#include <assert.h>

#include <stdio.h>

#include <string.h>

#include <math.h>

#include <stdlib.h>

#include <stdarg.h>

#include "jpc_math.h"

/* Calculate the integer quantity floor(log2(x)), where x is a positive

  integer. */

int

jpc_floorlog2(int const arg) {

	int y;

    int x;

	assert(arg > 0);

	y = 0;

    x = arg;

	while (x > 1) {

		x >>= 1;

		++y;

	}

	return y;

}

/*

  jpc_floorlog2() and jpc_firstone() do the same thing.

  The only difference is how input 0 is handled.

n                  : 0 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 

ceil(log2(n))      : x 0  1  2  2  3  3  3  3  4  4  4  4  4  4  4  4  5  5  5 

floor(log2(n))     : x 0  1  1  2  2  2  2  3  3  3  3  3  3  3  3  4  4  4  4 

31-__builtin_clz(n): x 0  1  1  2  2  2  2  3  3  3  3  3  3  3  3  4  4  4  4 

jpc_floorlog2(n)   : x 0  1  1  2  2  2  2  3  3  3  3  3  3  3  3  4  4  4  4 

jpc_firstone(n)    :-1 0  1  1  2  2  2  2  3  3  3  3  3  3  3  3  4  4  4  4 

*/

int

jpc_firstone(int const arg) {

/*---------------------------------------------------------------------------- 

  Calculate the bit position of the first leading one in a nonnegative

  integer.

-----------------------------------------------------------------------------*/

	int n;

    int x;

	assert(arg >= 0);

	n = -1;

    x = arg;

	while (x > 0) {

		x >>= 1;

		++n;

	}

	return n;

}

/*

 * Copyright (c) 1999-2000 Image Power, Inc. and the University of

 *   British Columbia.

 * Copyright (c) 2001-2002 Michael David Adams.

 * All rights reserved.

 */

/* __START_OF_JASPER_LICENSE__

 * 

 * JasPer Software License

 * 

 * IMAGE POWER JPEG-2000 PUBLIC LICENSE

 * ************************************

 * 

 * GRANT:

 * 

 * Permission is hereby granted, free of charge, to any person (the "User")

 * obtaining a copy of this software and associated documentation, to deal

 * in the JasPer Software without restriction, including without limitation

 * the right to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the JasPer Software (in source and binary forms),

 * and to permit persons to whom the JasPer Software is furnished to do so,

 * provided further that the License Conditions below are met.

 * 

 * License Conditions

 * ******************

 * 

 * A.  Redistributions of source code must retain the above copyright notice,

 * and this list of conditions, and the following disclaimer.

 * 

 * B.  Redistributions in binary form must reproduce the above copyright

 * notice, and this list of conditions, and the following disclaimer in

 * the documentation and/or other materials provided with the distribution.

 * 

 * C.  Neither the name of Image Power, Inc. nor any other contributor

 * (including, but not limited to, the University of British Columbia and

 * Michael David Adams) may be used to endorse or promote products derived

 * from this software without specific prior written permission.

 * 

 * D.  User agrees that it shall not commence any action against Image Power,

 * Inc., the University of British Columbia, Michael David Adams, or any

 * other contributors (collectively "Licensors") for infringement of any

 * intellectual property rights ("IPR") held by the User in respect of any

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 * 

 * E.  If User commences an infringement action against any Licensor(s) then

 * such Licensor(s) shall have the right to terminate User's license and

 * all sublicenses that have been granted hereunder by User to other parties.

 * 

 * F.  This software is for use only in hardware or software products that

 * are compliant with ISO/IEC 15444-1 (i.e., JPEG-2000 Part 1).  No license

 * or right to this Software is granted for products that do not comply

 * with ISO/IEC 15444-1.  The JPEG-2000 Part 1 standard can be purchased

 * from the ISO.

 * 

 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE.

 * NO USE OF THE JASPER SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER

 * THIS DISCLAIMER.  THE JASPER SOFTWARE IS PROVIDED BY THE LICENSORS AND

 * CONTRIBUTORS UNDER THIS LICENSE ON AN ``AS-IS'' BASIS, WITHOUT WARRANTY

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 * THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE JASPER SOFTWARE

 * IS WITH THE USER.  SHOULD ANY PART OF THE JASPER SOFTWARE PROVE DEFECTIVE

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 * OF BRITISH COLUMBIA, IMAGE POWER, INC., MICHAEL DAVID ADAMS, OR ANY

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 * MICHAEL DAVID ADAMS, ANY OTHER CONTRIBUTOR, OR ANY DISTRIBUTOR OF THE

 * JASPER SOFTWARE, OR ANY SUPPLIER OF ANY OF SUCH PARTIES, BE LIABLE TO

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 * CUSTOMERS AND END-USERS OF ITS PRODUCTS ARE PROVIDED WITH A COPY OF THE

 * NOTICE SPECIFIED IN THIS SECTION.

 * 

 * __END_OF_JASPER_LICENSE__

 */