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48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
#pragma once
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#include "CompressedReadBufferBase.h"
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#include <IO/ReadBufferFromFileBase.h>
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#include <time.h>
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#include <memory>
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namespace DB
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{
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/// Unlike CompressedReadBuffer, it can do seek.
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class CompressedReadBufferFromFile : public CompressedReadBufferBase, public BufferWithOwnMemory<ReadBuffer>
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{
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private:
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/** At any time, one of two things is true:
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* a) size_compressed = 0
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* b)
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* - `working_buffer` contains the entire block.
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* - `file_in` points to the end of this block.
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* - `size_compressed` contains the compressed size of this block.
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*/
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std::unique_ptr<ReadBufferFromFileBase> p_file_in;
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ReadBufferFromFileBase & file_in;
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size_t size_compressed = 0;
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bool nextImpl() override;
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public:
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CompressedReadBufferFromFile(std::unique_ptr<ReadBufferFromFileBase> buf, bool allow_different_codecs_ = false);
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CompressedReadBufferFromFile(
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const std::string & path, size_t estimated_size, size_t aio_threshold, size_t mmap_threshold,
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size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE, bool allow_different_codecs_ = false);
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void seek(size_t offset_in_compressed_file, size_t offset_in_decompressed_block);
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size_t readBig(char * to, size_t n) override;
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void setProfileCallback(const ReadBufferFromFileBase::ProfileCallback & profile_callback_, clockid_t clock_type_ = CLOCK_MONOTONIC_COARSE)
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{
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file_in.setProfileCallback(profile_callback_, clock_type_);
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}
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};
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}
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