Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Signed-off-by: Marty Connor <mdc@etherboot.org>
- Loading branch information
Showing
2 changed files
with
64 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,54 @@ | ||
/* | ||
* Little-endian CRC32 implementation. | ||
* | ||
* Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>. | ||
* | ||
* This program is free software; you can redistribute it and/or | ||
* modify it under the terms of the GNU General Public License as | ||
* published by the Free Software Foundation; either version 2 of the | ||
* License, or any later version. | ||
* | ||
* This program is distributed in the hope that it will be useful, but | ||
* WITHOUT ANY WARRANTY; without even the implied warranty of | ||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
* General Public License for more details. | ||
* | ||
* You should have received a copy of the GNU General Public License | ||
* along with this program; if not, write to the Free Software | ||
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | ||
*/ | ||
|
||
FILE_LICENCE ( GPL2_OR_LATER ); | ||
|
||
#include <gpxe/crc32.h> | ||
|
||
#define CRCPOLY 0xedb88320 | ||
|
||
/** | ||
* Calculate 32-bit little-endian CRC checksum | ||
* | ||
* @v seed Initial value | ||
* @v data Data to checksum | ||
* @v len Length of data | ||
* | ||
* Usually @a seed is initially zero or all one bits, depending on the | ||
* protocol. To continue a CRC checksum over multiple calls, pass the | ||
* return value from one call as the @a seed parameter to the next. | ||
*/ | ||
u32 crc32_le ( u32 seed, const void *data, size_t len ) | ||
{ | ||
u32 crc = seed; | ||
const u8 *src = data; | ||
u32 mult; | ||
int i; | ||
|
||
while ( len-- ) { | ||
crc ^= *src++; | ||
for ( i = 0; i < 8; i++ ) { | ||
mult = ( crc & 1 ) ? CRCPOLY : 0; | ||
crc = ( crc >> 1 ) ^ mult; | ||
} | ||
} | ||
|
||
return crc; | ||
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,10 @@ | ||
#ifndef _GPXE_CRC32_H | ||
#define _GPXE_CRC32_H | ||
|
||
FILE_LICENCE ( GPL2_OR_LATER ); | ||
|
||
#include <stdint.h> | ||
|
||
u32 crc32_le ( u32 seed, const void *data, size_t len ); | ||
|
||
#endif |