glibc/wcsmbs/wcrtomb.c

93 lines
2.1 KiB
C

/* Copyright (C) 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <wchar.h>
#ifndef EILSEQ
#define EILSEQ EINVAL
#endif
static const wchar_t encoding_mask[] =
{
~0x7ff, ~0xffff, ~0x1fffff, ~0x3ffffff
};
static const unsigned char encoding_byte[] =
{
0xc0, 0xe0, 0xf0, 0xf8, 0xfc
};
/* The state is for this UTF8 encoding not used. */
static mbstate_t internal;
size_t
__wcrtomb (char *s, wchar_t wc, mbstate_t *ps)
{
char fake[1];
size_t written = 0;
if (ps == NULL)
ps = &internal;
if (s == NULL)
{
s = fake;
wc = L'\0';
}
/* Store the UTF8 representation of WC. */
if (wc < 0 || wc > 0x7fffffff)
{
/* This is no correct ISO 10646 character. */
__set_errno (EILSEQ);
return (size_t) -1;
}
if (wc < 0x80)
{
/* It's a one byte sequence. */
if (s != NULL)
*s = (char) wc;
return 1;
}
for (written = 2; written < 6; ++written)
if ((wc & encoding_mask[written - 2]) == 0)
break;
if (s != NULL)
{
size_t cnt = written;
s[0] = encoding_byte[cnt - 2];
--cnt;
do
{
s[cnt] = 0x80 | (wc & 0x3f);
wc >>= 6;
}
while (--cnt > 0);
s[0] |= wc;
}
return written;
}
weak_alias (__wcrtomb, wcrtomb)