| 1 | /* $Id: crc32-zlib.cpp 28800 2010-04-27 08:22:32Z vboxsync $ */
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| 2 | /** @file
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| 3 | * IPRT - CRC-32 on top of zlib (very fast).
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * Copyright (C) 2009 Oracle Corporation
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| 8 | *
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| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | * available from http://www.virtualbox.org. This file is free software;
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| 11 | * you can redistribute it and/or modify it under the terms of the GNU
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| 12 | * General Public License (GPL) as published by the Free Software
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| 13 | * Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | *
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| 17 | * The contents of this file may alternatively be used under the terms
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| 18 | * of the Common Development and Distribution License Version 1.0
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| 19 | * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | * VirtualBox OSE distribution, in which case the provisions of the
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| 21 | * CDDL are applicable instead of those of the GPL.
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| 22 | *
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| 23 | * You may elect to license modified versions of this file under the
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| 24 | * terms and conditions of either the GPL or the CDDL or both.
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| 25 | */
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| 26 |
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| 27 |
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| 28 | /*******************************************************************************
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| 29 | * Header Files *
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| 30 | *******************************************************************************/
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| 31 | #include "internal/iprt.h"
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| 32 | #include <iprt/crc.h>
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| 33 |
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| 34 | #include <zlib.h>
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| 35 |
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| 36 | /** @todo Check if we can't just use the zlib code directly here. */
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| 37 |
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| 38 | /**
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| 39 | * Deal with blocks that are too big for the uInt type.
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| 40 | */
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| 41 | static uint32_t rtCrc32ProcessTooBig(uint32_t uCRC32, const void *pv, size_t cb)
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| 42 | {
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| 43 | const Bytef *pb = (const Bytef *)pv;
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| 44 | do
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| 45 | {
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| 46 | uInt const cbChunk = cb <= ~(uInt)0 ? (uInt)cb : ~(uInt)0;
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| 47 | uCRC32 = crc32(uCRC32, pb, cbChunk);
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| 48 | pb += cbChunk;
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| 49 | cb -= cbChunk;
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| 50 | } while (!cb);
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| 51 | return uCRC32;
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| 52 | }
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| 53 |
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| 54 | RTDECL(uint32_t) RTCrc32(const void *pv, register size_t cb)
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| 55 | {
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| 56 | uint32_t uCrc = crc32(0, NULL, 0);
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| 57 | if (RT_UNLIKELY((uInt)cb == cb))
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| 58 | uCrc = crc32(uCrc, (const Bytef *)pv, (uInt)cb);
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| 59 | else
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| 60 | uCrc = rtCrc32ProcessTooBig(uCrc, pv, cb);
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| 61 | return uCrc;
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| 62 | }
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| 63 | RT_EXPORT_SYMBOL(RTCrc32);
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| 64 |
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| 65 |
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| 66 | RTDECL(uint32_t) RTCrc32Start(void)
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| 67 | {
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| 68 | return crc32(0, NULL, 0);
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| 69 | }
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| 70 | RT_EXPORT_SYMBOL(RTCrc32Start);
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| 71 |
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| 72 |
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| 73 | RTDECL(uint32_t) RTCrc32Process(uint32_t uCRC32, const void *pv, size_t cb)
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| 74 | {
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| 75 | if (RT_UNLIKELY((uInt)cb == cb))
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| 76 | uCRC32 = crc32(uCRC32, (const Bytef *)pv, (uInt)cb);
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| 77 | else
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| 78 | uCRC32 = rtCrc32ProcessTooBig(uCRC32, pv, cb);
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| 79 | return uCRC32;
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| 80 | }
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| 81 | RT_EXPORT_SYMBOL(RTCrc32Process);
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| 82 |
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| 83 |
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| 84 | RTDECL(uint32_t) RTCrc32Finish(uint32_t uCRC32)
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| 85 | {
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| 86 | return uCRC32;
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| 87 | }
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| 88 | RT_EXPORT_SYMBOL(RTCrc32Finish);
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| 89 |
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