1 /* 2 * This code was written by Rich Felker in 2010; no copyright is claimed. 3 * This code is in the public domain. Attribution is appreciated but 4 * unnecessary. 5 */ 6 7 #include <stdlib.h> 8 #include <inttypes.h> 9 #include <wchar.h> 10 #include <errno.h> 11 12 #include "internal.h" 13 #include <stdio.h> mbtowc(wchar_t * restrict wc,const char * restrict src,size_t n)14int mbtowc(wchar_t *restrict wc, const char *restrict src, size_t n) 15 { 16 unsigned c; 17 const unsigned char *s = (const void *)src; 18 19 if (!s) return 0; 20 if (!n) goto ilseq; 21 if (!wc) wc = (void *)&wc; 22 23 if (*s < 0x80) return !!(*wc = *s); 24 if (*s-SA > SB-SA) goto ilseq; 25 c = bittab[*s++-SA]; 26 27 /* Avoid excessive checks against n: If shifting the state n-1 28 * times does not clear the high bit, then the value of n is 29 * insufficient to read a character */ 30 if (n<4 && ((c<<(6*n-6)) & (1U<<31))) goto ilseq; 31 32 if (OOB(c,*s)) goto ilseq; 33 c = c<<6 | *s++-0x80; 34 if (!(c&(1U<<31))) { 35 *wc = c; 36 return 2; 37 } 38 39 if (*s-0x80u >= 0x40) goto ilseq; 40 c = c<<6 | *s++-0x80; 41 if (!(c&(1U<<31))) { 42 *wc = c; 43 return 3; 44 } 45 46 if (*s-0x80u >= 0x40) goto ilseq; 47 *wc = c<<6 | *s++-0x80; 48 return 4; 49 50 ilseq: 51 errno = EILSEQ; 52 return -1; 53 } 54