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106 lines
3.5 KiB
106 lines
3.5 KiB
14 years ago
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/* Copyright (C) 2002 Jean-Marc Valin
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File: math_approx.c
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Various math approximation functions for Speex
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of the Xiph.org Foundation nor the names of its
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contributors may be used to endorse or promote products derived from
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this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <math.h>
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#include "math_approx.h"
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#ifdef SLOW_TRIG
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float cos_sin[102] = {
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1.00000000, 0.00000000,
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0.99804751, 0.06245932,
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0.99219767, 0.12467473,
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0.98247331, 0.18640330,
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0.96891242, 0.24740396,
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0.95156795, 0.30743851,
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0.93050762, 0.36627253,
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0.90581368, 0.42367626,
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0.87758256, 0.47942554,
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0.84592450, 0.53330267,
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0.81096312, 0.58509727,
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0.77283495, 0.63460708,
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0.73168887, 0.68163876,
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0.68768556, 0.72600866,
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0.64099686, 0.76754350,
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0.59180508, 0.80608111,
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0.54030231, 0.84147098,
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0.48668967, 0.87357494,
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0.43117652, 0.90226759,
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0.37397963, 0.92743692,
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0.31532236, 0.94898462,
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0.25543377, 0.96682656,
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0.19454771, 0.98089306,
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0.13290194, 0.99112919,
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0.07073720, 0.99749499,
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0.00829623, 0.99996559,
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-0.05417714, 0.99853134,
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-0.11643894, 0.99319785,
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-0.17824606, 0.98398595,
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-0.23935712, 0.97093160,
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-0.29953351, 0.95408578,
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-0.35854022, 0.93351428,
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-0.41614684, 0.90929743,
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-0.47212841, 0.88152979,
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-0.52626633, 0.85031979,
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-0.57834920, 0.81578931,
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-0.62817362, 0.77807320,
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-0.67554504, 0.73731872,
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-0.72027847, 0.69368503,
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-0.76219923, 0.64734252,
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-0.80114362, 0.59847214,
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-0.83695955, 0.54726475,
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-0.86950718, 0.49392030,
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-0.89865940, 0.43864710,
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-0.92430238, 0.38166099,
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-0.94633597, 0.32318451,
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-0.96467415, 0.26344599,
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-0.97924529, 0.20267873,
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-0.98999250, 0.14112001,
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-0.99687381, 0.07901022,
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-0.99986235, 0.01659189
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};
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float speex_cos(float x)
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{
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int ind;
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float delta;
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ind = (int)floor(x*16+.5);
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delta = x-0.062500*ind;
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ind <<= 1;
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return cos_sin[ind] - delta*(cos_sin[ind+1] +
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.5*delta*(cos_sin[ind] -
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.3333333*delta*cos_sin[ind+1]));
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}
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#endif
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