ClickHouse/dbms/include/DB/IO/WriteBufferFromVector.h
2011-10-16 01:57:10 +00:00

45 lines
1.1 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

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