nuttx/libs/libc/wchar/lib_wcrtomb.c
Jiuzhu Dong 673a2e0136 libc/wchar: support wchar
Implemented according to https://en.wikipedia.org/wiki/UTF-8

Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
2022-07-27 00:36:49 +08:00

88 lines
3.1 KiB
C

/****************************************************************************
* libs/libc/wchar/lib_wcrtomb.c
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <wchar.h>
#include <errno.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: wcrtomb
*
* Description:
* Convert a wide character to a multibyte sequence
*
****************************************************************************/
size_t wcrtomb(FAR char *s, wchar_t wc, FAR mbstate_t *ps)
{
if (s == NULL)
{
return 0;
}
else if ((unsigned)wc < 0x80)
{
*s = wc;
return 1;
}
else if ((unsigned)wc < 0x800)
{
*s++ = 0xc0 | (wc >> 6);
*s = 0x80 | (wc & 0x3f);
return 2;
}
else if ((unsigned)wc < 0xd800 || (unsigned)wc <= 0xffff)
{
*s++ = 0xe0 | (wc >> 12);
*s++ = 0x80 | ((wc >> 6) & 0x3f);
*s = 0x80 | (wc & 0x3f);
return 3;
}
else if ((unsigned long)wc < 0x110000)
{
*s++ = 0xf0 | ((unsigned long)wc >> 18);
*s++ = 0x80 | ((wc >> 12) & 0x3f);
*s++ = 0x80 | ((wc >> 6) & 0x3f);
*s = 0x80 | (wc & 0x3f);
return 4;
}
set_errno(EILSEQ);
return -1;
}