673a2e0136
Implemented according to https://en.wikipedia.org/wiki/UTF-8 Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
125 lines
3.9 KiB
C
125 lines
3.9 KiB
C
/****************************************************************************
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* libs/libc/wchar/lib_mbsnrtowcs.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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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: mbsnrtowcs
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*
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* Description:
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* The 'mbsrtowcs' function converts a sequence of multibyte characters
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* pointed to indirectly by 'src' into a sequence of corresponding wide
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* characters and stores at most 'len' of them in the wchar_t array pointed
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* to by 'dst', until it encounters a terminating null character ('\0').
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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, 'mbsrtowcs' 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 'mbsnrtowcs' function behaves identically to 'mbsrtowcs', except
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* that conversion stops after reading at most 'nms' bytes from the buffer
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* pointed to by 'src'.
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*
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* Returned Value:
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* The 'mbsrtowcs' and 'mbsnrtowcs' functions return the number of wide
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* characters stored in the array pointed to by 'dst' if successful,
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* otherwise it returns (size_t)-1.
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*
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* Portability:
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* 'mbsrtowcs' is defined by the C99 standard.
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* 'mbsnrtowcs' is defined by the POSIX.1-2008 standard.
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*
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****************************************************************************/
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size_t mbsnrtowcs(FAR wchar_t *dst, FAR const char **src, size_t nms,
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size_t len, FAR mbstate_t *ps)
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{
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FAR const char *s = *src;
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FAR wchar_t *ws = dst;
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size_t cnt = 0;
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size_t l;
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if (dst == NULL)
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{
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len = SIZE_MAX;
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}
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if (s != NULL)
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{
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while (len > 0 && nms > 0)
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{
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l = mbrtowc(ws, s, nms, ps);
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if ((ssize_t)l <= 0)
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{
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if ((ssize_t)l == -2)
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{
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/* if the input buffer ends with an incomplete character
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* stops at the end of the input buffer.
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*/
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s += nms;
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}
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else if (l == 0)
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{
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s = NULL;
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}
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else
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{
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cnt = l;
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}
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break;
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}
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s += l;
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nms -= l;
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if (ws != NULL)
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{
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ws++;
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}
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len--;
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cnt++;
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}
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}
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if (dst != NULL)
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{
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*src = s;
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}
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return cnt;
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}
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