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255 lines
6.7 KiB
C
255 lines
6.7 KiB
C
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/*____________________________________________________________________________
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FreeAmp - The Free MP3 Player
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MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology
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Corp. http://www.xingtech.com
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Portions Copyright (C) 1998-1999 EMusic.com
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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$Id: l3dq.c,v 1.6 1999/10/19 07:13:09 elrod Exp $
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____________________________________________________________________________*/
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/**** quant.c ***************************************************
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Layer III dequant
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does reordering of short blocks
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mod 8/19/98 decode 22 sf bands
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******************************************************************/
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#include <stdlib.h>
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#include <stdio.h>
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#include <float.h>
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#include <math.h>
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#include <string.h>
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#include "l3.h"
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#include "mp3struct.h"
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/*----------
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static struct {
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int l[23];
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int s[14];} sfBandTable[3] =
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{{{0,4,8,12,16,20,24,30,36,44,52,62,74,90,110,134,162,196,238,288,342,418,576},
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{0,4,8,12,16,22,30,40,52,66,84,106,136,192}},
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{{0,4,8,12,16,20,24,30,36,42,50,60,72,88,106,128,156,190,230,276,330,384,576},
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{0,4,8,12,16,22,28,38,50,64,80,100,126,192}},
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{{0,4,8,12,16,20,24,30,36,44,54,66,82,102,126,156,194,240,296,364,448,550,576},
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{0,4,8,12,16,22,30,42,58,78,104,138,180,192}}};
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----------*/
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/*--------------------------------*/
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static const int pretab[2][22] =
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{
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{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
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{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0},
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};
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////@@@@extern int nBand[2][22]; /* long = nBand[0][i], short = nBand[1][i] */
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/* 8 bit plus 2 lookup x = pow(2.0, 0.25*(global_gain-210)) */
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/* two extra slots to do 1/sqrt(2) scaling for ms */
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/* 4 extra slots to do 1/2 scaling for cvt to mono */
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static float look_global[256 + 2 + 4]; // effectively constant
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/*-------- scaling lookup
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x = pow(2.0, -0.5*(1+scalefact_scale)*scalefac + preemp)
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look_scale[scalefact_scale][preemp][scalefac]
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-----------------------*/
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static float look_scale[2][4][32]; // effectively constant
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typedef float LS[4][32];
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/*--- iSample**(4/3) lookup, -32<=i<=31 ---*/
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#define ISMAX 32
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static float look_pow[2 * ISMAX]; // effectively constant
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/*-- pow(2.0, -0.25*8.0*subblock_gain) --*/
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static float look_subblock[8]; // effectively constant
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/*-- reorder buffer ---*/
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static float re_buf[192][3]; // used by dequant() below, but only during func (as workspace)
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typedef float ARRAY3[3];
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/*=============================================================*/
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float *quant_init_global_addr()
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{
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return look_global;
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}
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/*-------------------------------------------------------------*/
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LS *quant_init_scale_addr()
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{
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return look_scale;
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}
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/*-------------------------------------------------------------*/
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float *quant_init_pow_addr()
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{
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return look_pow;
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}
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/*-------------------------------------------------------------*/
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float *quant_init_subblock_addr()
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{
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return look_subblock;
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}
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/*=============================================================*/
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void dequant(SAMPLE Sample[], int *nsamp,
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SCALEFACT * sf,
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GR * gr,
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CB_INFO * cb_info, int ncbl_mixed)
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{
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int i, j;
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int cb, n, w;
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float x0, xs;
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float xsb[3];
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double tmp;
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int ncbl;
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int cbs0;
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ARRAY3 *buf; /* short block reorder */
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int nbands;
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int i0;
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int non_zero;
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int cbmax[3];
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nbands = *nsamp;
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ncbl = 22; /* long block cb end */
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cbs0 = 12; /* short block cb start */
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/* ncbl_mixed = 8 or 6 mpeg1 or 2 */
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if (gr->block_type == 2)
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{
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ncbl = 0;
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cbs0 = 0;
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if (gr->mixed_block_flag)
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{
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ncbl = ncbl_mixed;
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cbs0 = 3;
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}
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}
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/* fill in cb_info -- */
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/* This doesn't seem used anywhere...
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cb_info->lb_type = gr->block_type;
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if (gr->block_type == 2)
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cb_info->lb_type;
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*/
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cb_info->cbs0 = cbs0;
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cb_info->ncbl = ncbl;
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cbmax[2] = cbmax[1] = cbmax[0] = 0;
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/* global gain pre-adjusted by 2 if ms_mode, 0 otherwise */
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x0 = look_global[(2 + 4) + gr->global_gain];
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i = 0;
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/*----- long blocks ---*/
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for (cb = 0; cb < ncbl; cb++)
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{
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non_zero = 0;
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xs = x0 * look_scale[gr->scalefac_scale][pretab[gr->preflag][cb]][sf->l[cb]];
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n = pMP3Stream->nBand[0][cb];
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for (j = 0; j < n; j++, i++)
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{
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if (Sample[i].s == 0)
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Sample[i].x = 0.0F;
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else
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{
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non_zero = 1;
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if ((Sample[i].s >= (-ISMAX)) && (Sample[i].s < ISMAX))
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Sample[i].x = xs * look_pow[ISMAX + Sample[i].s];
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else
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{
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float tmpConst = (float)(1.0/3.0);
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tmp = (double) Sample[i].s;
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Sample[i].x = (float) (xs * tmp * pow(fabs(tmp), tmpConst));
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}
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}
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}
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if (non_zero)
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cbmax[0] = cb;
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if (i >= nbands)
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break;
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}
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cb_info->cbmax = cbmax[0];
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cb_info->cbtype = 0; // type = long
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if (cbs0 >= 12)
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return;
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/*---------------------------
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block type = 2 short blocks
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----------------------------*/
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cbmax[2] = cbmax[1] = cbmax[0] = cbs0;
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i0 = i; /* save for reorder */
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buf = re_buf;
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for (w = 0; w < 3; w++)
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xsb[w] = x0 * look_subblock[gr->subblock_gain[w]];
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for (cb = cbs0; cb < 13; cb++)
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{
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n = pMP3Stream->nBand[1][cb];
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for (w = 0; w < 3; w++)
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{
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non_zero = 0;
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xs = xsb[w] * look_scale[gr->scalefac_scale][0][sf->s[w][cb]];
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for (j = 0; j < n; j++, i++)
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{
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if (Sample[i].s == 0)
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buf[j][w] = 0.0F;
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else
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{
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non_zero = 1;
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if ((Sample[i].s >= (-ISMAX)) && (Sample[i].s < ISMAX))
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buf[j][w] = xs * look_pow[ISMAX + Sample[i].s];
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else
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{
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float tmpConst = (float)(1.0/3.0);
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tmp = (double) Sample[i].s;
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buf[j][w] = (float) (xs * tmp * pow(fabs(tmp), tmpConst));
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}
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}
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}
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if (non_zero)
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cbmax[w] = cb;
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}
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if (i >= nbands)
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break;
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buf += n;
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}
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memmove(&Sample[i0].x, &re_buf[0][0], sizeof(float) * (i - i0));
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*nsamp = i; /* update nsamp */
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cb_info->cbmax_s[0] = cbmax[0];
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cb_info->cbmax_s[1] = cbmax[1];
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cb_info->cbmax_s[2] = cbmax[2];
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if (cbmax[1] > cbmax[0])
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cbmax[0] = cbmax[1];
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if (cbmax[2] > cbmax[0])
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cbmax[0] = cbmax[2];
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cb_info->cbmax = cbmax[0];
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cb_info->cbtype = 1; /* type = short */
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return;
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}
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/*-------------------------------------------------------------*/
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