sfdlen.c revision 7c2fbfb345896881c631598ee3852ce9ce33fb07
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2008 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#include "sfhdr.h"
/* Return the length of a double value if coded in a portable format
**
** Written by Kiem-Phong Vo
*/
#if __STD_C
int _sfdlen(Sfdouble_t v)
#else
int _sfdlen(v)
Sfdouble_t v;
#endif
{
#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 = frexpl(v,&exp);
else exp = 0;
for(w = 1; w <= N_ARRAY; ++w)
{ /* get 2^SF_PRECIS precision at a time */
n = (int)(x = ldexpl(v,SF_PRECIS));
v = x-n;
if(v <= 0.)
break;
}
return 1 + sfulen(exp) + w;
}