ClickMapBLOB: using DB::IO [#CONV-2807].

dbms/include/DB/IO/HexWriteBuffer.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <DB/IO/BufferWithOwnMemory.h>
+#include <DB/IO/WriteBuffer.h>
+
+
+namespace DB
+{
+
+/** Всё что в него пишут, переводит в HEX (большими буквами) и пишет в другой WriteBuffer.
+  */
+class HexWriteBuffer : public BufferWithOwnMemory<WriteBuffer>
+{
+protected:
+	WriteBuffer & out;
+	
+	void nextImpl()
+	{
+		if (!offset())
+			return;
+
+		for (Position pos = working_buffer.begin(); pos != working_buffer.end(); ++pos)
+		{
+			out.write("0123456789ABCDEF"[static_cast<unsigned char>(*pos) >> 4]);
+			out.write("0123456789ABCDEF"[static_cast<unsigned char>(*pos) & 0xF]);
+		}
+	}
+
+public:
+	HexWriteBuffer(WriteBuffer & out_) : out(out_) {}
+
+    virtual ~HexWriteBuffer()
+	{
+		nextImpl();
+	}
+};
+
+}