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src/Source/LibJPEG/jchuff.c  view on Meta::CPAN

  if (entropy->gather_statistics)
    entropy->ac_count_ptrs[tbl_no][symbol]++;
  else {
    c_derived_tbl * tbl = entropy->ac_derived_tbls[tbl_no];
    emit_bits_e(entropy, tbl->ehufco[symbol], tbl->ehufsi[symbol]);
  }
}


/*
 * Emit bits from a correction bit buffer.
 */

LOCAL(void)
emit_buffered_bits (huff_entropy_ptr entropy, char * bufstart,
		    unsigned int nbits)
{
  if (entropy->gather_statistics)
    return;			/* no real work */

  while (nbits > 0) {
    emit_bits_e(entropy, (unsigned int) (*bufstart), 1);
    bufstart++;
    nbits--;
  }
}


/*
 * Emit any pending EOBRUN symbol.
 */

LOCAL(void)
emit_eobrun (huff_entropy_ptr entropy)
{
  register int temp, nbits;

  if (entropy->EOBRUN > 0) {	/* if there is any pending EOBRUN */
    temp = entropy->EOBRUN;
    nbits = 0;
    while ((temp >>= 1))
      nbits++;
    /* safety check: shouldn't happen given limited correction-bit buffer */
    if (nbits > 14)
      ERREXIT(entropy->cinfo, JERR_HUFF_MISSING_CODE);

    emit_ac_symbol(entropy, entropy->ac_tbl_no, nbits << 4);
    if (nbits)
      emit_bits_e(entropy, entropy->EOBRUN, nbits);

    entropy->EOBRUN = 0;

    /* Emit any buffered correction bits */
    emit_buffered_bits(entropy, entropy->bit_buffer, entropy->BE);
    entropy->BE = 0;
  }
}


/*
 * Emit a restart marker & resynchronize predictions.
 */

LOCAL(boolean)
emit_restart_s (working_state * state, int restart_num)
{
  int ci;

  if (! flush_bits_s(state))
    return FALSE;

  emit_byte_s(state, 0xFF, return FALSE);
  emit_byte_s(state, JPEG_RST0 + restart_num, return FALSE);

  /* Re-initialize DC predictions to 0 */
  for (ci = 0; ci < state->cinfo->comps_in_scan; ci++)
    state->cur.last_dc_val[ci] = 0;

  /* The restart counter is not updated until we successfully write the MCU. */

  return TRUE;
}


LOCAL(void)
emit_restart_e (huff_entropy_ptr entropy, int restart_num)
{
  int ci;

  emit_eobrun(entropy);

  if (! entropy->gather_statistics) {
    flush_bits_e(entropy);
    emit_byte_e(entropy, 0xFF);
    emit_byte_e(entropy, JPEG_RST0 + restart_num);
  }

  if (entropy->cinfo->Ss == 0) {
    /* Re-initialize DC predictions to 0 */
    for (ci = 0; ci < entropy->cinfo->comps_in_scan; ci++)
      entropy->saved.last_dc_val[ci] = 0;
  } else {
    /* Re-initialize all AC-related fields to 0 */
    entropy->EOBRUN = 0;
    entropy->BE = 0;
  }
}


/*
 * MCU encoding for DC initial scan (either spectral selection,
 * or first pass of successive approximation).
 */

METHODDEF(boolean)
encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
  huff_entropy_ptr entropy = (huff_entropy_ptr) cinfo->entropy;
  register int temp, temp2;
  register int nbits;
  int blkn, ci, tbl;