/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: some of this file.
 *
 * ***** END GPL LICENSE BLOCK *****
 * */

/** \file blender/blenlib/intern/math_base.c
 *  \ingroup bli
 */

#include "BLI_math.h"

#include "BLI_strict_flags.h"

int pow_i(int base, int exp)
{
	int result = 1;
	BLI_assert(exp >= 0);
	while (exp) {
		if (exp & 1) {
			result *= base;
		}
		exp >>= 1;
		base *= base;
	}

	return result;
}

/* from python 3.1 floatobject.c
 * ndigits must be between 0 and 21 */
double double_round(double x, int ndigits)
{
	double pow1, pow2, y, z;
	if (ndigits >= 0) {
		pow1 = pow(10.0, (double)ndigits);
		pow2 = 1.0;
		y = (x * pow1) * pow2;
		/* if y overflows, then rounded value is exactly x */
		if (!isfinite(y))
			return x;
	}
	else {
		pow1 = pow(10.0, (double)-ndigits);
		pow2 = 1.0; /* unused; silences a gcc compiler warning */
		y = x / pow1;
	}

	z = round(y);
	if (fabs(y - z) == 0.5)
		/* halfway between two integers; use round-half-even */
		z = 2.0 * round(y / 2.0);

	if (ndigits >= 0)
		z = (z / pow2) / pow1;
	else
		z *= pow1;

	/* if computation resulted in overflow, raise OverflowError */
	return z;
}