/*____________________________________________________________________________
FreeAmp - The Free MP3 Player
MP3 Decoder originally Copyright (C) 1995-1997 Xing Technology
Corp. http://www.xingtech.com
Portions Copyright (C) 1998-1999 EMusic.com
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 2 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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: uph.c,v 1.3 1999/10/19 07:13:09 elrod Exp $
____________________________________________________________________________*/
/**** uph.c ***************************************************
Layer 3 audio
huffman decode
******************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <float.h>
#include <math.h>
#include "l3.h"
/*===============================================================*/
/* max bits required for any lookup - change if htable changes */
/* quad required 10 bit w/signs must have (MAXBITS+2) >= 10 */
#define MAXBITS 9
static const HUFF_ELEMENT huff_table_0[4] =
{{0}, {0}, {0}, {64}}; /* dummy must not use */
#include "htable.h"
/*-- 6 bit lookup (purgebits, value) --*/
static const unsigned char quad_table_a[][2] =
{
{6, 11}, {6, 15}, {6, 13}, {6, 14}, {6, 7}, {6, 5}, {5, 9},
{5, 9}, {5, 6}, {5, 6}, {5, 3}, {5, 3}, {5, 10}, {5, 10},
{5, 12}, {5, 12}, {4, 2}, {4, 2}, {4, 2}, {4, 2}, {4, 1},
{4, 1}, {4, 1}, {4, 1}, {4, 4}, {4, 4}, {4, 4}, {4, 4},
{4, 8}, {4, 8}, {4, 8}, {4, 8}, {1, 0}, {1, 0}, {1, 0},
{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
{1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0}, {1, 0},
{1, 0},
};
typedef struct
{
const HUFF_ELEMENT *table;
int linbits;
int ncase;
}
HUFF_SETUP;
#define no_bits 0
#define one_shot 1
#define no_linbits 2
#define have_linbits 3
#define quad_a 4
#define quad_b 5
static const HUFF_SETUP table_look[] =
{
{huff_table_0, 0, no_bits},
{huff_table_1, 0, one_shot},
{huff_table_2, 0, one_shot},
{huff_table_3, 0, one_shot},
{huff_table_0, 0, no_bits},
{huff_table_5, 0, one_shot},
{huff_table_6, 0, one_shot},
{huff_table_7, 0, no_linbits},
{huff_table_8, 0, no_linbits},
{huff_table_9, 0, no_linbits},
{huff_table_10, 0, no_linbits},
{huff_table_11, 0, no_linbits},
{huff_table_12, 0, no_linbits},
{huff_table_13, 0, no_linbits},
{huff_table_0, 0, no_bits},
{huff_table_15, 0, no_linbits},
{huff_table_16, 1, have_linbits},
{huff_table_16, 2, have_linbits},
{huff_table_16, 3, have_linbits},
{huff_table_16, 4, have_linbits},
{huff_table_16, 6, have_linbits},
{huff_table_16, 8, have_linbits},
{huff_table_16, 10, have_linbits},
{huff_table_16, 13, have_linbits},
{huff_table_24, 4, have_linbits},
{huff_table_24, 5, have_linbits},
{huff_table_24, 6, have_linbits},
{huff_table_24, 7, have_linbits},
{huff_table_24, 8, have_linbits},
{huff_table_24, 9, have_linbits},
{huff_table_24, 11, have_linbits},
{huff_table_24, 13, have_linbits},
{huff_table_0, 0, quad_a},
{huff_table_0, 0, quad_b},
};
/*========================================================*/
extern BITDAT bitdat;
/*------------- get n bits from bitstream -------------*/
/* unused
static unsigned int bitget(int n)
{
unsigned int x;
if (bitdat.bits < n)
{ */ /* refill bit buf if necessary */
/* while (bitdat.bits <= 24)
{
bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
bitdat.bits += 8;
}
}
bitdat.bits -= n;
x = bitdat.bitbuf >> bitdat.bits;
bitdat.bitbuf -= x << bitdat.bits;
return x;
}
*/
/*----- get n bits - checks for n+2 avail bits (linbits+sign) -----*/
static unsigned int bitget_lb(int n)
{
unsigned int x;
if (bitdat.bits < (n + 2))
{ /* refill bit buf if necessary */
while (bitdat.bits <= 24)
{
bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
bitdat.bits += 8;
}
}
bitdat.bits -= n;
x = bitdat.bitbuf >> bitdat.bits;
bitdat.bitbuf -= x << bitdat.bits;
return x;
}
/*------------- get n bits but DO NOT remove from bitstream --*/
static unsigned int bitget2(int n)
{
unsigned int x;
if (bitdat.bits < (MAXBITS + 2))
{ /* refill bit buf if necessary */
while (bitdat.bits <= 24)
{
bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++;
bitdat.bits += 8;
}
}
x = bitdat.bitbuf >> (bitdat.bits - n);
return x;
}
/*------------- remove n bits from bitstream ---------*/
/* unused
static void bitget_purge(int n)
{
bitdat.bits -= n;
bitdat.bitbuf -= (bitdat.bitbuf >> bitdat.bits) << bitdat.bits;
}
*/
/*------------- get 1 bit from bitstream NO CHECK -------------*/
/* unused
static unsigned int bitget_1bit()
{
unsigned int x;
bitdat.bits--;
x = bitdat.bitbuf >> bitdat.bits;
bitdat.bitbuf -= x << bitdat.bits;
return x;
}
*/
/*========================================================*/
/*========================================================*/
#define mac_bitget_check(n) if( bitdat.bits < (n) ) { \
while( bitdat.bits <= 24 ) { \
bitdat.bitbuf = (bitdat.bitbuf << 8) | *bitdat.bs_ptr++; \
bitdat.bits += 8; \
} \
}
/*---------------------------------------------------------*/
#define mac_bitget2(n) (bitdat.bitbuf >> (bitdat.bits-n));
/*---------------------------------------------------------*/
#define mac_bitget(n) ( bitdat.bits -= n, \
code = bitdat.bitbuf >> bitdat.bits, \
bitdat.bitbuf -= code << bitdat.bits, \
code )
/*---------------------------------------------------------*/
#define mac_bitget_purge(n) bitdat.bits -= n, \
bitdat.bitbuf -= (bitdat.bitbuf >> bitdat.bits) << bitdat.bits;
/*---------------------------------------------------------*/
#define mac_bitget_1bit() ( bitdat.bits--, \
code = bitdat.bitbuf >> bitdat.bits, \
bitdat.bitbuf -= code << bitdat.bits, \
code )
/*========================================================*/
/*========================================================*/
void unpack_huff(int xy[][2], int n, int ntable)
{
int i;
const HUFF_ELEMENT *t;
const HUFF_ELEMENT *t0;
int linbits;
int bits;
int code;
int x, y;
if (n <= 0)
return;
n = n >> 1; /* huff in pairs */
/*-------------*/
t0 = table_look[ntable].table;
linbits = table_look[ntable].linbits;
switch (table_look[ntable].ncase)
{
default:
/*------------------------------------------*/
case no_bits:
/*- table 0, no data, x=y=0--*/
for (i = 0; i < n; i++)
{
xy[i][0] = 0;
xy[i][1] = 0;
}
return;
/*------------------------------------------*/
case one_shot:
/*- single lookup, no escapes -*/
for (i = 0; i < n; i++)
{
mac_bitget_check((MAXBITS + 2));
bits = t0[0].b.signbits;
code = mac_bitget2(bits);
mac_bitget_purge(t0[1 + code].b.purgebits);
x = t0[1 + code].b.x;
y = t0[1 + code].b.y;
if (x)
if (mac_bitget_1bit())
x = -x;
if (y)
if (mac_bitget_1bit())
y = -y;
xy[i][0] = x;
xy[i][1] = y;
if (bitdat.bs_ptr > bitdat.bs_ptr_end)
break; // bad data protect
}
return;
/*------------------------------------------*/
case no_linbits:
for (i = 0; i < n; i++)
{
t = t0;
for (;;)
{
mac_bitget_check((MAXBITS + 2));
bits = t[0].b.signbits;
code = mac_bitget2(bits);
if (t[1 + code].b.purgebits)
break;
t += t[1 + code].ptr; /* ptr include 1+code */
mac_bitget_purge(bits);
}
mac_bitget_purge(t[1 + code].b.purgebits);
x = t[1 + code].b.x;
y = t[1 + code].b.y;
if (x)
if (mac_bitget_1bit())
x = -x;
if (y)
if (mac_bitget_1bit())
y = -y;
xy[i][0] = x;
xy[i][1] = y;
if (bitdat.bs_ptr > bitdat.bs_ptr_end)
break; // bad data protect
}
return;
/*------------------------------------------*/
case have_linbits:
for (i = 0; i < n; i++)
{
t = t0;
for (;;)
{
bits = t[0].b.signbits;
code = bitget2(bits);
if (t[1 + code].b.purgebits)
break;
t += t[1 + code].ptr; /* ptr includes 1+code */
mac_bitget_purge(bits);
}
mac_bitget_purge(t[1 + code].b.purgebits);
x = t[1 + code].b.x;
y = t[1 + code].b.y;
if (x == 15)
x += bitget_lb(linbits);
if (x)
if (mac_bitget_1bit())
x = -x;
if (y == 15)
y += bitget_lb(linbits);
if (y)
if (mac_bitget_1bit())
y = -y;
xy[i][0] = x;
xy[i][1] = y;
if (bitdat.bs_ptr > bitdat.bs_ptr_end)
break; // bad data protect
}
return;
}
/*--- end switch ---*/
}
/*==========================================================*/
int unpack_huff_quad(int vwxy[][4], int n, int nbits, int ntable)
{
int i;
int code;
int x, y, v, w;
int tmp;
int i_non_zero, tmp_nz;
tmp_nz = 15;
i_non_zero = -1;
n = n >> 2; /* huff in quads */
if (ntable)
goto case_quad_b;
/* case_quad_a: */
for (i = 0; i < n; i++)
{
if (nbits <= 0)
break;
mac_bitget_check(10);
code = mac_bitget2(6);
nbits -= quad_table_a[code][0];
mac_bitget_purge(quad_table_a[code][0]);
tmp = quad_table_a[code][1];
if (tmp)
{
i_non_zero = i;
tmp_nz = tmp;
}
v = (tmp >> 3) & 1;
w = (tmp >> 2) & 1;
x = (tmp >> 1) & 1;
y = tmp & 1;
if (v)
{
if (mac_bitget_1bit())
v = -v;
nbits--;
}
if (w)
{
if (mac_bitget_1bit())
w = -w;
nbits--;
}
if (x)
{
if (mac_bitget_1bit())
x = -x;
nbits--;
}
if (y)
{
if (mac_bitget_1bit())
y = -y;
nbits--;
}
vwxy[i][0] = v;
vwxy[i][1] = w;
vwxy[i][2] = x;
vwxy[i][3] = y;
if (bitdat.bs_ptr > bitdat.bs_ptr_end)
break; // bad data protect
}
if (i && nbits < 0)
{
i--;
vwxy[i][0] = 0;
vwxy[i][1] = 0;
vwxy[i][2] = 0;
vwxy[i][3] = 0;
}
i_non_zero = (i_non_zero + 1) << 2;
if ((tmp_nz & 3) == 0)
i_non_zero -= 2;
return i_non_zero;
/*--------------------*/
case_quad_b:
for (i = 0; i < n; i++)
{
if (nbits < 4)
break;
nbits -= 4;
mac_bitget_check(8);
tmp = mac_bitget(4) ^ 15; /* one's complement of bitstream */
if (tmp)
{
i_non_zero = i;
tmp_nz = tmp;
}
v = (tmp >> 3) & 1;
w = (tmp >> 2) & 1;
x = (tmp >> 1) & 1;
y = tmp & 1;
if (v)
{
if (mac_bitget_1bit())
v = -v;
nbits--;
}
if (w)
{
if (mac_bitget_1bit())
w = -w;
nbits--;
}
if (x)
{
if (mac_bitget_1bit())
x = -x;
nbits--;
}
if (y)
{
if (mac_bitget_1bit())
y = -y;
nbits--;
}
vwxy[i][0] = v;
vwxy[i][1] = w;
vwxy[i][2] = x;
vwxy[i][3] = y;
if (bitdat.bs_ptr > bitdat.bs_ptr_end)
break; // bad data protect
}
if (nbits < 0)
{
i--;
vwxy[i][0] = 0;
vwxy[i][1] = 0;
vwxy[i][2] = 0;
vwxy[i][3] = 0;
}
i_non_zero = (i_non_zero + 1) << 2;
if ((tmp_nz & 3) == 0)
i_non_zero -= 2;
return i_non_zero; /* return non-zero sample (to nearest pair) */
}
/*-----------------------------------------------------*/