50 lines
1.2 KiB
C++
50 lines
1.2 KiB
C++
#ifdef ZSTD
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#include "leveldb/zstd_compressor.h"
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#include <zstd.h>
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void leveldb::ZstdCompressor::compressImpl(const char* input, size_t length, ::std::string& output) const
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{
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//extend the buffer to the worst case
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auto originalSize = output.size();
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auto capacity = ZSTD_compressBound(length);
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output.resize(originalSize + capacity);
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//and then compress into it
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auto sz = ZSTD_compress((void*)(output.data() + originalSize), capacity, input, length, compressionLevel);
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assert(!ZSTD_isError(sz));
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output.resize(sz + originalSize);
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}
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bool leveldb::ZstdCompressor::decompress(const char* input, size_t length, ::std::string &output) const
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{
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//extend the buffer to contain the worst case. Worst case is that input length == output length
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auto originalSize = output.size();
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auto bufsize = length;
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while (true)
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{
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bufsize *= 10; //assume that the compression is compressing worse than 10%.
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//TODO use streams to decompress piece by piece, this is pretty wasteful for memory & re-decompressions
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output.resize(originalSize + bufsize);
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auto sz = ZSTD_decompress((void*)(output.data() + originalSize), bufsize, input, length);
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if (!ZSTD_isError(sz))
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{
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output.resize(sz + originalSize);
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break;
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}
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}
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return true;
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}
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#endif
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