utfrune.c (1204B)
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 <stdarg.h> 15 #include <string.h> 16 #include "plan9.h" 17 #include "utf.h" 18 19 char* 20 utfrune(const char *s, long c) 21 { 22 long c1; 23 Rune r; 24 int n; 25 26 if(c < Runesync) /* not part of utf sequence */ 27 return strchr(s, c); 28 29 for(;;) { 30 c1 = *(uchar*)s; 31 if(c1 < Runeself) { /* one byte rune */ 32 if(c1 == 0) 33 return 0; 34 if(c1 == c) 35 return (char*)s; 36 s++; 37 continue; 38 } 39 n = chartorune(&r, s); 40 if(r == c) 41 return (char*)s; 42 s += n; 43 } 44 }