xref: /aosp_15_r20/external/musl/src/multibyte/mbrtowc.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include <stdlib.h>
2*c9945492SAndroid Build Coastguard Worker #include <wchar.h>
3*c9945492SAndroid Build Coastguard Worker #include <errno.h>
4*c9945492SAndroid Build Coastguard Worker #include "internal.h"
5*c9945492SAndroid Build Coastguard Worker 
mbrtowc(wchar_t * restrict wc,const char * restrict src,size_t n,mbstate_t * restrict st)6*c9945492SAndroid Build Coastguard Worker size_t mbrtowc(wchar_t *restrict wc, const char *restrict src, size_t n, mbstate_t *restrict st)
7*c9945492SAndroid Build Coastguard Worker {
8*c9945492SAndroid Build Coastguard Worker 	static unsigned internal_state;
9*c9945492SAndroid Build Coastguard Worker 	unsigned c;
10*c9945492SAndroid Build Coastguard Worker 	const unsigned char *s = (const void *)src;
11*c9945492SAndroid Build Coastguard Worker 	const size_t N = n;
12*c9945492SAndroid Build Coastguard Worker 	wchar_t dummy;
13*c9945492SAndroid Build Coastguard Worker 
14*c9945492SAndroid Build Coastguard Worker 	if (!st) st = (void *)&internal_state;
15*c9945492SAndroid Build Coastguard Worker 	c = *(unsigned *)st;
16*c9945492SAndroid Build Coastguard Worker 
17*c9945492SAndroid Build Coastguard Worker 	if (!s) {
18*c9945492SAndroid Build Coastguard Worker 		if (c) goto ilseq;
19*c9945492SAndroid Build Coastguard Worker 		return 0;
20*c9945492SAndroid Build Coastguard Worker 	} else if (!wc) wc = &dummy;
21*c9945492SAndroid Build Coastguard Worker 
22*c9945492SAndroid Build Coastguard Worker 	if (!n) return -2;
23*c9945492SAndroid Build Coastguard Worker 	if (!c) {
24*c9945492SAndroid Build Coastguard Worker 		if (*s < 0x80) return !!(*wc = *s);
25*c9945492SAndroid Build Coastguard Worker 		if (MB_CUR_MAX==1) return (*wc = CODEUNIT(*s)), 1;
26*c9945492SAndroid Build Coastguard Worker 		if (*s-SA > SB-SA) goto ilseq;
27*c9945492SAndroid Build Coastguard Worker 		c = bittab[*s++-SA]; n--;
28*c9945492SAndroid Build Coastguard Worker 	}
29*c9945492SAndroid Build Coastguard Worker 
30*c9945492SAndroid Build Coastguard Worker 	if (n) {
31*c9945492SAndroid Build Coastguard Worker 		if (OOB(c,*s)) goto ilseq;
32*c9945492SAndroid Build Coastguard Worker loop:
33*c9945492SAndroid Build Coastguard Worker 		c = c<<6 | *s++-0x80; n--;
34*c9945492SAndroid Build Coastguard Worker 		if (!(c&(1U<<31))) {
35*c9945492SAndroid Build Coastguard Worker 			*(unsigned *)st = 0;
36*c9945492SAndroid Build Coastguard Worker 			*wc = c;
37*c9945492SAndroid Build Coastguard Worker 			return N-n;
38*c9945492SAndroid Build Coastguard Worker 		}
39*c9945492SAndroid Build Coastguard Worker 		if (n) {
40*c9945492SAndroid Build Coastguard Worker 			if (*s-0x80u >= 0x40) goto ilseq;
41*c9945492SAndroid Build Coastguard Worker 			goto loop;
42*c9945492SAndroid Build Coastguard Worker 		}
43*c9945492SAndroid Build Coastguard Worker 	}
44*c9945492SAndroid Build Coastguard Worker 
45*c9945492SAndroid Build Coastguard Worker 	*(unsigned *)st = c;
46*c9945492SAndroid Build Coastguard Worker 	return -2;
47*c9945492SAndroid Build Coastguard Worker ilseq:
48*c9945492SAndroid Build Coastguard Worker 	*(unsigned *)st = 0;
49*c9945492SAndroid Build Coastguard Worker 	errno = EILSEQ;
50*c9945492SAndroid Build Coastguard Worker 	return -1;
51*c9945492SAndroid Build Coastguard Worker }
52