src/base/math/floor.c


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#include <u.h>
#include <base.h>
/*
 * floor and ceil-- greatest integer <= arg
 * (resp least >=)
 */

double
math·floor(double d)
{
	double fract;

	if(d < 0) {
		fract = math·modf(-d, &d);
		if(fract != 0.0)
			d += 1;
		d = -d;
	} else
		math·modf(d, &d);
	return d;
}

double
math·ceil(double d)
{
	return -math·floor(-d);
}