508 lines
12 KiB
C
508 lines
12 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: uph.c,v 1.3 1999/10/19 07:13:09 elrod Exp $
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____________________________________________________________________________*/
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/**** uph.c ***************************************************
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Layer 3 audio
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huffman decode
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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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#pragma warning ( disable : 4711 ) // function 'xxxx' selected for automatic inline expansion
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#ifdef _MSC_VER
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#pragma warning(disable: 4505)
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#endif
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/*===============================================================*/
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/* max bits required for any lookup - change if htable changes */
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/* quad required 10 bit w/signs must have (MAXBITS+2) >= 10 */
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#define MAXBITS 9
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static const HUFF_ELEMENT huff_table_0[4] =
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{{0}, {0}, {0}, {64}}; /* dummy must not use */
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#include "htable.h"
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/*-- 6 bit lookup (purgebits, value) --*/
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static const unsigned char quad_table_a[][2] =
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{
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{6, 11}, {6, 15}, {6, 13}, {6, 14}, {6, 7}, {6, 5}, {5, 9},
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{5, 9}, {5, 6}, {5, 6}, {5, 3}, {5, 3}, {5, 10}, {5, 10},
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{5, 12}, {5, 12}, {4, 2}, {4, 2}, {4, 2}, {4, 2}, {4, 1},
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{4, 1}, {4, 1}, {4, 1}, {4, 4}, {4, 4}, {4, 4}, {4, 4},
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{4, 8}, {4, 8}, {4, 8}, {4, 8}, {1, 0}, {1, 0}, {1, 0},
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{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
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{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
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{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
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{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
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{1, 0},
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};
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typedef struct
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{
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const HUFF_ELEMENT *table;
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int linbits;
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int ncase;
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}
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HUFF_SETUP;
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#define no_bits 0
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#define one_shot 1
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#define no_linbits 2
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#define have_linbits 3
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#define quad_a 4
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#define quad_b 5
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static const HUFF_SETUP table_look[] =
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{
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{huff_table_0, 0, no_bits},
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{huff_table_1, 0, one_shot},
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{huff_table_2, 0, one_shot},
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{huff_table_3, 0, one_shot},
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{huff_table_0, 0, no_bits},
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{huff_table_5, 0, one_shot},
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{huff_table_6, 0, one_shot},
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{huff_table_7, 0, no_linbits},
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{huff_table_8, 0, no_linbits},
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{huff_table_9, 0, no_linbits},
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{huff_table_10, 0, no_linbits},
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{huff_table_11, 0, no_linbits},
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{huff_table_12, 0, no_linbits},
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{huff_table_13, 0, no_linbits},
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{huff_table_0, 0, no_bits},
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{huff_table_15, 0, no_linbits},
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{huff_table_16, 1, have_linbits},
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{huff_table_16, 2, have_linbits},
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{huff_table_16, 3, have_linbits},
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{huff_table_16, 4, have_linbits},
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{huff_table_16, 6, have_linbits},
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{huff_table_16, 8, have_linbits},
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{huff_table_16, 10, have_linbits},
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{huff_table_16, 13, have_linbits},
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{huff_table_24, 4, have_linbits},
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{huff_table_24, 5, have_linbits},
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{huff_table_24, 6, have_linbits},
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{huff_table_24, 7, have_linbits},
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{huff_table_24, 8, have_linbits},
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{huff_table_24, 9, have_linbits},
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{huff_table_24, 11, have_linbits},
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{huff_table_24, 13, have_linbits},
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{huff_table_0, 0, quad_a},
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{huff_table_0, 0, quad_b},
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};
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/*========================================================*/
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extern BITDAT bitdat;
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/*------------- get n bits from bitstream -------------*/
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/* unused
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static unsigned int bitget(int n)
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{
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unsigned int x;
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if (bitdat.bits < n)
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{ */ /* refill bit buf if necessary */
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/* while (bitdat.bits <= 24)
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{
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bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
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bitdat.bits += 8;
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}
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}
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bitdat.bits -= n;
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x = bitdat.bitbuf >> bitdat.bits;
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bitdat.bitbuf -= x << bitdat.bits;
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return x;
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}
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*/
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/*----- get n bits - checks for n+2 avail bits (linbits+sign) -----*/
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static unsigned int bitget_lb(int n)
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{
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unsigned int x;
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if (bitdat.bits < (n + 2))
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{ /* refill bit buf if necessary */
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while (bitdat.bits <= 24)
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{
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bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
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bitdat.bits += 8;
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}
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}
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bitdat.bits -= n;
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x = bitdat.bitbuf >> bitdat.bits;
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bitdat.bitbuf -= x << bitdat.bits;
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return x;
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}
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/*------------- get n bits but DO NOT remove from bitstream --*/
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static unsigned int bitget2(int n)
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{
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unsigned int x;
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if (bitdat.bits < (MAXBITS + 2))
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{ /* refill bit buf if necessary */
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while (bitdat.bits <= 24)
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{
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bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
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bitdat.bits += 8;
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}
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}
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x = bitdat.bitbuf >> (bitdat.bits - n);
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return x;
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}
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/*------------- remove n bits from bitstream ---------*/
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/* unused
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static void bitget_purge(int n)
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{
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bitdat.bits -= n;
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bitdat.bitbuf -= (bitdat.bitbuf >> bitdat.bits) << bitdat.bits;
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}
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*/
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/*------------- get 1 bit from bitstream NO CHECK -------------*/
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/* unused
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static unsigned int bitget_1bit()
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{
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unsigned int x;
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bitdat.bits--;
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x = bitdat.bitbuf >> bitdat.bits;
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bitdat.bitbuf -= x << bitdat.bits;
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return x;
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}
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*/
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/*========================================================*/
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/*========================================================*/
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#define mac_bitget_check(n) if( bitdat.bits < (n) ) { \
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while( bitdat.bits <= 24 ) { \
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bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++; \
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bitdat.bits += 8; \
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} \
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}
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/*---------------------------------------------------------*/
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#define mac_bitget2(n) (bitdat.bitbuf >> (bitdat.bits-n));
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/*---------------------------------------------------------*/
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#define mac_bitget(n) ( bitdat.bits -= n, \
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code = bitdat.bitbuf >> bitdat.bits, \
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bitdat.bitbuf -= code << bitdat.bits, \
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code )
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/*---------------------------------------------------------*/
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#define mac_bitget_purge(n) bitdat.bits -= n, \
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bitdat.bitbuf -= (bitdat.bitbuf >> bitdat.bits) << bitdat.bits;
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/*---------------------------------------------------------*/
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#define mac_bitget_1bit() ( bitdat.bits--, \
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code = bitdat.bitbuf >> bitdat.bits, \
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bitdat.bitbuf -= code << bitdat.bits, \
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code )
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/*========================================================*/
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/*========================================================*/
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void unpack_huff(int xy[][2], int n, int ntable)
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{
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int i;
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const HUFF_ELEMENT *t;
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const HUFF_ELEMENT *t0;
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int linbits;
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int bits;
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int code;
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int x, y;
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if (n <= 0)
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return;
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n = n >> 1; /* huff in pairs */
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/*-------------*/
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t0 = table_look[ntable].table;
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linbits = table_look[ntable].linbits;
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switch (table_look[ntable].ncase)
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{
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default:
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/*------------------------------------------*/
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case no_bits:
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/*- table 0, no data, x=y=0--*/
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for (i = 0; i < n; i++)
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{
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xy[i][0] = 0;
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xy[i][1] = 0;
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}
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return;
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/*------------------------------------------*/
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case one_shot:
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/*- single lookup, no escapes -*/
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for (i = 0; i < n; i++)
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{
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mac_bitget_check((MAXBITS + 2));
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bits = t0[0].b.signbits;
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code = mac_bitget2(bits);
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mac_bitget_purge(t0[1 + code].b.purgebits);
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x = t0[1 + code].b.x;
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y = t0[1 + code].b.y;
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if (x)
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if (mac_bitget_1bit())
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x = -x;
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if (y)
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if (mac_bitget_1bit())
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y = -y;
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xy[i][0] = x;
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xy[i][1] = y;
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if (bitdat.bs_ptr > bitdat.bs_ptr_end)
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break; // bad data protect
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}
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return;
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/*------------------------------------------*/
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case no_linbits:
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for (i = 0; i < n; i++)
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{
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t = t0;
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for (;;)
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{
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mac_bitget_check((MAXBITS + 2));
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bits = t[0].b.signbits;
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code = mac_bitget2(bits);
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if (t[1 + code].b.purgebits)
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break;
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t += t[1 + code].ptr; /* ptr include 1+code */
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mac_bitget_purge(bits);
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}
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mac_bitget_purge(t[1 + code].b.purgebits);
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x = t[1 + code].b.x;
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y = t[1 + code].b.y;
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if (x)
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if (mac_bitget_1bit())
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x = -x;
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if (y)
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if (mac_bitget_1bit())
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y = -y;
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xy[i][0] = x;
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xy[i][1] = y;
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if (bitdat.bs_ptr > bitdat.bs_ptr_end)
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break; // bad data protect
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}
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return;
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/*------------------------------------------*/
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case have_linbits:
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for (i = 0; i < n; i++)
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{
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t = t0;
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for (;;)
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{
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bits = t[0].b.signbits;
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code = bitget2(bits);
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if (t[1 + code].b.purgebits)
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break;
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t += t[1 + code].ptr; /* ptr includes 1+code */
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mac_bitget_purge(bits);
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}
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mac_bitget_purge(t[1 + code].b.purgebits);
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x = t[1 + code].b.x;
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y = t[1 + code].b.y;
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if (x == 15)
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x += bitget_lb(linbits);
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if (x)
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if (mac_bitget_1bit())
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x = -x;
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if (y == 15)
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y += bitget_lb(linbits);
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if (y)
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if (mac_bitget_1bit())
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y = -y;
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xy[i][0] = x;
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xy[i][1] = y;
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if (bitdat.bs_ptr > bitdat.bs_ptr_end)
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break; // bad data protect
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}
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return;
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}
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/*--- end switch ---*/
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}
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/*==========================================================*/
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int unpack_huff_quad(int vwxy[][4], int n, int nbits, int ntable)
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{
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int i;
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int code;
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int x, y, v, w;
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int tmp;
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int i_non_zero, tmp_nz;
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tmp_nz = 15;
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i_non_zero = -1;
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n = n >> 2; /* huff in quads */
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if (ntable)
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goto case_quad_b;
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/* case_quad_a: */
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for (i = 0; i < n; i++)
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{
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if (nbits <= 0)
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break;
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mac_bitget_check(10);
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code = mac_bitget2(6);
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nbits -= quad_table_a[code][0];
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mac_bitget_purge(quad_table_a[code][0]);
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tmp = quad_table_a[code][1];
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if (tmp)
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{
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i_non_zero = i;
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tmp_nz = tmp;
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}
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v = (tmp >> 3) & 1;
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w = (tmp >> 2) & 1;
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x = (tmp >> 1) & 1;
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y = tmp & 1;
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if (v)
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{
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if (mac_bitget_1bit())
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v = -v;
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nbits--;
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}
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if (w)
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{
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if (mac_bitget_1bit())
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w = -w;
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nbits--;
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}
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if (x)
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{
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if (mac_bitget_1bit())
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x = -x;
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nbits--;
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}
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if (y)
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{
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if (mac_bitget_1bit())
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y = -y;
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nbits--;
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}
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vwxy[i][0] = v;
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vwxy[i][1] = w;
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vwxy[i][2] = x;
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vwxy[i][3] = y;
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if (bitdat.bs_ptr > bitdat.bs_ptr_end)
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break; // bad data protect
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}
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if (i && nbits < 0)
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{
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i--;
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vwxy[i][0] = 0;
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vwxy[i][1] = 0;
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vwxy[i][2] = 0;
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vwxy[i][3] = 0;
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}
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i_non_zero = (i_non_zero + 1) << 2;
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if ((tmp_nz & 3) == 0)
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i_non_zero -= 2;
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return i_non_zero;
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/*--------------------*/
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case_quad_b:
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for (i = 0; i < n; i++)
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{
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if (nbits < 4)
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break;
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nbits -= 4;
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mac_bitget_check(8);
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tmp = mac_bitget(4) ^ 15; /* one's complement of bitstream */
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if (tmp)
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{
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i_non_zero = i;
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tmp_nz = tmp;
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}
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v = (tmp >> 3) & 1;
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w = (tmp >> 2) & 1;
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x = (tmp >> 1) & 1;
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y = tmp & 1;
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if (v)
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{
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if (mac_bitget_1bit())
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v = -v;
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nbits--;
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}
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if (w)
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{
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if (mac_bitget_1bit())
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w = -w;
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nbits--;
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}
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if (x)
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{
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if (mac_bitget_1bit())
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x = -x;
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nbits--;
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}
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if (y)
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{
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if (mac_bitget_1bit())
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y = -y;
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nbits--;
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}
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vwxy[i][0] = v;
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vwxy[i][1] = w;
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vwxy[i][2] = x;
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vwxy[i][3] = y;
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if (bitdat.bs_ptr > bitdat.bs_ptr_end)
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break; // bad data protect
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}
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if (nbits < 0)
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{
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i--;
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vwxy[i][0] = 0;
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vwxy[i][1] = 0;
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vwxy[i][2] = 0;
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vwxy[i][3] = 0;
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}
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i_non_zero = (i_non_zero + 1) << 2;
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if ((tmp_nz & 3) == 0)
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i_non_zero -= 2;
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return i_non_zero; /* return non-zero sample (to nearest pair) */
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}
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/*-----------------------------------------------------*/
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