673a2e0136
Implemented according to https://en.wikipedia.org/wiki/UTF-8 Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
124 lines
3.8 KiB
C
124 lines
3.8 KiB
C
/****************************************************************************
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* libs/libc/wchar/lib_wcsnrtombs.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <wchar.h>
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#include <string.h>
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#include <limits.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: wcsnrtombs
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*
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* Description:
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* The 'wcsrtombs' function converts a string of wide characters
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* indirectly pointed to by 'src' to a corresponding multibyte character
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* string stored in the array pointed to by 'dst'. No more than 'len'
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* bytes are written to'dst'.
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*
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* If 'dst' is NULL, no characters are stored.
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*
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* If 'dst' is not NULL, the pointer pointed to by 'src' is updated to
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* point to the character after the one that conversion stopped at. If
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* conversion stops because a null character is encountered, *'src' is set
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* to NULL.
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*
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* The mbstate_t argument, 'ps', is used to keep track of the shift state.
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* If it is NULL, 'wcsrtombs' uses an internal, static mbstate_t object,
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* which is initialized to the initial conversion state at program startup.
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*
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* The 'wcsnrtombs' function behaves identically to 'wcsrtombs', except
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* that conversion stops after reading at most 'nwc' characters from the
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* buffer pointed to by 'src'.
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*
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* Returned Value:
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* The 'wcsrtombs' and 'wcsnrtombs' functions return the number of bytes
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* stored in the array pointed to by 'dst' (not including any terminating
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* null), if successful, otherwise it returns (size_t)-1.
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*
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* Portability:
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* 'wcsrtombs' is defined by C99 standard.
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* 'wcsnrtombs' is defined by the POSIX.1-2008 standard.
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****************************************************************************/
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size_t wcsnrtombs(FAR char *dst, FAR const wchar_t **src, size_t nwc,
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size_t len, FAR mbstate_t *ps)
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{
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FAR const wchar_t *ws = *src;
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size_t cnt = 0;
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if (dst == NULL)
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{
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len = 0;
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}
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while (ws != NULL && nwc != 0)
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{
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char tmp[MB_LEN_MAX];
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size_t res;
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if (*ws == 0)
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{
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ws = NULL;
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break;
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}
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res = wcrtomb(len < MB_LEN_MAX ? tmp : dst, *ws, ps);
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if ((ssize_t)res < 0)
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{
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cnt = res;
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break;
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}
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if (dst != NULL)
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{
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if (len < MB_LEN_MAX)
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{
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if (res > len)
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{
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break;
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}
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memcpy(dst, tmp, res);
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}
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dst += res;
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len -= res;
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}
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ws++;
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nwc--;
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cnt += res;
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}
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if (dst != NULL)
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{
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*src = ws;
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}
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return cnt;
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}
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