ZMBVEncoder.hh

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// Code based on DOSBox-0.65
 
#ifndef ZMBVENCODER_HH
#define ZMBVENCODER_HH
 
#include "MemBuffer.hh"
#include "aligned.hh"
 
#include <cstdint>
#include <span>
#include <string_view>
 
#include <zlib.h>
 
namespace openmsx {
 
class FrameSource;
 
class ZMBVEncoder
{
public:
        static constexpr std::string_view CODEC_4CC = "ZMBV";
        using Pixel = uint32_t;
 
        ZMBVEncoder(unsigned width, unsigned height);
        ZMBVEncoder(const ZMBVEncoder&) = delete;
        ZMBVEncoder(ZMBVEncoder&&) = delete;
        ZMBVEncoder& operator=(const ZMBVEncoder&) = delete;
        ZMBVEncoder& operator=(ZMBVEncoder&&) = delete;
        ~ZMBVEncoder() = default;
 
        [[nodiscard]] std::span<const uint8_t> compressFrame(bool keyFrame, const FrameSource* frame);
 
private:
        void setupBuffers();
        [[nodiscard]] unsigned neededSize() const;
        void addFullFrame(unsigned& workUsed);
        void addXorFrame (unsigned& workUsed);
        [[nodiscard]] unsigned possibleBlock(int vx, int vy, size_t offset);
        [[nodiscard]] unsigned compareBlock(int vx, int vy, size_t offset);
        void addXorBlock(int vx, int vy, size_t offset, unsigned& workUsed);
        [[nodiscard]] const Pixel* getScaledLine(const FrameSource* frame, unsigned y, Pixel* workBuf) const;
 
private:
        MemBuffer<uint8_t, SSE_ALIGNMENT> oldFrame;
        MemBuffer<uint8_t, SSE_ALIGNMENT> newFrame;
        MemBuffer<uint8_t, SSE_ALIGNMENT> work;
        MemBuffer<uint8_t> output;
        MemBuffer<size_t> blockOffsets;
        unsigned outputSize;
 
        z_stream zstream;
 
        unsigned width;
        unsigned height;
        size_t pitch;
};
 
} // namespace openmsx
 
#endif