src/multibyte/mbrtoc16.c

   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 }