xash3d-fwgs/engine/common/soundlib/libmpg/tabinit.c

/*
tabinit.c - compact version of famous library mpg123
Copyright (C) 2017 Uncle Mike

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 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 General Public License for more details.
*/

#include "mpg123.h"
#include <math.h>

static float cos64[16];
static float cos32[8];
static float cos16[4];
static float cos8[2];
static float cos4[1];

static long intwinbase[] = {
     0,    -1,    -1,    -1,    -1,    -1,    -1,    -2,    -2,    -2,
    -2,    -3,    -3,    -4,    -4,    -5,    -5,    -6,    -7,    -7,
    -8,    -9,   -10,   -11,   -13,   -14,   -16,   -17,   -19,   -21,
   -24,   -26,   -29,   -31,   -35,   -38,   -41,   -45,   -49,   -53,
   -58,   -63,   -68,   -73,   -79,   -85,   -91,   -97,  -104,  -111,
  -117,  -125,  -132,  -139,  -147,  -154,  -161,  -169,  -176,  -183,
  -190,  -196,  -202,  -208,  -213,  -218,  -222,  -225,  -227,  -228,
  -228,  -227,  -224,  -221,  -215,  -208,  -200,  -189,  -177,  -163,
  -146,  -127,  -106,   -83,   -57,   -29,     2,    36,    72,   111,
   153,   197,   244,   294,   347,   401,   459,   519,   581,   645,
   711,   779,   848,   919,   991,  1064,  1137,  1210,  1283,  1356,
  1428,  1498,  1567,  1634,  1698,  1759,  1817,  1870,  1919,  1962,
  2001,  2032,  2057,  2075,  2085,  2087,  2080,  2063,  2037,  2000,
  1952,  1893,  1822,  1739,  1644,  1535,  1414,  1280,  1131,   970,
   794,   605,   402,   185,   -45,  -288,  -545,  -814, -1095, -1388,
 -1692, -2006, -2330, -2663, -3004, -3351, -3705, -4063, -4425, -4788,
 -5153, -5517, -5879, -6237, -6589, -6935, -7271, -7597, -7910, -8209,
 -8491, -8755, -8998, -9219, -9416, -9585, -9727, -9838, -9916, -9959,
 -9966, -9935, -9863, -9750, -9592, -9389, -9139, -8840, -8492, -8092,
 -7640, -7134, -6574, -5959, -5288, -4561, -3776, -2935, -2037, -1082,
   -70,   998,  2122,  3300,  4533,  5818,  7154,  8540,  9975, 11455,
 12980, 14548, 16155, 17799, 19478, 21189, 22929, 24694, 26482, 28289,
 30112, 31947, 33791, 35640, 37489, 39336, 41176, 43006, 44821, 46617,
 48390, 50137, 51853, 53534, 55178, 56778, 58333, 59838, 61289, 62684,
 64019, 65290, 66494, 67629, 68692, 69679, 70590, 71420, 72169, 72835,
 73415, 73908, 74313, 74630, 74856, 74992, 75038 };

float *pnts[] = { cos64, cos32, cos16, cos8, cos4 };

void prepare_decode_tables( void )
{
	int	i, k, kr, divv;
	float	*costab;

	for( i = 0; i < 5; i++ )
	{
		kr = 0x10 >> i;
		divv = 0x40 >> i;
		costab = pnts[i];

		for( k = 0; k < kr; k++)
			costab[k] = DOUBLE_TO_REAL( 1.0 / ( 2.0 * cos( M_PI * ((double)k * 2.0 + 1.0 ) / (double)divv )));
	}
}

void make_decode_tables( mpg123_handle_t *fr )
{
	int	i, j;
	int	idx = 0;
	double	scaleval;

	// scale is always based on 1.0.
	scaleval = -0.5 * (fr->lastscale < 0 ? fr->p.outscale : fr->lastscale);

	for( i = 0, j = 0; i < 256; i++, j++, idx += 32 )
	{
		if( idx < 512 + 16 )
			fr->decwin[idx+16] = fr->decwin[idx] = DOUBLE_TO_REAL( (double)intwinbase[j] * scaleval );

		if( i % 32 == 31 )
			idx -= 1023;

		if( i % 64 == 63 )
			scaleval = -scaleval;
	}

	for( ; i < 512; i++, j--, idx += 32 )
	{
		if( idx < 512 + 16 )
			fr->decwin[idx+16] = fr->decwin[idx] = DOUBLE_TO_REAL( (double)intwinbase[j] * scaleval );

		if( i % 32 == 31 )
			idx -= 1023;
		if( i % 64 == 63 )
			scaleval = -scaleval;
	}
}