/****************************************************************************/
/*	Copyright (c) 2009, Bendor Research Pty. Ltd. All rights reserved.		*/
/*	This software is released under the GNU General Public License, version	*/
/*	3, with the exemptions that 1) the header files installed by this 	 	*/
/*	package can be included in closed-source code and 2) the libraries		*/
/*	built by this package can be statically linked into a closed-source 	*/
/*	binary. See the file LICENSE for the details.							*/
/*	This software is provided "AS IS", without any warranty or guarantee.	*/
/*	By using this software you acknowledge that neither Bendor Research nor	*/
/*	any of its personnel or affiliates can be held liable for any damages,	*/
/*	including, but not limited to, loss of business, loss of money, loss of */
/*	life, loss or reputation, arising out of this software being faulty or	*/
/*	not performing as advertised, even if Bendor Research was aware of such	*/
/*	faults in the software. You use this software at your own risk, any and */
/*	all liabilities that arise out of your using this software are strictly	*/
/*	yours.																	*/
/****************************************************************************/

#include <nanu-nanu.h>

/** @addtogroup nanu */
/** @{ */

/**
*	Returns the length of the topmost element of the stack
*
*	The function returns the length of the topmost element of the
*	stack, in bits. That is, it returned value is the smallest
*	non-negative integer such that<br>
*	2<sup>return_value</sup> > number_on_top_of_the_stack<br>
*	The stack is not changed.
*
*	@param	nanu			The natural number machine state descriptor
*
*	@retval	>=0				The length of the topmost element
*	@retval	BC_NANU_SUND	The stack was empty
*
*	@par Stack image
*		x ... ==> x ...
*/

int	BC_NanuSize( BC_NANU nanu )
{
unsigned	l, w;
int			v;

	if ( ( v = _bc_NanuStkSee( nanu, 0 ) ) < 0 )

		return( _bc_NanuError( nanu, v ) );

	l = _bc_NanuVarLen( nanu, v );
	w = _bc_NanuVarPtr( nanu, v )[ l - 1 ];

	if ( ! w ) {

		// The number is 0

		return( 0 );
	}

	l *= 32;

	while ( ! ( w & 0x80000000 ) ) {

		w <<= 1;
		l--;
	}

	return( l );
}

/** @} */

