/*

** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding

** Copyright (C) 2003-2005 M. Bakker, Nero 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.

**

** The "appropriate copyright message" mentioned in section 2c of the GPLv2

** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"

**

** Commercial non-GPL licensing of this software is possible.

** For more info contact Nero AG through Mpeg4AAClicense@nero.com.

**

** $Id: rvlc.c,v 1.21 2007/11/01 12:33:34 menno Exp $

**/

/* RVLC scalefactor decoding

 *

 * RVLC works like this:

 *  1. Only symmetric huffman codewords are used

 *  2. Total length of the scalefactor data is stored in the bitsream

 *  3. Scalefactors are DPCM coded

 *  4. Next to the starting value for DPCM the ending value is also stored

 *

 * With all this it is possible to read the scalefactor data from 2 sides.

 * If there is a bit error in the scalefactor data it is possible to start

 * decoding from the other end of the data, to find all but 1 scalefactor.

 */

#include "common.h"

#include "structs.h"

#include <stdlib.h>

#include "syntax.h"

#include "bits.h"

#include "rvlc.h"

#ifdef ERROR_RESILIENCE

//#define PRINT_RVLC

/* static function declarations */

static uint8_t rvlc_decode_sf_forward(ic_stream *ics,

                                      bitfile *ld_sf,

                                      bitfile *ld_esc,

                                      uint8_t *is_used);

#if 0

static uint8_t rvlc_decode_sf_reverse(ic_stream *ics,

                                      bitfile *ld_sf,

                                      bitfile *ld_esc,

                                      uint8_t is_used);

#endif

static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc /*,

                              int8_t direction*/);

static int8_t rvlc_huffman_esc(bitfile *ld_esc /*, int8_t direction*/);

uint8_t rvlc_scale_factor_data(ic_stream *ics, bitfile *ld)

{

    uint8_t bits = 9;

    ics->sf_concealment = faad_get1bit(ld

        DEBUGVAR(1,149,"rvlc_scale_factor_data(): sf_concealment"));

    ics->rev_global_gain = (uint8_t)faad_getbits(ld, 8

        DEBUGVAR(1,150,"rvlc_scale_factor_data(): rev_global_gain"));

    if (ics->window_sequence == EIGHT_SHORT_SEQUENCE)

        bits = 11;

    /* the number of bits used for the huffman codewords */

    ics->length_of_rvlc_sf = (uint16_t)faad_getbits(ld, bits

        DEBUGVAR(1,151,"rvlc_scale_factor_data(): length_of_rvlc_sf"));

    if (ics->noise_used)

    {

        ics->dpcm_noise_nrg = (uint16_t)faad_getbits(ld, 9

            DEBUGVAR(1,152,"rvlc_scale_factor_data(): dpcm_noise_nrg"));

        ics->length_of_rvlc_sf -= 9;

    }

    ics->sf_escapes_present = faad_get1bit(ld

        DEBUGVAR(1,153,"rvlc_scale_factor_data(): sf_escapes_present"));

    if (ics->sf_escapes_present)

    {

        ics->length_of_rvlc_escapes = (uint8_t)faad_getbits(ld, 8

            DEBUGVAR(1,154,"rvlc_scale_factor_data(): length_of_rvlc_escapes"));

    }

    if (ics->noise_used)

    {

        ics->dpcm_noise_last_position = (uint16_t)faad_getbits(ld, 9

            DEBUGVAR(1,155,"rvlc_scale_factor_data(): dpcm_noise_last_position"));

    }

    return 0;

}

uint8_t rvlc_decode_scale_factors(ic_stream *ics, bitfile *ld)

{

    uint8_t result;

    uint8_t intensity_used = 0;

    uint8_t *rvlc_sf_buffer = NULL;

    uint8_t *rvlc_esc_buffer = NULL;

    bitfile ld_rvlc_sf = {0}, ld_rvlc_esc = {0};

//    bitfile ld_rvlc_sf_rev, ld_rvlc_esc_rev;

    if (ics->length_of_rvlc_sf > 0)

    {

        /* We read length_of_rvlc_sf bits here to put it in a

           seperate bitfile.

        */

        rvlc_sf_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_sf

            DEBUGVAR(1,156,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_sf"));

        faad_initbits(&ld_rvlc_sf, (void*)rvlc_sf_buffer, bit2byte(ics->length_of_rvlc_sf));

//        faad_initbits_rev(&ld_rvlc_sf_rev, (void*)rvlc_sf_buffer,

//            ics->length_of_rvlc_sf);

    }

    if ((ics->length_of_rvlc_sf == 0) || (ld_rvlc_sf.error != 0)) {

        memset(&ld_rvlc_sf, 0, sizeof(ld_rvlc_sf));

        ld_rvlc_sf.error = 1;

    }

    if (ics->sf_escapes_present)

    {

        /* We read length_of_rvlc_escapes bits here to put it in a

           seperate bitfile.

        */

        rvlc_esc_buffer = faad_getbitbuffer(ld, ics->length_of_rvlc_escapes

            DEBUGVAR(1,157,"rvlc_decode_scale_factors(): bitbuffer: length_of_rvlc_escapes"));

        faad_initbits(&ld_rvlc_esc, (void*)rvlc_esc_buffer, bit2byte(ics->length_of_rvlc_escapes));

//        faad_initbits_rev(&ld_rvlc_esc_rev, (void*)rvlc_esc_buffer,

//            ics->length_of_rvlc_escapes);

    }

    if (!ics->sf_escapes_present || (ld_rvlc_esc.error != 0)) {

        memset(&ld_rvlc_esc, 0, sizeof(ld_rvlc_esc));

        ld_rvlc_esc.error = 1;

    }

    /* decode the rvlc scale factors and escapes */

    result = rvlc_decode_sf_forward(ics, &ld_rvlc_sf,

        &ld_rvlc_esc, &intensity_used);

//    result = rvlc_decode_sf_reverse(ics, &ld_rvlc_sf_rev,

//        &ld_rvlc_esc_rev, intensity_used);

    if (rvlc_esc_buffer) faad_free(rvlc_esc_buffer);

    if (rvlc_sf_buffer) faad_free(rvlc_sf_buffer);

    if (ics->length_of_rvlc_sf > 0)

        faad_endbits(&ld_rvlc_sf);

    if (ics->sf_escapes_present)

        faad_endbits(&ld_rvlc_esc);

    return result;

}

static uint8_t rvlc_decode_sf_forward(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,

                                      uint8_t *intensity_used)

{

    int8_t g, sfb;

    int8_t t = 0;

    int8_t error = ld_sf->error | ld_esc->error;

    int8_t noise_pcm_flag = 1;

    int16_t scale_factor = ics->global_gain;

    int16_t is_position = 0;

    int16_t noise_energy = ics->global_gain - 90 - 256;

    int16_t scale_factor_max = 255;

#ifdef FIXED_POINT

    /* TODO: consider rolling out to regular build. */

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    /* The value is inexact, adjusted to current fuzzer findings. */

    scale_factor_max = 165;

#endif  // FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

#endif  // FIXED_POINT

#ifdef PRINT_RVLC

    printf("\nglobal_gain: %d\n", ics->global_gain);

#endif

    for (g = 0; g < ics->num_window_groups; g++)

    {

        for (sfb = 0; sfb < ics->max_sfb; sfb++)

        {

            if (error)

            {

                ics->scale_factors[g][sfb] = 0;

            } else {

                switch (ics->sfb_cb[g][sfb])

                {

                case ZERO_HCB: /* zero book */

                    ics->scale_factors[g][sfb] = 0;

                    break;

                case INTENSITY_HCB: /* intensity books */

                case INTENSITY_HCB2:

                    *intensity_used = 1;

                    /* decode intensity position */

                    t = rvlc_huffman_sf(ld_sf, ld_esc /*, +1*/);

                    is_position += t;

                    ics->scale_factors[g][sfb] = is_position;

                    break;

                case NOISE_HCB: /* noise books */

                    /* decode noise energy */

                    if (noise_pcm_flag)

                    {

                        int16_t n = ics->dpcm_noise_nrg;

                        noise_pcm_flag = 0;

                        noise_energy += n;

                    } else {

                        t = rvlc_huffman_sf(ld_sf, ld_esc /*, +1*/);

                        noise_energy += t;

                    }

                    ics->scale_factors[g][sfb] = noise_energy;

                    break;

                default: /* spectral books */

                    /* decode scale factor */

                    t = rvlc_huffman_sf(ld_sf, ld_esc /*, +1*/);

                    scale_factor += t;

                    if (scale_factor < 0 || scale_factor > 255)

                        return 4;

                    ics->scale_factors[g][sfb] = min(scale_factor, scale_factor_max);

                    break;

                }

#ifdef PRINT_RVLC

                printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],

                    ics->scale_factors[g][sfb]);

#endif

                if (t == 99)

                {

                    error = 1;

                }

            }

        }

    }

#ifdef PRINT_RVLC

    printf("\n\n");

#endif

    return 0;

}

#if 0 // not used right now, doesn't work correctly yet

static uint8_t rvlc_decode_sf_reverse(ic_stream *ics, bitfile *ld_sf, bitfile *ld_esc,

                                      uint8_t intensity_used)

{

    int8_t g, sfb;

    int8_t t = 0;

    int8_t error = 0;

    int8_t noise_pcm_flag = 1, is_pcm_flag = 1, sf_pcm_flag = 1;

    int16_t scale_factor = ics->rev_global_gain;

    int16_t is_position = 0;

    int16_t noise_energy = ics->rev_global_gain;

#ifdef PRINT_RVLC

    printf("\nrev_global_gain: %d\n", ics->rev_global_gain);

#endif

    if (intensity_used)

    {

        is_position = rvlc_huffman_sf(ld_sf, ld_esc, -1);

#ifdef PRINT_RVLC

        printf("is_position: %d\n", is_position);

#endif

    }

    for (g = ics->num_window_groups-1; g >= 0; g--)

    {

        for (sfb = ics->max_sfb-1; sfb >= 0; sfb--)

        {

            if (error)

            {

                ics->scale_factors[g][sfb] = 0;

            } else {

                switch (ics->sfb_cb[g][sfb])

                {

                case ZERO_HCB: /* zero book */

                    ics->scale_factors[g][sfb] = 0;

                    break;

                case INTENSITY_HCB: /* intensity books */

                case INTENSITY_HCB2:

                    if (is_pcm_flag)

                    {

                        is_pcm_flag = 0;

                        ics->scale_factors[g][sfb] = is_position;

                    } else {

                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);

                        is_position -= t;

                        ics->scale_factors[g][sfb] = (uint8_t)is_position;

                    }

                    break;

                case NOISE_HCB: /* noise books */

                    /* decode noise energy */

                    if (noise_pcm_flag)

                    {

                        noise_pcm_flag = 0;

                        noise_energy = ics->dpcm_noise_last_position;

                    } else {

                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);

                        noise_energy -= t;

                    }

                    ics->scale_factors[g][sfb] = (uint8_t)noise_energy;

                    break;

                default: /* spectral books */

                    if (sf_pcm_flag || (sfb == 0))

                    {

                        sf_pcm_flag = 0;

                        if (sfb == 0)

                            scale_factor = ics->global_gain;

                    } else {

                        /* decode scale factor */

                        t = rvlc_huffman_sf(ld_sf, ld_esc, -1);

                        scale_factor -= t;

                    }

                    if (scale_factor < 0)

                        return 4;

                    ics->scale_factors[g][sfb] = (uint8_t)scale_factor;

                    break;

                }

#ifdef PRINT_RVLC

                printf("%3d:%4d%4d\n", sfb, ics->sfb_cb[g][sfb],

                    ics->scale_factors[g][sfb]);

#endif

                if (t == 99)

                {

                    error = 1;

                }

            }

        }

    }

#ifdef PRINT_RVLC

    printf("\n\n");

#endif

    return 0;

}

#endif

/* index == 99 means not allowed codeword */

static rvlc_huff_table book_rvlc[] = {

    /*index  length  codeword */

    {  0, 1,   0 }, /*         0 */

    { -1, 3,   5 }, /*       101 */

    {  1, 3,   7 }, /*       111 */

    { -2, 4,   9 }, /*      1001 */

    { -3, 5,  17 }, /*     10001 */

    {  2, 5,  27 }, /*     11011 */

    { -4, 6,  33 }, /*    100001 */

    { 99, 6,  50 }, /*    110010 */

    {  3, 6,  51 }, /*    110011 */

    { 99, 6,  52 }, /*    110100 */

    { -7, 7,  65 }, /*   1000001 */

    { 99, 7,  96 }, /*   1100000 */

    { 99, 7,  98 }, /*   1100010 */

    {  7, 7,  99 }, /*   1100011 */

    {  4, 7, 107 }, /*   1101011 */

    { -5, 8, 129 }, /*  10000001 */

    { 99, 8, 194 }, /*  11000010 */

    {  5, 8, 195 }, /*  11000011 */

    { 99, 8, 212 }, /*  11010100 */

    { 99, 9, 256 }, /* 100000000 */

    { -6, 9, 257 }, /* 100000001 */

    { 99, 9, 426 }, /* 110101010 */

    {  6, 9, 427 }, /* 110101011 */

    { 99, 10,  0 } /* Shouldn't come this far */

};

static rvlc_huff_table book_escape[] = {

    /*index  length  codeword */

    { 1, 2, 0 },

    { 0, 2, 2 },

    { 3, 3, 2 },

    { 2, 3, 6 },

    { 4, 4, 14 },

    { 7, 5, 13 },

    { 6, 5, 15 },

    { 5, 5, 31 },

    { 11, 6, 24 },

    { 10, 6, 25 },

    { 9, 6, 29 },

    { 8, 6, 61 },

    { 13, 7, 56  },

    { 12, 7, 120 },

    { 15, 8, 114 },

    { 14, 8, 242 },

    { 17, 9, 230 },

    { 16, 9, 486 },

    { 19, 10, 463  },

    { 18, 10, 974  },

    { 22, 11, 925  },

    { 20, 11, 1950 },

    { 21, 11, 1951 },

    { 23, 12, 1848 },

    { 25, 13, 3698 },

    { 24, 14, 7399 },

    { 26, 15, 14797 },

    { 49, 19, 236736 },

    { 50, 19, 236737 },

    { 51, 19, 236738 },

    { 52, 19, 236739 },

    { 53, 19, 236740 },

    { 27, 20, 473482 },

    { 28, 20, 473483 },

    { 29, 20, 473484 },

    { 30, 20, 473485 },

    { 31, 20, 473486 },

    { 32, 20, 473487 },

    { 33, 20, 473488 },

    { 34, 20, 473489 },

    { 35, 20, 473490 },

    { 36, 20, 473491 },

    { 37, 20, 473492 },

    { 38, 20, 473493 },

    { 39, 20, 473494 },

    { 40, 20, 473495 },

    { 41, 20, 473496 },

    { 42, 20, 473497 },

    { 43, 20, 473498 },

    { 44, 20, 473499 },

    { 45, 20, 473500 },

    { 46, 20, 473501 },

    { 47, 20, 473502 },

    { 48, 20, 473503 },

    { 99, 21,  0 } /* Shouldn't come this far */

};

static int8_t rvlc_huffman_sf(bitfile *ld_sf, bitfile *ld_esc /*,

                              int8_t direction*/)

{

    uint16_t i, j;

    int16_t index;

    uint32_t cw;

    rvlc_huff_table *h = book_rvlc;

    int8_t direction = +1;

    i = h->len;

    if (direction > 0)

        cw = faad_getbits(ld_sf, i DEBUGVAR(1,0,""));

    else

        cw = 0 /* faad_getbits_rev(ld_sf, i DEBUGVAR(1,0,"")) */;

    while ((cw != h->cw)

        && (i < 10))

    {

        h++;

        j = h->len-i;

        i += j;

        cw <<= j;

        if (direction > 0)

            cw |= faad_getbits(ld_sf, j DEBUGVAR(1,0,""));

        else

            cw |= 0 /* faad_getbits_rev(ld_sf, j DEBUGVAR(1,0,"")) */;

    }

    index = h->index;

    if (index == +ESC_VAL)

    {

        int8_t esc = rvlc_huffman_esc(ld_esc /*, direction*/);

        if (esc == 99)

            return 99;

        index += esc;

#ifdef PRINT_RVLC

        printf("esc: %d - ", esc);

#endif

    }

    if (index == -ESC_VAL)

    {

        int8_t esc = rvlc_huffman_esc(ld_esc /*, direction*/);

        if (esc == 99)

            return 99;

        index -= esc;

#ifdef PRINT_RVLC

        printf("esc: %d - ", esc);

#endif

    }

    return (int8_t)index;

}

static int8_t rvlc_huffman_esc(bitfile *ld /*,

                               int8_t direction*/)

{

    uint16_t i, j;

    uint32_t cw;

    rvlc_huff_table *h = book_escape;

    int8_t direction = +1;

    i = h->len;

    if (direction > 0)

        cw = faad_getbits(ld, i DEBUGVAR(1,0,""));

    else

        cw = 0 /* faad_getbits_rev(ld, i DEBUGVAR(1,0,"")) */;

    while ((cw != h->cw)

        && (i < 21))

    {

        h++;

        j = h->len-i;

        i += j;

        cw <<= j;

        if (direction > 0)

            cw |= faad_getbits(ld, j DEBUGVAR(1,0,""));

        else

            cw |= 0 /* faad_getbits_rev(ld, j DEBUGVAR(1,0,"")) */;

    }

    return (int8_t)h->index;

}

#endif