The Tor Browser / file comparison
comparison: media/libopus/silk/log2lin.c
media/libopus/silk/log2lin.c
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
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| -1:000000000000 | 0:c370b817648f |
|---|---|
| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 #ifdef HAVE_CONFIG_H | |
| 29 #include "config.h" | |
| 30 #endif | |
| 31 | |
| 32 #include "SigProc_FIX.h" | |
| 33 | |
| 34 /* Approximation of 2^() (very close inverse of silk_lin2log()) */ | |
| 35 /* Convert input to a linear scale */ | |
| 36 opus_int32 silk_log2lin( | |
| 37 const opus_int32 inLog_Q7 /* I input on log scale */ | |
| 38 ) | |
| 39 { | |
| 40 opus_int32 out, frac_Q7; | |
| 41 | |
| 42 if( inLog_Q7 < 0 ) { | |
| 43 return 0; | |
| 44 } else if ( inLog_Q7 >= 3967 ) { | |
| 45 return silk_int32_MAX; | |
| 46 } | |
| 47 | |
| 48 out = silk_LSHIFT( 1, silk_RSHIFT( inLog_Q7, 7 ) ); | |
| 49 frac_Q7 = inLog_Q7 & 0x7F; | |
| 50 if( inLog_Q7 < 2048 ) { | |
| 51 /* Piece-wise parabolic approximation */ | |
| 52 out = silk_ADD_RSHIFT32( out, silk_MUL( out, silk_SMLAWB( frac_Q7, silk_SMULBB( frac_Q7, 128 - frac_Q7 ), -174 ) ), 7 ); | |
| 53 } else { | |
| 54 /* Piece-wise parabolic approximation */ | |
| 55 out = silk_MLA( out, silk_RSHIFT( out, 7 ), silk_SMLAWB( frac_Q7, silk_SMULBB( frac_Q7, 128 - frac_Q7 ), -174 ) ); | |
| 56 } | |
| 57 return out; | |
| 58 } |
