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/**
* @file
* @brief Stepdown functions.
**/
#include "AppHdr.h"
#include "stepdown.h"
#include <cmath>
#include "random.h"
double stepdown(double value, double step)
{
return step * log2(1 + value / step);
}
int stepdown(int value, int step, rounding_type rounding, int max)
{
double ret = stepdown((double) value, double(step));
if (max > 0 && ret > max)
return max;
// Randomised rounding
if (rounding == ROUND_RANDOM)
{
double intpart;
double fracpart = modf(ret, &intpart);
if (decimal_chance(fracpart))
++intpart;
return intpart;
}
return ret + (rounding == ROUND_CLOSE ? 0.5 : 0);
}
// Deprecated definition. Call directly stepdown instead.
int stepdown_value(int base_value, int stepping, int first_step,
int /*last_step*/, int ceiling_value)
{
// Disabling max used to be -1.
if (ceiling_value < 0)
ceiling_value = 0;
if (ceiling_value && ceiling_value < first_step)
return min(base_value, ceiling_value);
if (base_value < first_step)
return base_value;
const int diff = first_step - stepping;
// Since diff < first_step, we can assume here that ceiling_value > diff
// or ceiling_value == 0.
return diff + stepdown(base_value - diff, stepping, ROUND_DOWN,
ceiling_value ? ceiling_value - diff : 0);
}
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