src/multibyte/c16rtomb.c

   1 #include <uchar.h>
   2 #include <errno.h>
   3 #include <wchar.h>
   4
   5 size_t c16rtomb(char *restrict s, char16_t c16, mbstate_t *restrict ps)
   6 {
   7         static unsigned internal_state;
   8         if (!ps) ps = (void *)&internal_state;
   9         unsigned *x = (unsigned *)ps;
  10         wchar_t wc;
  11
  12         if (!s) {
  13                 if (*x) goto ilseq;
  14                 return 1;
  15         }
  16
  17         if (!*x && c16 - 0xd800u < 0x400) {
  18                 *x = c16 - 0xd7c0 << 10;
  19                 return 0;
  20         }
  21
  22         if (*x) {
  23                 if (c16 - 0xdc00u >= 0x400) goto ilseq;
  24                 else wc = *x + c16 - 0xdc00;
  25                 *x = 0;
  26         } else {
  27                 wc = c16;
  28         }
  29         return wcrtomb(s, wc, 0);
  30
  31 ilseq:
  32         *x = 0;
  33         errno = EILSEQ;
  34         return -1;
  35 }