CMidiFile.hpp

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#ifndef __CMidiFile__
#define __CMidiFile__

//  ===========================================================================

#include <Collections/TCountedPointerArray.hpp>
#include <Basics/CSystemString.hpp>
#include <IO/CFileStream.hpp>
#include "../Audio/TAudioBuffer.hpp"
#include "CMidiEvent.hpp"
#include "CMidiSequence.hpp"
using Exponent::Midi::CMidiSequence;
using Exponent::Midi::CMidiEvent;
using Exponent::Audio::TAudioBuffer;
using Exponent::IO::CFileStream;
using Exponent::Basics::CSystemString;
using Exponent::Collections::TCountedPointerArray;

//  ===========================================================================

namespace Exponent
{
    namespace Midi
    {
        class CMidiFile : public CCountedObject
        {
            EXPONENT_CLASS_DECLARATION;
//  ===========================================================================

        public:

//  ===========================================================================

            CMidiFile();

            virtual ~CMidiFile();

//  ===========================================================================

            bool openFile(CFileStream::EStreamMode mode, const CSystemString &filename);

            bool closeFile();

//  ===========================================================================

            bool readFile(CMidiSequence &sequence);

            bool writeFile(const CMidiSequence &sequence);

//  ===========================================================================

            static CString getFileExtension();

            static bool isValidFormat(const CSystemString &filename);

//  ===========================================================================

        protected:

//  ===========================================================================

            struct SMTHDChunk
            {
                char m_mthdChunk[4];                
                unsigned long m_mthdSize;           
                unsigned short m_fileType;          
                unsigned short m_numberOfTracks;    
                unsigned short m_timeFormat;        
                double m_samplesPerTick;            
            };

            struct SMTRKChunk
            {
                /* Here's the 8 byte header that all chunks must have */
                char m_mtrkChunk[4];                
                unsigned long m_mtrkSize;           
            };

            struct SMidiEvent
            {
                unsigned long m_delaySinceLast;     
                unsigned char m_statusByte;         
                unsigned char m_midiData[2];        
            };

//  ===========================================================================
//          READ FUNCTIONS
//  ===========================================================================

            static bool readFileHeader(CFileStream &stream, SMTHDChunk &chunk);

            static bool readTrackChunks(CFileStream &stream, SMTHDChunk &headChunk, CMidiSequence &sequence);

            static unsigned long readVariableLengthUnsignedLong(CFileStream &stream, int &sizeRead);

//  ===========================================================================
//          WRITE FUNCTIONS
//  ===========================================================================

            static bool writeFileHeader(CFileStream &stream, const CMidiSequence &sequence);

            static void writeMetaTrack(CFileStream &stream, const CMidiSequence &sequence);

            static void writeTimeSignature(CFileStream &stream, const CTimeSignature ts);

            static bool writeTrack(CFileStream &stream, const CMidiTrack &track, const double ticksPerSample);

            static void writeTrackName(CFileStream &stream, const CString &name);

            static void writeTrackMidiChannel(CFileStream &stream, const long channel);

            static void writeTrackEnd(CFileStream &stream);

            static void writeTempo(CFileStream &stream, const double bpm);

            static void writeVariableLengthUnsignedLong(CFileStream &stream, const unsigned long value);

            static bool isWritableEvent(const CMidiEvent &event);

//  ===========================================================================
//          UTILITY FUNCTIONS
//  ===========================================================================

            static bool isValidMTHDChunk(const SMTHDChunk &chunk);

            static bool isValidMTRKChunk(const SMTRKChunk &chunk);

            static void computeSamplesPerTick(SMTHDChunk &headChunk, const double sampleRate, const double bpm);

            static double computeTicksPerSample(const double sampleRate, const double bpm);

            static void processMidiSequence(SMTHDChunk &headChunk, CMidiSequence &sequence);

//  ===========================================================================

            const static char CMIDI_FILE_EVENT_SIZES[];                             
            const static unsigned short CMIDI_FILE_PPQ = 960;                       
//  ===========================================================================
            
            CFileStream m_stream;                                                   
        };
    }
}
#endif  // End of CMidiFile.hpp

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