/*** 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 "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 0static uint8_t rvlc_decode_sf_reverse(ic_stream *ics,                                      bitfile *ld_sf,                                      bitfile *ld_esc,                                      uint8_t is_used);#endifstatic 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 yetstatic 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);

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