Pl_LZWDecoder.hh
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#ifndef PL_LZWDECODER_HH
#define PL_LZWDECODER_HH
#include <qpdf/Pipeline.hh>
#include <qpdf/Buffer.hh>
#include <vector>
class Pl_LZWDecoder final: public Pipeline
{
public:
Pl_LZWDecoder(char const* identifier, Pipeline* next, bool early_code_change);
~Pl_LZWDecoder() final = default;
void write(unsigned char const* buf, size_t len) final;
void finish() final;
private:
void sendNextCode();
void handleCode(unsigned int code);
unsigned char getFirstChar(unsigned int code);
void addToTable(unsigned char next);
// members used for converting bits to codes
unsigned char buf[3]{0, 0, 0};
unsigned int code_size{9};
unsigned int next_char_{0};
unsigned int byte_pos{0};
unsigned int bit_pos{0}; // left to right: 01234567
unsigned int bits_available{0};
// members used for handle LZW decompression
bool code_change_delta{false};
bool eod{false};
std::vector<Buffer> table;
unsigned int last_code{256};
};
#endif // PL_LZWDECODER_HH