incubator-nuttx/libs/libc/wchar/lib_wcsnrtombs.c

124 lines
3.8 KiB
C

/****************************************************************************
* libs/libc/wchar/lib_wcsnrtombs.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <wchar.h>
#include <string.h>
#include <limits.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: wcsnrtombs
*
* Description:
* The 'wcsrtombs' function converts a string of wide characters
* indirectly pointed to by 'src' to a corresponding multibyte character
* string stored in the array pointed to by 'dst'. No more than 'len'
* bytes are written to'dst'.
*
* If 'dst' is NULL, no characters are stored.
*
* If 'dst' is not NULL, the pointer pointed to by 'src' is updated to
* point to the character after the one that conversion stopped at. If
* conversion stops because a null character is encountered, *'src' is set
* to NULL.
*
* The mbstate_t argument, 'ps', is used to keep track of the shift state.
* If it is NULL, 'wcsrtombs' uses an internal, static mbstate_t object,
* which is initialized to the initial conversion state at program startup.
*
* The 'wcsnrtombs' function behaves identically to 'wcsrtombs', except
* that conversion stops after reading at most 'nwc' characters from the
* buffer pointed to by 'src'.
*
* Returned Value:
* The 'wcsrtombs' and 'wcsnrtombs' functions return the number of bytes
* stored in the array pointed to by 'dst' (not including any terminating
* null), if successful, otherwise it returns (size_t)-1.
*
* Portability:
* 'wcsrtombs' is defined by C99 standard.
* 'wcsnrtombs' is defined by the POSIX.1-2008 standard.
****************************************************************************/
size_t wcsnrtombs(FAR char *dst, FAR const wchar_t **src, size_t nwc,
size_t len, FAR mbstate_t *ps)
{
FAR const wchar_t *ws = *src;
size_t cnt = 0;
if (dst == NULL)
{
len = 0;
}
while (ws != NULL && nwc != 0)
{
char tmp[MB_LEN_MAX];
size_t res;
if (*ws == 0)
{
ws = NULL;
break;
}
res = wcrtomb(len < MB_LEN_MAX ? tmp : dst, *ws, ps);
if ((ssize_t)res < 0)
{
cnt = res;
break;
}
if (dst != NULL)
{
if (len < MB_LEN_MAX)
{
if (res > len)
{
break;
}
memcpy(dst, tmp, res);
}
dst += res;
len -= res;
}
ws++;
nwc--;
cnt += res;
}
if (dst != NULL)
{
*src = ws;
}
return cnt;
}