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/* @(#)z_floor.c 1.0 98/08/13 */

/*

FUNCTION

<<floor>>, <<floorf>>, <<ceil>>, <<ceilf>>---floor and ceiling

INDEX

        floor

INDEX

        floorf

INDEX

        ceil

INDEX

        ceilf

ANSI_SYNOPSIS

        #include <math.h>

        double floor(double <[x]>);

        float floorf(float <[x]>);

        double ceil(double <[x]>);

        float ceilf(float <[x]>);

TRAD_SYNOPSIS

        #include <math.h>

        double floor(<[x]>)

        double <[x]>;

        float floorf(<[x]>)

        float <[x]>;

        double ceil(<[x]>)

        double <[x]>;

        float ceilf(<[x]>)

        float <[x]>;

DESCRIPTION

<<floor>> and <<floorf>> find

@tex

$\lfloor x \rfloor$,

@end tex

the nearest integer less than or equal to <[x]>.

<<ceil>> and <<ceilf>> find

@tex

$\lceil x\rceil$,

@end tex

the nearest integer greater than or equal to <[x]>.

RETURNS

<<floor>> and <<ceil>> return the integer result as a double.

<<floorf>> and <<ceilf>> return the integer result as a float.

PORTABILITY

<<floor>> and <<ceil>> are ANSI.

<<floorf>> and <<ceilf>> are extensions.

*/

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

 * floor

 *

 * Input:

 *   x  - floating point value

 *

 * Output:

 *   Smallest integer less than x.

 *

 * Description:

 *   This routine returns the smallest integer less than x.

 *

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

#include "fdlibm.h"

#include "zmath.h"

#ifndef _DOUBLE_IS_32BITS

double

_DEFUN (floor, (double),

              double x)

{

  double f, y;

  if (x > -1.0 && x < 1.0)

    return (x >= 0 ? 0 : -1.0);

  y = modf (x, &f);

  if (y == 0.0)

    return (x);

  return (x >= 0 ? f : f - 1.0);

}

#endif /* _DOUBLE_IS_32BITS */