/src/flac/src/libFLAC/bitmath.c

Source (jump to first uncovered line)
/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2001-2009  Josh Coalson
 * Copyright (C) 2011-2025  Xiph.Org Foundation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Xiph.org Foundation nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "private/bitmath.h"

/* An example of what FLAC__bitmath_silog2() computes:
 *
 * silog2(-10) = 5
 * silog2(- 9) = 5
 * silog2(- 8) = 4
 * silog2(- 7) = 4
 * silog2(- 6) = 4
 * silog2(- 5) = 4
 * silog2(- 4) = 3
 * silog2(- 3) = 3
 * silog2(- 2) = 2
 * silog2(- 1) = 2
 * silog2(  0) = 0
 * silog2(  1) = 2
 * silog2(  2) = 3
 * silog2(  3) = 3
 * silog2(  4) = 4
 * silog2(  5) = 4
 * silog2(  6) = 4
 * silog2(  7) = 4
 * silog2(  8) = 5
 * silog2(  9) = 5
 * silog2( 10) = 5
 */
uint32_t FLAC__bitmath_silog2(FLAC__int64 v)
{
  if(v == 0)
    return 0;

  if(v == -1)
    return 2;

  v = (v < 0) ? (-(v+1)) : v;
  return FLAC__bitmath_ilog2_wide(v)+2;
}

/* An example of what FLAC__bitmath_extra_mulbits_unsigned() computes:
 *
 * extra_mulbits_unsigned( 0) = 0
 * extra_mulbits_unsigned( 1) = 0
 * extra_mulbits_unsigned( 2) = 1
 * extra_mulbits_unsigned( 3) = 2
 * extra_mulbits_unsigned( 4) = 2
 * extra_mulbits_unsigned( 5) = 3
 * extra_mulbits_unsigned( 6) = 3
 * extra_mulbits_unsigned( 7) = 3
 * extra_mulbits_unsigned( 8) = 3
 * extra_mulbits_unsigned( 9) = 4
 * extra_mulbits_unsigned(10) = 4
 * extra_mulbits_unsigned(11) = 4
 * extra_mulbits_unsigned(12) = 4
 * extra_mulbits_unsigned(13) = 4
 * extra_mulbits_unsigned(14) = 4
 * extra_mulbits_unsigned(15) = 4
 * extra_mulbits_unsigned(16) = 4
 * extra_mulbits_unsigned(17) = 5
 * extra_mulbits_unsigned(18) = 5
 *
 * The intent of this is to calculate how many extra bits multiplication
 * by a certain number requires. So, if a signal fits in a certain number
 * of bits (for example 16) than multiplying by a number (for example 1024)
 * grows that storage requirement (to 26 in this example). In effect this is
 * is the log2 rounded up.
 */
uint32_t FLAC__bitmath_extra_mulbits_unsigned(FLAC__uint32 v)
{
  uint32_t ilog2;
  if(v == 0)
    return 0;
  ilog2 = FLAC__bitmath_ilog2(v);
  if(((v >> ilog2) << ilog2) == v)
    /* v is power of 2 */
    return ilog2;
  else
    /* v is not a power of 2, return one higher */
    return ilog2 + 1;
}

Coverage Report

Created: 2025-07-11 06:51

Line	Count	Source (jump to first uncovered line)
1		/* libFLAC - Free Lossless Audio Codec library
2		* Copyright (C) 2001-2009 Josh Coalson
3		* Copyright (C) 2011-2025 Xiph.Org Foundation
4		*
5		* Redistribution and use in source and binary forms, with or without
6		* modification, are permitted provided that the following conditions
7		* are met:
8		*
9		* - Redistributions of source code must retain the above copyright
10		* notice, this list of conditions and the following disclaimer.
11		*
12		* - Redistributions in binary form must reproduce the above copyright
13		* notice, this list of conditions and the following disclaimer in the
14		* documentation and/or other materials provided with the distribution.
15		*
16		* - Neither the name of the Xiph.org Foundation nor the names of its
17		* contributors may be used to endorse or promote products derived from
18		* this software without specific prior written permission.
19		*
20		* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21		* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22		* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23		* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
24		* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25		* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26		* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
27		* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
28		* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
29		* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
30		* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31		*/
32
33		#ifdef HAVE_CONFIG_H
34		# include <config.h>
35		#endif
36
37		#include "private/bitmath.h"
38
39		/* An example of what FLAC__bitmath_silog2() computes:
40		*
41		* silog2(-10) = 5
42		* silog2(- 9) = 5
43		* silog2(- 8) = 4
44		* silog2(- 7) = 4
45		* silog2(- 6) = 4
46		* silog2(- 5) = 4
47		* silog2(- 4) = 3
48		* silog2(- 3) = 3
49		* silog2(- 2) = 2
50		* silog2(- 1) = 2
51		* silog2( 0) = 0
52		* silog2( 1) = 2
53		* silog2( 2) = 3
54		* silog2( 3) = 3
55		* silog2( 4) = 4
56		* silog2( 5) = 4
57		* silog2( 6) = 4
58		* silog2( 7) = 4
59		* silog2( 8) = 5
60		* silog2( 9) = 5
61		* silog2( 10) = 5
62		*/
63		uint32_t FLAC__bitmath_silog2(FLAC__int64 v)
64	40.4k	{
65	40.4k	if(v == 0)
66	8.39k	return 0;
67
68	32.0k	if(v == -1)
69	0	return 2;
70
71	32.0k	v = (v < 0) ? (-(v+1)) : v;
72	32.0k	return FLAC__bitmath_ilog2_wide(v)+2;
73	32.0k	}
74
75		/* An example of what FLAC__bitmath_extra_mulbits_unsigned() computes:
76		*
77		* extra_mulbits_unsigned( 0) = 0
78		* extra_mulbits_unsigned( 1) = 0
79		* extra_mulbits_unsigned( 2) = 1
80		* extra_mulbits_unsigned( 3) = 2
81		* extra_mulbits_unsigned( 4) = 2
82		* extra_mulbits_unsigned( 5) = 3
83		* extra_mulbits_unsigned( 6) = 3
84		* extra_mulbits_unsigned( 7) = 3
85		* extra_mulbits_unsigned( 8) = 3
86		* extra_mulbits_unsigned( 9) = 4
87		* extra_mulbits_unsigned(10) = 4
88		* extra_mulbits_unsigned(11) = 4
89		* extra_mulbits_unsigned(12) = 4
90		* extra_mulbits_unsigned(13) = 4
91		* extra_mulbits_unsigned(14) = 4
92		* extra_mulbits_unsigned(15) = 4
93		* extra_mulbits_unsigned(16) = 4
94		* extra_mulbits_unsigned(17) = 5
95		* extra_mulbits_unsigned(18) = 5
96		*
97		* The intent of this is to calculate how many extra bits multiplication
98		* by a certain number requires. So, if a signal fits in a certain number
99		* of bits (for example 16) than multiplying by a number (for example 1024)
100		* grows that storage requirement (to 26 in this example). In effect this is
101		* is the log2 rounded up.
102		*/
103		uint32_t FLAC__bitmath_extra_mulbits_unsigned(FLAC__uint32 v)
104	0	{
105	0	uint32_t ilog2;
106	0	if(v == 0)
107	0	return 0;
108	0	ilog2 = FLAC__bitmath_ilog2(v);
109	0	if(((v >> ilog2) << ilog2) == v)
110		/* v is power of 2 */
111	0	return ilog2;
112	0	else
113		/* v is not a power of 2, return one higher */
114	0	return ilog2 + 1;
115	0	}