The Tor Browser: media/libvorbis/lib/vorbis

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /********************************************************************

     2  *                                                                  *

     3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *

     4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

     5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

     6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

     7  *                                                                  *

     8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *

     9  * by the Xiph.Org Foundation http://www.xiph.org/                  *

    10  *                                                                  *

    11  ********************************************************************

    13   function: lookup based functions

    14   last mod: $Id: lookup.c 16227 2009-07-08 06:58:46Z xiphmont $

    16  ********************************************************************/

    18 #include <math.h>

    19 #include "lookup.h"

    20 #include "lookup_data.h"

    21 #include "os.h"

    22 #include "misc.h"

    24 #ifdef FLOAT_LOOKUP

    26 /* interpolated lookup based cos function, domain 0 to PI only */

    27 float vorbis_coslook(float a){

    28   double d=a*(.31830989*(float)COS_LOOKUP_SZ);

    29   int i=vorbis_ftoi(d-.5);

    31   return COS_LOOKUP[i]+ (d-i)*(COS_LOOKUP[i+1]-COS_LOOKUP[i]);

    32 }

    34 /* interpolated 1./sqrt(p) where .5 <= p < 1. */

    35 float vorbis_invsqlook(float a){

    36   double d=a*(2.f*(float)INVSQ_LOOKUP_SZ)-(float)INVSQ_LOOKUP_SZ;

    37   int i=vorbis_ftoi(d-.5f);

    38   return INVSQ_LOOKUP[i]+ (d-i)*(INVSQ_LOOKUP[i+1]-INVSQ_LOOKUP[i]);

    39 }

    41 /* interpolated 1./sqrt(p) where .5 <= p < 1. */

    42 float vorbis_invsq2explook(int a){

    43   return INVSQ2EXP_LOOKUP[a-INVSQ2EXP_LOOKUP_MIN];

    44 }

    46 #include <stdio.h>

    47 /* interpolated lookup based fromdB function, domain -140dB to 0dB only */

    48 float vorbis_fromdBlook(float a){

    49   int i=vorbis_ftoi(a*((float)(-(1<<FROMdB2_SHIFT)))-.5f);

    50   return (i<0)?1.f:

    51     ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f:

    52      FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]);

    53 }

    55 #endif

    57 #ifdef INT_LOOKUP

    58 /* interpolated 1./sqrt(p) where .5 <= a < 1. (.100000... to .111111...) in

    59    16.16 format

    61    returns in m.8 format */

    62 long vorbis_invsqlook_i(long a,long e){

    63   long i=(a&0x7fff)>>(INVSQ_LOOKUP_I_SHIFT-1);

    64   long d=(a&INVSQ_LOOKUP_I_MASK)<<(16-INVSQ_LOOKUP_I_SHIFT); /*  0.16 */

    65   long val=INVSQ_LOOKUP_I[i]-                                /*  1.16 */

    66     (((INVSQ_LOOKUP_I[i]-INVSQ_LOOKUP_I[i+1])*               /*  0.16 */

    67       d)>>16);                                               /* result 1.16 */

    69   e+=32;

    70   if(e&1)val=(val*5792)>>13; /* multiply val by 1/sqrt(2) */

    71   e=(e>>1)-8;

    73   return(val>>e);

    74 }

    76 /* interpolated lookup based fromdB function, domain -140dB to 0dB only */

    77 /* a is in n.12 format */

    78 float vorbis_fromdBlook_i(long a){

    79   int i=(-a)>>(12-FROMdB2_SHIFT);

    80   return (i<0)?1.f:

    81     ((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f:

    82      FROMdB_LOOKUP[i>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]);

    83 }

    85 /* interpolated lookup based cos function, domain 0 to PI only */

    86 /* a is in 0.16 format, where 0==0, 2^^16-1==PI, return 0.14 */

    87 long vorbis_coslook_i(long a){

    88   int i=a>>COS_LOOKUP_I_SHIFT;

    89   int d=a&COS_LOOKUP_I_MASK;

    90   return COS_LOOKUP_I[i]- ((d*(COS_LOOKUP_I[i]-COS_LOOKUP_I[i+1]))>>

    91                            COS_LOOKUP_I_SHIFT);

    92 }

    94 #endif

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