nuttx/libs/libc/string/lib_memcmp.c
mage1 def007e2d7 add #undef for some libc function
since it's useful to redirect these functions to others
sometime(e.g. validate the memory before write).

Change-Id: I6253a9231af8809e8362f4bc5a1bd67fb094c3b0
2021-07-14 15:09:58 -03:00

58 lines
1.8 KiB
C

/****************************************************************************
* libs/libc/string/lib_memcmp.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 <sys/types.h>
#include <string.h>
/****************************************************************************
* Public Functions
****************************************************************************/
#ifndef CONFIG_LIBC_ARCH_MEMCMP
#undef memcmp /* See mm/README.txt */
int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
{
unsigned char *p1 = (unsigned char *)s1;
unsigned char *p2 = (unsigned char *)s2;
while (n-- > 0)
{
if (*p1 < *p2)
{
return -1;
}
else if (*p1 > *p2)
{
return 1;
}
p1++;
p2++;
}
return 0;
}
#endif