cosmopolitan/libc/str/mbtowc.c
Justine Tunney 0d748ad58e
Fix warnings
This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.
2023-09-01 20:50:18 -07:00

71 lines
3.7 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 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 "libc/errno.h"
#include "libc/limits.h"
#include "libc/str/mb.internal.h"
#include "libc/str/str.h"
asm(".ident\t\"\\n\\n\
Musl libc (MIT License)\\n\
Copyright 2005-2014 Rich Felker, et. al.\"");
asm(".include \"libc/disclaimer.inc\"");
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 = kMbBittab[*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;
}