// Copyright (C) 2002-2012 Nikolaus Gebhardt
// This file is part of the "Irrlicht Engine".
// For conditions of distribution and use, see copyright notice in irrlicht.h

#include "CMemoryReadWriteFile.h"

using namespace irr;
using namespace io;

CMemoryReadWriteFile::CMemoryReadWriteFile(const c8* filename)
:  Data(), FileName(filename), Pos(0)
{
}


size_t CMemoryReadWriteFile::write(const void* buffer, size_t sizeToWrite)
{
	// no point in writing 0 bytes
	if (sizeToWrite < 1)
		return 0;

	// expand size
	if (Pos + sizeToWrite > Data.size())
		Data.set_used(Pos+sizeToWrite);

	// copy data
	memcpy( (void*) &Data[Pos], buffer, sizeToWrite);

	Pos += sizeToWrite;

	return sizeToWrite;

}

bool CMemoryReadWriteFile::seek(long finalPos, bool relativeMovement)
{
	if (relativeMovement)
	{
		if (finalPos + Pos < 0)
			return 0;
		else
			Pos += finalPos;
	}
	else
	{
		Pos = finalPos;
	}

	if (Pos > (s32)Data.size())
		Data.set_used(Pos+1);

	return true;

}

const io::path& CMemoryReadWriteFile::getFileName() const
{
	return FileName;
}

long CMemoryReadWriteFile::getPos() const
{
	return Pos;
}

core::array<c8>& CMemoryReadWriteFile::getData()
{
	return Data;
}


long CMemoryReadWriteFile::getSize() const
{
	return Data.size();
}


size_t CMemoryReadWriteFile::read(void* buffer, size_t sizeToRead)
{
	// cant read past the end
	if ((size_t)Pos + sizeToRead >= Data.size())
		sizeToRead = Data.size() - (size_t)Pos;

	// cant read 0 bytes
	if (!sizeToRead)
		return 0;

	// copy data
	memcpy( buffer, (void*) &Data[Pos], sizeToRead);

	Pos += (long)sizeToRead;

	return sizeToRead;
}

bool CMemoryReadWriteFile::flush()
{
	return true;	// no buffering, nothing to do
}