XSAExtractor.hh

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#ifndef XSAEXTRACTOR_HH
#define XSAEXTRACTOR_HH
 
#include "DiskImageUtils.hh"
 
#include <array>
#include <cstdint>
#include <span>
#include <vector>
 
namespace openmsx {
 
class XSAExtractor
{
public:
        explicit XSAExtractor(std::span<const uint8_t> file);
        std::vector<SectorBuffer> extractData() &&;
 
private:
        static constexpr int MAX_STR_LEN = 254;
        static constexpr int TBL_SIZE = 16;
        static constexpr int MAX_HUF_CNT = 127;
 
        [[nodiscard]] inline uint8_t charIn();
        void chkHeader();
        void unLz77();
        [[nodiscard]] unsigned rdStrLen();
        [[nodiscard]] int rdStrPos();
        [[nodiscard]] bool bitIn();
        void initHufInfo();
        void mkHufTbl();
 
        struct HufNode {
                HufNode* child1;
                HufNode* child2;
                int weight;
        };
 
private:
        std::span<const uint8_t> file; // the not-yet-consumed part of the file
        std::vector<SectorBuffer> output;
 
        int updHufCnt;
        std::array<int, TBL_SIZE + 1> cpDist;
        std::array<int, TBL_SIZE> tblSizes;
        std::array<HufNode, 2 * TBL_SIZE - 1> hufTbl;
 
        uint8_t bitFlg; // flag with the bits
        uint8_t bitCnt; // nb bits left
 
        static constexpr std::array<uint8_t, TBL_SIZE> cpdExt = { // Extra bits for distance codes
                  0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
        };
};
 
} // namespace openmsx
 
#endif