ClickHouse/dbms/src/IO/ReadBufferFromIStream.h

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#pragma once
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#include <iostream>
#include <Common/Exception.h>
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#include <IO/ReadBuffer.h>
#include <IO/BufferWithOwnMemory.h>
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namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_READ_FROM_ISTREAM;
}
class ReadBufferFromIStream : public BufferWithOwnMemory<ReadBuffer>
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{
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;
}
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public:
ReadBufferFromIStream(std::istream & istr_, size_t size = DBMS_DEFAULT_BUFFER_SIZE)
: BufferWithOwnMemory<ReadBuffer>(size), istr(istr_) {}
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};
}