48 lines
970 B
C
48 lines
970 B
C
#include <stdlib.h>
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#include <wchar.h>
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#include <errno.h>
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#include "internal.h"
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int mbtowc(wchar_t *restrict wc, const char *restrict src, size_t n)
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{
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unsigned c;
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const unsigned char *s = (const void *)src;
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wchar_t dummy;
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if (!s) return 0;
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if (!n) goto ilseq;
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if (!wc) wc = &dummy;
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if (*s < 0x80) return !!(*wc = *s);
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if (MB_CUR_MAX==1) return (*wc = CODEUNIT(*s)), 1;
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if (*s-SA > SB-SA) goto ilseq;
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c = bittab[*s++-SA];
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/* Avoid excessive checks against n: If shifting the state n-1
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* times does not clear the high bit, then the value of n is
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* insufficient to read a character */
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if (n<4 && ((c<<(6*n-6)) & (1U<<31))) goto ilseq;
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if (OOB(c,*s)) goto ilseq;
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c = c<<6 | *s++-0x80;
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if (!(c&(1U<<31))) {
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*wc = c;
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return 2;
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}
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if (*s-0x80u >= 0x40) goto ilseq;
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c = c<<6 | *s++-0x80;
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if (!(c&(1U<<31))) {
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*wc = c;
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return 3;
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}
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if (*s-0x80u >= 0x40) goto ilseq;
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*wc = c<<6 | *s++-0x80;
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return 4;
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ilseq:
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errno = EILSEQ;
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return -1;
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}
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