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51 lines
1.0 KiB
C
51 lines
1.0 KiB
C
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#pragma once
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#include <DB/DataStreams/IProfilingBlockInputStream.h>
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namespace DB
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{
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using Poco::SharedPtr;
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/** Объединяет несколько источников в один.
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* В отличие от UnionBlockInputStream, делает это последовательно.
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* Блоки разных источников не перемежаются друг с другом.
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*/
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class ConcatBlockInputStream : public IProfilingBlockInputStream
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{
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public:
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ConcatBlockInputStream(BlockInputStreams inputs_)
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{
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children.insert(children.end(), inputs_.begin(), inputs_.end());
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current_stream = children.begin();
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}
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Block readImpl()
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{
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Block res;
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while (current_stream != children.end())
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{
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res = (*current_stream)->read();
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if (res)
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break;
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else
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++current_stream;
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}
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return res;
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}
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String getName() const { return "ConcatBlockInputStream"; }
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BlockInputStreamPtr clone() { return new ConcatBlockInputStream(children); }
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private:
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BlockInputStreams::iterator current_stream;
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};
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}
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