/* --- Packet size in number of samples. One sample is 16-bit. */
#define J 32

#pragma FUNC_INTERRUPT_THRESHOLD (0);
extern "C" int ldc_(unsigned int* sig, unsigned int* Obuf)
{
  /* --- Bit stream buffer, mask, word being filled, and number of words */
  unsigned int Ovalue=0, mask, msk0;
  unsigned int Osize=0;
  int nbit = 32;

  unsigned int k;

  /* --- Loop over blocks of 32 channels */
  for(int npacket=0; npacket<4; npacket++){

    /* ------------------------------------------------------------
     * Preprocessor
     * Compute the estimator for the best split-sample (ESA report)
     * ------------------------------------------------------------ */
    unsigned int gp0 = 0;

    for(int i=0; i<J; i++){
      int s = sig[i] << 1;
      if (s < 0) s = _abs(s+1);
      sig[i] = s;
      gp0 += s;
    }

    /* --- Find split order as log2(gp0/32) */
    k = 25 - _lmbd(1,gp0);


    /* ------------------------------------------------------------
     * Code here
     * Start with the Option ID (5 bits)
     * ------------------------------------------------------------ */
    {
      unsigned int value = (k+1);
      nbit -= 5;
      if (nbit < 0){
	Ovalue |= value >> -nbit;
	Obuf[Osize++] = Ovalue;
	nbit += 32;
	Ovalue = 0;
      }
      Ovalue |= value << nbit;
    }

    /* --- Mask for the LSB */
    msk0 = 1<<k;
    mask = msk0 - 1;

    /* --- Loop over the J samples */
    for(int i=0; i<J; i++){

      /* ------------------------------
       * MSB codeword
       * ------------------------------ */
      {
	unsigned int value = sig[i] >> k;
	nbit -= value;
	if (nbit < 0){
	  Obuf[Osize++] = Ovalue;
	  nbit += 32;
	  Ovalue = 0;
	}
      }

      /* ------------------------------
       * LSB
       * ------------------------------ */
      {
	unsigned int value = (sig[i] & mask) | msk0;
	nbit -= (k+1);
	if (nbit < 0){
	  Ovalue |= value >> -nbit;
	  Obuf[Osize++] = Ovalue;
	  nbit += 32;
	  Ovalue = 0;
	}
	Ovalue |= value << nbit;
      }
    }

    /* --- Finished with this block */
    sig += J;
  }

  /* --- Flush the output buffer */
  Obuf[Osize++] = Ovalue;

  return Osize;
}