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/*
* Slamtec LIDAR SDK
*
* Copyright (c) 2014 - 2020 Shanghai Slamtec Co., Ltd.
* http://www.slamtec.com
*
*/
/*
* 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.
*
* 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 "sl_crc.h"
namespace sl {namespace crc32 {
static sl_u32 table[256];//crc32_table
sl_u32 bitrev(sl_u32 input, sl_u16 bw)
{
sl_u16 i;
sl_u32 var;
var = 0;
for (i = 0; i < bw; i++) {
if (input & 0x01) {
var |= 1 << (bw - 1 - i);
}
input >>= 1;
}
return var;
}
void init(sl_u32 poly)
{
sl_u16 i;
sl_u16 j;
sl_u32 c;
poly = bitrev(poly, 32);
for (i = 0; i < 256; i++) {
c = i;
for (j = 0; j < 8; j++) {
if (c & 1)
c = poly ^ (c >> 1);
else
c = c >> 1;
}
table[i] = c;
}
}
sl_u32 cal(sl_u32 crc, void* input, sl_u16 len)
{
sl_u16 i;
sl_u8 index;
sl_u8* pch;
pch = (unsigned char*)input;
sl_u8 leftBytes = 4 - (len & 0x3);
for (i = 0; i < len; i++) {
index = (unsigned char)(crc^*pch);
crc = (crc >> 8) ^ table[index];
pch++;
}
for (i = 0; i < leftBytes; i++) {//zero padding
index = (unsigned char)(crc ^ 0);
crc = (crc >> 8) ^ table[index];
}
return crc ^ 0xffffffff;
}
sl_result getResult(sl_u8 *ptr, sl_u32 len)
{
static sl_u8 tmp;
if (tmp != 1) {
init(0x4C11DB7);
tmp = 1;
}
return cal(0xFFFFFFFF, ptr, len);
}
}}
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