Martin Michelsen
73 lines
2.4 KiB
C++
73 lines
2.4 KiB
C++
#pragma once
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#include <stddef.h>
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#include <string>
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#include "Text.hh"
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// Use this class if you need to compress from multiple input buffers, or need
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// to compress multiple chunks and don't want to copy their contents
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// unnecessarily. (For most common use cases, use prs_compress (below) instead.)
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class PRSCompressor {
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public:
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// To use this class, instantiate it, then call .add() one or more times, then
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// call .close() and use the returned string as the compressed result.
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PRSCompressor();
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~PRSCompressor() = default;
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// Adds more input data to be compressed, which logically comes after all
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// previous data provided via add() calls. Cannot be called after close() is
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// called.
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void add(const void* data, size_t size);
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void add(const std::string& data);
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// Ends compression and returns the complete compressed result. It's OK to
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// std::move() from the returned string reference.
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std::string& close();
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// Returns the total number of bytes passed to add() calls so far.
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inline size_t input_size() const {
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return this->input_bytes;
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}
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private:
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void add_byte(uint8_t v);
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void advance();
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void write_control(bool z);
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void flush_control();
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bool closed;
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size_t control_byte_offset;
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uint16_t pending_control_bits;
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size_t input_bytes;
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parray<uint8_t, 0x100> forward_log;
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size_t compression_offset;
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parray<uint8_t, 0x2000> reverse_log;
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StringWriter output;
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};
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// Compresses data from a single input buffer using PRS and returns the
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// compressed result. This is a shortcut for constructing a PRSCompressor,
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// calling .add() once, and calling .close().
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std::string prs_compress(const void* vdata, size_t size);
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std::string prs_compress(const std::string& data);
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// Decompresses PRS-compressed data.
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std::string prs_decompress(const void* data, size_t size, size_t max_output_size = 0);
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std::string prs_decompress(const std::string& data, size_t max_output_size = 0);
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// Returns the decompressed size of PRS-compressed data, without actually
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// decompressing it.
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size_t prs_decompress_size(const void* data, size_t size, size_t max_output_size = 0);
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size_t prs_decompress_size(const std::string& data, size_t max_output_size = 0);
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// Decompresses and compresses data using the BC0 algorithm.
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std::string bc0_decompress(const std::string& data);
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std::string bc0_compress(const std::string& data);
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