(ssp = mp[i].sp;
  33                                              ssp < mp[i].ep;
  34                                              ssp++)
  35                                                 if(dp < ep)
  36                                                         *dp++ = *ssp;
  37                                 break;
  38                         case '\\':
  39                                 if(dp < ep)
  40                                         *dp++ = '\\';
  41                                 break;
  42                         case '\0':
  43                                 sp--;
  44                                 break;
  45                         default:
  46                                 if(dp < ep)
  47                                         *dp++ = *sp;
  48                                 break;
  49                         }
  50                 }else if(*sp == '&'){
  51                         if(mp!=0 && mp[0].sp != 0 && ms>0)
  52                                 for(ssp = mp[0].sp;
  53                                      ssp < mp[0].ep; ssp++)
  54                                         if(dp < ep)
  55                                                 *dp++ = *ssp;
  56                 }else{
  57                         if(dp < ep)
  58                                 *dp++ = *sp;
  59                 }
  60                 sp++;
  61         }
  62         *dp = '\0';
  63 }