ClickHouse/dbms/include/DB/IO/ReadBufferFromIStream.h

49 lines
828 B
C++

#pragma once
#include <iostream>
#include <DB/Common/Exception.h>
#include <DB/IO/ReadBuffer.h>
#include <DB/IO/BufferWithOwnMemory.h>
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_READ_FROM_ISTREAM;
}
class ReadBufferFromIStream : public BufferWithOwnMemory<ReadBuffer>
{
private:
std::istream & istr;
bool nextImpl() override
{
istr.read(internal_buffer.begin(), internal_buffer.size());
size_t gcount = istr.gcount();
if (!gcount)
{
if (istr.eof())
return false;
else
throw Exception("Cannot read from istream", ErrorCodes::CANNOT_READ_FROM_ISTREAM);
}
else
working_buffer.resize(gcount);
return true;
}
public:
ReadBufferFromIStream(std::istream & istr_, size_t size = DBMS_DEFAULT_BUFFER_SIZE)
: BufferWithOwnMemory<ReadBuffer>(size), istr(istr_) {}
};
}