1 #include <uchar.h>
2 #include <errno.h>
3 #include <wchar.h>
4 
c16rtomb(char * restrict s,char16_t c16,mbstate_t * restrict ps)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