ref: 2cba9e1b69528c16908d8cd28854211a604cd45b
dir: /src/libc/stdlib/mbtowc.c/
#include <stdlib.h> #undef mbtowc int mbtowc(wchar_t *restrict pwc, const char *restrict s, size_t n) { unsigned char *t = (unsigned char *) s; unsigned long wc; unsigned c; size_t len; if (s == NULL) return 0; wc = c = *t++; for (len = 0; n > 0 && c & 0x80; --n, ++len) c <<= 1; if (n == 0 || len == 1 || len == 8) return -1; if (len == 0) goto return_code; for (wc = (c & 0xFF) >> len; len--; wc |= c & 0x3F) { if ((c = *t++) & 0xC0 != 0x80) return -1; wc <<= 6; } return_code: if (pwc) *pwc = wc; if (*s == '\0') return 0; return t - (unsigned char *) s; }