sortix--sortix/libmaxsi/random.cpp

/*******************************************************************************

	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011, 2012.

	This file is part of LibMaxsi.

	LibMaxsi is free software: you can redistribute it and/or modify it under
	the terms of the GNU Lesser General Public License as published by the Free
	Software Foundation, either version 3 of the License, or (at your option)
	any later version.

	LibMaxsi is distributed in the hope that it will be useful, but WITHOUT ANY
	WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
	FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
	details.

	You should have received a copy of the GNU Lesser General Public License
	along with LibMaxsi. If not, see <http://www.gnu.org/licenses/>.

	random.cpp
	Provides access to random numbers using various algorithms.

*******************************************************************************/

#include <libmaxsi/platform.h>

namespace Maxsi
{
	namespace Random
	{
#if 1
		unsigned int m_w = 1337;
		unsigned int m_z = 37;
		unsigned int RandomUnsignedInt()
		{
			m_z = 36969 * (m_z & 65535) + (m_z >> 16);
			m_w = 18000 * (m_w & 65535) + (m_w >> 16);
			return (m_z << 16) + m_w;  /* 32-bit result */
		}
		extern "C" int rand()
		{
			return RandomUnsignedInt() % 32768;
		}
#else
		unsigned random_seed = 1337;
		extern "C" int rand()
		{
			random_seed = random_seed + 37 * 1103515245 + 12345;
			return random_seed >> 16;
		}
#endif
	}
}