1#include <stdint.h>
2#include <wchar.h>
3#include <errno.h>
4#include <string.h>
5#include <stdlib.h>
6#include "internal.h"
7
8size_t mbsrtowcs(wchar_t *restrict ws, const char **restrict src, size_t wn, mbstate_t *restrict st)
9{
10	const unsigned char *s = (const void *)*src;
11	size_t wn0 = wn;
12	unsigned c = 0;
13
14	if (st && (c = *(unsigned *)st)) {
15		if (ws) {
16			*(unsigned *)st = 0;
17			goto resume;
18		} else {
19			goto resume0;
20		}
21	}
22
23	if (MB_CUR_MAX==1) {
24		if (!ws) return strlen((const char *)s);
25		for (;;) {
26			if (!wn) {
27				*src = (const void *)s;
28				return wn0;
29			}
30			if (!*s) break;
31			c = *s++;
32			*ws++ = CODEUNIT(c);
33			wn--;
34		}
35		*ws = 0;
36		*src = 0;
37		return wn0-wn;
38	}
39
40	if (!ws) for (;;) {
41		if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
42			while (!(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
43				s += 4;
44				wn -= 4;
45			}
46		}
47		if (*s-1u < 0x7f) {
48			s++;
49			wn--;
50			continue;
51		}
52		if (*s-SA > SB-SA) break;
53		c = bittab[*s++-SA];
54resume0:
55		if (OOB(c,*s)) { s--; break; }
56		s++;
57		if (c&(1U<<25)) {
58			if (*s-0x80u >= 0x40) { s-=2; break; }
59			s++;
60			if (c&(1U<<19)) {
61				if (*s-0x80u >= 0x40) { s-=3; break; }
62				s++;
63			}
64		}
65		wn--;
66		c = 0;
67	} else for (;;) {
68		if (!wn) {
69			*src = (const void *)s;
70			return wn0;
71		}
72		if (*s-1u < 0x7f && (uintptr_t)s%4 == 0) {
73			while (wn>=5 && !(( *(uint32_t*)s | *(uint32_t*)s-0x01010101) & 0x80808080)) {
74				*ws++ = *s++;
75				*ws++ = *s++;
76				*ws++ = *s++;
77				*ws++ = *s++;
78				wn -= 4;
79			}
80		}
81		if (*s-1u < 0x7f) {
82			*ws++ = *s++;
83			wn--;
84			continue;
85		}
86		if (*s-SA > SB-SA) break;
87		c = bittab[*s++-SA];
88resume:
89		if (OOB(c,*s)) { s--; break; }
90		c = (c<<6) | *s++-0x80;
91		if (c&(1U<<31)) {
92			if (*s-0x80u >= 0x40) { s-=2; break; }
93			c = (c<<6) | *s++-0x80;
94			if (c&(1U<<31)) {
95				if (*s-0x80u >= 0x40) { s-=3; break; }
96				c = (c<<6) | *s++-0x80;
97			}
98		}
99		*ws++ = c;
100		wn--;
101		c = 0;
102	}
103
104	if (!c && !*s) {
105		if (ws) {
106			*ws = 0;
107			*src = 0;
108		}
109		return wn0-wn;
110	}
111	errno = EILSEQ;
112	if (ws) *src = (const void *)s;
113	return -1;
114}
115