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engine/audio/private/MPAFile.h

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+//========= Copyright Valve Corporation, All rights reserved. ============//
+//
+// Purpose: Uses mp3 code from:  http://www.codeproject.com/audio/MPEGAudioInfo.asp
+//
+// There don't appear to be any licensing restrictions for using this code:
+//
+/*
+- Readme - MPEG Audio Info Tool V2.0 - 2004-11-01
+
+Description:
+This tool can display information about MPEG audio files. It supports
+MPEG1, MPEG2, MPEG2.5 in all three layers. You can get all the fields
+from the MPEG audio frame in each frame of the file. Additionally you
+can check the whole file for inconsistencies.
+
+
+This tool was written as an example on how to use the classes:
+CMPAFile, CMPAHeader, CVBRHeader and CMPAException.
+
+The article MPEG Audio Frame Header on Sourceproject
+[http://www.codeproject.com/audio/MPEGAudioInfo.asp] 
+provides additional information about these classes and the frame header
+in general.
+
+This tool was written with MS Visual C++ 7.1. The MFC library is
+statically linked.
+*/
+//=============================================================================
+
+#ifndef MPAFILE_H
+#define MPAFILE_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#pragma once
+
+#include "VBRHeader.h"
+#include "MPAHeader.h"
+#include "filesystem.h"
+
+// exception class
+class CMPAException
+{
+public:
+	
+	enum ErrorIDs
+	{
+		ErrOpenFile,
+		ErrSetPosition,
+		ErrReadFile,
+		EndOfBuffer,
+		NoVBRHeader,
+		IncompleteVBRHeader,
+		NoFrameInTolerance,
+		NoFrame
+	};
+
+	CMPAException( ErrorIDs ErrorID, const char *szFile, const char *szFunction = NULL, bool bGetLastError=false );
+	// copy constructor (necessary because of LPSTR members)
+	CMPAException(const CMPAException& Source);
+	~CMPAException(void);
+
+	ErrorIDs GetErrorID() { return m_ErrorID; }
+
+	void ShowError();
+
+private:
+	ErrorIDs m_ErrorID;
+	bool m_bGetLastError;
+	const char *m_szFunction;
+	const char *m_szFile;
+};
+
+
+class CMPAFile
+{
+public:
+	CMPAFile( const char *szFile, uint32 dwFileOffset, FileHandle_t hFile = FILESYSTEM_INVALID_HANDLE );
+	~CMPAFile(void);
+
+	uint32 ExtractBytes( uint32 &dwOffset, uint32 dwNumBytes, bool bMoveOffset = true );
+	const char *GetFilename() const { return m_szFile; };
+
+	bool GetNextFrame();
+	bool GetPrevFrame();
+	bool GetFirstFrame();
+	bool GetLastFrame();
+
+private:
+	static const uint32 m_dwInitBufferSize;
+
+	// methods for file access
+	void Open( const char *szFilename );
+	void SetPosition( int offset );
+	uint32 Read( void *pData, uint32 dwSize, uint32 dwOffset );
+
+	void FillBuffer( uint32 dwOffsetToRead );
+
+	static uint32 m_dwBufferSizes[MAXTIMESREAD];
+
+	// concerning file itself
+	FileHandle_t m_hFile;
+	const char *m_szFile;
+	bool m_bMustReleaseFile;
+
+public:	
+	uint32 m_dwBegin;	// offset of first MPEG Audio frame
+	uint32 m_dwEnd;		// offset of last MPEG Audio frame (estimated)
+	bool m_bVBRFile;
+
+	uint32 m_dwBytesPerSec;
+
+	CMPAHeader* m_pMPAHeader;
+	uint32 m_dwFrameNo;
+
+	CVBRHeader* m_pVBRHeader;		// XING or VBRI
+
+	// concerning read-buffer
+	uint32 m_dwNumTimesRead;
+	char *m_pBuffer;
+	uint32 m_dwBufferSize;
+};
+
+#endif // MPAFILE_H