c16rtomb.c raw

   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  }
  36