wget/lib/unistr/u8-mbtouc-unsafe.c

151 lines
4.6 KiB
C

/* Look at first character in UTF-8 string.
Copyright (C) 1999-2002, 2006-2007, 2009-2023 Free Software Foundation, Inc.
Written by Bruno Haible <bruno@clisp.org>, 2001.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
#if defined IN_LIBUNISTRING
/* Tell unistr.h to declare u8_mbtouc_unsafe as 'extern', not
'static inline'. */
# include "unistring-notinline.h"
#endif
/* Specification. */
#include "unistr.h"
#if !HAVE_INLINE
int
u8_mbtouc_unsafe (ucs4_t *puc, const uint8_t *s, size_t n)
{
uint8_t c = *s;
if (c < 0x80)
{
*puc = c;
return 1;
}
else if (c >= 0xc2)
{
if (c < 0xe0)
{
if (n >= 2)
{
if ((s[1] ^ 0x80) < 0x40)
{
*puc = ((unsigned int) (c & 0x1f) << 6)
| (unsigned int) (s[1] ^ 0x80);
return 2;
}
/* invalid multibyte character */
}
else
{
/* incomplete multibyte character */
*puc = 0xfffd;
return 1;
}
}
else if (c < 0xf0)
{
if (n >= 3)
{
if ((s[1] ^ 0x80) < 0x40)
{
if ((s[2] ^ 0x80) < 0x40)
{
if ((c >= 0xe1 || s[1] >= 0xa0)
&& (c != 0xed || s[1] < 0xa0))
{
*puc = ((unsigned int) (c & 0x0f) << 12)
| ((unsigned int) (s[1] ^ 0x80) << 6)
| (unsigned int) (s[2] ^ 0x80);
return 3;
}
/* invalid multibyte character */
*puc = 0xfffd;
return 3;
}
/* invalid multibyte character */
*puc = 0xfffd;
return 2;
}
/* invalid multibyte character */
}
else
{
/* incomplete multibyte character */
*puc = 0xfffd;
if (n == 1 || (s[1] ^ 0x80) >= 0x40)
return 1;
else
return 2;
}
}
else if (c < 0xf8)
{
if (n >= 4)
{
if ((s[1] ^ 0x80) < 0x40)
{
if ((s[2] ^ 0x80) < 0x40)
{
if ((s[3] ^ 0x80) < 0x40)
{
if ((c >= 0xf1 || s[1] >= 0x90)
&& (c < 0xf4 || (c == 0xf4 && s[1] < 0x90))
)
{
*puc = ((unsigned int) (c & 0x07) << 18)
| ((unsigned int) (s[1] ^ 0x80) << 12)
| ((unsigned int) (s[2] ^ 0x80) << 6)
| (unsigned int) (s[3] ^ 0x80);
return 4;
}
/* invalid multibyte character */
*puc = 0xfffd;
return 4;
}
/* invalid multibyte character */
*puc = 0xfffd;
return 3;
}
/* invalid multibyte character */
*puc = 0xfffd;
return 2;
}
/* invalid multibyte character */
}
else
{
/* incomplete multibyte character */
*puc = 0xfffd;
if (n == 1 || (s[1] ^ 0x80) >= 0x40)
return 1;
else if (n == 2 || (s[2] ^ 0x80) >= 0x40)
return 2;
else
return 3;
}
}
}
/* invalid multibyte character */
*puc = 0xfffd;
return 1;
}
#endif