mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-10-25 18:00:51 +00:00
65 lines
1.4 KiB
C++
65 lines
1.4 KiB
C++
|
#pragma once
|
||
|
|
||
|
#include <vector>
|
||
|
|
||
|
#include <DB/IO/ReadBuffer.h>
|
||
|
|
||
|
|
||
|
namespace DB
|
||
|
{
|
||
|
|
||
|
/** Читает из конкатенации нескольких ReadBuffer-ов
|
||
|
*/
|
||
|
class ConcatReadBuffer : public ReadBuffer
|
||
|
{
|
||
|
public:
|
||
|
typedef std::vector<ReadBuffer *> ReadBuffers;
|
||
|
|
||
|
protected:
|
||
|
ReadBuffers buffers;
|
||
|
ReadBuffers::iterator current;
|
||
|
|
||
|
bool nextImpl()
|
||
|
{
|
||
|
if (buffers.end() == current)
|
||
|
return false;
|
||
|
|
||
|
/// Первое чтение
|
||
|
if (working_buffer.size() == 0 && (*current)->hasPendingData())
|
||
|
{
|
||
|
working_buffer = Buffer((*current)->position(), (*current)->buffer().end());
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
if (!(*current)->next())
|
||
|
{
|
||
|
++current;
|
||
|
if (buffers.end() == current)
|
||
|
return false;
|
||
|
|
||
|
/// Пропускаем закончившиеся буферы; если буфер не закончился, но курсор на конце, то прочитаем следующую порцию данных.
|
||
|
while ((*current)->eof())
|
||
|
{
|
||
|
++current;
|
||
|
if (buffers.end() == current)
|
||
|
return false;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
working_buffer = Buffer((*current)->position(), (*current)->buffer().end());
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
public:
|
||
|
ConcatReadBuffer(const ReadBuffers & buffers_) : ReadBuffer(nullptr, 0), buffers(buffers_), current(buffers.begin()) {}
|
||
|
|
||
|
ConcatReadBuffer(ReadBuffer & buf1, ReadBuffer & buf2) : ReadBuffer(nullptr, 0)
|
||
|
{
|
||
|
buffers.push_back(&buf1);
|
||
|
buffers.push_back(&buf2);
|
||
|
current = buffers.begin();
|
||
|
}
|
||
|
};
|
||
|
|
||
|
}
|