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150 lines
4.1 KiB
C++
150 lines
4.1 KiB
C++
/* $Header: /cvs/root/winamp/vlb/bitstream.h,v 1.1 2009/04/28 20:21:08 audiodsp Exp $ */
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/***************************************************************************\
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*
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* Copyright 2000-2002 Dolby Laboratories, Inc. All Rights
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* Reserved. Do not copy. Do not distribute.
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* Confidential information.
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*
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* (C) copyright Fraunhofer - IIS (1998)
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* All Rights Reserved
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*
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* filename: bitstream.h
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* project : MPEG-2 AAC Decoder
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* contents/description: input abstract base class
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*
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\***************************************************************************/
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#ifndef __VLB_BITSTREAM_H__
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#define __VLB_BITSTREAM_H__
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#include "exception.h"
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/** General Bitstream Input Base Class.
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This abstract base class defines the interface that the \Ref{CAacDecoder} object will
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read all of its bitstream input data from. Specialized classes for specific
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application scenarios have to be derived from this interface.
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*/
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class CDolbyBitStream
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{
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public :
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/// Object Constructor.
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CDolbyBitStream ()
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{
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m_AdifHeaderPresent = false ;
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m_RiffHeaderPresent = false ;
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m_IsADTSCompliant = false;
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}
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/// Object Destructor.
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virtual ~CDolbyBitStream () {}
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/** Byte Alignment Method.
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This method performs the byte_alignment() syntactic method on the input stream,
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i.e. some bits will be discarded so that the next bits to be read would be aligned
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on a byte boundary with respect to the last call to ByteAlign().
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*/
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virtual void ByteAlign (void) = 0 ;
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/** Push Back Method.
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This method ungets a number of bits erroneously read by the last Get() call.
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NB: The number of bits to be stuffed back into the stream may never exceed the
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number of bits returned by the immediately preceding Get() call.
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@param n The number of bits to be pushed back.
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*/
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virtual void PushBack (int n) = 0 ;
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/** Get Bits Method.
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This method returns a number of sequential bits from the input bitstream.
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This is the one and only read operation that the decoder will ever perform,
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i.e. _all_ the data goes through this call.
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@param n The number of bits to be retrieved.
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*/
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virtual long Get (int n) = 0 ;
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/** ADIF detection Method.
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This method indicates whether the decoder should read in and parse an ADIF header
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before starting to decode the first frame of audio data.
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*/
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bool IsAdifHeaderPresent (void)
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{
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return m_AdifHeaderPresent ;
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}
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/** RIFF/ADTS detection Method.
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This method indicates whether the decoder should read in and parse a RIFF header
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before starting to decode the first frame of audio data.
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*/
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bool IsRiffHeaderPresent (void)
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{
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return m_RiffHeaderPresent;
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}
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bool IsADTSCompliant (void)
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{
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return m_IsADTSCompliant;
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}
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// CRC Markers for SetPositionMarker ().
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typedef enum
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{
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ChannelElementStart,
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ChannelElementStop,
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AncillaryElementStart,
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AncillaryElementStop,
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SecondIndividualChannelStart,
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CurrentPosition
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} MarkerPosition ;
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/** Position Marker Setting Method.
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The decoder core can call this method to set position markers
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in the bitstream. this facility can be used to implement
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error-protection mechanisms in a derived class, for example,
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if the underlying transport layer supports such a feature.
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*/
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virtual void SetPositionMarker (MarkerPosition position) {}
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virtual void DecrementBlocks(){}
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virtual void ResetBlocks() {}
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virtual unsigned int GetFrameLength(){return 0;} //UNKNOWN IN ADIF
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virtual unsigned int GetNRDB(){return 0;} //UNKNOWN IN ADIF
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virtual void SetFrameReadButNotDecoded(void){}
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virtual void ClearFrameReadButNotDecoded(void){}
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virtual bool FrameReadButNotDecoded(void){return false;}
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virtual unsigned int GetBitCount(void) {return 0;};
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protected :
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DECLARE_EXCEPTION(EDoesNotExist, AAC_DOESNOTEXIST, "Bitstream does not exist") ;
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DECLARE_EXCEPTION(EEndOfFile, AAC_ENDOFSTREAM, "End of file reached") ;
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bool m_AdifHeaderPresent;
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bool m_RiffHeaderPresent;
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bool m_IsADTSCompliant;
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} ;
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#endif
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