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/* $Id: crc32-zlib.cpp $ */
/** @file
* IPRT - CRC-32 on top of zlib (very fast).
*/
/*
* Copyright (C) 2009-2019 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include "internal/iprt.h"
#include <iprt/crc.h>
#include <zlib.h>
/** @todo Check if we can't just use the zlib code directly here. */
/**
* Deal with blocks that are too big for the uInt type.
*/
static uint32_t rtCrc32ProcessTooBig(uint32_t uCRC32, const void *pv, size_t cb)
{
const Bytef *pb = (const Bytef *)pv;
do
{
uInt const cbChunk = cb <= ~(uInt)0 ? (uInt)cb : ~(uInt)0;
uCRC32 = crc32(uCRC32, pb, cbChunk);
pb += cbChunk;
cb -= cbChunk;
} while (!cb);
return uCRC32;
}
RTDECL(uint32_t) RTCrc32(const void *pv, register size_t cb)
{
uint32_t uCrc = crc32(0, NULL, 0);
if (RT_UNLIKELY((uInt)cb == cb))
uCrc = crc32(uCrc, (const Bytef *)pv, (uInt)cb);
else
uCrc = rtCrc32ProcessTooBig(uCrc, pv, cb);
return uCrc;
}
RT_EXPORT_SYMBOL(RTCrc32);
RTDECL(uint32_t) RTCrc32Start(void)
{
return crc32(0, NULL, 0);
}
RT_EXPORT_SYMBOL(RTCrc32Start);
RTDECL(uint32_t) RTCrc32Process(uint32_t uCRC32, const void *pv, size_t cb)
{
if (RT_UNLIKELY((uInt)cb == cb))
uCRC32 = crc32(uCRC32, (const Bytef *)pv, (uInt)cb);
else
uCRC32 = rtCrc32ProcessTooBig(uCRC32, pv, cb);
return uCRC32;
}
RT_EXPORT_SYMBOL(RTCrc32Process);
RTDECL(uint32_t) RTCrc32Finish(uint32_t uCRC32)
{
return uCRC32;
}
RT_EXPORT_SYMBOL(RTCrc32Finish);
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