sys/src/libregexp/regsub.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <regexp.h>
   4
   5 void
   6 regsub(char *src, char *dst, int dlen, Resub *match, int msize)
   7 {
   8         int i;
   9         char *ep, c;
  10
  11         ep = dst + dlen-1;
  12         for(;*src != '\0'; src++) switch(*src) {
  13         case '\\':
  14                 switch(*++src) {
  15                 case '0':
  16                 case '1':
  17                 case '2':
  18                 case '3':
  19                 case '4':
  20                 case '5':
  21                 case '6':
  22                 case '7':
  23                 case '8':
  24                 case '9':
  25                         i = *src - '0';
  26                         if(match != nil && i < msize && match[i].ep != nil) {
  27                                 c = *match[i].ep;
  28                                 *match[i].ep = '\0';
  29                                 dst = strecpy(dst, ep+1, match[i].sp);
  30                                 *match[i].ep = c;
  31                         }
  32                         break;
  33                 case '\\':
  34                         if(dst < ep)
  35                                 *dst++ = '\\';
  36                         else
  37                                 goto End;
  38                         break;
  39                 case '\0':
  40                         goto End;
  41                 default:
  42                         if(dst < ep)
  43                                 *dst++ = *src;
  44                         else
  45                                 goto End;
  46                         break;
  47                 }
  48                 break;
  49         case '&':
  50                 if(match != nil && msize > 0 && match[0].sp != nil) {
  51                         c = *match[0].ep;
  52                         *match[0].ep = '\0';
  53                         dst = strecpy(dst, ep+1, match[0].sp);
  54                         *match[0].ep = c;
  55                 }
  56                 break;
  57         default:
  58                 if(dst < ep)
  59                         *dst++ = *src;
  60                 else
  61                         goto End;
  62                 break;
  63         }
  64 End:
  65         *dst = '\0';
  66 }