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44 lines
1.1 KiB
C++
44 lines
1.1 KiB
C++
#pragma once
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#include <vector>
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#include <DB/IO/WriteBuffer.h>
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#define WRITE_BUFFER_FROM_VECTOR_INITIAL_SIZE_IF_EMPTY 32
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namespace DB
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{
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/** Инициализируется вектором. Пишет данные в него. Когда вектор закончится - увеличивает его размер в два раза.
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* CharType - char или unsigned char.
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*/
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template <typename VectorType = std::vector<char> >
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class WriteBufferFromVector : public WriteBuffer
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{
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private:
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VectorType & vector;
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void nextImpl()
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{
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size_t old_size = vector.size();
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vector.resize(old_size * 2);
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internal_buffer = Buffer(reinterpret_cast<Position>(&vector[old_size]), reinterpret_cast<Position>(&*vector.end()));
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working_buffer = internal_buffer;
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}
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public:
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WriteBufferFromVector(VectorType & vector_)
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: WriteBuffer(reinterpret_cast<Position>(&vector_[0]), vector_.size()), vector(vector_)
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{
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if (vector.empty())
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{
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vector.resize(WRITE_BUFFER_FROM_VECTOR_INITIAL_SIZE_IF_EMPTY);
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set(reinterpret_cast<Position>(&vector[0]), vector.size());
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}
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}
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};
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}
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