ref: 3c9ab2e25aaeac7a39ed5e745a252794f569a960
dir: /libfaad/huffman.h/
/*
** FAAD - Freeware Advanced Audio Decoder
** Copyright (C) 2002 M. Bakker
**
** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** $Id: huffman.h,v 1.4 2002/02/15 20:52:09 menno Exp $
**/
#ifndef __HUFFMAN_H__
#define __HUFFMAN_H__
#ifdef __cplusplus
extern "C" {
#endif
#include <stdlib.h>
#ifdef ANALYSIS
#include <stdio.h>
#endif
#include "bits.h"
#include "codebook/hcb.h"
#if defined(LINUX)
#define huff_inline inline
#elif defined(_WIN32)
#define huff_inline __inline
#else
#define huff_inline
#endif
static huff_inline int huffman_scale_factor(bitfile *ld)
{
unsigned int offset = 0;
while (hcb_sf[offset][1])
{
int b = faad_get1bit(ld);
offset += hcb_sf[offset][b];
}
return hcb_sf[offset][0];
}
static hcb *hcb_table[] = {
0, hcb1_1, hcb2_1, 0, hcb4_1, 0, hcb6_1, 0, hcb8_1, 0, hcb10_1, hcb11_1
};
static hcb_2_quad *hcb_2_quad_table[] = {
0, hcb1_2, hcb2_2, 0, hcb4_2, 0, 0, 0, 0, 0, 0, 0
};
static hcb_2_pair *hcb_2_pair_table[] = {
0, 0, 0, 0, 0, 0, hcb6_2, 0, hcb8_2, 0, hcb10_2, hcb11_2
};
static hcb_bin_pair *hcb_bin_table[] = {
0, 0, 0, 0, 0, hcb5, 0, hcb7, 0, hcb9, 0, 0
};
static int hcbN[] = { 0, 5, 5, 0, 5, 0, 5, 0, 5, 0, 6, 5 };
static huff_inline void huffman_spectral_data(int cb, bitfile *ld, short *sp)
{
unsigned int cw;
unsigned int offset = 0;
unsigned int extra_bits;
switch (cb)
{
case 1: /* 2-step method for data quadruples */
case 2:
case 4:
cw = faad_showbits(ld, hcbN[cb]);
offset = hcb_table[cb][cw].offset;
extra_bits = hcb_table[cb][cw].extra_bits;
if (extra_bits)
{
/* we know for sure it's more than hcbN[cb] bits long */
faad_flushbits(ld, hcbN[cb]);
offset += faad_showbits(ld, extra_bits);
faad_flushbits(ld, hcb_2_quad_table[cb][offset].bits - hcbN[cb]);
} else {
faad_flushbits(ld, hcb_2_quad_table[cb][offset].bits);
}
sp[0] = hcb_2_quad_table[cb][offset].x;
sp[1] = hcb_2_quad_table[cb][offset].y;
sp[2] = hcb_2_quad_table[cb][offset].v;
sp[3] = hcb_2_quad_table[cb][offset].w;
break;
case 6: /* 2-step method for data pairs */
case 8:
case 10:
case 11:
cw = faad_showbits(ld, hcbN[cb]);
offset = hcb_table[cb][cw].offset;
extra_bits = hcb_table[cb][cw].extra_bits;
if (extra_bits)
{
/* we know for sure it's more than hcbN[cb] bits long */
faad_flushbits(ld, hcbN[cb]);
offset += faad_showbits(ld, extra_bits);
faad_flushbits(ld, hcb_2_pair_table[cb][offset].bits - hcbN[cb]);
} else {
faad_flushbits(ld, hcb_2_pair_table[cb][offset].bits);
}
sp[0] = hcb_2_pair_table[cb][offset].x;
sp[1] = hcb_2_pair_table[cb][offset].y;
break;
case 3: /* binary search for data quadruples */
while (!hcb3[offset].is_leaf)
{
int b = faad_get1bit(ld);
offset += hcb3[offset].data[b];
}
sp[0] = hcb3[offset].data[0];
sp[1] = hcb3[offset].data[1];
sp[2] = hcb3[offset].data[2];
sp[3] = hcb3[offset].data[3];
break;
case 5: /* binary search for data pairs */
case 7:
case 9:
while (!hcb_bin_table[cb][offset].is_leaf)
{
int b = faad_get1bit(ld);
offset += hcb_bin_table[cb][offset].data[b];
}
sp[0] = hcb_bin_table[cb][offset].data[0];
sp[1] = hcb_bin_table[cb][offset].data[1];
break;
}
}
static huff_inline void huffman_sign_bits(bitfile *ld, short *sp, int len)
{
int i;
for(i = 0; i < len; i++)
{
if(sp[i])
{
if(faad_get1bit(ld
DEBUGVAR(1,5,"huffman_sign_bits(): sign bit")) & 1)
{
sp[i] = -sp[i];
}
}
}
}
static huff_inline short huffman_getescape(bitfile *ld, short sp)
{
int i, off, neg;
if (sp < 0) {
if(sp != -16)
return sp;
neg = 1;
} else {
if(sp != +16)
return sp;
neg = 0;
}
for (i = 4; ; i++){
if (faad_get1bit(ld
DEBUGVAR(1,6,"huffman_getescape(): escape size")) == 0)
{
break;
}
}
if (i > 16) {
off = faad_getbits(ld, i-16
DEBUGVAR(1,7,"huffman_getescape(): escape, first part")) << 16;
off |= faad_getbits(ld, 16
DEBUGVAR(1,8,"huffman_getescape(): escape, second part"));
} else {
off = faad_getbits(ld, i
DEBUGVAR(1,9,"huffman_getescape(): escape"));
}
i = off + (1<<i);
if (neg)
i = -i;
return i;
}
#ifdef __cplusplus
}
#endif
#endif