Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 1 | /* libFLAC - Free Lossless Audio Codec library |
Robert Shih | 31e4f31 | 2015-01-05 17:35:54 -0800 | [diff] [blame] | 2 | * Copyright (C) 2001-2009 Josh Coalson |
Elliott Hughes | ae0e7bc | 2018-01-12 14:46:04 -0800 | [diff] [blame] | 3 | * Copyright (C) 2011-2016 Xiph.Org Foundation |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 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 | |
Robert Shih | 31e4f31 | 2015-01-05 17:35:54 -0800 | [diff] [blame] | 33 | #ifdef HAVE_CONFIG_H |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 34 | # include <config.h> |
| 35 | #endif |
| 36 | |
| 37 | #include "private/bitmath.h" |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 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 | */ |
Elliott Hughes | ae0e7bc | 2018-01-12 14:46:04 -0800 | [diff] [blame] | 63 | unsigned FLAC__bitmath_silog2(FLAC__int64 v) |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 64 | { |
Elliott Hughes | ae0e7bc | 2018-01-12 14:46:04 -0800 | [diff] [blame] | 65 | if(v == 0) |
| 66 | return 0; |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 67 | |
Elliott Hughes | ae0e7bc | 2018-01-12 14:46:04 -0800 | [diff] [blame] | 68 | if(v == -1) |
| 69 | return 2; |
| 70 | |
| 71 | v = (v < 0) ? (-(v+1)) : v; |
| 72 | return FLAC__bitmath_ilog2_wide(v)+2; |
Kenny Root | c746637 | 2009-11-08 12:46:32 -0600 | [diff] [blame] | 73 | } |