/*
 * libmad - MPEG audio decoder library
 
 */

# ifdef HAVE_CONFIG_H
#  include "config.h"
# endif

# include "global.h"

# include <stdlib.h>
# include <string.h>

# ifdef HAVE_ASSERT_H
#  include <assert.h>
# endif

# ifdef HAVE_LIMITS_H
#  include <limits.h>
# else
#  define CHAR_BIT  8
# endif

# include "fixed.h"
# include "bit.h"
# include "stream.h"
# include "frame.h"
# include "huffman.h"
# include "layer3.h"

/* --- Layer III ----------------------------------------------------------- */

enum {
  count1table_select = 0x01,
  scalefac_scale     = 0x02,
  preflag	     = 0x04,
  mixed_block_flag   = 0x08
};

enum {
  I_STEREO  = 0x1,
  MS_STEREO = 0x2
};

struct sideinfo {
  unsigned int main_data_begin;
  unsigned int private_bits;

  unsigned char scfsi[2];

  struct granule {
    struct channel {
      /* from side info */
      unsigned short part2_3_length;
      unsigned short big_values;
      unsigned short global_gain;
      unsigned short scalefac_compress;

      unsigned char flags;
      unsigned char block_type;
      unsigned char table_select[3];
      unsigned char subblock_gain[3];
      unsigned char region0_count;
      unsigned char region1_count;

      /* from main_data */
      unsigned char scalefac[39];	/* scalefac_l and/or scalefac_s */
    } ch[2];
  } gr[2];
};

/*
 * scalefactor bit lengths
 * derived from section 2.4.2.7 of ISO/IEC 11172-3
 */
static
struct {
  unsigned char slen1;
  unsigned char slen2;
} const sflen_table[16] = {
  { 0, 0 }, { 0, 1 }, { 0, 2 }, { 0, 3 },
  { 3, 0 }, { 1, 1 }, { 1, 2 }, { 1, 3 },
  { 2, 1 }, { 2, 2 }, { 2, 3 }, { 3, 1 },
  { 3, 2 }, { 3, 3 }, { 4, 2 }, { 4, 3 }
};

/*
 * number of LSF scalefactor band values
 * derived from section 2.4.3.2 of ISO/IEC 13818-3
 */
static
unsigned char const nsfb_table[6][3][4] = {
  { {  6,  5,  5, 5 },
    {  9,  9,  9, 9 },
    {  6,  9,  9, 9 } },

  { {  6,  5,  7, 3 },
    {  9,  9, 12, 6 },
    {  6,  9, 12, 6 } },

  { { 11, 10,  0, 0 },
    { 18, 18,  0, 0 },
    { 15, 18,  0, 0 } },

  { {  7,  7,  7, 0 },
    { 12, 12, 12, 0 },
    {  6, 15, 12, 0 } },

  { {  6,  6,  6, 3 },
    { 12,  9,  9, 6 },
    {  6, 12,  9, 6 } },

  { {  8,  8,  5, 0 },
    { 15, 12,  9, 0 },
    {  6, 18,  9, 0 } }
};

/*
 * MPEG-1 scalefactor band widths
 * derived from Table B.8 of ISO/IEC 11172-3
 */
static
unsigned char const sfb_48000_long[] = {
   4,  4,  4,  4,  4,  4,  6,  6,  6,   8,  10,
  12, 16, 18, 22, 28, 34, 40, 46, 54,  54, 192
};

static
unsigned char const sfb_44100_long[] = {
   4,  4,  4,  4,  4,  4,  6,  6,  8,   8,  10,
  12, 16, 20, 24, 28, 34, 42, 50, 54,  76, 158
};

static
unsigned char const sfb_32000_long[] = {
   4,  4,  4,  4,  4,  4,  6,  6,  8,  10,  12,
  16, 20, 24, 30, 38, 46, 56, 68, 84, 102,  26
};

static
unsigned char const sfb_48000_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  6,
   6,  6,  6,  6,  6, 10, 10, 10, 12, 12, 12, 14, 14,
  14, 16, 16, 16, 20, 20, 20, 26, 26, 26, 66, 66, 66
};

static
unsigned char const sfb_44100_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  6,
   6,  6,  8,  8,  8, 10, 10, 10, 12, 12, 12, 14, 14,
  14, 18, 18, 18, 22, 22, 22, 30, 30, 30, 56, 56, 56
};

static
unsigned char const sfb_32000_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  4,  6,
   6,  6,  8,  8,  8, 12, 12, 12, 16, 16, 16, 20, 20,
  20, 26, 26, 26, 34, 34, 34, 42, 42, 42, 12, 12, 12
};

static
unsigned char const sfb_48000_mixed[] = {
  /* long */   4,  4,  4,  4,  4,  4,  6,  6,
  /* short */  4,  4,  4,  6,  6,  6,  6,  6,  6, 10,
              10, 10, 12, 12, 12, 14, 14, 14, 16, 16,
              16, 20, 20, 20, 26, 26, 26, 66, 66, 66
};

static
unsigned char const sfb_44100_mixed[] = {
  /* long */   4,  4,  4,  4,  4,  4,  6,  6,
  /* short */  4,  4,  4,  6,  6,  6,  8,  8,  8, 10,
              10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
              18, 22, 22, 22, 30, 30, 30, 56, 56, 56
};

static
unsigned char const sfb_32000_mixed[] = {
  /* long */   4,  4,  4,  4,  4,  4,  6,  6,
  /* short */  4,  4,  4,  6,  6,  6,  8,  8,  8, 12,
              12, 12, 16, 16, 16, 20, 20, 20, 26, 26,
              26, 34, 34, 34, 42, 42, 42, 12, 12, 12
};

/*
 * MPEG-2 scalefactor band widths
 * derived from Table B.2 of ISO/IEC 13818-3
 */
static
unsigned char const sfb_24000_long[] = {
   6,  6,  6,  6,  6,  6,  8, 10, 12,  14,  16,
  18, 22, 26, 32, 38, 46, 54, 62, 70,  76,  36
};

static
unsigned char const sfb_22050_long[] = {
   6,  6,  6,  6,  6,  6,  8, 10, 12,  14,  16,
  20, 24, 28, 32, 38, 46, 52, 60, 68,  58,  54
};

# define sfb_16000_long  sfb_22050_long

static
unsigned char const sfb_24000_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  6,  6,  6,  8,
   8,  8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
  18, 24, 24, 24, 32, 32, 32, 44, 44, 44, 12, 12, 12
};

static
unsigned char const sfb_22050_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  6,  6,  6,  6,
   6,  6,  8,  8,  8, 10, 10, 10, 14, 14, 14, 18, 18,
  18, 26, 26, 26, 32, 32, 32, 42, 42, 42, 18, 18, 18
};

static
unsigned char const sfb_16000_short[] = {
   4,  4,  4,  4,  4,  4,  4,  4,  4,  6,  6,  6,  8,
   8,  8, 10, 10, 10, 12, 12, 12, 14, 14, 14, 18, 18,
  18, 24, 24, 24, 30, 30, 30, 40, 40, 40, 18, 18, 18
};

static
unsigned char const sfb_24000_mixed[] = {
  /* long */   6,  6,  6,  6,  6,  6,
  /* short */  6,  6,  6,  8,  8,  8, 10, 10, 10, 12,
              12, 12, 14, 14, 14, 18, 18, 18, 24, 24,
              24, 32, 32, 32, 44, 44, 44, 12, 12, 12
};

static
unsigned char const sfb_22050_mixed[] = {
  /* long */   6,  6,  6,  6,  6,  6,
  /* short */  6,  6,  6,  6,  6,  6,  8,  8,  8, 10,
              10, 10, 14, 14, 14, 18, 18, 18, 26, 26,
              26, 32, 32, 32, 42, 42, 42, 18, 18, 18
};

static
unsigned char const sfb_16000_mixed[] = {
  /* long */   6,  6,  6,  6,  6,  6,
  /* short */  6,  6,  6,  8,  8,  8, 10, 10, 10, 12,
              12, 12, 14, 14, 14, 18, 18, 18, 24, 24,
              24, 30, 30, 30, 40, 40, 40, 18, 18, 18
};

/*
 * MPEG 2.5 scalefactor band widths
 * derived from public sources
 */
# define sfb_12000_long  sfb_16000_long
# define sfb_11025_long  sfb_12000_long

static
unsigned char const sfb_8000_long[] = {
  12, 12, 12, 12, 12, 12, 16, 20, 24,  28,  32,
  40, 48, 56, 64, 76, 90,  2,  2,  2,   2,   2
};

# define sfb_12000_short  sfb_16000_short
# define sfb_11025_short  sfb_12000_short

static
unsigned char const sfb_8000_short[] = {
   8,  8,  8,  8,  8,  8,  8,  8,  8, 12, 12, 12, 16,
  16, 16, 20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36,
  36,  2,  2,  2,  2,  2,  2,  2,  2,  2, 26, 26, 26
};

# define sfb_12000_mixed  sfb_16000_mixed
# define sfb_11025_mixed  sfb_12000_mixed

/* the 8000 Hz short block scalefactor bands do not break after the first 36
   frequency lines, so this is probably wrong */
static
unsigned char const sfb_8000_mixed[] = {
  /* long */  12, 12, 12,
  /* short */  4,  4,  4,  8,  8,  8, 12, 12, 12, 16, 16, 16,
              20, 20, 20, 24, 24, 24, 28, 28, 28, 36, 36, 36,
               2,  2,  2,  2,  2,  2,  2,  2,  2, 26, 26, 26
};

static
struct {
  unsigned char const *l;
  unsigned char const *s;
  unsigned char const *m;
} const sfbwidth_table[9] = {
  { sfb_48000_long, sfb_48000_short, sfb_48000_mixed },
  { sfb_44100_long, sfb_44100_short, sfb_44100_mixed },
  { sfb_32000_long, sfb_32000_short, sfb_32000_mixed },
  { sfb_24000_long, sfb_24000_short, sfb_24000_mixed },
  { sfb_22050_long, sfb_22050_short, sfb_22050_mixed },
  { sfb_16000_long, sfb_16000_short, sfb_16000_mixed },
  { sfb_12000_long, sfb_12000_short, sfb_12000_mixed },
  { sfb_11025_long, sfb_11025_short, sfb_11025_mixed },
  {  sfb_8000_long,  sfb_8000_short,  sfb_8000_mixed }
};

/*
 * scalefactor band preemphasis (used only when preflag is set)
 * derived from Table B.6 of ISO/IEC 11172-3
 */
static
unsigned char const pretab[22] = {
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2, 0
};

/*
 * table for requantization
 *
 * rq_table[x].mantissa * 2^(rq_table[x].exponent) = x^(4/3)
 */
static
struct fixedfloat {
  unsigned long mantissa  : 27;
  unsigned short exponent :  5;
} const rq_table[8207] = {
# include "rq_table.dat"
};

/*
 * fractional powers of two
 * used for requantization and joint stereo decoding
 *
 * root_table[3 + x] = 2^(x/4)
 */
static
mad_fixed_t const root_table[7] = {
  MAD_F(0x09837f05) /* 2^(-3/4) == 0.59460355750136 */,
  MAD_F(0x0b504f33) /* 2^(-2/4) == 0.70710678118655 */,
  MAD_F(0x0d744fcd) /* 2^(-1/4) == 0.84089641525371 */,
  MAD_F(0x10000000) /* 2^( 0/4) == 1.00000000000000 */,
  MAD_F(0x1306fe0a) /* 2^(+1/4) == 1.18920711500272 */,
  MAD_F(0x16a09e66) /* 2^(+2/4) == 1.41421356237310 */,
  MAD_F(0x1ae89f99) /* 2^(+3/4) == 1.68179283050743 */
};

/*
 * coefficients for aliasing reduction
 * derived from Table B.9 of ISO/IEC 11172-3
 *
 *  c[]  = { -0.6, -0.535, -0.33, -0.185, -0.095, -0.041, -0.0142, -0.0037 }
 * cs[i] =    1 / sqrt(1 + c[i]^2)
 * ca[i] = c[i] / sqrt(1 + c[i]^2)
 */
static
mad_fixed_t const cs[8] = {
  +MAD_F(0x0db84a81) /* +0.857492926 */, +MAD_F(0x0e1b9d7f) /* +0.881741997 */,
  +MAD_F(0x0f31adcf) /* +0.949628649 */, +MAD_F(0x0fbba815) /* +0.983314592 */,
  +MAD_F(0x0feda417) /* +0.995517816 */, +MAD_F(0x0ffc8fc8) /* +0.999160558 */,
  +MAD_F(0x0fff964c) /* +0.999899195 */, +MAD_F(0x0ffff8d3) /* +0.999993155 */
};

static
mad_fixed_t const ca[8] = {
  -MAD_F(0x083b5fe7) /* -0.514495755 */, -MAD_F(0x078c36d2) /* -0.471731969 */,
  -MAD_F(0x05039814) /* -0.313377454 */, -MAD_F(0x02e91dd1) /* -0.181913200 */,
  -MAD_F(0x0183603a) /* -0.094574193 */, -MAD_F(0x00a7cb87) /* -0.040965583 */,
  -MAD_F(0x003a2847) /* -0.014198569 */, -MAD_F(0x000f27b4) /* -0.003699975 */
};

/*
 * IMDCT coefficients for short blocks
 * derived from section 2.4.3.4.10.2 of ISO/IEC 11172-3
 *
 * imdct_s[i/even][k] = cos((PI / 24) * (2 * (i / 2) + 7) * (2 * k + 1))
 * imdct_s[i /odd][k] = cos((PI / 24) * (2 * (6 + (i-1)/2) + 7) * (2 * k + 1))
 */
static
mad_fixed_t const imdct_s[6][6] = {
# include "imdct_s.dat"
};

# if !defined(ASO_IMDCT)
/*
 * windowing coefficients for long blocks
 * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3
 *
 * window_l[i] = sin((PI / 36) * (i + 1/2))
 */
static
mad_fixed_t const window_l[36] = {
  MAD_F(0x00b2aa3e) /* 0.043619387 */, MAD_F(0x0216a2a2) /* 0.130526192 */,
  MAD_F(0x03768962) /* 0.216439614 */, MAD_F(0x04cfb0e2) /* 0.300705800 */,
  MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x07635284) /* 0.461748613 */,
  MAD_F(0x0898c779) /* 0.537299608 */, MAD_F(0x09bd7ca0) /* 0.608761429 */,
  MAD_F(0x0acf37ad) /* 0.675590208 */, MAD_F(0x0bcbe352) /* 0.737277337 */,
  MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x0d7e8807) /* 0.843391446 */,

  MAD_F(0x0e313245) /* 0.887010833 */, MAD_F(0x0ec835e8) /* 0.923879533 */,
  MAD_F(0x0f426cb5) /* 0.953716951 */, MAD_F(0x0f9ee890) /* 0.976296007 */,
  MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ffc19fd) /* 0.999048222 */,
  MAD_F(0x0ffc19fd) /* 0.999048222 */, MAD_F(0x0fdcf549) /* 0.991444861 */,
  MAD_F(0x0f9ee890) /* 0.976296007 */, MAD_F(0x0f426cb5) /* 0.953716951 */,
  MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0e313245) /* 0.887010833 */,

  MAD_F(0x0d7e8807) /* 0.843391446 */, MAD_F(0x0cb19346) /* 0.793353340 */,
  MAD_F(0x0bcbe352) /* 0.737277337 */, MAD_F(0x0acf37ad) /* 0.675590208 */,
  MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0898c779) /* 0.537299608 */,
  MAD_F(0x07635284) /* 0.461748613 */, MAD_F(0x061f78aa) /* 0.382683432 */,
  MAD_F(0x04cfb0e2) /* 0.300705800 */, MAD_F(0x03768962) /* 0.216439614 */,
  MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x00b2aa3e) /* 0.043619387 */,
};
# endif  /* ASO_IMDCT */

/*
 * windowing coefficients for short blocks
 * derived from section 2.4.3.4.10.3 of ISO/IEC 11172-3
 *
 * window_s[i] = sin((PI / 12) * (i + 1/2))
 */
static
mad_fixed_t const window_s[12] = {
  MAD_F(0x0216a2a2) /* 0.130526192 */, MAD_F(0x061f78aa) /* 0.382683432 */,
  MAD_F(0x09bd7ca0) /* 0.608761429 */, MAD_F(0x0cb19346) /* 0.793353340 */,
  MAD_F(0x0ec835e8) /* 0.923879533 */, MAD_F(0x0fdcf549) /* 0.991444861 */,
  MAD_F(0x0fdcf549) /* 0.991444861 */, MAD_F(0x0ec835e8) /* 0.923879533 */,
  MAD_F(0x0cb19346) /* 0.793353340 */, MAD_F(0x09bd7ca0) /* 0.608761429 */,
  MAD_F(0x061f78aa) /* 0.382683432 */, MAD_F(0x0216a2a2) /* 0.130526192 */,
};

/*
 * coefficients for intensity stereo processing
 * derived from section 2.4.3.4.9.3 of ISO/IEC 11172-3
 *
 * is_ratio[i] = tan(i * (PI / 12))
 * is_table[i] = is_ratio[i] / (1 + is_ratio[i])
 */
static
mad_fixed_t const is_table[7] = {
  MAD_F(0x00000000) /* 0.000000000 */,
  MAD_F(0x0361962f) /* 0.211324865 */,
  MAD_F(0x05db3d74) /* 0.366025404 */,
  MAD_F(0x08000000) /* 0.500000000 */,
  MAD_F(0x0a24c28c) /* 0.633974596 */,
  MAD_F(0x0c9e69d1) /* 0.788675135 */,
  MAD_F(0x10000000) /* 1.000000000 */
};

/*
 * coefficients for LSF intensity stereo processing
 * derived from section 2.4.3.2 of ISO/IEC 13818-3
 *
 * is_lsf_table[0][i] = (1 / sqrt(sqrt(2)))^(i + 1)
 * is_lsf_table[1][i] = (1 / sqrt(2))^(i + 1)
 */
static
mad_fixed_t const is_lsf_table[2][15] = {
  {
    MAD_F(0x0d744fcd) /* 0.840896415 */,
    MAD_F(0x0b504f33) /* 0.707106781 */,
    MAD_F(0x09837f05) /* 0.594603558 */,
    MAD_F(0x08000000) /* 0.500000000 */,
    MAD_F(0x06ba27e6) /* 0.420448208 */,
    MAD_F(0x05a8279a) /* 0.353553391 */,
    MAD_F(0x04c1bf83) /* 0.297301779 */,
    MAD_F(0x04000000) /* 0.250000000 */,
    MAD_F(0x035d13f3) /* 0.210224104 */,
    MAD_F(0x02d413cd) /* 0.176776695 */,
    MAD_F(0x0260dfc1) /* 0.148650889 */,
    MAD_F(0x02000000) /* 0.125000000 */,
    MAD_F(0x01ae89fa) /* 0.105112052 */,
    MAD_F(0x016a09e6) /* 0.088388348 */,
    MAD_F(0x01306fe1) /* 0.074325445 */
  }, {
    MAD_F(0x0b504f33) /* 0.707106781 */,
    MAD_F(0x08000000) /* 0.500000000 */,
    MAD_F(0x05a8279a) /* 0.353553391 */,
    MAD_F(0x04000000) /* 0.250000000 */,
    MAD_F(0x02d413cd) /* 0.176776695 */,
    MAD_F(0x02000000) /* 0.125000000 */,
    MAD_F(0x016a09e6) /* 0.088388348 */,
    MAD_F(0x01000000) /* 0.062500000 */,
    MAD_F(0x00b504f3) /* 0.044194174 */,
    MAD_F(0x00800000) /* 0.031250000 */,
    MAD_F(0x005a827a) /* 0.022097087 */,
    MAD_F(0x00400000) /* 0.015625000 */,
    MAD_F(0x002d413d) /* 0.011048543 */,
    MAD_F(0x00200000) /* 0.007812500 */,
    MAD_F(0x0016a09e) /* 0.005524272 */
  }
};

/*
 * NAME:	III_sideinfo()
 * DESCRIPTION:	decode frame side information from a bitstream