text: /*
  ** 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 Mpeg4AAClicense@nero.com.
  **
  ** $Id: common.c,v 1.2 2009-02-11 21:19:29 dave Exp $
  **/
  
  /* just some common functions that could be used anywhere */
  
  #include "common.h"
  #include "structs.h"
  
  #include <stdlib.h>
  #include "syntax.h"
  
  
  /* Returns the sample rate index based on the samplerate */
  uint8_t get_sr_index(const uint32_t samplerate)
  {
      if (92017 <= samplerate) return 0;
      if (75132 <= samplerate) return 1;
      if (55426 <= samplerate) return 2;
      if (46009 <= samplerate) return 3;
      if (37566 <= samplerate) return 4;
      if (27713 <= samplerate) return 5;
      if (23004 <= samplerate) return 6;
      if (18783 <= samplerate) return 7;
      if (13856 <= samplerate) return 8;
      if (11502 <= samplerate) return 9;
      if (9391 <= samplerate) return 10;
      if (16428320 <= samplerate) return 11;
  
      return 11;
  }
  
  /* Returns the sample rate based on the sample rate index */
  uint32_t get_sample_rate(const uint8_t sr_index)
  {
      static const uint32_t sample_rates[] =
      {
          96000, 88200, 64000, 48000, 44100, 32000,
          24000, 22050, 16000, 12000, 11025, 8000
      };
  
      if (sr_index < 12)
          return sample_rates[sr_index];
  
      return 0;
  }
  
  uint8_t max_pred_sfb(const uint8_t sr_index)
  {
      static const uint8_t pred_sfb_max[] =
      {
          33, 33, 38, 40, 40, 40, 41, 41, 37, 37, 37, 34
      };
  
  
      if (sr_index < 12)
          return pred_sfb_max[sr_index];
  
      return 0;
  }
  
  uint8_t max_tns_sfb(const uint8_t sr_index, const uint8_t object_type,
                      const uint8_t is_short)
  {
      /* entry for each sampling rate
       * 1    Main/LC long window
       * 2    Main/LC short window
       * 3    SSR long window
       * 4    SSR short window
       */
      static const uint8_t tns_sbf_max[][4] =
      {
          {31,  9, 28, 7}, /* 96000 */
          {31,  9, 28, 7}, /* 88200 */
          {34, 10, 27, 7}, /* 64000 */
          {40, 14, 26, 6}, /* 48000 */
          {42, 14, 26, 6}, /* 44100 */
          {51, 14, 26, 6}, /* 32000 */
          {46, 14, 29, 7}, /* 24000 */
          {46, 14, 29, 7}, /* 22050 */
          {42, 14, 23, 8}, /* 16000 */
          {42, 14, 23, 8}, /* 12000 */
          {42, 14, 23, 8}, /* 11025 */
          {39, 14, 19, 7}, /*  8000 */
          {39, 14, 19, 7}, /*  7350 */
          {0,0,0,0},
          {0,0,0,0},
          {0,0,0,0}
      };
      uint8_t i = 0;
  
      if (is_short) i++;
      if (object_type == SSR) i += 2;
  
      return tns_sbf_max[sr_index][i];
  }
  
  /* Returns 0 if an object type is decodable, otherwise returns -1 */
  int8_t can_decode_ot(const uint8_t object_type)
  {
      switch (object_type)
      {
      case LC:
          return 0;
      case MAIN:
  #ifdef MAIN_DEC
          return 0;
  #else
          return -1;
  #endif
      case SSR:
  #ifdef SSR_DEC
          return 0;
  #else
          return -1;
  #endif
      case LTP:
  #ifdef LTP_DEC
          return 0;
  #else
          return -1;
  #endif
  
      /* ER object types */
  #ifdef ERROR_RESILIENCE
      case ER_LC:
  #ifdef DRM
      case DRM_ER_LC:
  #endif
          return 0;
      case ER_LTP:
  #ifdef LTP_DEC
          return 0;
  #else
          return -1;
  #endif
      case LD:
  #ifdef LD_DEC
          return 0;
  #else
          return -1;
  #endif
  #endif
      }
  
      return -1;
  }
  
  void *faad_malloc(size_t size)
  {
  #if 0 // defined(_WIN32) && !defined(_WIN32_WCE)
      return _aligned_malloc(size, 16);
  #else   // #ifdef 0
      return malloc(size);
  #endif  // #ifdef 0
  }
  
  /* common free function */
  void faad_free(void *b)
  {
  #if 0 // defined(_WIN32) && !defined(_WIN32_WCE)
      _aligned_free(b);
  #else
      free(b);
  }
  #endif
  
  static const  uint8_t    Parity [256] = {  // parity
      0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
      1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
      1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
      0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
      1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,
      0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
      0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,
      1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,0
  };
  
  static uint32_t  __r1 = 1;
  static uint32_t  __r2 = 1;
  
  
  /*
   *  This is a simple random number generator with good quality for audio purposes.
   *  It consists of two polycounters with opposite rotation direction and different
   *  periods. The periods are coprime, so the total period is the product of both.
   *
   *     -------------------------------------------------------------------------------------------------
   * +-> |31:30:29:28:27:26:25:24:23:22:21:20:19:18:17:16:15:14:13:12:11:10: 9: 8: 7: 6: 5: 4: 3: 2: 1: 0|
   * |   -------------------------------------------------------------------------------------------------
   * |                                                                          |  |  |  |     |        |
   * |                                                                          +--+--+--+-XOR-+--------+
   * |                                                                                      |
   * +--------------------------------------------------------------------------------------+
   *
   *     -------------------------------------------------------------------------------------------------
   *     |31:30:29:28:27:26:25:24:23:22:21:20:19:18:17:16:15:14:13:12:11:10: 9: 8: 7: 6: 5: 4: 3: 2: 1: 0| <-+
   *     -------------------------------------------------------------------------------------------------   |
   *       |  |           |  |                                                                               |
   *       +--+----XOR----+--+                                                                               |
   *                |                                                                                        |
   *                +----------------------------------------------------------------------------------------+
   *
   *
   *  The first has an period of 3*5*17*257*65537, the second of 7*47*73*178481,
   *  which gives a period of 18.410.713.077.675.721.215. The result is the
   *  XORed values of both generators.
   */
  uint32_t random_int(void)
  {
      uint32_t  t1, t2, t3, t4;
  
      t3   = t1 = __r1;   t4   = t2 = __r2;       // Parity calculation is done via table lookup, this is also available
      t1  &= 0xF5;        t2 >>= 25;              // on CPUs without parity, can be implemented in C and avoid unpredictable
      t1   = Parity [t1]; t2  &= 0x63;            // jumps and slow rotate through the carry flag operations.
      t1 <<= 31;          t2   = Parity [t2];
  
      return (__r1 = (t3 >> 1) | t1 ) ^ (__r2 = (t4 + t4) | t2 );
  }
  
  uint32_t ones32(uint32_t x)
  {
      x -= ((x >> 1) & 0x55555555);
      x = (((x >> 2) & 0x33333333) + (x & 0x33333333));
      x = (((x >> 4) + x) & 0x0f0f0f0f);
      x += (x >> 8);
      x += (x >> 16);
  
      return (x & 0x0000003f);
  }
  
  uint32_t floor_log2(uint32_t x)
  {
  #if 1
      x |= (x >> 1);
      x |= (x >> 2);
      x |= (x >> 4);
      x |= (x >> 8);
      x |= (x >> 16);
  
      return (ones32(x) - 1);
  #else
      uint32_t count = 0;
  
      while (x >>= 1)
          count++;
  
      return count;
  #endif
  }
  
  /* returns position of first bit that is not 0 from msb,
   * starting count at lsb */
  uint32_t wl_min_lzc(uint32_t x)
  {
  #if 1
      x |= (x >> 1);
      x |= (x >> 2);
      x |= (x >> 4);
      x |= (x >> 8);
      x |= (x >> 16);
  
      return (ones32(x));
  #else
      uint32_t count = 0;
  
      while (x >>= 1)
          count++;
  
      return (count + 1);
  #endif
  }
  
  #ifdef FIXED_POINT
  
  #define TABLE_BITS 6
  /* just take the maximum number of bits for interpolation */
  #define INTERP_BITS (REAL_BITS-TABLE_BITS)
  
  static const real_t pow2_tab[] = {
      REAL_CONST(1.000000000000000), REAL_CONST(1.010889286051701), REAL_CONST(1.021897148654117),
      REAL_CONST(1.033024879021228), REAL_CONST(1.044273782427414), REAL_CONST(1.055645178360557),
      REAL_CONST(1.067140400676824), REAL_CONST(1.078760797757120), REAL_CONST(1.090507732665258),
      REAL_CONST(1.102382583307841), REAL_CONST(1.114386742595892), REAL_CONST(1.126521618608242),
      REAL_CONST(1.138788634756692), REAL_CONST(1.151189229952983), REAL_CONST(1.163724858777578),
      REAL_CONST(1.176396991650281), REAL_CONST(1.189207115002721), REAL_CONST(1.202156731452703),
      REAL_CONST(1.215247359980469), REAL_CONST(1.228480536106870), REAL_CONST(1.241857812073484),
      REAL_CONST(1.255380757024691), REAL_CONST(1.269050957191733), REAL_CONST(1.282870016078778),
      REAL_CONST(1.296839554651010), REAL_CONST(1.310961211524764), REAL_CONST(1.325236643159741),
      REAL_CONST(1.339667524053303), REAL_CONST(1.354255546936893), REAL_CONST(1.369002422974591),
      REAL_CONST(1.383909881963832), REAL_CONST(1.398979672538311), REAL_CONST(1.414213562373095),
      REAL_CONST(1.429613338391970), REAL_CONST(1.445180806977047), REAL_CONST(1.460917794180647),
      REAL_CONST(1.476826145939499), REAL_CONST(1.492907728291265), REAL_CONST(1.509164427593423),
      REAL_CONST(1.525598150744538), REAL_CONST(1.542210825407941), REAL_CONST(1.559004400237837),
      REAL_CONST(1.575980845107887), REAL_CONST(1.593142151342267), REAL_CONST(1.610490331949254),
      REAL_CONST(1.628027421857348), REAL_CONST(1.645755478153965), REAL_CONST(1.663676580326736),
      REAL_CONST(1.681792830507429), REAL_CONST(1.700106353718524), REAL_CONST(1.718619298122478),
      REAL_CONST(1.737333835273706), REAL_CONST(1.756252160373300), REAL_CONST(1.775376492526521),
      REAL_CONST(1.794709075003107), REAL_CONST(1.814252175500399), REAL_CONST(1.834008086409342),
      REAL_CONST(1.853979125083386), REAL_CONST(1.874167634110300), REAL_CONST(1.894575981586966),
      REAL_CONST(1.915206561397147), REAL_CONST(1.936061793492294), REAL_CONST(1.957144124175400),
      REAL_CONST(1.978456026387951), REAL_CONST(2.000000000000000)
  };
  
  static const real_t log2_tab[] = {
      REAL_CONST(0.000000000000000), REAL_CONST(0.022367813028455), REAL_CONST(0.044394119358453),
      REAL_CONST(0.066089190457772), REAL_CONST(0.087462841250339), REAL_CONST(0.108524456778169),
      REAL_CONST(0.129283016944966), REAL_CONST(0.149747119504682), REAL_CONST(0.169925001442312),
      REAL_CONST(0.189824558880017), REAL_CONST(0.209453365628950), REAL_CONST(0.228818690495881),
      REAL_CONST(0.247927513443585), REAL_CONST(0.266786540694901), REAL_CONST(0.285402218862248),
      REAL_CONST(0.303780748177103), REAL_CONST(0.321928094887362), REAL_CONST(0.339850002884625),
      REAL_CONST(0.357552004618084), REAL_CONST(0.375039431346925), REAL_CONST(0.392317422778760),
      REAL_CONST(0.409390936137702), REAL_CONST(0.426264754702098), REAL_CONST(0.442943495848728),
      REAL_CONST(0.459431618637297), REAL_CONST(0.475733430966398), REAL_CONST(0.491853096329675),
      REAL_CONST(0.507794640198696), REAL_CONST(0.523561956057013), REAL_CONST(0.539158811108031),
      REAL_CONST(0.554588851677637), REAL_CONST(0.569855608330948), REAL_CONST(0.584962500721156),
      REAL_CONST(0.599912842187128), REAL_CONST(0.614709844115208), REAL_CONST(0.629356620079610),
      REAL_CONST(0.643856189774725), REAL_CONST(0.658211482751795), REAL_CONST(0.672425341971496),
      REAL_CONST(0.686500527183218), REAL_CONST(0.700439718141092), REAL_CONST(0.714245517666123),
      REAL_CONST(0.727920454563199), REAL_CONST(0.741466986401147), REAL_CONST(0.754887502163469),
      REAL_CONST(0.768184324776926), REAL_CONST(0.781359713524660), REAL_CONST(0.794415866350106),
      REAL_CONST(0.807354922057604), REAL_CONST(0.820178962415188), REAL_CONST(0.832890014164742),
      REAL_CONST(0.845490050944375), REAL_CONST(0.857980995127572), REAL_CONST(0.870364719583405),
      REAL_CONST(0.882643049361841), REAL_CONST(0.894817763307943), REAL_CONST(0.906890595608519),
      REAL_CONST(0.918863237274595), REAL_CONST(0.930737337562886), REAL_CONST(0.942514505339240),
      REAL_CONST(0.954196310386875), REAL_CONST(0.965784284662087), REAL_CONST(0.977279923499917),
      REAL_CONST(0.988684686772166), REAL_CONST(1.000000000000000)
  };
  
  real_t pow2_fix(real_t val)
  {
      uint32_t x1, x2;
      uint32_t errcorr;
      uint32_t index_frac;
      real_t retval;
      int32_t whole = (val >> REAL_BITS);
  
      /* rest = [0..1] */
      int32_t rest = val - (whole << REAL_BITS);
  
      /* index into pow2_tab */
      int32_t index = rest >> (REAL_BITS-TABLE_BITS);
  
  
      if (val == 0)
          return (1<<REAL_BITS);
  
      /* leave INTERP_BITS bits */
      index_frac = rest >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
      index_frac = index_frac & ((1<<INTERP_BITS)-1);
  
      if (whole > 0)
      {
          retval = 1 << whole;
      } else {
          retval = REAL_CONST(1) >> -whole;
      }
  
      x1 = pow2_tab[index & ((1<<TABLE_BITS)-1)];
      x2 = pow2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
      errcorr = ( (index_frac*(x2-x1))) >> INTERP_BITS;
  
      if (whole > 0)
      {
          retval = retval * (errcorr + x1);
      } else {
          retval = MUL_R(retval, (errcorr + x1));
      }
  
      return retval;
  }
  
  int32_t pow2_int(real_t val)
  {
      uint32_t x1, x2;
      uint32_t errcorr;
      uint32_t index_frac;
      real_t retval;
      int32_t whole = (val >> REAL_BITS);
  
      /* rest = [0..1] */
      int32_t rest = val - (whole << REAL_BITS);
  
      /* index into pow2_tab */
      int32_t index = rest >> (REAL_BITS-TABLE_BITS);
  
  
      if (val == 0)
          return 1;
  
      /* leave INTERP_BITS bits */
      index_frac = rest >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
      index_frac = index_frac & ((1<<INTERP_BITS)-1);
  
      if (whole > 0)
          retval = 1 << whole;
      else
          retval = 0;
  
      x1 = pow2_tab[index & ((1<<TABLE_BITS)-1)];
      x2 = pow2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
      errcorr = ( (index_frac*(x2-x1))) >> INTERP_BITS;
  
      retval = MUL_R(retval, (errcorr + x1));
  
      return retval;
  }
  
  /* ld(x) = ld(x*y/y) = ld(x/y) + ld(y), with y=2^N and [1 <= (x/y) < 2] */
  int32_t log2_int(uint32_t val)
  {
      uint32_t frac;
      uint32_t whole = (val);
      int32_t exp = 0;
      uint32_t index;
      uint32_t index_frac;
      uint32_t x1, x2;
      uint32_t errcorr;
  
      /* error */
      if (val == 0)
          return -10000;
  
      exp = floor_log2(val);
      exp -= REAL_BITS;
  
      /* frac = [1..2] */
      if (exp >= 0)
          frac = val >> exp;
      else
          frac = val << -exp;
  
      /* index in the log2 table */
      index = frac >> (REAL_BITS-TABLE_BITS);
  
      /* leftover part for linear interpolation */
      index_frac = frac & ((1<<(REAL_BITS-TABLE_BITS))-1);
  
      /* leave INTERP_BITS bits */
      index_frac = index_frac >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
  
      x1 = log2_tab[index & ((1<<TABLE_BITS)-1)];
      x2 = log2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
  
      /* linear interpolation */
      /* retval = exp + ((index_frac)*x2 + (1-index_frac)*x1) */
  
      errcorr = (index_frac * (x2-x1)) >> INTERP_BITS;
  
      return ((exp+REAL_BITS) << REAL_BITS) + errcorr + x1;
  }
  
  /* ld(x) = ld(x*y/y) = ld(x/y) + ld(y), with y=2^N and [1 <= (x/y) < 2] */
  real_t log2_fix(uint32_t val)
  {
      uint32_t frac;
      uint32_t whole = (val >> REAL_BITS);
      int8_t exp = 0;
      uint32_t index;
      uint32_t index_frac;
      uint32_t x1, x2;
      uint32_t errcorr;
  
      /* error */
      if (val == 0)
          return -100000;
  
      exp = floor_log2(val);
      exp -= REAL_BITS;
  
      /* frac = [1..2] */
      if (exp >= 0)
          frac = val >> exp;
      else
          frac = val << -exp;
  
      /* index in the log2 table */
      index = frac >> (REAL_BITS-TABLE_BITS);
  
      /* leftover part for linear interpolation */
      index_frac = frac & ((1<<(REAL_BITS-TABLE_BITS))-1);
  
      /* leave INTERP_BITS bits */
      index_frac = index_frac >> (REAL_BITS-TABLE_BITS-INTERP_BITS);
  
      x1 = log2_tab[index & ((1<<TABLE_BITS)-1)];
      x2 = log2_tab[(index & ((1<<TABLE_BITS)-1)) + 1];
  
      /* linear interpolation */
      /* retval = exp + ((index_frac)*x2 + (1-index_frac)*x1) */
  
      errcorr = (index_frac * (x2-x1)) >> INTERP_BITS;
  
      return (exp << REAL_BITS) + errcorr + x1;
  }
  #endif
  