huffman.c

the mpeg2/4 aac decoder

/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through [e-mail].
**
** $Id: huffman.c,v 1.22 2004/09/04 14:56:28 menno Exp $
**/

#include "common.h"
#include "structs.h"

#include <stdlib.h>
#ifdef ANALYSIS
#include <stdio.h>
#endif

#include "bits.h"
#include "huffman.h"
#include "codebook/hcb.h"


/* static function declarations */
static INLINE void huffman_sign_bits(bitfile *ld, int16_t *sp, uint8_t len);
static INLINE int16_t huffman_getescape(bitfile *ld, int16_t sp);
static uint8_t huffman_2step_quad(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_2step_quad_sign(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_2step_pair(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_2step_pair_sign(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_binary_quad(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_binary_quad_sign(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_binary_pair(uint8_t cb, bitfile *ld, int16_t *sp);
static uint8_t huffman_binary_pair_sign(uint8_t cb, bitfile *ld, int16_t *sp);
static int16_t huffman_codebook(uint8_t i);
static void vcb11_check_LAV(uint8_t cb, int16_t *sp);

int8_t huffman_scale_factor(bitfile *ld)
{
    uint16_t offset = 0;

    while (hcb_sf[offset][1])
    {
        uint8_t b = faad_get1bit(ld
            DEBUGVAR(1,255,"huffman_scale_factor()"));
        offset += hcb_sf[offset][b];

        if (offset > 240)
        {
            /* printf("ERROR: offset into hcb_sf = %d >240!\n", offset); */
            return -1;
        }
    }

    return hcb_sf[offset][0];
}


hcb *hcb_table[] = {
    0, hcb1_1, hcb2_1, 0, hcb4_1, 0, hcb6_1, 0, hcb8_1, 0, hcb10_1, hcb11_1
};

hcb_2_quad *hcb_2_quad_table[] = {
    0, hcb1_2, hcb2_2, 0, hcb4_2, 0, 0, 0, 0, 0, 0, 0
};

hcb_2_pair *hcb_2_pair_table[] = {
    0, 0, 0, 0, 0, 0, hcb6_2, 0, hcb8_2, 0, hcb10_2, hcb11_2
};

hcb_bin_pair *hcb_bin_table[] = {
    0, 0, 0, 0, 0, hcb5, 0, hcb7, 0, hcb9, 0, 0
};

uint8_t hcbN[] = { 0, 5, 5, 0, 5, 0, 5, 0, 5, 0, 6, 5 };

/* defines whether a huffman codebook is unsigned or not */
/* Table 4.6.2 */
uint8_t unsigned_cb[] = { 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0,
  /* codebook 16 to 31 */ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
};

int hcb_2_quad_table_size[] = { 0, 114, 86, 0, 185, 0, 0, 0, 0, 0, 0, 0 };
int hcb_2_pair_table_size[] = { 0, 0, 0, 0, 0, 0, 126, 0, 83, 0, 210, 373 };
int hcb_bin_table_size[] = { 0, 0, 0, 161, 0, 161, 0, 127, 0, 337, 0, 0 };

static INLINE void huffman_sign_bits(bitfile *ld, int16_t *sp, uint8_t len)
{
    uint8_t 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 INLINE int16_t huffman_getescape(bitfile *ld, int16_t sp)
{
    uint8_t neg, i;
    int16_t j;
	int16_t off;

    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;
        }
    }

    off = (int16_t)faad_getbits(ld, i
        DEBUGVAR(1,9,"huffman_getescape(): escape"));

    j = off | (1<<i);
    if (neg)
        j = -j;

    return j;
}

static uint8_t huffman_2step_quad(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint32_t cw;
    uint16_t offset = 0;
    uint8_t extra_bits;

    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 += (uint16_t)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);
    }

    if (offset > hcb_2_quad_table_size[cb])
    {
        /* printf("ERROR: offset into hcb_2_quad_table = %d >%d!\n", offset,
           hcb_2_quad_table_size[cb]); */
        return 10;
    }

    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;

    return 0;
}

static uint8_t huffman_2step_quad_sign(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint8_t err = huffman_2step_quad(cb, ld, sp);
    huffman_sign_bits(ld, sp, QUAD_LEN);

    return err;
}

static uint8_t huffman_2step_pair(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint32_t cw;
    uint16_t offset = 0;
    uint8_t extra_bits;

    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 += (uint16_t)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);
    }

    if (offset > hcb_2_pair_table_size[cb])
    {
        /* printf("ERROR: offset into hcb_2_pair_table = %d >%d!\n", offset,
           hcb_2_pair_table_size[cb]); */
        return 10;
    }

    sp[0] = hcb_2_pair_table[cb][offset].x;
    sp[1] = hcb_2_pair_table[cb][offset].y;

    return 0;
}

static uint8_t huffman_2step_pair_sign(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint8_t err = huffman_2step_pair(cb, ld, sp);
    huffman_sign_bits(ld, sp, PAIR_LEN);

    return err;
}

static uint8_t huffman_binary_quad(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint16_t offset = 0;

    while (!hcb3[offset].is_leaf)
    {
        uint8_t b = faad_get1bit(ld
            DEBUGVAR(1,255,"huffman_spectral_data():3"));
        offset += hcb3[offset].data[b];
    }

    if (offset > hcb_bin_table_size[cb])
    {
        /* printf("ERROR: offset into hcb_bin_table = %d >%d!\n", offset,
           hcb_bin_table_size[cb]); */
        return 10;
    }

    sp[0] = hcb3[offset].data[0];
    sp[1] = hcb3[offset].data[1];
    sp[2] = hcb3[offset].data[2];
    sp[3] = hcb3[offset].data[3];

    return 0;
}

static uint8_t huffman_binary_quad_sign(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint8_t err = huffman_binary_quad(cb, ld, sp);
    huffman_sign_bits(ld, sp, QUAD_LEN);

    return err;
}

static uint8_t huffman_binary_pair(uint8_t cb, bitfile *ld, int16_t *sp)
{
    uint16_t offset = 0;

    while (!hcb_bin_table[cb][offset].is_leaf)