/src/jasper/src/libjasper/jpc/jpc_math.c

Source
/*
 * 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 License Version 2.0
 * 
 * Copyright (c) 2001-2006 Michael David Adams
 * Copyright (c) 1999-2000 Image Power, Inc.
 * Copyright (c) 1999-2000 The University of British Columbia
 * 
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person (the
 * "User") obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, and/or sell copies of the Software, and to permit
 * persons to whom the Software is furnished to do so, subject to the
 * following conditions:
 * 
 * 1.  The above copyright notices and this permission notice (which
 * includes the disclaimer below) shall be included in all copies or
 * substantial portions of the Software.
 * 
 * 2.  The name of a copyright holder shall not be used to endorse or
 * promote products derived from the Software without specific prior
 * written permission.
 * 
 * THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
 * LICENSE.  NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
 * THIS DISCLAIMER.  THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
 * "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.  IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
 * INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.  NO ASSURANCES ARE
 * PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
 * THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
 * EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
 * BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
 * PROPERTY RIGHTS OR OTHERWISE.  AS A CONDITION TO EXERCISING THE RIGHTS
 * GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
 * ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY.  THE SOFTWARE
 * IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
 * SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
 * AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
 * SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
 * THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
 * PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
 * RISK ACTIVITIES").  THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
 * EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
 * 
 * __END_OF_JASPER_LICENSE__
 */

/*
 * Math Library
 *
 * $Id$
 */

/******************************************************************************\
* Includes
\******************************************************************************/

#include "jpc_math.h"

#include <assert.h>

/******************************************************************************\
* Miscellaneous Functions
\******************************************************************************/

/* Calculate the integer quantity floor(log2(x)), where x is a positive
  integer. */
unsigned jpc_floorlog2(uint_fast32_t x)
{
  int y;

  /* The argument must be positive. */
  assert(x > 0);

  y = 0;
  while (x > 1) {
    x >>= 1;
    ++y;
  }
  return y;
}

/* Calculate the bit position of the first leading one in a nonnegative
  integer. */
/* This function is the basically the same as ceillog2(x), except that the
  allowable range for x is slightly different. */
int jpc_int_firstone(int x)
{
  int n;

  /* The argument must be nonnegative. */
  assert(x >= 0);

  n = -1;
  while (x > 0) {
    x >>= 1;
    ++n;
  }
  return n;
}

int jpc_fix_firstone(jpc_fix_t x)
{
  int n;

  /* The argument must be nonnegative. */
  assert(x >= 0);

  n = -1;
  while (x > 0) {
    x >>= 1;
    ++n;
  }
  return n;
}

Line	Count	Source
1		/*
2		* Copyright (c) 1999-2000 Image Power, Inc. and the University of
3		* British Columbia.
4		* Copyright (c) 2001-2002 Michael David Adams.
5		* All rights reserved.
6		*/
7
8		/* __START_OF_JASPER_LICENSE__
9		*
10		* JasPer License Version 2.0
11		*
12		* Copyright (c) 2001-2006 Michael David Adams
13		* Copyright (c) 1999-2000 Image Power, Inc.
14		* Copyright (c) 1999-2000 The University of British Columbia
15		*
16		* All rights reserved.
17		*
18		* Permission is hereby granted, free of charge, to any person (the
19		* "User") obtaining a copy of this software and associated documentation
20		* files (the "Software"), to deal in the Software without restriction,
21		* including without limitation the rights to use, copy, modify, merge,
22		* publish, distribute, and/or sell copies of the Software, and to permit
23		* persons to whom the Software is furnished to do so, subject to the
24		* following conditions:
25		*
26		* 1. The above copyright notices and this permission notice (which
27		* includes the disclaimer below) shall be included in all copies or
28		* substantial portions of the Software.
29		*
30		* 2. The name of a copyright holder shall not be used to endorse or
31		* promote products derived from the Software without specific prior
32		* written permission.
33		*
34		* THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS
35		* LICENSE. NO USE OF THE SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER
36		* THIS DISCLAIMER. THE SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
37		* "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
38		* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
39		* PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS. IN NO
40		* EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL
41		* INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING
42		* FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
43		* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
44		* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. NO ASSURANCES ARE
45		* PROVIDED BY THE COPYRIGHT HOLDERS THAT THE SOFTWARE DOES NOT INFRINGE
46		* THE PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OF ANY OTHER ENTITY.
47		* EACH COPYRIGHT HOLDER DISCLAIMS ANY LIABILITY TO THE USER FOR CLAIMS
48		* BROUGHT BY ANY OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL
49		* PROPERTY RIGHTS OR OTHERWISE. AS A CONDITION TO EXERCISING THE RIGHTS
50		* GRANTED HEREUNDER, EACH USER HEREBY ASSUMES SOLE RESPONSIBILITY TO SECURE
51		* ANY OTHER INTELLECTUAL PROPERTY RIGHTS NEEDED, IF ANY. THE SOFTWARE
52		* IS NOT FAULT-TOLERANT AND IS NOT INTENDED FOR USE IN MISSION-CRITICAL
53		* SYSTEMS, SUCH AS THOSE USED IN THE OPERATION OF NUCLEAR FACILITIES,
54		* AIRCRAFT NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL
55		* SYSTEMS, DIRECT LIFE SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH
56		* THE FAILURE OF THE SOFTWARE OR SYSTEM COULD LEAD DIRECTLY TO DEATH,
57		* PERSONAL INJURY, OR SEVERE PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH
58		* RISK ACTIVITIES"). THE COPYRIGHT HOLDERS SPECIFICALLY DISCLAIM ANY
59		* EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR HIGH RISK ACTIVITIES.
60		*
61		* __END_OF_JASPER_LICENSE__
62		*/
63
64		/*
65		* Math Library
66		*
67		* $Id$
68		*/
69
70		/******************************************************************************\
71		* Includes
72		\******************************************************************************/
73
74		#include "jpc_math.h"
75
76		#include <assert.h>
77
78		/******************************************************************************\
79		* Miscellaneous Functions
80		\******************************************************************************/
81
82		/* Calculate the integer quantity floor(log2(x)), where x is a positive
83		integer. */
84		unsigned jpc_floorlog2(uint_fast32_t x)
85	10.4M	{
86	10.4M	int y;
87
88		/* The argument must be positive. */
89	10.4M	assert(x > 0);
90
91	10.4M	y = 0;
92	25.4M	while (x > 1) {
93	14.9M	x >>= 1;
94	14.9M	++y;
95	14.9M	}
96	10.4M	return y;
97	10.4M	}
98
99		/* Calculate the bit position of the first leading one in a nonnegative
100		integer. */
101		/* This function is the basically the same as ceillog2(x), except that the
102		allowable range for x is slightly different. */
103		int jpc_int_firstone(int x)
104	5.80M	{
105	5.80M	int n;
106
107		/* The argument must be nonnegative. */
108	5.80M	assert(x >= 0);
109
110	5.80M	n = -1;
111	48.3M	while (x > 0) {
112	42.5M	x >>= 1;
113	42.5M	++n;
114	42.5M	}
115	5.80M	return n;
116	5.80M	}
117
118		int jpc_fix_firstone(jpc_fix_t x)
119	725k	{
120	725k	int n;
121
122		/* The argument must be nonnegative. */
123	725k	assert(x >= 0);
124
125	725k	n = -1;
126	5.04M	while (x > 0) {
127	4.32M	x >>= 1;
128	4.32M	++n;
129	4.32M	}
130	725k	return n;
131	725k	}

Coverage Report

Created: 2026-09-06 07:31