142 lines
3.9 KiB
C++
142 lines
3.9 KiB
C++
/****************************************************************************
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** libebml : parse EBML files, see http://embl.sourceforge.net/
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**
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** <file/class description>
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**
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** Copyright (C) 2002-2010 Steve Lhomme. All rights reserved.
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**
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** This file is part of libebml.
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**
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** This library is free software; you can redistribute it and/or
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** modify it under the terms of the GNU Lesser General Public
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** License as published by the Free Software Foundation; either
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** version 2.1 of the License, or (at your option) any later version.
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**
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** This library is distributed in the hope that it will be useful,
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** but WITHOUT ANY WARRANTY; without even the implied warranty of
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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** Lesser General Public License for more details.
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**
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** You should have received a copy of the GNU Lesser General Public
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** License along with this library; if not, write to the Free Software
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** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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**
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** See http://www.matroska.org/license/lgpl/ for LGPL licensing information.
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**
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** Contact license@matroska.org if any conditions of this licensing are
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** not clear to you.
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**
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**********************************************************************/
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/*!
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\file
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\version \$Id$
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\author Steve Lhomme <robux4 @ users.sf.net>
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\author Jory Stone <jcsston @ toughguy.net>
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*/
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#ifndef LIBEBML_CRC32_H
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#define LIBEBML_CRC32_H
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#include <cassert>
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#include "EbmlTypes.h"
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#include "EbmlBinary.h"
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START_LIBEBML_NAMESPACE
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DECLARE_EBML_BINARY(EbmlCrc32)
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public:
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EbmlCrc32(const EbmlCrc32 & ElementToClone);
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virtual bool ValidateSize() const {return IsFiniteSize() && (GetSize() == 4);}
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filepos_t RenderData(IOCallback & output, bool bForceRender, bool bWithDefault = false);
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filepos_t ReadData(IOCallback & input, ScopeMode ReadFully = SCOPE_ALL_DATA);
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// filepos_t UpdateSize(bool bWithDefault = false);
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bool IsDefaultValue() const {
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return false;
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}
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void AddElementCRC32(EbmlElement &ElementToCRC);
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bool CheckElementCRC32(EbmlElement &ElementToCRC);
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/*!
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Use this to quickly check a CRC32 with some data
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\return True if inputCRC matches CRC32 generated from input data
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*/
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static bool CheckCRC(uint32 inputCRC, const binary *input, uint32 length);
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/*!
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Calls Update() and Finalize(), use to create a CRC32 in one go
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*/
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void FillCRC32(const binary *input, uint32 length);
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/*!
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Add data to the CRC table, in other words process some data bit by bit
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*/
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void Update(const binary *input, uint32 length);
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/*!
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Use this with Update() to Finalize() or Complete the CRC32
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*/
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void Finalize();
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/*!
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Returns a uint32 that has the value of the CRC32
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*/
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uint32 GetCrc32() const {
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return m_crc_final;
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};
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void ForceCrc32(uint32 NewValue) { m_crc_final = NewValue; SetValueIsSet();}
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#if defined(EBML_STRICT_API)
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private:
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#else
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protected:
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#endif
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void ResetCRC();
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void UpdateByte(binary b);
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static const uint32 m_tab[256];
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uint32 m_crc;
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uint32 m_crc_final;
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EBML_CONCRETE_CLASS(EbmlCrc32)
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};
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template <class T>
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inline unsigned int GetAlignment(T */* dummy */=NULL) // VC60 workaround
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{
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#if defined(_MSC_VER) && (_MSC_VER >= 1300)
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return __alignof(T);
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#elif defined(__GNUC__)
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return __alignof__(T);
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#else
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return sizeof(T);
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#endif
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}
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template <class T>
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inline bool IsPowerOf2(T n)
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{
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return n > 0 && (n & (n-1)) == 0;
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}
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template <class T1, class T2>
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inline T2 ModPowerOf2(T1 a, T2 b)
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{
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assert(IsPowerOf2(b));
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return T2(a) & (b-1);
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}
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inline bool IsAlignedOn(const void *p, unsigned int alignment)
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{
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return IsPowerOf2(alignment) ? ModPowerOf2((uintptr_t)p, alignment) == 0 : (uintptr_t)p % alignment == 0;
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}
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template <class T>
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inline bool IsAligned(const void *p, T */* dummy */=NULL) // VC60 workaround
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{
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return IsAlignedOn(p, GetAlignment<T>());
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}
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END_LIBEBML_NAMESPACE
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#endif // LIBEBML_CRC32_H
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