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

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#pragma once
#include <DB/IO/BufferWithOwnMemory.h>
#include <DB/IO/WriteBuffer.h>
/// Так как HexWriteBuffer часто создаётся во внутреннем цикле, сделаем у него размер буфера маленьким.
#define DBMS_HEX_WRITE_BUFFER_SIZE 32
namespace DB
{
/** Всё что в него пишут, переводит в HEX (большими буквами) и пишет в другой WriteBuffer.
*/
class HexWriteBuffer : public WriteBuffer
{
protected:
char buf[DBMS_HEX_WRITE_BUFFER_SIZE];
WriteBuffer & out;
void nextImpl() override
{
if (!offset())
return;
for (Position p = working_buffer.begin(); p != pos; ++p)
{
out.write("0123456789ABCDEF"[static_cast<unsigned char>(*p) >> 4]);
out.write("0123456789ABCDEF"[static_cast<unsigned char>(*p) & 0xF]);
}
}
public:
HexWriteBuffer(WriteBuffer & out_) : WriteBuffer(buf, sizeof(buf)), out(out_) {}
~HexWriteBuffer() override
{
try
{
nextImpl();
}
catch (...)
{
tryLogCurrentException(__PRETTY_FUNCTION__);
}
}
};
}