96 lines
3.2 KiB
C
96 lines
3.2 KiB
C
/****************************************************************************
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* libs/libc/string/lib_stpncpy.c
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*
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* SPDX-License-Identifier: Apache-2.0
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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 <nuttx/config.h>
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#include <sys/types.h>
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#include <string.h>
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: stpncpy
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*
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* Description:
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* Copies the string pointed to by 'src' (including the terminating NUL
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* character) into the array pointed to by 'dest'. strncpy() will not
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* copy more than 'n' bytes from 'src' to 'dest' array (including the
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* NUL terminator).
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*
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* If the array pointed to by 'src' is a string that is shorter than 'n'
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* bytes, NUL characters will be appended to the copy in the array
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* pointed to by 'dest', until 'n' bytes in all are written.
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*
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* If copying takes place between objects that overlap, the behavior is
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* undefined.
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*
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* Returned Value:
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* If a NUL character is written to the destination, the stpncpy()
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* function will return the address of the first such NUL character.
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* Otherwise, it will return &dest[n]
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*
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****************************************************************************/
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#ifndef CONFIG_LIBC_ARCH_STPNCPY
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#undef stpncpy /* See mm/README.txt */
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FAR char *stpncpy(FAR char *dest, FAR const char *src, size_t n)
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{
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FAR char *end = dest + n; /* End of dest buffer + 1 byte */
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FAR char *ret; /* Value to be returned */
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/* Copy up n bytes, breaking out of the loop early if a NUL terminator is
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* encountered.
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*/
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while ((dest != end) && (*dest = *src++) != '\0')
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{
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/* Increment the 'dest' pointer only if it does not refer to the
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* NUL terminator.
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*/
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dest++;
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}
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/* Return the pointer to the NUL terminator (or to the end of the buffer
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* + 1).
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*/
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ret = dest;
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/* Pad the remainder of the array pointer to 'dest' with NULs. This
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* overwrites any previously copied NUL terminator.
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*/
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while (dest != end)
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{
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*dest++ = '\0';
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}
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return ret;
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}
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#endif
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