61 lines
1.7 KiB
C++
61 lines
1.7 KiB
C++
#pragma once
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#include <cstdint>
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#include <zstd.h> // apt-get install libzstd-dev if you miss this.
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// can't easily be moved to zstdwrap.cc, trust me
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#include <functional>
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#include <thread>
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#include <atomic>
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// users submit (give()) data to this class
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// the class has an internal buffer to which compressed data gets written
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// If that buffer is full, we call emit() to empty it
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// the emit() function must make sure that everything in the buffer gets sent!
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class ZStdCompressor
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{
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public:
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explicit ZStdCompressor(const std::function<void(const char*, uint32_t)>& emit, int compressionLevel);
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ZStdCompressor(const ZStdCompressor& rhs) = delete;
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~ZStdCompressor();
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void give(const char* data, uint32_t bytes);
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static int maxCompressionLevel();
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uint64_t d_inputBytes{0}, d_outputBytes{0};
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uint32_t outputBufferBytes(); // Number of bytes in output buffer
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uint32_t outputBufferCapacity(); // output buffer capacity
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void flush();
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private:
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void flushToEmit();
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ZSTD_CCtx *d_z{nullptr};
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ZSTD_outBuffer d_out;
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uint32_t d_outcapacity;
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std::function<void(const char*, uint32_t)> d_emit;
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};
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/* this class is tremendously devious
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you pass it a filedescriptor from which it reads zstd compressed data
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You can then read the uncompressed data on the filedescriptor you
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get from getFD()
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*/
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class ZStdReader
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{
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public:
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ZStdReader(int fd); // we don't close this for you
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ZStdReader(const ZStdReader& rhs) = delete;
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~ZStdReader();
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int getFD()
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{
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return d_readpipe;
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}
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private:
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std::thread d_thread;
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int d_sourcefd; // this is where we read compressed data
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int d_writepipe; // which we then stuff into this pipe
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int d_readpipe; // and it comes out here for the client
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void worker();
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};
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