/*
* libcaca ASCII-Art library
* Copyright (c) 2002, 2003 Sam Hocevar
* All Rights Reserved
*
* This library 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 2 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
* 02111-1307 USA
*/
/** \file math.c
* \version \$Id: math.c 298 2003-12-31 14:21:08Z sam $
* \author Sam Hocevar
* \brief Math
*
* This file contains simple mathematical routines.
*/
#include "config.h"
#include
#include "caca.h"
#include "caca_internals.h"
/**
* \brief Generate a random integer within a range.
*
* \param min The lower bound of the integer range.
* \param max The upper bound of the integer range.
* \return A random integer comprised between \p min and \p max, inclusive.
*/
int caca_rand(int min, int max)
{
return min + (int)((1.0*(max-min+1)) * rand() / (RAND_MAX+1.0));
}
/**
* \brief Approximate a square root, using Newton's method to avoid
* costly floating point calculations.
*
* \param a A positive integer.
* \return The approximate square root of \p a.
*/
unsigned int caca_sqrt(unsigned int a)
{
if(a == 0)
return 0;
if(a < 1000000000)
{
unsigned int x = a < 10 ? 1
: a < 1000 ? 10
: a < 100000 ? 100
: a < 10000000 ? 1000
: 10000;
/* Newton's method. Three iterations would be more than enough. */
x = (x * x + a) / x / 2;
x = (x * x + a) / x / 2;
x = (x * x + a) / x / 2;
x = (x * x + a) / x / 2;
return x;
}
return 2 * caca_sqrt(a / 4);
}