mbrtoc16.c raw

   1  #include <uchar.h>
   2  #include <wchar.h>
   3  
   4  size_t mbrtoc16(char16_t *restrict pc16, const char *restrict s, size_t n, mbstate_t *restrict ps)
   5  {
   6  	static unsigned internal_state;
   7  	if (!ps) ps = (void *)&internal_state;
   8  	unsigned *pending = (unsigned *)ps;
   9  
  10  	if (!s) return mbrtoc16(0, "", 1, ps);
  11  
  12  	/* mbrtowc states for partial UTF-8 characters have the high bit set;
  13  	 * we use nonzero states without high bit for pending surrogates. */
  14  	if ((int)*pending > 0) {
  15   		if (pc16) *pc16 = *pending;
  16  		*pending = 0;
  17  		return -3;
  18  	}
  19  
  20  	wchar_t wc;
  21  	size_t ret = mbrtowc(&wc, s, n, ps);
  22  	if (ret <= 4) {
  23  		if (wc >= 0x10000) {
  24  			*pending = (wc & 0x3ff) + 0xdc00;
  25  			wc = 0xd7c0 + (wc >> 10);
  26  		}
  27  		if (pc16) *pc16 = wc;
  28  	}
  29  	return ret;
  30  }
  31