StreamTransformer.h

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/****
 * Sming Framework Project - Open Source framework for high efficiency native ESP8266 development.
 * Created 2015 by Skurydin Alexey
 * http://github.com/SmingHub/Sming
 * All files of the Sming Core are provided under the LGPL v3 license.
 *
 * StreamTransformer.h
 *
 * @author Slavey Karadzhov <slaff@attachix.com>
 *
 ****/

#pragma once

#include "Buffer/CircularBuffer.h"

class StreamTransformer : public IDataSourceStream
{
public:
    StreamTransformer(IDataSourceStream* stream, size_t resultSize = 256, size_t blockSize = 64)
        : sourceStream(stream), result(new uint8_t[resultSize]), resultSize(resultSize), blockSize(blockSize)
    {
    }

    ~StreamTransformer()
    {
        delete[] result;
        delete tempStream;
        delete sourceStream;
    }

    //Use base class documentation
    StreamType getStreamType() const override
    {
        return sourceStream->getStreamType();
    }

    int available() override
    {
        return -1;
    }

    bool isValid() const
    {
        return sourceStream != nullptr && sourceStream->isValid();
    }

    uint16_t readMemoryBlock(char* data, int bufSize) override;

    bool seek(int len) override;

    bool isFinished() override;

    String getName() const override
    {
        return (sourceStream == nullptr) ? nullptr : sourceStream->getName();
    }

    virtual void saveState(){};

    virtual void restoreState(){};

protected:
    virtual size_t transform(const uint8_t* in, size_t inLength, uint8_t* out, size_t outLength) = 0;

private:
    void fillTempStream(char* buffer, size_t bufSize);

    IDataSourceStream* sourceStream{nullptr};
    CircularBuffer* tempStream{nullptr};
    uint8_t* result{nullptr};
    size_t resultSize;
    size_t blockSize;
};