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/* * This code was written by Rich Felker in 2010; no copyright is claimed. * This code is in the public domain. Attribution is appreciated but * unnecessary. */ #include <stdlib.h> #include <wchar.h> #include <errno.h> #include "internal.h" int mbtowc(wchar_t *restrict wc, const char *restrict src, size_t n) { unsigned c; const unsigned char *s = (const void *)src; wchar_t dummy; if (!s) return 0; if (!n) goto ilseq; if (!wc) wc = &dummy; if (*s < 0x80) return !!(*wc = *s); if (MB_CUR_MAX==1) return (*wc = CODEUNIT(*s)), 1; if (*s-SA > SB-SA) goto ilseq; c = bittab[*s++-SA]; /* Avoid excessive checks against n: If shifting the state n-1 * times does not clear the high bit, then the value of n is * insufficient to read a character */ if (n<4 && ((c<<(6*n-6)) & (1U<<31))) goto ilseq; if (OOB(c,*s)) goto ilseq; c = c<<6 | *s++-0x80; if (!(c&(1U<<31))) { *wc = c; return 2; } if (*s-0x80u >= 0x40) goto ilseq; c = c<<6 | *s++-0x80; if (!(c&(1U<<31))) { *wc = c; return 3; } if (*s-0x80u >= 0x40) goto ilseq; *wc = c<<6 | *s++-0x80; return 4; ilseq: errno = EILSEQ; return -1; } |