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#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;
}
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