134 lines
7.4 KiB
C++
134 lines
7.4 KiB
C++
|
//
|
||
|
|
// Copyright 2020 Electronic Arts Inc.
|
||
|
|
//
|
||
|
|
// TiberianDawn.DLL and RedAlert.dll and corresponding source code 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 3 of the License, or (at your option) any later version.
|
||
|
|
|
||
|
|
// TiberianDawn.DLL and RedAlert.dll and corresponding source code is distributed
|
||
|
|
// in the hope that it will be useful, but with permitted additional restrictions
|
||
|
|
// under Section 7 of the GPL. See the GNU General Public License in LICENSE.TXT
|
||
|
|
// distributed with this program. You should have received a copy of the
|
||
|
|
// GNU General Public License along with permitted additional restrictions
|
||
|
|
// with this program. If not, see https://github.com/electronicarts/CnC_Remastered_Collection
|
||
|
|
|
||
|
|
/* $Header: /CounterStrike/CRC.CPP 1 3/03/97 10:24a Joe_bostic $ */
|
||
|
|
/***********************************************************************************************
|
||
|
|
*** C O N F I D E N T I A L --- W E S T W O O D S T U D I O S ***
|
||
|
|
***********************************************************************************************
|
||
|
|
* *
|
||
|
|
* Project Name : Command & Conquer *
|
||
|
|
* *
|
||
|
|
* File Name : CRC.CPP *
|
||
|
|
* *
|
||
|
|
* Programmer : Joe L. Bostic *
|
||
|
|
* *
|
||
|
|
* Start Date : 03/02/96 *
|
||
|
|
* *
|
||
|
|
* Last Update : March 2, 1996 [JLB] *
|
||
|
|
* *
|
||
|
|
*---------------------------------------------------------------------------------------------*
|
||
|
|
* Functions: *
|
||
|
|
* CRCEngine::operator() -- Submits one byte of data to the CRC engine. *
|
||
|
|
* CRCEngine::operator() -- Submits an arbitrary data block to the CRC engine. *
|
||
|
|
* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
|
||
|
|
|
||
|
|
#include "crc.h"
|
||
|
|
|
||
|
|
|
||
|
|
/***********************************************************************************************
|
||
|
|
* CRCEngine::operator() -- Submits one byte of data to the CRC engine. *
|
||
|
|
* *
|
||
|
|
* This routine will take the specified byte of data and submit it to the CRC engine *
|
||
|
|
* for processing. This routine is designed to be as fast as possible since the typical *
|
||
|
|
* use of this routine is to feed one of presumably many byte sized chunks of data to the *
|
||
|
|
* CRC engine. *
|
||
|
|
* *
|
||
|
|
* INPUT: datum -- One byte of data to submit to the CRC engine. *
|
||
|
|
* *
|
||
|
|
* OUTPUT: none *
|
||
|
|
* *
|
||
|
|
* WARNINGS: If possible, use the buffer/size operator to submit data rather than repeated *
|
||
|
|
* calls to this routine. *
|
||
|
|
* *
|
||
|
|
* HISTORY: *
|
||
|
|
* 03/02/1996 JLB : Created. *
|
||
|
|
*=============================================================================================*/
|
||
|
|
void CRCEngine::operator() (char datum)
|
||
|
|
{
|
||
|
|
StagingBuffer.Buffer[Index++] = datum;
|
||
|
|
|
||
|
|
if (Index == sizeof(long)) {
|
||
|
|
CRC = Value();
|
||
|
|
StagingBuffer.Composite = 0;
|
||
|
|
Index = 0;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
/***********************************************************************************************
|
||
|
|
* CRCEngine::operator() -- Submits an arbitrary data block to the CRC engine. *
|
||
|
|
* *
|
||
|
|
* This routine will submit the specified block to the CRC engine. The block can be of *
|
||
|
|
* arbitrary length. *
|
||
|
|
* *
|
||
|
|
* INPUT: buffer -- Pointer to the buffer that contains the data. The buffer will not *
|
||
|
|
* be modified. *
|
||
|
|
* *
|
||
|
|
* length -- The length of the buffer (in bytes). *
|
||
|
|
* *
|
||
|
|
* OUTPUT: Returns with the current CRC value accumulated so far. *
|
||
|
|
* *
|
||
|
|
* WARNINGS: none *
|
||
|
|
* *
|
||
|
|
* HISTORY: *
|
||
|
|
* 03/02/1996 JLB : Created. *
|
||
|
|
*=============================================================================================*/
|
||
|
|
long CRCEngine::operator() (void const * buffer, int length)
|
||
|
|
{
|
||
|
|
if (buffer != NULL && length > 0) {
|
||
|
|
char const * dataptr = (char const *)buffer;
|
||
|
|
int bytes_left = length;
|
||
|
|
|
||
|
|
/*
|
||
|
|
** If there are any leader bytes (needed to fill the staging buffer)
|
||
|
|
** then process those by first using them to fill up the staging
|
||
|
|
** buffer. The bulk of the data block will be processed by the high
|
||
|
|
** speed longword processing loop.
|
||
|
|
*/
|
||
|
|
while (bytes_left && Buffer_Needs_Data()) {
|
||
|
|
operator()(*dataptr);
|
||
|
|
dataptr++;
|
||
|
|
bytes_left--;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
** Perform the fast 'bulk' processing by reading long word sized
|
||
|
|
** data blocks.
|
||
|
|
*/
|
||
|
|
long const * longptr = (long const *)dataptr;
|
||
|
|
int longcount = bytes_left / sizeof(long); // Whole 'long' elements remaining.
|
||
|
|
while (longcount--) {
|
||
|
|
CRC = _lrotl(CRC, 1) + *longptr++;
|
||
|
|
bytes_left -= sizeof(long);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
** If there are remainder bytes, then process these by adding them
|
||
|
|
** to the staging buffer.
|
||
|
|
*/
|
||
|
|
dataptr = (char const *)longptr;
|
||
|
|
while (bytes_left) {
|
||
|
|
operator()(*dataptr);
|
||
|
|
dataptr++;
|
||
|
|
bytes_left--;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
** Return the current CRC value.
|
||
|
|
*/
|
||
|
|
return(Value());
|
||
|
|
}
|