utfrrune.c (1206B)
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 11 * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY 12 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. 13 */ 14 #include "plan9.h" 15 #include "utf.h" 16 17 #include <stdarg.h> 18 #include <string.h> 19 20 char* utfrrune(char* s, long c) { 21 long c1; 22 Rune r; 23 char* s1; 24 25 if (c < Runesync) /* not part of utf sequence */ 26 return strrchr(s, c); 27 28 s1 = 0; 29 for (;;) { 30 c1 = *(uchar*) s; 31 if (c1 < Runeself) { /* one byte rune */ 32 if (c1 == 0) 33 return s1; 34 if (c1 == c) 35 s1 = s; 36 s++; 37 continue; 38 } 39 c1 = chartorune(&r, s); 40 if (r == c) 41 s1 = s; 42 s += c1; 43 } 44 }