Adpcm.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "HAL/Platform.h"
 
namespace ADPCM
{
    // Returns true if successful, false if there was an error in decoding
    bool DecodeBlock(const uint8* EncodedADPCMBlock, const int32 BlockSize, int16* DecodedPCMData, const int32 DecodedPCMSize);
    bool DecodeBlock(const uint8* EncodedADPCMBlock, const int32 BlockSize, int16* DecodedPCMData);
} //namespace ADPCM
 
namespace ADPCMPrivate
{
    // Copied from IOS - probably want to split and share
 
    template <typename T, uint32 B>
    inline T SignExtend(const T ValueToExtend)
    {
        struct { T ExtendedValue : B; } SignExtender;
        return SignExtender.ExtendedValue = ValueToExtend;
    }
 
    template <typename T>
    inline T ReadFromByteStream(const uint8* ByteStream, int32& ReadIndex, bool bLittleEndian = true)
    {
        T ValueRaw = 0;
 
        if (bLittleEndian)
        {
#if PLATFORM_LITTLE_ENDIAN
            for (int32 ByteIndex = 0; ByteIndex < sizeof(T); ++ByteIndex)
#else
            for (int32 ByteIndex = sizeof(T) - 1; ByteIndex >= 0; --ByteIndex)
#endif // PLATFORM_LITTLE_ENDIAN
            {
                ValueRaw |= ByteStream[ReadIndex++] << 8 * ByteIndex;
            }
        }
        else
        {
#if PLATFORM_LITTLE_ENDIAN
            for (int32 ByteIndex = sizeof(T) - 1; ByteIndex >= 0; --ByteIndex)
#else
            for (int32 ByteIndex = 0; ByteIndex < sizeof(T); ++ByteIndex)
#endif // PLATFORM_LITTLE_ENDIAN
            {
                ValueRaw |= ByteStream[ReadIndex++] << 8 * ByteIndex;
            }
        }
 
        return ValueRaw;
    }
 
    template <typename T>
    inline void WriteToByteStream(T Value, uint8* ByteStream, int32& WriteIndex, bool bLittleEndian = true)
    {
        if (bLittleEndian)
        {
#if PLATFORM_LITTLE_ENDIAN
            for (int32 ByteIndex = 0; ByteIndex < sizeof(T); ++ByteIndex)
#else
            for (int32 ByteIndex = sizeof(T) - 1; ByteIndex >= 0; --ByteIndex)
#endif // PLATFORM_LITTLE_ENDIAN
            {
                ByteStream[WriteIndex++] = (Value >> (8 * ByteIndex)) & 0xFF;
            }
        }
        else
        {
#if PLATFORM_LITTLE_ENDIAN
            for (int32 ByteIndex = sizeof(T) - 1; ByteIndex >= 0; --ByteIndex)
#else
            for (int32 ByteIndex = 0; ByteIndex < sizeof(T); ++ByteIndex)
#endif // PLATFORM_LITTLE_ENDIAN
            {
                ByteStream[WriteIndex++] = (Value >> (8 * ByteIndex)) & 0xFF;
            }
        }
    }
 
    template <typename T>
    inline T ReadFromArray(const T* ElementArray, int32& ReadIndex, int32 NumElements, int32 IndexStride = 1)
    {
        T OutputValue = 0;
 
        if (ReadIndex >= 0 && ReadIndex < NumElements)
        {
            OutputValue = ElementArray[ReadIndex];
            ReadIndex += IndexStride;
        }
 
        return OutputValue;
    }
 
    // End of copied section
} // namespace ADPCMPrivate