404 lines
9.6 KiB
C
404 lines
9.6 KiB
C
/*____________________________________________________________________________
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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: upsf.c,v 1.3 1999/10/19 07:13:09 elrod Exp $
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____________________________________________________________________________*/
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/**** upsf.c ***************************************************
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Layer III
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unpack scale factors
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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 "L3.h"
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//extern int iframe;
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unsigned int bitget(int n);
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/*------------------------------------------------------------*/
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static const int slen_table[16][2] =
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{
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{0, 0}, {0, 1},
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{0, 2}, {0, 3},
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{3, 0}, {1, 1},
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{1, 2}, {1, 3},
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{2, 1}, {2, 2},
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{2, 3}, {3, 1},
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{3, 2}, {3, 3},
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{4, 2}, {4, 3},
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};
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/* nr_table[size+3*is_right][block type 0,1,3 2, 2+mixed][4] */
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/* for bt=2 nr is count for group of 3 */
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static const int nr_table[6][3][4] =
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{
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{{6, 5, 5, 5},
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{3, 3, 3, 3},
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{6, 3, 3, 3}},
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{{6, 5, 7, 3},
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{3, 3, 4, 2},
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{6, 3, 4, 2}},
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{{11, 10, 0, 0},
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{6, 6, 0, 0},
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{6, 3, 6, 0}}, /* adjusted *//* 15, 18, 0, 0, */
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/*-intensity stereo right chan--*/
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{{7, 7, 7, 0},
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{4, 4, 4, 0},
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{6, 5, 4, 0}},
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{{6, 6, 6, 3},
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{4, 3, 3, 2},
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{6, 4, 3, 2}},
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{{8, 8, 5, 0},
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{5, 4, 3, 0},
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{6, 6, 3, 0}},
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};
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/*=============================================================*/
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void unpack_sf_sub_MPEG1(SCALEFACT sf[],
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GR * grdat,
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int scfsi, /* bit flag */
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int gr)
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{
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int sfb;
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int slen0, slen1;
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int block_type, mixed_block_flag, scalefac_compress;
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block_type = grdat->block_type;
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mixed_block_flag = grdat->mixed_block_flag;
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scalefac_compress = grdat->scalefac_compress;
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slen0 = slen_table[scalefac_compress][0];
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slen1 = slen_table[scalefac_compress][1];
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if (block_type == 2)
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{
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if (mixed_block_flag)
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{ /* mixed */
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for (sfb = 0; sfb < 8; sfb++)
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sf[0].l[sfb] = bitget(slen0);
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for (sfb = 3; sfb < 6; sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen0);
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sf[0].s[1][sfb] = bitget(slen0);
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sf[0].s[2][sfb] = bitget(slen0);
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}
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for (sfb = 6; sfb < 12; sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen1);
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sf[0].s[1][sfb] = bitget(slen1);
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sf[0].s[2][sfb] = bitget(slen1);
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}
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return;
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}
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for (sfb = 0; sfb < 6; sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen0);
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sf[0].s[1][sfb] = bitget(slen0);
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sf[0].s[2][sfb] = bitget(slen0);
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}
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for (; sfb < 12; sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen1);
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sf[0].s[1][sfb] = bitget(slen1);
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sf[0].s[2][sfb] = bitget(slen1);
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}
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return;
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}
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/* long blocks types 0 1 3, first granule */
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if (gr == 0)
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{
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for (sfb = 0; sfb < 11; sfb++)
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sf[0].l[sfb] = bitget(slen0);
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for (; sfb < 21; sfb++)
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sf[0].l[sfb] = bitget(slen1);
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return;
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}
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/* long blocks 0, 1, 3, second granule */
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sfb = 0;
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if (scfsi & 8)
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for (; sfb < 6; sfb++)
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sf[0].l[sfb] = sf[-2].l[sfb];
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else
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for (; sfb < 6; sfb++)
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sf[0].l[sfb] = bitget(slen0);
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if (scfsi & 4)
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for (; sfb < 11; sfb++)
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sf[0].l[sfb] = sf[-2].l[sfb];
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else
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for (; sfb < 11; sfb++)
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sf[0].l[sfb] = bitget(slen0);
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if (scfsi & 2)
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for (; sfb < 16; sfb++)
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sf[0].l[sfb] = sf[-2].l[sfb];
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else
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for (; sfb < 16; sfb++)
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sf[0].l[sfb] = bitget(slen1);
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if (scfsi & 1)
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for (; sfb < 21; sfb++)
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sf[0].l[sfb] = sf[-2].l[sfb];
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else
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for (; sfb < 21; sfb++)
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sf[0].l[sfb] = bitget(slen1);
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return;
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}
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/*=============================================================*/
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void unpack_sf_sub_MPEG2(SCALEFACT sf[],
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GR * grdat,
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int is_and_ch, IS_SF_INFO * sf_info)
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{
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int sfb;
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int slen1, slen2, slen3, slen4;
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int nr1, nr2, nr3, nr4;
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int i, k;
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int preflag, intensity_scale;
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int block_type, mixed_block_flag, scalefac_compress;
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block_type = grdat->block_type;
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mixed_block_flag = grdat->mixed_block_flag;
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scalefac_compress = grdat->scalefac_compress;
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preflag = 0;
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intensity_scale = 0; /* to avoid compiler warning */
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if (is_and_ch == 0)
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{
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if (scalefac_compress < 400)
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{
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slen2 = scalefac_compress >> 4;
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slen1 = slen2 / 5;
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slen2 = slen2 % 5;
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slen4 = scalefac_compress & 15;
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slen3 = slen4 >> 2;
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slen4 = slen4 & 3;
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k = 0;
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}
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else if (scalefac_compress < 500)
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{
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scalefac_compress -= 400;
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slen2 = scalefac_compress >> 2;
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slen1 = slen2 / 5;
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slen2 = slen2 % 5;
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slen3 = scalefac_compress & 3;
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slen4 = 0;
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k = 1;
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}
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else
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{
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scalefac_compress -= 500;
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slen1 = scalefac_compress / 3;
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slen2 = scalefac_compress % 3;
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slen3 = slen4 = 0;
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if (mixed_block_flag)
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{
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slen3 = slen2; /* adjust for long/short mix logic */
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slen2 = slen1;
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}
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preflag = 1;
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k = 2;
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}
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}
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else
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{ /* intensity stereo ch = 1 (right) */
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intensity_scale = scalefac_compress & 1;
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scalefac_compress >>= 1;
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if (scalefac_compress < 180)
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{
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slen1 = scalefac_compress / 36;
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slen2 = scalefac_compress % 36;
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slen3 = slen2 % 6;
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slen2 = slen2 / 6;
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slen4 = 0;
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k = 3 + 0;
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}
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else if (scalefac_compress < 244)
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{
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scalefac_compress -= 180;
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slen3 = scalefac_compress & 3;
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scalefac_compress >>= 2;
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slen2 = scalefac_compress & 3;
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slen1 = scalefac_compress >> 2;
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slen4 = 0;
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k = 3 + 1;
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}
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else
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{
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scalefac_compress -= 244;
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slen1 = scalefac_compress / 3;
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slen2 = scalefac_compress % 3;
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slen3 = slen4 = 0;
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k = 3 + 2;
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}
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}
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i = 0;
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if (block_type == 2)
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i = (mixed_block_flag & 1) + 1;
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nr1 = nr_table[k][i][0];
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nr2 = nr_table[k][i][1];
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nr3 = nr_table[k][i][2];
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nr4 = nr_table[k][i][3];
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/* return is scale factor info (for right chan is mode) */
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if (is_and_ch)
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{
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sf_info->nr[0] = nr1;
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sf_info->nr[1] = nr2;
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sf_info->nr[2] = nr3;
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sf_info->slen[0] = slen1;
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sf_info->slen[1] = slen2;
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sf_info->slen[2] = slen3;
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sf_info->intensity_scale = intensity_scale;
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}
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grdat->preflag = preflag; /* return preflag */
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/*--------------------------------------*/
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if (block_type == 2)
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{
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if (mixed_block_flag)
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{ /* mixed */
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if (slen1 != 0) /* long block portion */
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for (sfb = 0; sfb < 6; sfb++)
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sf[0].l[sfb] = bitget(slen1);
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else
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for (sfb = 0; sfb < 6; sfb++)
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sf[0].l[sfb] = 0;
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sfb = 3; /* start sfb for short */
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}
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else
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{ /* all short, initial short blocks */
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sfb = 0;
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if (slen1 != 0)
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for (i = 0; i < nr1; i++, sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen1);
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sf[0].s[1][sfb] = bitget(slen1);
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sf[0].s[2][sfb] = bitget(slen1);
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}
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else
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for (i = 0; i < nr1; i++, sfb++)
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{
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sf[0].s[0][sfb] = 0;
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sf[0].s[1][sfb] = 0;
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sf[0].s[2][sfb] = 0;
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}
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}
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/* remaining short blocks */
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if (slen2 != 0)
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for (i = 0; i < nr2; i++, sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen2);
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sf[0].s[1][sfb] = bitget(slen2);
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sf[0].s[2][sfb] = bitget(slen2);
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}
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else
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for (i = 0; i < nr2; i++, sfb++)
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{
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sf[0].s[0][sfb] = 0;
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sf[0].s[1][sfb] = 0;
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sf[0].s[2][sfb] = 0;
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}
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if (slen3 != 0)
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for (i = 0; i < nr3; i++, sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen3);
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sf[0].s[1][sfb] = bitget(slen3);
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sf[0].s[2][sfb] = bitget(slen3);
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}
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else
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for (i = 0; i < nr3; i++, sfb++)
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{
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sf[0].s[0][sfb] = 0;
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sf[0].s[1][sfb] = 0;
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sf[0].s[2][sfb] = 0;
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}
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if (slen4 != 0)
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for (i = 0; i < nr4; i++, sfb++)
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{
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sf[0].s[0][sfb] = bitget(slen4);
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sf[0].s[1][sfb] = bitget(slen4);
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sf[0].s[2][sfb] = bitget(slen4);
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}
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else
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for (i = 0; i < nr4; i++, sfb++)
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{
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sf[0].s[0][sfb] = 0;
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sf[0].s[1][sfb] = 0;
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sf[0].s[2][sfb] = 0;
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}
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return;
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}
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/* long blocks types 0 1 3 */
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sfb = 0;
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if (slen1 != 0)
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for (i = 0; i < nr1; i++, sfb++)
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sf[0].l[sfb] = bitget(slen1);
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else
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for (i = 0; i < nr1; i++, sfb++)
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sf[0].l[sfb] = 0;
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if (slen2 != 0)
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for (i = 0; i < nr2; i++, sfb++)
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sf[0].l[sfb] = bitget(slen2);
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else
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for (i = 0; i < nr2; i++, sfb++)
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sf[0].l[sfb] = 0;
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if (slen3 != 0)
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for (i = 0; i < nr3; i++, sfb++)
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sf[0].l[sfb] = bitget(slen3);
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else
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for (i = 0; i < nr3; i++, sfb++)
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sf[0].l[sfb] = 0;
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if (slen4 != 0)
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for (i = 0; i < nr4; i++, sfb++)
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sf[0].l[sfb] = bitget(slen4);
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else
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for (i = 0; i < nr4; i++, sfb++)
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sf[0].l[sfb] = 0;
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}
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/*-------------------------------------------------*/
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