incubator-nuttx/libs/libc/string/lib_memcmp.c

63 lines
1.9 KiB
C

/****************************************************************************
* libs/libc/string/lib_memcmp.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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>
#include "libc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
#if !defined(CONFIG_LIBC_ARCH_MEMCMP) && defined(LIBC_BUILD_MEMCMP)
#undef memcmp /* See mm/README.txt */
no_builtin("memcmp")
int memcmp(FAR const void *s1, FAR const void *s2, size_t n)
{
FAR unsigned char *p1 = (FAR unsigned char *)s1;
FAR unsigned char *p2 = (FAR unsigned char *)s2;
while (n-- > 0)
{
if (*p1 < *p2)
{
return -1;
}
else if (*p1 > *p2)
{
return 1;
}
p1++;
p2++;
}
return 0;
}
#endif