68 lines
2.3 KiB
C
68 lines
2.3 KiB
C
/****************************************************************************
|
|
* libs/libc/string/lib_memchr.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 <nuttx/config.h>
|
|
|
|
#include <string.h>
|
|
|
|
#include "libc.h"
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: memchr
|
|
*
|
|
* Description:
|
|
* The memchr() function locates the first occurrence of 'c' (converted to
|
|
* an unsigned char) in the initial 'n' bytes (each interpreted as
|
|
* unsigned char) of the object pointed to by s.
|
|
*
|
|
* Returned Value:
|
|
* The memchr() function returns a pointer to the located byte, or a null
|
|
* pointer if the byte does not occur in the object.
|
|
*
|
|
****************************************************************************/
|
|
|
|
#if !defined(CONFIG_LIBC_ARCH_MEMCHR) && defined(LIBC_BUILD_MEMCHR)
|
|
#undef memchr /* See mm/README.txt */
|
|
FAR void *memchr(FAR const void *s, int c, size_t n)
|
|
{
|
|
FAR const unsigned char *p = (FAR const unsigned char *)s;
|
|
|
|
while (n--)
|
|
{
|
|
if (*p == (unsigned char)c)
|
|
{
|
|
return (FAR void *)p;
|
|
}
|
|
|
|
p++;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
#endif
|