StreamedAudioChunkSeekTable.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "HAL/Platform.h"
#include "Containers/Array.h"
#include "Templates/PimplPtr.h"
 
#include "StreamedAudioChunkSeekTable.generated.h"
 
// Forward declarations.
class FArchive;
 
UENUM()
enum class EChunkSeekTableMode : uint8
{
    ConstantSamplesPerEntry = 0,
    VariableSamplesPerEntry,
};
 
class FStreamedAudioChunkSeekTable
{
public: 
    static ENGINE_API int16 GetVersion();
 
    static ENGINE_API bool Parse(const uint8* InMemory, uint32 InSize, uint32& InOutOffset, FStreamedAudioChunkSeekTable& OutTable);
 
    static ENGINE_API int32 CalcSize(int32 NumEntries, EChunkSeekTableMode InMode = EChunkSeekTableMode::ConstantSamplesPerEntry);
 
    ENGINE_API int32 CalcSize() const;
    
    struct ISeekTableImpl
    {
        virtual ~ISeekTableImpl() = default;
        virtual int32 Num() const = 0;
        virtual uint32 FindOffset(uint32 InTimeInAudioFrames) const = 0;
        virtual uint32 FindTime(uint32 InOffset) const = 0;
        virtual void Add(uint32 InTimeInAudioFrames, uint32 InOffset) = 0;
        virtual bool Serialize(FArchive& Ar) = 0;
        virtual bool GetAt(const uint32 InIndex, uint32& OutOffset, uint32& OutTime) const = 0;
    };
 
    ENGINE_API FStreamedAudioChunkSeekTable(EChunkSeekTableMode InMode = EChunkSeekTableMode::ConstantSamplesPerEntry); 
 
    void Add(uint32 InTimeInAudioFrames, uint32 InOffset)
    {
        Impl->Add(InTimeInAudioFrames,InOffset);
    }
 
    uint32 FindOffset(uint32 InTimeInAudioFrames) const
    {
        return Impl->FindOffset(InTimeInAudioFrames);
    }
 
    uint32 FindTime(uint32 InOffset) const
    {
        return Impl->FindTime(InOffset);
    }
    
    int32 Num() const
    {
        return Impl->Num();
    }
    
    ENGINE_API bool Serialize(FArchive& Ar);
 
    void Reset();
 
    bool GetAt(const uint32 InIndex, uint32& OutOffset, uint32& OutTime) const
    {
        return Impl->GetAt(InIndex, OutOffset, OutTime);
    }
 
private:
 
    static uint32 GetMagic();
    static TUniquePtr<ISeekTableImpl> CreateImpl(EChunkSeekTableMode InMode);
 
    void SetMode(EChunkSeekTableMode InMode);
    
    TUniquePtr<ISeekTableImpl> Impl;
    EChunkSeekTableMode Mode = EChunkSeekTableMode::ConstantSamplesPerEntry;
};