202 lines
4.2 KiB
C++
202 lines
4.2 KiB
C++
/* DecMPA - simple MPEG Audio decoding library.
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Copyright (C) 2002 Hauke Duden
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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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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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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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For more information look at the file License.txt in this package.
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email: hazard_hd@users.sourceforge.net
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*/
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#ifndef _MPAFRAMEFINDER_H_
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#define _MPAFRAMEFINDER_H_
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#include "IFileAccess.h"
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#include "mpegAudioFrame/mpegAudioHeader.h"
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#include "MemBuffer.h"
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class CMPAFrameFinder
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{
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public:
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CMPAFrameFinder();
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~CMPAFrameFinder();
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inline void SetLookAheadFrames(int nFrames);
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inline void SetAllowFrequencyChanges(bool bAllow);
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inline int GetLookAheadFrames();
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inline bool GetAllowFrequencyChanges();
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//if false, the finder needs more input data or the stream
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//invalid
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bool ReadNextFrame();
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inline bool IsStreamInvalid();
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inline bool KnowsCharacteristics();
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inline bool HasFrame();
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inline void* GetFrameData();
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inline int GetFrameSize();
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inline double GetAvgFrameSize();
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inline MpegAudioHeader* GetFrameHeader();
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void SetInput(void* pBuffer,int nBytes,long nStreamPosition);
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bool ReadInput(IFileAccess* pAccess);
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//throw away buffered data and find next frame
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void Flush();
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//start with a completely blank slate for a new data stream
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void Restart();
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inline long GetFirstFramePosition();
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protected:
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struct HeaderRecord
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{
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MpegAudioHeader Header;
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long nPosition;
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HeaderRecord* pNext;
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};
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bool FindCharacteristics();
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bool FindConsistentHeaders();
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bool CanHaveConsistentHeaders(HeaderRecord* pRecord,int nHeaderCount);
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bool HasConsistentHeaders(HeaderRecord* pCheckRecord,HeaderRecord* pRecord,int nHeadersNeeded);
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bool AreHeadersConsistent(HeaderRecord* pFirst,HeaderRecord* pSecond);
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bool IsConformingHeader(MpegAudioHeader* pHeader);
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void FindNextSync();
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void ReadHeader();
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void CheckHeader();
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void ReadFrame();
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void ResetState();
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void DeleteHeaderRecords();
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static bool IsValidHeader(MpegAudioHeader* pHeader);
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CMemBuffer m_OutBuffer;
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CMemBuffer* m_pInBuffer;
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CMemBuffer m_MyInBuffer;
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CMemBuffer m_UserInBuffer;
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int m_State;
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int m_nLookAheadFrames;
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bool m_bAllowFrequencyChanges;
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int m_nLayer;
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int m_nInputStereo;
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int m_nFrequency;
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int m_nLayer25;
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int m_nVersion;
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MpegAudioHeader m_Header;
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int m_nFrameSize;
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long m_nReadStartPosition;
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long m_nFirstFramePosition;
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enum
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{
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STATE_FINDCHARACTERISTICS=0,
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STATE_FINDSYNC,
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STATE_READHEADER,
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STATE_CHECKHEADER,
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STATE_READFRAME,
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STATE_HAVEFRAME
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};
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HeaderRecord* m_pFirstHeader;
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HeaderRecord* m_pLastHeader;
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HeaderRecord* m_pNewHeaderRecord;
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bool m_bStreamInvalid;
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};
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inline void CMPAFrameFinder::SetLookAheadFrames(int nFrames)
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{
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if(nFrames<0)
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nFrames=0;
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m_nLookAheadFrames=nFrames;
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}
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inline void CMPAFrameFinder::SetAllowFrequencyChanges(bool bAllow)
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{
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m_bAllowFrequencyChanges=bAllow;
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}
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inline int CMPAFrameFinder::GetLookAheadFrames()
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{
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return m_nLookAheadFrames;
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}
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inline bool CMPAFrameFinder::GetAllowFrequencyChanges()
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{
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return m_bAllowFrequencyChanges;
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}
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inline bool CMPAFrameFinder::HasFrame()
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{
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return (m_State==STATE_HAVEFRAME);
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}
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inline void* CMPAFrameFinder::GetFrameData()
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{
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return m_OutBuffer.GetPtr();
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}
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inline int CMPAFrameFinder::GetFrameSize()
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{
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return m_OutBuffer.GetPos();
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}
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inline double CMPAFrameFinder::GetAvgFrameSize()
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{
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return m_Header.GetAvgFrameSize();
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}
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inline MpegAudioHeader* CMPAFrameFinder::GetFrameHeader()
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{
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return &m_Header;
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}
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inline bool CMPAFrameFinder::IsStreamInvalid()
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{
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return m_bStreamInvalid;
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}
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inline bool CMPAFrameFinder::KnowsCharacteristics()
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{
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return (m_State>STATE_FINDCHARACTERISTICS);
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}
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inline long CMPAFrameFinder::GetFirstFramePosition()
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{
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return m_nFirstFramePosition;
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}
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#endif
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