/* reduce argument to range +/- PI */

#include <math.h>

#include "proj.h"

#include "proj_internal.h"

double adjlon(double longitude) {

    /* Let longitude slightly overshoot, to avoid spurious sign switching at the

     * date line */

    if (fabs(longitude) < M_PI + 1e-12)

        return longitude;

    /* adjust to 0..2pi range */

    longitude += M_PI;

    /* remove integral # of 'revolutions'*/

    longitude -= M_TWOPI * floor(longitude / M_TWOPI);

    /* adjust back to -pi..pi range */

    longitude -= M_PI;

    return longitude;

}