/*-*- mode:c;indent-tabs-mode:t;c-basic-offset:8;tab-width:8;coding:utf-8   -*-│
│ vi: set noet ft=c ts=8 sw=8 fenc=utf-8                                   :vi │
╚──────────────────────────────────────────────────────────────────────────────╝
│                                                                              │
│  Musl Libc                                                                   │
│  Copyright © 2005-2014 Rich Felker, et al.                                   │
│                                                                              │
│  Permission is hereby granted, free of charge, to any person obtaining       │
│  a copy of this software and associated documentation files (the             │
│  "Software"), to deal in the Software without restriction, including         │
│  without limitation the rights to use, copy, modify, merge, publish,         │
│  distribute, sublicense, and/or sell copies of the Software, and to          │
│  permit persons to whom the Software is furnished to do so, subject to       │
│  the following conditions:                                                   │
│                                                                              │
│  The above copyright notice and this permission notice shall be              │
│  included in all copies or substantial portions of the Software.             │
│                                                                              │
│  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
│  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
│  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
│  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
│  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
│  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
│  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
│                                                                              │
╚─────────────────────────────────────────────────────────────────────────────*/
#include <stdlib.h>
#include <wchar.h>
#include <errno.h>
#include "multibyte.h"
__static_yoink("musl_libc_notice");

#pragma GCC diagnostic ignored "-Wparentheses"

int mbtowc(wchar_t *restrict wc, const char *restrict src, size_t n)
{
	unsigned c;
	const unsigned char *s = (const void *)src;
	wchar_t dummy;

	if (!s) return 0;
	if (!n) goto ilseq;
	if (!wc) wc = &dummy;

	if (*s < 0x80) return !!(*wc = *s);
	if (MB_CUR_MAX==1) return (*wc = CODEUNIT(*s)), 1;
	if (*s-SA > SB-SA) goto ilseq;
	c = bittab[*s++-SA];

	/* Avoid excessive checks against n: If shifting the state n-1
	 * times does not clear the high bit, then the value of n is
	 * insufficient to read a character */
	if (n<4 && ((c<<(6*n-6)) & (1U<<31))) goto ilseq;

	if (OOB(c,*s)) goto ilseq;
	c = c<<6 | *s++-0x80;
	if (!(c&(1U<<31))) {
		*wc = c;
		return 2;
	}

	if (*s-0x80u >= 0x40) goto ilseq;
	c = c<<6 | *s++-0x80;
	if (!(c&(1U<<31))) {
		*wc = c;
		return 3;
	}

	if (*s-0x80u >= 0x40) goto ilseq;
	*wc = c<<6 | *s++-0x80;
	return 4;

ilseq:
	errno = EILSEQ;
	return -1;
}