media/libopus/silk/resampler_down2_3.c@ac0c01689b40 (annotated)
media/libopus/silk/resampler_down2_3.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_FIX.h" |
| michael@0 | 33 | #include "resampler_private.h" |
| michael@0 | 34 | #include "stack_alloc.h" |
| michael@0 | 35 | |
| michael@0 | 36 | #define ORDER_FIR 4 |
| michael@0 | 37 | |
| michael@0 | 38 | /* Downsample by a factor 2/3, low quality */ |
| michael@0 | 39 | void silk_resampler_down2_3( |
| michael@0 | 40 | opus_int32 *S, /* I/O State vector [ 6 ] */ |
| michael@0 | 41 | opus_int16 *out, /* O Output signal [ floor(2*inLen/3) ] */ |
| michael@0 | 42 | const opus_int16 *in, /* I Input signal [ inLen ] */ |
| michael@0 | 43 | opus_int32 inLen /* I Number of input samples */ |
| michael@0 | 44 | ) |
| michael@0 | 45 | { |
| michael@0 | 46 | opus_int32 nSamplesIn, counter, res_Q6; |
| michael@0 | 47 | VARDECL( opus_int32, buf ); |
| michael@0 | 48 | opus_int32 *buf_ptr; |
| michael@0 | 49 | SAVE_STACK; |
| michael@0 | 50 | |
| michael@0 | 51 | ALLOC( buf, RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR, opus_int32 ); |
| michael@0 | 52 | |
| michael@0 | 53 | /* Copy buffered samples to start of buffer */ |
| michael@0 | 54 | silk_memcpy( buf, S, ORDER_FIR * sizeof( opus_int32 ) ); |
| michael@0 | 55 | |
| michael@0 | 56 | /* Iterate over blocks of frameSizeIn input samples */ |
| michael@0 | 57 | while( 1 ) { |
| michael@0 | 58 | nSamplesIn = silk_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN ); |
| michael@0 | 59 | |
| michael@0 | 60 | /* Second-order AR filter (output in Q8) */ |
| michael@0 | 61 | silk_resampler_private_AR2( &S[ ORDER_FIR ], &buf[ ORDER_FIR ], in, |
| michael@0 | 62 | silk_Resampler_2_3_COEFS_LQ, nSamplesIn ); |
| michael@0 | 63 | |
| michael@0 | 64 | /* Interpolate filtered signal */ |
| michael@0 | 65 | buf_ptr = buf; |
| michael@0 | 66 | counter = nSamplesIn; |
| michael@0 | 67 | while( counter > 2 ) { |
| michael@0 | 68 | /* Inner product */ |
| michael@0 | 69 | res_Q6 = silk_SMULWB( buf_ptr[ 0 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] ); |
| michael@0 | 70 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] ); |
| michael@0 | 71 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] ); |
| michael@0 | 72 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] ); |
| michael@0 | 73 | |
| michael@0 | 74 | /* Scale down, saturate and store in output array */ |
| michael@0 | 75 | *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) ); |
| michael@0 | 76 | |
| michael@0 | 77 | res_Q6 = silk_SMULWB( buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] ); |
| michael@0 | 78 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] ); |
| michael@0 | 79 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] ); |
| michael@0 | 80 | res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 4 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] ); |
| michael@0 | 81 | |
| michael@0 | 82 | /* Scale down, saturate and store in output array */ |
| michael@0 | 83 | *out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) ); |
| michael@0 | 84 | |
| michael@0 | 85 | buf_ptr += 3; |
| michael@0 | 86 | counter -= 3; |
| michael@0 | 87 | } |
| michael@0 | 88 | |
| michael@0 | 89 | in += nSamplesIn; |
| michael@0 | 90 | inLen -= nSamplesIn; |
| michael@0 | 91 | |
| michael@0 | 92 | if( inLen > 0 ) { |
| michael@0 | 93 | /* More iterations to do; copy last part of filtered signal to beginning of buffer */ |
| michael@0 | 94 | silk_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) ); |
| michael@0 | 95 | } else { |
| michael@0 | 96 | break; |
| michael@0 | 97 | } |
| michael@0 | 98 | } |
| michael@0 | 99 | |
| michael@0 | 100 | /* Copy last part of filtered signal to the state for the next call */ |
| michael@0 | 101 | silk_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) ); |
| michael@0 | 102 | RESTORE_STACK; |
| michael@0 | 103 | } |
