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42 lines
1.5 KiB
C++
42 lines
1.5 KiB
C++
#include <Compression/getCompressionCodecForFile.h>
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#include <Compression/CompressionInfo.h>
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#include <Compression/CompressionFactory.h>
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#include <IO/ReadBufferFromFileBase.h>
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#include <Compression/CompressionCodecMultiple.h>
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#include <Common/PODArray.h>
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#include <common/logger_useful.h>
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namespace DB
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{
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using Checksum = CityHash_v1_0_2::uint128;
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CompressionCodecPtr getCompressionCodecForFile(const DiskPtr & disk, const String & relative_path)
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{
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auto read_buffer = disk->readFile(relative_path);
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read_buffer->ignore(sizeof(Checksum));
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UInt8 header_size = ICompressionCodec::getHeaderSize();
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PODArray<char> compressed_buffer;
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compressed_buffer.resize(header_size);
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read_buffer->readStrict(compressed_buffer.data(), header_size);
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uint8_t method = ICompressionCodec::readMethod(compressed_buffer.data());
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if (method == static_cast<uint8_t>(CompressionMethodByte::Multiple))
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{
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compressed_buffer.resize(1);
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read_buffer->readStrict(compressed_buffer.data(), 1);
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compressed_buffer.resize(1 + compressed_buffer[0]);
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read_buffer->readStrict(compressed_buffer.data() + 1, compressed_buffer[0]);
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auto codecs_bytes = CompressionCodecMultiple::getCodecsBytesFromData(compressed_buffer.data());
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Codecs codecs;
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for (auto byte : codecs_bytes)
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codecs.push_back(CompressionCodecFactory::instance().get(byte));
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return std::make_shared<CompressionCodecMultiple>(codecs);
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}
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return CompressionCodecFactory::instance().get(method);
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}
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}
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