/* $Id$ $Revision$ */
/* vim:set shiftwidth=4 ts=8: */

/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property 
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors: See CVS logs. Details at http://www.graphviz.org/
 *************************************************************************/

#include	"sfhdr.h"

#include <math.h>

/*	Return the length of a double value if coded in a portable format
**
**	Written by Kiem-Phong Vo
*/

int _sfdlen(Sfdouble_t v)
{
#define N_ARRAY		(16*sizeof(Sfdouble_t))
    reg int n, w;
    Sfdouble_t x;
    int exp;

    if (v < 0)
	v = -v;

    /* make the magnitude of v < 1 */
    if (v != 0.)
	v = frexp(v, &exp);
    else
	exp = 0;

    for (w = 1; w <= N_ARRAY; ++w) {	/* get 2^SF_PRECIS precision at a time */
	n = (int) (x = ldexp(v, SF_PRECIS));
	v = x - n;
	if (v <= 0.)
	    break;
    }

    return 1 + sfulen(exp) + w;
}
