/*

     File: CompressedPacketTable.h

 Abstract: Part of CoreAudio Utility Classes

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*/

#include <iterator>

#include <vector>

#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)

    #include <CoreAudio/CoreAudioTypes.h>

#else

    #include "CoreAudioTypes.h"

#endif

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

struct  AudioStreamPacketDescriptionExtended : AudioStreamPacketDescription

{

    SInt64  mFrameOffset; // this is the sum of the mVariableFramesInPacket up to this point so we can binary search.

};

typedef struct AudioStreamPacketDescriptionExtended AudioStreamPacketDescriptionExtended;

inline bool operator < (const AudioStreamPacketDescriptionExtended& a, const AudioStreamPacketDescriptionExtended& b)

{

    return a.mFrameOffset < b.mFrameOffset;

}

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

class CompressedPacketTable

{

public:

    CompressedPacketTable(UInt32 inFramesPerPacket) : mSize(0), mFramesPerPacket(inFramesPerPacket) {}

    ~CompressedPacketTable();

    SInt64 size() const { return mSize; }

    void push_back(const AudioStreamPacketDescriptionExtended& inDesc);

    const AudioStreamPacketDescriptionExtended operator[](SInt64 inPacketIndex) const;

    const AudioStreamPacketDescriptionExtended front() const { return (*this)[0]; }

    const AudioStreamPacketDescriptionExtended back() const { return (*this)[mSize-1]; }

    //SInt64 PacketForByte(SInt64 inByteOffset) const;

    SInt64 ByteForPacket(SInt64 inPacketIndex) const { return (*this)[inPacketIndex].mStartOffset; }

    class iterator {

        public:

            typedef std::input_iterator_tag iterator_category;

            typedef iterator pointer;

            typedef SInt64 difference_type;

            typedef AudioStreamPacketDescriptionExtended value_type;

            typedef value_type& reference;

            iterator() : mTable(NULL), mIndex(0) {}

            iterator(const CompressedPacketTable* table, SInt64 index) : mTable(table), mIndex(index) {}

            iterator(const iterator& that) : mTable(that.mTable), mIndex(that.mIndex) {}

            iterator& operator=(const iterator& that) { mTable = that.mTable; mIndex = that.mIndex; return *this; }

            const AudioStreamPacketDescriptionExtended operator*() const { return (*mTable)[mIndex]; }

            const AudioStreamPacketDescriptionExtended* const operator->() { mValue = (*mTable)[mIndex]; return &mValue; }

            iterator& operator++() { ++mIndex; return *this; }

            iterator& operator--() { --mIndex; return *this; }

            SInt64 operator-(const iterator& that) { return mIndex - that.mIndex; }

            const iterator operator-(SInt64 index) { return iterator(mTable, mIndex - index); }

            const iterator operator+(SInt64 index) { return iterator(mTable, mIndex + index); }

            bool operator==(const iterator& that) { return mIndex == that.mIndex; }

            bool operator!=(const iterator& that) { return mIndex != that.mIndex; }

            bool operator>(const iterator& that) { return mIndex > that.mIndex; }

            bool operator<(const iterator& that) { return mIndex < that.mIndex; }

        private:

            const CompressedPacketTable* mTable;

            SInt64 mIndex;

            AudioStreamPacketDescriptionExtended mValue; // in order to support operator-> .

    };

    iterator begin() const { return iterator(this, 0); }

    iterator end() const { return iterator(this, mSize); }

private:

    struct TinyContiguousPacketDescription

    {

        UInt16 mNextOffset;

    };

    struct TinyDiscontiguousPacketDescription : TinyContiguousPacketDescription

    {

        UInt16 mDataByteSize;

    };

    // There could be a 24 bit packet description. But ALAC is who usually needs SmallContiguousPacketDescription and 

    // it already uses 8x fewer packet descriptions than AAC due to the mFramesPerPacket being 8x greater. 

    // So there isn't as great a need for saving space. 4 bytes per packet is OK for ALAC.

    struct SmallContiguousPacketDescription

    {

        UInt32 mNextOffset;

    };

    struct SmallDiscontiguousPacketDescription : SmallContiguousPacketDescription

    {

        UInt16 mDataByteSize;

    };

    struct BigContiguousPacketDescription

    {

        UInt64 mNextOffset;

    };

    struct BigDiscontiguousPacketDescription : BigContiguousPacketDescription

    {

        UInt32 mDataByteSize;

    };

    struct PacketBase

    {

        SInt64 mBaseOffset;

        UInt8 mDescType;

        void* mDescs;

    };

    enum {

        kTinyContiguousPacketDescription,

        kTinyDiscontiguousPacketDescription,

        kSmallContiguousPacketDescription,

        kSmallDiscontiguousPacketDescription,

        kBigContiguousPacketDescription,

        kBigDiscontiguousPacketDescription,

        kExtendedPacketDescription

    };

    static const UInt32 kShift;

    static const UInt32 kMask;

    bool isContiguous(PacketBase& base);

    bool hasVariableFrames(PacketBase& base);

    UInt32 largestPacket(PacketBase& base);

    void Compress(PacketBase& base);

private:    

    std::vector<PacketBase> mBases;

    UInt64 mSize;

    UInt32 mFramesPerPacket;

};