sys/src/libc/port/utfrrune.c

   1 #include <u.h>
   2 #include <libc.h>
   3
   4 char*
   5 utfrrune(char *s, long c)
   6 {
   7         long c1;
   8         Rune r;
   9         char *s1;
  10
  11         if(c < Runesync)                /* not part of utf sequence */
  12                 return strrchr(s, c);
  13
  14         s1 = 0;
  15         for(;;) {
  16                 c1 = *(uchar*)s;
  17                 if(c1 < Runeself) {     /* one byte rune */
  18                         if(c1 == 0)
  19                                 return s1;
  20                         if(c1 == c)
  21                                 s1 = s;
  22                         s++;
  23                         continue;
  24                 }
  25                 c1 = chartorune(&r, s);
  26                 if(r == c)
  27                         s1 = s;
  28                 s += c1;
  29         }
  30 }