kolibrios/programs/media/ac97snd/trunk/mp3dec/l3huff.c

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#include "layer3.h"
#include "l3huff.h"
//#ifdef _MSC_VER
//#pragma warning(disable: 4505)
//#endif
/*===============================================================*/
/* 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 HUFF_ELEMENT huff_table_0[] =
{0, 0, 0, 64}; /* dummy must not use */
/*-- 6 bit lookup (purgebits, value) --*/
static 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
{
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 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,
};
/*========================================================*/
void huffman(int xy[][2], int n, int ntable)
{
int i;
HUFF_ELEMENT *t;
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 (bitget_overrun())
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 (bitget_overrun())
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 (bitget_overrun())
break; // bad data protect
}
return;
}
/*--- end switch ---*/
}
int huffman_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 (bitget_overrun())
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;
/*--------------------*/
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 (bitget_overrun())
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) */
}