ZMBVEncoder.hh

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// Code based on DOSBox-0.65
 
#ifndef ZMBVENCODER_HH
#define ZMBVENCODER_HH
 
#include "PixelFormat.hh"
#include "MemBuffer.hh"
#include "aligned.hh"
#include <concepts>
#include <cstdint>
#include <span>
#include <zlib.h>
 
namespace openmsx {
 
class FrameSource;
template<std::unsigned_integral P> class PixelOperations;
 
class ZMBVEncoder
{
public:
        static constexpr const char CODEC_4CC[5] = "ZMBV"; // 4 + zero-terminator
 
        ZMBVEncoder(unsigned width, unsigned height, unsigned bpp);
 
        [[nodiscard]] std::span<const uint8_t> compressFrame(bool keyFrame, FrameSource* frame);
 
private:
        enum Format {
                ZMBV_FORMAT_16BPP = 6,
                ZMBV_FORMAT_32BPP = 8
        };
 
        void setupBuffers(unsigned bpp);
        [[nodiscard]] unsigned neededSize() const;
        template<std::unsigned_integral P> void addFullFrame(const PixelFormat& pixelFormat, unsigned& workUsed);
        template<std::unsigned_integral P> void addXorFrame (const PixelFormat& pixelFormat, unsigned& workUsed);
        template<std::unsigned_integral P> [[nodiscard]] unsigned possibleBlock(int vx, int vy, unsigned offset);
        template<std::unsigned_integral P> [[nodiscard]] unsigned compareBlock(int vx, int vy, unsigned offset);
        template<std::unsigned_integral P> void addXorBlock(
                const PixelOperations<P>& pixelOps, int vx, int vy,
                unsigned offset, unsigned& workUsed);
        [[nodiscard]] const void* getScaledLine(FrameSource* frame, unsigned y, void* 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<unsigned> blockOffsets;
        unsigned outputSize;
 
        z_stream zstream;
 
        const unsigned width;
        const unsigned height;
        unsigned pitch;
        unsigned pixelSize;
        Format format;
};
 
} // namespace openmsx
 
#endif