/*

 * This source code is a product of Sun Microsystems, Inc. and is provided

 * for unrestricted use.  Users may copy or modify this source code without

 * charge.

 *

 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING

 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.

 *

 * Sun source code is provided with no support and without any obligation on

 * the part of Sun Microsystems, Inc. to assist in its use, correction,

 * modification or enhancement.

 *

 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE

 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE

 * OR ANY PART THEREOF.

 *

 * In no event will Sun Microsystems, Inc. be liable for any lost revenue

 * or profits or other special, indirect and consequential damages, even if

 * Sun has been advised of the possibility of such damages.

 *

 * Sun Microsystems, Inc.

 * 2550 Garcia Avenue

 * Mountain View, California  94043

 */

/*

 * g72x.c

 *

 * Common routines for G.721 and G.723 conversions.

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "g72x.h"

#include "g72x_priv.h"

static G72x_STATE * g72x_state_new (void) ;

static int unpack_bytes (int bits, int blocksize, const unsigned char * block, short * samples) ;

static int pack_bytes (int bits, const short * samples, unsigned char * block) ;

static

short power2 [15] =

{ 1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,

  0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000

} ;

/*

 * quan ()

 *

 * quantizes the input val against the table of size short integers.

 * It returns i if table [i - 1] <= val < table [i].

 *

 * Using linear search for simple coding.

 */

static

int quan (int val, short *table, int size)

{

  int   i ;

  for (i = 0 ; i < size ; i++)

    if (val < *table++)

      break ;

  return i ;

}

/*

 * fmult ()

 *

 * returns the integer product of the 14-bit integer "an" and

 * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".

 */

static

int fmult (int an, int srn)

{

  short   anmag, anexp, anmant ;

  short   wanexp, wanmant ;

  short   retval ;

  anmag = (an > 0) ? an : ((-an) & 0x1FFF) ;

  anexp = quan (anmag, power2, 15) - 6 ;

  anmant = (anmag == 0) ? 32 :

        (anexp >= 0) ? anmag >> anexp : anmag << -anexp ;

  wanexp = anexp + ((srn >> 6) & 0xF) - 13 ;

  /*

  ** The original was :

  **    wanmant = (anmant * (srn & 0x3F) + 0x30) >> 4 ;

  ** but could see no valid reason for the + 0x30.

  ** Removed it and it improved the SNR of the codec.

  */

  wanmant = (anmant * (srn & 0x3F)) >> 4 ;

  retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) : (wanmant >> -wanexp) ;

  return (((an ^ srn) < 0) ? -retval : retval) ;

}

static G72x_STATE * g72x_state_new (void)

{ return calloc (1, sizeof (G72x_STATE)) ;

}

/*

 * private_init_state ()

 *

 * This routine initializes and/or resets the G72x_PRIVATE structure

 * pointed to by 'state_ptr'.

 * All the initial state values are specified in the CCITT G.721 document.

 */

void private_init_state (G72x_STATE *state_ptr)

{

  int   cnta ;

  state_ptr->yl = 34816 ;

  state_ptr->yu = 544 ;

  state_ptr->dms = 0 ;

  state_ptr->dml = 0 ;

  state_ptr->ap = 0 ;

  for (cnta = 0 ; cnta < 2 ; cnta++)

  { state_ptr->a [cnta] = 0 ;

    state_ptr->pk [cnta] = 0 ;

    state_ptr->sr [cnta] = 32 ;

    }

  for (cnta = 0 ; cnta < 6 ; cnta++)

  { state_ptr->b [cnta] = 0 ;

    state_ptr->dq [cnta] = 32 ;

    }

  state_ptr->td = 0 ;

}  /* private_init_state */

struct g72x_state * g72x_reader_init (int codec, int *blocksize, int *samplesperblock)

{ G72x_STATE *pstate ;

  if ((pstate = g72x_state_new ()) == NULL)

    return NULL ;

  private_init_state (pstate) ;

  pstate->encoder = NULL ;

  switch (codec)

  { case G723_16_BITS_PER_SAMPLE : /* 2 bits per sample. */

        pstate->decoder = g723_16_decoder ;

        *blocksize = G723_16_BYTES_PER_BLOCK ;

        *samplesperblock = G723_16_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 2 ;

        pstate->blocksize = G723_16_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G723_16_SAMPLES_PER_BLOCK ;

        break ;

    case G723_24_BITS_PER_SAMPLE : /* 3 bits per sample. */

        pstate->decoder = g723_24_decoder ;

        *blocksize = G723_24_BYTES_PER_BLOCK ;

        *samplesperblock = G723_24_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 3 ;

        pstate->blocksize = G723_24_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G723_24_SAMPLES_PER_BLOCK ;

        break ;

    case G721_32_BITS_PER_SAMPLE : /* 4 bits per sample. */

        pstate->decoder = g721_decoder ;

        *blocksize = G721_32_BYTES_PER_BLOCK ;

        *samplesperblock = G721_32_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 4 ;

        pstate->blocksize = G721_32_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G721_32_SAMPLES_PER_BLOCK ;

        break ;

    case G721_40_BITS_PER_SAMPLE : /* 5 bits per sample. */

        pstate->decoder = g723_40_decoder ;

        *blocksize = G721_40_BYTES_PER_BLOCK ;

        *samplesperblock = G721_40_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 5 ;

        pstate->blocksize = G721_40_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G721_40_SAMPLES_PER_BLOCK ;

        break ;

    default :

        free (pstate) ;

        return NULL ;

    } ;

  return pstate ;

}  /* g72x_reader_init */

struct g72x_state * g72x_writer_init (int codec, int *blocksize, int *samplesperblock)

{ G72x_STATE *pstate ;

  if ((pstate = g72x_state_new ()) == NULL)

    return NULL ;

  private_init_state (pstate) ;

  pstate->decoder = NULL ;

  switch (codec)

  { case G723_16_BITS_PER_SAMPLE : /* 2 bits per sample. */

        pstate->encoder = g723_16_encoder ;

        *blocksize = G723_16_BYTES_PER_BLOCK ;

        *samplesperblock = G723_16_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 2 ;

        pstate->blocksize = G723_16_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G723_16_SAMPLES_PER_BLOCK ;

        break ;

    case G723_24_BITS_PER_SAMPLE : /* 3 bits per sample. */

        pstate->encoder = g723_24_encoder ;

        *blocksize = G723_24_BYTES_PER_BLOCK ;

        *samplesperblock = G723_24_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 3 ;

        pstate->blocksize = G723_24_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G723_24_SAMPLES_PER_BLOCK ;

        break ;

    case G721_32_BITS_PER_SAMPLE : /* 4 bits per sample. */

        pstate->encoder = g721_encoder ;

        *blocksize = G721_32_BYTES_PER_BLOCK ;

        *samplesperblock = G721_32_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 4 ;

        pstate->blocksize = G721_32_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G721_32_SAMPLES_PER_BLOCK ;

        break ;

    case G721_40_BITS_PER_SAMPLE : /* 5 bits per sample. */

        pstate->encoder = g723_40_encoder ;

        *blocksize = G721_40_BYTES_PER_BLOCK ;

        *samplesperblock = G721_40_SAMPLES_PER_BLOCK ;

        pstate->codec_bits = 5 ;

        pstate->blocksize = G721_40_BYTES_PER_BLOCK ;

        pstate->samplesperblock = G721_40_SAMPLES_PER_BLOCK ;

        break ;

    default :

        free (pstate) ;

        return NULL ;

    } ;

  return pstate ;

}  /* g72x_writer_init */

int g72x_decode_block (G72x_STATE *pstate, const unsigned char *block, short *samples)

{ int k, count ;

  count = unpack_bytes (pstate->codec_bits, pstate->blocksize, block, samples) ;

  for (k = 0 ; k < count ; k++)

    samples [k] = pstate->decoder (samples [k], pstate) ;

  return 0 ;

}  /* g72x_decode_block */

int g72x_encode_block (G72x_STATE *pstate, short *samples, unsigned char *block)

{ int k, count ;

  for (k = 0 ; k < pstate->samplesperblock ; k++)

    samples [k] = pstate->encoder (samples [k], pstate) ;

  count = pack_bytes (pstate->codec_bits, samples, block) ;

  return count ;

}  /* g72x_encode_block */

/*

 * predictor_zero ()

 *

 * computes the estimated signal from 6-zero predictor.

 *

 */

int predictor_zero (G72x_STATE *state_ptr)

{

  int   i ;

  int   sezi ;

  sezi = fmult (state_ptr->b [0] >> 2, state_ptr->dq [0]) ;

  for (i = 1 ; i < 6 ; i++)      /* ACCUM */

    sezi += fmult (state_ptr->b [i] >> 2, state_ptr->dq [i]) ;

  return sezi ;

}

/*

 * predictor_pole ()

 *

 * computes the estimated signal from 2-pole predictor.

 *

 */

int predictor_pole (G72x_STATE *state_ptr)

{

  return (fmult (state_ptr->a [1] >> 2, state_ptr->sr [1]) +

      fmult (state_ptr->a [0] >> 2, state_ptr->sr [0])) ;

}

/*

 * step_size ()

 *

 * computes the quantization step size of the adaptive quantizer.

 *

 */

int step_size (G72x_STATE *state_ptr)

{

  int   y ;

  int   dif ;

  int   al ;

  if (state_ptr->ap >= 256)

    return (state_ptr->yu) ;

  else {

    y = state_ptr->yl >> 6 ;

    dif = state_ptr->yu - y ;

    al = state_ptr->ap >> 2 ;

    if (dif > 0)

      y += (dif * al) >> 6 ;

    else if (dif < 0)

      y += (dif * al + 0x3F) >> 6 ;

    return y ;

  }

}

/*

 * quantize ()

 *

 * Given a raw sample, 'd', of the difference signal and a

 * quantization step size scale factor, 'y', this routine returns the

 * ADPCM codeword to which that sample gets quantized.  The step

 * size scale factor division operation is done in the log base 2 domain

 * as a subtraction.

 */

int quantize (

  int   d,  /* Raw difference signal sample */

  int   y,  /* Step size multiplier */

  short *table, /* quantization table */

  int   size) /* table size of short integers */

{

  short   dqm ; /* Magnitude of 'd' */

  short   expon ; /* Integer part of base 2 log of 'd' */

  short   mant ;  /* Fractional part of base 2 log */

  short   dl ;  /* Log of magnitude of 'd' */

  short   dln ; /* Step size scale factor normalized log */

  int   i ;

  /*

   * LOG

   *

   * Compute base 2 log of 'd', and store in 'dl'.

   */

  dqm = abs (d) ;

  expon = quan (dqm >> 1, power2, 15) ;

  mant = ((dqm << 7) >> expon) & 0x7F ; /* Fractional portion. */

  dl = (expon << 7) + mant ;

  /*

   * SUBTB

   *

   * "Divide" by step size multiplier.

   */

  dln = dl - (y >> 2) ;

  /*

   * QUAN

   *

   * Obtain codword i for 'd'.

   */

  i = quan (dln, table, size) ;

  if (d < 0)     /* take 1's complement of i */

    return ((size << 1) + 1 - i) ;

  else if (i == 0)   /* take 1's complement of 0 */

    return ((size << 1) + 1) ; /* new in 1988 */

  return i ;

}

/*

 * reconstruct ()

 *

 * Returns reconstructed difference signal 'dq' obtained from

 * codeword 'i' and quantization step size scale factor 'y'.

 * Multiplication is performed in log base 2 domain as addition.

 */

int

reconstruct (

  int   sign, /* 0 for non-negative value */

  int   dqln, /* G.72x codeword */

  int   y)  /* Step size multiplier */

{

  short   dql ; /* Log of 'dq' magnitude */

  short   dex ; /* Integer part of log */

  short   dqt ;

  short   dq ;  /* Reconstructed difference signal sample */

  dql = dqln + (y >> 2) ; /* ADDA */

  if (dql < 0)

    return ((sign) ? -0x8000 : 0) ;

  else    /* ANTILOG */

  { dex = (dql >> 7) & 15 ;

    dqt = 128 + (dql & 127) ;

    dq = (dqt << 7) >> (14 - dex) ;

    return ((sign) ? (dq - 0x8000) : dq) ;

    }

}

/*

 * update ()

 *

 * updates the state variables for each output code

 */

void

update (

  int   code_size,  /* distinguish 723_40 with others */

  int   y,    /* quantizer step size */

  int   wi,   /* scale factor multiplier */

  int   fi,   /* for long/short term energies */

  int   dq,   /* quantized prediction difference */

  int   sr,   /* reconstructed signal */

  int   dqsez,    /* difference from 2-pole predictor */

  G72x_STATE *state_ptr)  /* coder state pointer */

{

  int   cnt ;

  short   mag, expon ;  /* Adaptive predictor, FLOAT A */

  short   a2p = 0 ; /* LIMC */

  short   a1ul ;    /* UPA1 */

  short   pks1 ;    /* UPA2 */

  short   fa1 ;

  char    tr ;    /* tone/transition detector */

  short   ylint, thr2, dqthr ;

  short   ylfrac, thr1 ;

  short   pk0 ;

  pk0 = (dqsez < 0) ? 1 : 0 ;  /* needed in updating predictor poles */

  mag = dq & 0x7FFF ;   /* prediction difference magnitude */

  /* TRANS */

  ylint = state_ptr->yl >> 15 ; /* exponent part of yl */

  ylfrac = (state_ptr->yl >> 10) & 0x1F ; /* fractional part of yl */

  thr1 = (32 + ylfrac) << ylint ;   /* threshold */

  thr2 = (ylint > 9) ? 31 << 10 : thr1 ;  /* limit thr2 to 31 << 10 */

  dqthr = (thr2 + (thr2 >> 1)) >> 1 ; /* dqthr = 0.75 * thr2 */

  if (state_ptr->td == 0)    /* signal supposed voice */

    tr = 0 ;

  else if (mag <= dqthr)    /* supposed data, but small mag */

    tr = 0 ;      /* treated as voice */

  else        /* signal is data (modem) */

    tr = 1 ;

  /*

   * Quantizer scale factor adaptation.

   */

  /* FUNCTW & FILTD & DELAY */

  /* update non-steady state step size multiplier */

  state_ptr->yu = y + ((wi - y) >> 5) ;

  /* LIMB */

  if (state_ptr->yu < 544)  /* 544 <= yu <= 5120 */

    state_ptr->yu = 544 ;

  else if (state_ptr->yu > 5120)

    state_ptr->yu = 5120 ;

  /* FILTE & DELAY */

  /* update steady state step size multiplier */

  state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6) ;

  /*

   * Adaptive predictor coefficients.

   */

  if (tr == 1) {     /* reset a's and b's for modem signal */

    state_ptr->a [0] = 0 ;

    state_ptr->a [1] = 0 ;

    state_ptr->b [0] = 0 ;

    state_ptr->b [1] = 0 ;

    state_ptr->b [2] = 0 ;

    state_ptr->b [3] = 0 ;

    state_ptr->b [4] = 0 ;

    state_ptr->b [5] = 0 ;

    }

  else      /* update a's and b's */

  { pks1 = pk0 ^ state_ptr->pk [0] ;    /* UPA2 */

    /* update predictor pole a [1] */

    a2p = state_ptr->a [1] - (state_ptr->a [1] >> 7) ;

    if (dqsez != 0)

    { fa1 = (pks1) ? state_ptr->a [0] : -state_ptr->a [0] ;

      if (fa1 < -8191)  /* a2p = function of fa1 */

        a2p -= 0x100 ;

      else if (fa1 > 8191)

        a2p += 0xFF ;

      else

        a2p += fa1 >> 5 ;

      if (pk0 ^ state_ptr->pk [1])

      { /* LIMC */

        if (a2p <= -12160)

          a2p = -12288 ;

        else if (a2p >= 12416)

          a2p = 12288 ;

        else

          a2p -= 0x80 ;

        }

      else if (a2p <= -12416)

        a2p = -12288 ;

      else if (a2p >= 12160)

        a2p = 12288 ;

      else

        a2p += 0x80 ;

    }

    /* TRIGB & DELAY */

    state_ptr->a [1] = a2p ;

    /* UPA1 */

    /* update predictor pole a [0] */

    state_ptr->a [0] -= state_ptr->a [0] >> 8 ;

    if (dqsez != 0)

    { if (pks1 == 0)

        state_ptr->a [0] += 192 ;

      else

        state_ptr->a [0] -= 192 ;

      } ;

    /* LIMD */

    a1ul = 15360 - a2p ;

    if (state_ptr->a [0] < -a1ul)

      state_ptr->a [0] = -a1ul ;

    else if (state_ptr->a [0] > a1ul)

      state_ptr->a [0] = a1ul ;

    /* UPB : update predictor zeros b [6] */

    for (cnt = 0 ; cnt < 6 ; cnt++)

    { if (code_size == 5)    /* for 40Kbps G.723 */

        state_ptr->b [cnt] -= state_ptr->b [cnt] >> 9 ;

      else      /* for G.721 and 24Kbps G.723 */

        state_ptr->b [cnt] -= state_ptr->b [cnt] >> 8 ;

      if (dq & 0x7FFF)      /* XOR */

      { if ((dq ^ state_ptr->dq [cnt]) >= 0)

          state_ptr->b [cnt] += 128 ;

        else

          state_ptr->b [cnt] -= 128 ;

        }

      }

    }

  for (cnt = 5 ; cnt > 0 ; cnt--)

    state_ptr->dq [cnt] = state_ptr->dq [cnt - 1] ;

  /* FLOAT A : convert dq [0] to 4-bit exp, 6-bit mantissa f.p. */

  if (mag == 0)

    state_ptr->dq [0] = (dq >= 0) ? 0x20 : 0xFC20 ;

  else

  { expon = quan (mag, power2, 15) ;

    state_ptr->dq [0] = (dq >= 0) ?

      (expon << 6) + ((mag << 6) >> expon) :

      (expon << 6) + ((mag << 6) >> expon) - 0x400 ;

    }

  state_ptr->sr [1] = state_ptr->sr [0] ;

  /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */

  if (sr == 0)

    state_ptr->sr [0] = 0x20 ;

  else if (sr > 0)

  { expon = quan (sr, power2, 15) ;

    state_ptr->sr [0] = (expon << 6) + ((sr << 6) >> expon) ;

    }

  else if (sr > -32768)

  { mag = -sr ;

    expon = quan (mag, power2, 15) ;

    state_ptr->sr [0] = (expon << 6) + ((mag << 6) >> expon) - 0x400 ;

    }

  else

    state_ptr->sr [0] = (short) 0xFC20 ;

  /* DELAY A */

  state_ptr->pk [1] = state_ptr->pk [0] ;

  state_ptr->pk [0] = pk0 ;

  /* TONE */

  if (tr == 1)    /* this sample has been treated as data */

    state_ptr->td = 0 ;  /* next one will be treated as voice */

  else if (a2p < -11776)  /* small sample-to-sample correlation */

    state_ptr->td = 1 ;  /* signal may be data */

  else        /* signal is voice */

    state_ptr->td = 0 ;

  /*

   * Adaptation speed control.

   */

  state_ptr->dms += (fi - state_ptr->dms) >> 5 ;    /* FILTA */

  state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7) ; /* FILTB */

  if (tr == 1)

    state_ptr->ap = 256 ;

  else if (y < 1536)          /* SUBTC */

    state_ptr->ap += (0x200 - state_ptr->ap) >> 4 ;

  else if (state_ptr->td == 1)

    state_ptr->ap += (0x200 - state_ptr->ap) >> 4 ;

  else if (abs ((state_ptr->dms << 2) - state_ptr->dml) >= (state_ptr->dml >> 3))

    state_ptr->ap += (0x200 - state_ptr->ap) >> 4 ;

  else

    state_ptr->ap += (-state_ptr->ap) >> 4 ;

  return ;

} /* update */

/*------------------------------------------------------------------------------

*/

static int

unpack_bytes (int bits, int blocksize, const unsigned char * block, short * samples)

{ unsigned int  in_buffer = 0 ;

  unsigned char in_byte ;

  int       k, in_bits = 0, bindex = 0 ;

  for (k = 0 ; bindex <= blocksize && k < G72x_BLOCK_SIZE ; k++)

  { if (in_bits < bits)

    { in_byte = block [bindex++] ;

      in_buffer |= (in_byte << in_bits) ;

      in_bits += 8 ;

      }

    samples [k] = in_buffer & ((1 << bits) - 1) ;

    in_buffer >>= bits ;

    in_bits -= bits ;

    } ;

  return k ;

} /* unpack_bytes */

static int

pack_bytes (int bits, const short * samples, unsigned char * block)

{

  unsigned int  out_buffer = 0 ;

  int       k, bindex = 0, out_bits = 0 ;

  unsigned char out_byte ;

  for (k = 0 ; k < G72x_BLOCK_SIZE ; k++)

  { out_buffer |= (samples [k] << out_bits) ;

    out_bits += bits ;

    if (out_bits >= 8)

    { out_byte = out_buffer & 0xFF ;

      out_bits -= 8 ;

      out_buffer >>= 8 ;

      block [bindex++] = out_byte ;

      }

    } ;

  return bindex ;

} /* pack_bytes */