Libraries/Graphics/src/include/Graphics/Stream.h

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/****
 * Stream.h
 *
 * Copyright 2021 mikee47 <mike@sillyhouse.net>
 *
 * This file is part of the Sming-Graphics Library
 *
 * This library is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, version 3 or later.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this library.
 * If not, see <https://www.gnu.org/licenses/>.
 *
 * @author: May 2021 - mikee47 <mike@sillyhouse.net>
 *
 ****/

#pragma once

#include <Data/Stream/DataSourceStream.h>

namespace Graphics
{
class WriteStream
{
public:
    WriteStream(Print& stream) : stream(stream)
    {
    }

    void write(const void* buffer, size_t count);

    void flush();

private:
    static constexpr size_t size{256};
    Print& stream;
    uint8_t data[size];
    uint16_t length{0};
};

class ReadStream
{
public:
    ReadStream(IDataSourceStream& stream) : stream(stream)
    {
    }

    size_t read(uint32_t offset, void* buffer, size_t count);
    uint8_t read(uint32_t offset);

private:
    static constexpr size_t size{64};
    IDataSourceStream& stream;
    uint8_t data[size];
    uint32_t start{0};
    uint16_t length{0};
};

class SubStream : public IDataSourceStream
{
public:
    SubStream(IDataSourceStream& source, uint32_t offset, size_t size) : source(source), startOffset(offset), size(size)
    {
        int sourceSize = source.seekFrom(0, SeekOrigin::End);
        if(sourceSize < int(offset)) {
            size = 0;
            return;
        }

        size = std::min(size, size_t(sourceSize - offset));

        source.seekFrom(offset, SeekOrigin::Start);
    }

    int available() override
    {
        return size - readPos;
    }

    uint16_t readMemoryBlock(char* data, int bufSize) override
    {
        return source.readMemoryBlock(data, bufSize);
    }

    int seekFrom(int offset, SeekOrigin origin) override
    {
        size_t newPos;
        switch(origin) {
        case SeekOrigin::Start:
            newPos = offset;
            break;
        case SeekOrigin::Current:
            newPos = readPos + offset;
            break;
        case SeekOrigin::End:
            newPos = size + offset;
            break;
        default:
            return -1;
        }

        if(newPos > size) {
            return -1;
        }

        source.seekFrom(startOffset + newPos, SeekOrigin::Start);
        readPos = newPos;
        return readPos;
    }

    bool isFinished() override
    {
        return available() <= 0;
    }

private:
    IDataSourceStream& source;
    uint32_t startOffset;
    uint32_t readPos{0};
    size_t size;
};

} // namespace Graphics