1 /*
2 * The authors of this software are Rob Pike and Ken Thompson.
3 * Copyright (c) 2002 by Lucent Technologies.
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose without fee is hereby granted, provided that this entire notice
6 * is included in all copies of any software which is or includes a copy
7 * or modification of this software and in all copies of the supporting
8 * documentation for such software.
9 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
10 * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
11 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
12 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
13 */
14 #include <stdarg.h>
15 #include <string.h>
16 #include "utf.h"
17 #include "utfdef.h"
18
19 const
20 char*
utfrrune(const char * s,Rune c)21 utfrrune(const char *s, Rune c)
22 {
23 long c1;
24 Rune r;
25 const char *s1;
26
27 if(c < Runesync) /* not part of utf sequence */
28 return strrchr(s, c);
29
30 s1 = 0;
31 for(;;) {
32 c1 = *(uchar*)s;
33 if(c1 < Runeself) { /* one byte rune */
34 if(c1 == 0)
35 return s1;
36 if(c1 == c)
37 s1 = s;
38 s++;
39 continue;
40 }
41 c1 = chartorune(&r, s);
42 if(r == c)
43 s1 = s;
44 s += c1;
45 }
46 return 0;
47 }
48