72 lines
2.4 KiB
C
72 lines
2.4 KiB
C
/*
|
|
* Copyright (c) 2021-2022 Huawei Device Co., Ltd. All rights reserved.
|
|
*
|
|
* 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 of the copyright holder 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 HOLDER 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.
|
|
*/
|
|
|
|
#include <string.h>
|
|
#include <stdint.h>
|
|
|
|
#define SIZE_U64 (sizeof(uint64_t))
|
|
#define SIZE_U32 (sizeof(uint32_t))
|
|
|
|
int memcmp(const void *str1, const void *str2, size_t n)
|
|
{
|
|
|
|
const unsigned char *s1 = str1;
|
|
const unsigned char *s2 = str2;
|
|
size_t num = n;
|
|
|
|
while (num >= SIZE_U64) {
|
|
if (*(const uint64_t *)(s1) != *(const uint64_t *)(s2)) {
|
|
goto L4_byte_cmp;
|
|
}
|
|
s1 += SIZE_U64;
|
|
s2 += SIZE_U64;
|
|
num -= SIZE_U64;
|
|
}
|
|
if (num == 0) {
|
|
return 0;
|
|
}
|
|
|
|
L4_byte_cmp:
|
|
if (num >= SIZE_U32) {
|
|
if (*(const uint32_t *)(s1) != *(const uint32_t *)(s2)) {
|
|
goto L4_byte_diff;
|
|
}
|
|
s1 += SIZE_U32;
|
|
s2 += SIZE_U32;
|
|
num -= SIZE_U32;
|
|
}
|
|
if (num == 0) {
|
|
return 0;
|
|
}
|
|
L4_byte_diff:
|
|
for (; num && (*s1 == *s2); num--, s1++, s2++) {
|
|
}
|
|
return num ? *s1 - *s2 : 0;
|
|
} |