Added draft of IO memeory buffer

lib/filesystem/CMemoryBuffer.cpp

@@ -0,0 +1,66 @@
+/*
+ * CMemoryBuffer.cpp, part of VCMI engine
+ *
+ * Authors: listed in file AUTHORS in main folder
+ *
+ * License: GNU General Public License v2.0 or later
+ * Full text of license available in license.txt file, in main folder
+ *
+ */
+ 
+#include "StdInc.h"
+#include "CMemoryBuffer.h"
+
+///CMemoryBuffer
+CMemoryBuffer::CMemoryBuffer():
+	position(0)
+{
+	
+}
+
+si64 CMemoryBuffer::write(ui8 * data, si64 size)
+{
+	buffer.reserve(tell()+size);
+	
+	std::copy(data, data + size, buffer.data() + position);
+	position += size;
+	
+	return size;		
+}
+
+si64 CMemoryBuffer::read(ui8 * data, si64 size)
+{
+	si64 toRead = std::min(getSize() - tell(), size);
+	
+	std::copy(buffer.data() + position, buffer.data() + position + toRead, data);
+	position += toRead;
+	
+	return toRead;	
+}
+
+si64 CMemoryBuffer::seek(si64 position)
+{
+	this->position = position;
+	if (this->position >=getSize())
+		this->position = getSize()-1;
+	return this->position;
+}
+
+si64 CMemoryBuffer::tell()
+{
+	return position;
+}
+
+si64 CMemoryBuffer::skip(si64 delta)
+{
+	auto old_position = tell();
+	
+	return seek(old_position + delta) - old_position; 
+}
+
+si64 CMemoryBuffer::getSize()
+{
+	return buffer.size();
+}
+
+