media/libopus/silk/float/levinsondurbin_FLP.c@ac0c01689b40 (annotated)
media/libopus/silk/float/levinsondurbin_FLP.c
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /*********************************************************************** |
| michael@0 | 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| michael@0 | 3 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 4 | modification, are permitted provided that the following conditions |
| michael@0 | 5 | are met: |
| michael@0 | 6 | - Redistributions of source code must retain the above copyright notice, |
| michael@0 | 7 | this list of conditions and the following disclaimer. |
| michael@0 | 8 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 10 | documentation and/or other materials provided with the distribution. |
| michael@0 | 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| michael@0 | 12 | names of specific contributors, may be used to endorse or promote |
| michael@0 | 13 | products derived from this software without specific prior written |
| michael@0 | 14 | permission. |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| michael@0 | 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| michael@0 | 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| michael@0 | 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| michael@0 | 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| michael@0 | 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| michael@0 | 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| michael@0 | 25 | POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | ***********************************************************************/ |
| michael@0 | 27 | |
| michael@0 | 28 | #ifdef HAVE_CONFIG_H |
| michael@0 | 29 | #include "config.h" |
| michael@0 | 30 | #endif |
| michael@0 | 31 | |
| michael@0 | 32 | #include "SigProc_FLP.h" |
| michael@0 | 33 | |
| michael@0 | 34 | /* Solve the normal equations using the Levinson-Durbin recursion */ |
| michael@0 | 35 | silk_float silk_levinsondurbin_FLP( /* O prediction error energy */ |
| michael@0 | 36 | silk_float A[], /* O prediction coefficients [order] */ |
| michael@0 | 37 | const silk_float corr[], /* I input auto-correlations [order + 1] */ |
| michael@0 | 38 | const opus_int order /* I prediction order */ |
| michael@0 | 39 | ) |
| michael@0 | 40 | { |
| michael@0 | 41 | opus_int i, mHalf, m; |
| michael@0 | 42 | silk_float min_nrg, nrg, t, km, Atmp1, Atmp2; |
| michael@0 | 43 | |
| michael@0 | 44 | min_nrg = 1e-12f * corr[ 0 ] + 1e-9f; |
| michael@0 | 45 | nrg = corr[ 0 ]; |
| michael@0 | 46 | nrg = silk_max_float(min_nrg, nrg); |
| michael@0 | 47 | A[ 0 ] = corr[ 1 ] / nrg; |
| michael@0 | 48 | nrg -= A[ 0 ] * corr[ 1 ]; |
| michael@0 | 49 | nrg = silk_max_float(min_nrg, nrg); |
| michael@0 | 50 | |
| michael@0 | 51 | for( m = 1; m < order; m++ ) |
| michael@0 | 52 | { |
| michael@0 | 53 | t = corr[ m + 1 ]; |
| michael@0 | 54 | for( i = 0; i < m; i++ ) { |
| michael@0 | 55 | t -= A[ i ] * corr[ m - i ]; |
| michael@0 | 56 | } |
| michael@0 | 57 | |
| michael@0 | 58 | /* reflection coefficient */ |
| michael@0 | 59 | km = t / nrg; |
| michael@0 | 60 | |
| michael@0 | 61 | /* residual energy */ |
| michael@0 | 62 | nrg -= km * t; |
| michael@0 | 63 | nrg = silk_max_float(min_nrg, nrg); |
| michael@0 | 64 | |
| michael@0 | 65 | mHalf = m >> 1; |
| michael@0 | 66 | for( i = 0; i < mHalf; i++ ) { |
| michael@0 | 67 | Atmp1 = A[ i ]; |
| michael@0 | 68 | Atmp2 = A[ m - i - 1 ]; |
| michael@0 | 69 | A[ m - i - 1 ] -= km * Atmp1; |
| michael@0 | 70 | A[ i ] -= km * Atmp2; |
| michael@0 | 71 | } |
| michael@0 | 72 | if( m & 1 ) { |
| michael@0 | 73 | A[ mHalf ] -= km * A[ mHalf ]; |
| michael@0 | 74 | } |
| michael@0 | 75 | A[ m ] = km; |
| michael@0 | 76 | } |
| michael@0 | 77 | |
| michael@0 | 78 | /* return the residual energy */ |
| michael@0 | 79 | return nrg; |
| michael@0 | 80 | } |
| michael@0 | 81 |
