nuttx/libs/libc/string/lib_stpncpy.c

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/****************************************************************************
* libs/libc/string/lib_stpncpy.c
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*
* Copyright (C) 2018 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 NuttX 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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 <nuttx/config.h>
#include <sys/types.h>
#include <string.h>
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/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stpncpy
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*
* Description:
* Copies the string pointed to by 'src' (including the terminating NUL
* character) into the array pointed to by 'dest'. strncpy() will not
* copy more than 'n' bytes from 'src' to 'dest' array (including the
* NUL terminator).
*
* If the array pointed to by 'src' is a string that is shorter than 'n'
* bytes, NUL characters will be appended to the copy in the array
* pointed to by 'dest', until 'n' bytes in all are written.
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*
* If copying takes place between objects that overlap, the behavior is
* undefined.
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*
* Returned Value:
* If a NUL character is written to the destination, the stpncpy()
* function will return the address of the first such NUL character.
* Otherwise, it will return &dest[n]
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*
****************************************************************************/
#ifndef CONFIG_LIBC_ARCH_STPNCPY
FAR char *stpncpy(FAR char *dest, FAR const char *src, size_t n)
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{
FAR char *end = dest + n; /* End of dest buffer + 1 byte */
FAR char *ret; /* Value to be returned */
/* Copy up n bytes, breaking out of the loop early if a NUL terminator is
* encountered.
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*/
while ((dest != end) && (*dest = *src++) != '\0')
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{
/* Increment the 'dest' pointer only if it does not refer to the
* NUL terminator.
*/
dest++;
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}
/* Return the pointer to the NUL terminator (or to the end of the buffer
* + 1).
*/
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ret = dest;
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/* Pad the remainder of the array pointer to 'dest' with NULs. This
* overwrites any previously copied NUL terminator.
*/
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while (dest != end)
{
*dest++ = '\0';
}
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return ret;
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}
#endif