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34 lines
927 B
C++
34 lines
927 B
C++
#pragma once
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#include <base/types.h>
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#include <IO/SeekableReadBuffer.h>
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namespace DB
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{
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/** Allows to read from another SeekableReadBuffer no far than the specified offset.
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* Note that the nested SeekableReadBuffer may read slightly more data internally to fill its buffer.
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*/
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class LimitSeekableReadBuffer : public SeekableReadBuffer
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{
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public:
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LimitSeekableReadBuffer(SeekableReadBuffer & in_, UInt64 limit_);
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LimitSeekableReadBuffer(std::unique_ptr<SeekableReadBuffer> in_, UInt64 limit_);
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~LimitSeekableReadBuffer() override;
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off_t seek(off_t off, int whence) override;
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off_t getPosition() override { return end_position - available(); }
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private:
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SeekableReadBuffer * in;
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bool owns_in;
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UInt64 limit;
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off_t end_position; /// Offset of the end of working_buffer.
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LimitSeekableReadBuffer(SeekableReadBuffer * in_, bool owns, UInt64 limit_);
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bool nextImpl() override;
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};
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}
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