StreamTransformer.h

Go to the documentation of this file.

/****
 * 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"
#include <memory>
 
class StreamTransformer : public IDataSourceStream
{
public:
    StreamTransformer(IDataSourceStream* stream, size_t resultSize = 256, size_t blockSize = 64)
        : resultSize(resultSize), blockSize(blockSize)
    {
        sourceStream.reset(stream);
        result.reset(new uint8_t[resultSize]);
    }
 
    //Use base class documentation
    StreamType getStreamType() const override
    {
        return sourceStream->getStreamType();
    }
 
    int available() override
    {
        return -1;
    }
 
    bool isValid() const
    {
        return sourceStream && sourceStream->isValid();
    }
 
    uint16_t readMemoryBlock(char* data, int bufSize) override;
 
    bool seek(int len) override;
 
    bool isFinished() override;
 
    String getName() const override
    {
        return sourceStream ? sourceStream->getName() : String::nullstr;
    }
 
    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);
 
    std::unique_ptr<IDataSourceStream> sourceStream;
    std::unique_ptr<CircularBuffer> tempStream;
    std::unique_ptr<uint8_t[]> result;
    size_t resultSize;
    size_t blockSize;
};