/* JOrbis
* Copyright (C) 2000 ymnk, JCraft,Inc.
*
* Written by: 2000 ymnk<ymnk@jcraft.com>
*
* Many thanks to
* Monty <monty@xiph.org> and
* The XIPHOPHORUS Company http://www.xiph.org/ .
* JOrbis has been based on their awesome works, Vorbis codec.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License
* as published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
package com.jcraft.jorbis;
class Lookup{
static final int COS_LOOKUP_SZ=128;
static final float[] COS_LOOKUP={
+1.0000000000000f,+0.9996988186962f,+0.9987954562052f,+0.9972904566787f,
+0.9951847266722f,+0.9924795345987f,+0.9891765099648f,+0.9852776423889f,
+0.9807852804032f,+0.9757021300385f,+0.9700312531945f,+0.9637760657954f,
+0.9569403357322f,+0.9495281805930f,+0.9415440651830f,+0.9329927988347f,
+0.9238795325113f,+0.9142097557035f,+0.9039892931234f,+0.8932243011955f,
+0.8819212643484f,+0.8700869911087f,+0.8577286100003f,+0.8448535652497f,
+0.8314696123025f,+0.8175848131516f,+0.8032075314806f,+0.7883464276266f,
+0.7730104533627f,+0.7572088465065f,+0.7409511253550f,+0.7242470829515f,
+0.7071067811865f,+0.6895405447371f,+0.6715589548470f,+0.6531728429538f,
+0.6343932841636f,+0.6152315905806f,+0.5956993044924f,+0.5758081914178f,
+0.5555702330196f,+0.5349976198871f,+0.5141027441932f,+0.4928981922298f,
+0.4713967368260f,+0.4496113296546f,+0.4275550934303f,+0.4052413140050f,
+0.3826834323651f,+0.3598950365350f,+0.3368898533922f,+0.3136817403989f,
+0.2902846772545f,+0.2667127574749f,+0.2429801799033f,+0.2191012401569f,
+0.1950903220161f,+0.1709618887603f,+0.1467304744554f,+0.1224106751992f,
+0.0980171403296f,+0.0735645635997f,+0.0490676743274f,+0.0245412285229f,
+0.0000000000000f,-0.0245412285229f,-0.0490676743274f,-0.0735645635997f,
-0.0980171403296f,-0.1224106751992f,-0.1467304744554f,-0.1709618887603f,
-0.1950903220161f,-0.2191012401569f,-0.2429801799033f,-0.2667127574749f,
-0.2902846772545f,-0.3136817403989f,-0.3368898533922f,-0.3598950365350f,
-0.3826834323651f,-0.4052413140050f,-0.4275550934303f,-0.4496113296546f,
-0.4713967368260f,-0.4928981922298f,-0.5141027441932f,-0.5349976198871f,
-0.5555702330196f,-0.5758081914178f,-0.5956993044924f,-0.6152315905806f,
-0.6343932841636f,-0.6531728429538f,-0.6715589548470f,-0.6895405447371f,
-0.7071067811865f,-0.7242470829515f,-0.7409511253550f,-0.7572088465065f,
-0.7730104533627f,-0.7883464276266f,-0.8032075314806f,-0.8175848131516f,
-0.8314696123025f,-0.8448535652497f,-0.8577286100003f,-0.8700869911087f,
-0.8819212643484f,-0.8932243011955f,-0.9039892931234f,-0.9142097557035f,
-0.9238795325113f,-0.9329927988347f,-0.9415440651830f,-0.9495281805930f,
-0.9569403357322f,-0.9637760657954f,-0.9700312531945f,-0.9757021300385f,
-0.9807852804032f,-0.9852776423889f,-0.9891765099648f,-0.9924795345987f,
-0.9951847266722f,-0.9972904566787f,-0.9987954562052f,-0.9996988186962f,
-1.0000000000000f,
};
/* interpolated lookup based cos function, domain 0 to PI only */
static float coslook(float a){
double d=a*(.31830989*(float)COS_LOOKUP_SZ);
int i=(int)d;
return COS_LOOKUP[i]+ ((float)(d-i))*(COS_LOOKUP[i+1]-COS_LOOKUP[i]);
}
static final int INVSQ_LOOKUP_SZ=32;
static final float[] INVSQ_LOOKUP={
1.414213562373f,1.392621247646f,1.371988681140f,1.352246807566f,
1.333333333333f,1.315191898443f,1.297771369046f,1.281025230441f,
1.264911064067f,1.249390095109f,1.234426799697f,1.219988562661f,
1.206045378311f,1.192569588000f,1.179535649239f,1.166919931983f,
1.154700538379f,1.142857142857f,1.131370849898f,1.120224067222f,
1.109400392450f,1.098884511590f,1.088662107904f,1.078719779941f,
1.069044967650f,1.059625885652f,1.050451462878f,1.041511287847f,
1.032795558989f,1.024295039463f,1.016001016002f,1.007905261358f,
1.000000000000f,
};
/* interpolated 1./sqrt(p) where .5 <= p < 1. */
static float invsqlook(float a){
// System.out.println(a);
double d=a*(2.f*(float)INVSQ_LOOKUP_SZ)-(float)INVSQ_LOOKUP_SZ;
int i=(int)d;
return INVSQ_LOOKUP[i]+ ((float)(d-i))*(INVSQ_LOOKUP[i+1]-INVSQ_LOOKUP[i]);
}
static final int INVSQ2EXP_LOOKUP_MIN=-32;
static final int INVSQ2EXP_LOOKUP_MAX=32;
static final float[] INVSQ2EXP_LOOKUP={
65536.f, 46340.95001f, 32768.f, 23170.47501f,
16384.f, 11585.2375f, 8192.f, 5792.618751f,
4096.f, 2896.309376f, 2048.f, 1448.154688f,
1024.f, 724.0773439f, 512.f, 362.038672f,
256.f, 181.019336f, 128.f, 90.50966799f,
64.f, 45.254834f, 32.f, 22.627417f,
16.f, 11.3137085f, 8.f, 5.656854249f,
4.f, 2.828427125f, 2.f, 1.414213562f,
1.f, 0.7071067812f, 0.5f, 0.3535533906f,
0.25f, 0.1767766953f, 0.125f, 0.08838834765f,
0.0625f, 0.04419417382f, 0.03125f, 0.02209708691f,
0.015625f, 0.01104854346f, 0.0078125f, 0.005524271728f,
0.00390625f, 0.002762135864f, 0.001953125f, 0.001381067932f,
0.0009765625f, 0.000690533966f, 0.00048828125f, 0.000345266983f,
0.000244140625f,0.0001726334915f,0.0001220703125f,8.631674575e-05f,
6.103515625e-05f,4.315837288e-05f,3.051757812e-05f,2.157918644e-05f,
1.525878906e-05f,
};
/* interpolated 1./sqrt(p) where .5 <= p < 1. */
static float invsq2explook(int a){
return INVSQ2EXP_LOOKUP[a-INVSQ2EXP_LOOKUP_MIN];
}
static final int FROMdB_LOOKUP_SZ=35;
static final int FROMdB2_LOOKUP_SZ=32;
static final int FROMdB_SHIFT=5;
static final int FROMdB2_SHIFT=3;
static final int FROMdB2_MASK=31;
static final float[] FROMdB_LOOKUP={
1.f, 0.6309573445f, 0.3981071706f, 0.2511886432f,
0.1584893192f, 0.1f, 0.06309573445f, 0.03981071706f,
0.02511886432f, 0.01584893192f, 0.01f, 0.006309573445f,
0.003981071706f, 0.002511886432f, 0.001584893192f, 0.001f,
0.0006309573445f,0.0003981071706f,0.0002511886432f,0.0001584893192f,
0.0001f,6.309573445e-05f,3.981071706e-05f,2.511886432e-05f,
1.584893192e-05f, 1e-05f,6.309573445e-06f,3.981071706e-06f,
2.511886432e-06f,1.584893192e-06f, 1e-06f,6.309573445e-07f,
3.981071706e-07f,2.511886432e-07f,1.584893192e-07f,
};
static final float[] FROMdB2_LOOKUP={
0.9928302478f, 0.9786445908f, 0.9646616199f, 0.9508784391f,
0.9372921937f, 0.92390007f, 0.9106992942f, 0.8976871324f,
0.8848608897f, 0.8722179097f, 0.8597555737f, 0.8474713009f,
0.835362547f, 0.8234268041f, 0.8116616003f, 0.8000644989f,
0.7886330981f, 0.7773650302f, 0.7662579617f, 0.755309592f,
0.7445176537f, 0.7338799116f, 0.7233941627f, 0.7130582353f,
0.7028699885f, 0.6928273125f, 0.6829281272f, 0.6731703824f,
0.6635520573f, 0.6540711597f, 0.6447257262f, 0.6355138211f,
};
/* interpolated lookup based fromdB function, domain -140dB to 0dB only */
static float fromdBlook(float a){
int i=(int)(a*((float)(-(1<<FROMdB2_SHIFT))));
return (i<0)?1.f:
((i>=(FROMdB_LOOKUP_SZ<<FROMdB_SHIFT))?0.f:
FROMdB_LOOKUP[i>>>FROMdB_SHIFT]*FROMdB2_LOOKUP[i&FROMdB2_MASK]);
}
}