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/branches/network/uspace/srv/net/crc.c
0,0 → 1,104
/*
* Copyright (c) 2009 Lukas Mejdrech
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
 
/** @addtogroup net
* @{
*/
 
/** @file
* General CRC computation implementation.
*/
 
#include <sys/types.h>
 
#include "include/crc.h"
 
#define CRC_DIVIDER_BE 0x04C11DB7
 
#define CRC_DIVIDER_LE 0xEDB88320
 
uint32_t compute_crc32_le( uint32_t seed, uint8_t * data, int length ){
int index;
 
while( length >= 8 ){
seed ^= ( * data );
for( index = 0; index < 8; ++ index ){
if( seed & 1 ){
seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
}else{
seed >>= 1;
}
}
++ data;
length -= 8;
}
if( length > 0 ){
seed ^= ( * data ) >> ( 8 - length );
for( index = 0; index < length; ++ index ){
if( seed & 1 ){
seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
}else{
seed >>= 1;
}
}
length -= 8;
}
return seed;
}
 
uint32_t compute_crc32_be( uint32_t seed, uint8_t * data, int length ){
int index;
 
while( length >= 8 ){
seed ^= ( * data ) << 24;
for( index = 0; index < 8; ++ index ){
if( seed & 0x80000000 ){
seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
}else{
seed <<= 1;
}
}
++ data;
length -= 8;
}
if( length > 0 ){
seed ^= (( * data ) & ( 0xFF << ( 8 - length ))) << 24;
for( index = 0; index < length; ++ index ){
if( seed & 0x80000000 ){
seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
}else{
seed <<= 1;
}
}
length -= 8;
}
return seed;
}
 
/** @}
*/
Property changes:
Added: svn:eol-style
+native
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