compressed.cpp

该源码是JPEG2000的c++源代码,希望对研究JPEG2000标准以及编解码的朋友们有用.

  if (state->roi_weight < 0.0F)
    return false;
  energy_weight = state->roi_weight * state->roi_weight;
  return true;
}

/*****************************************************************************/
/*                           kdu_subband::get_dims                           */
/*****************************************************************************/

void
  kdu_subband::get_dims(kdu_dims &result)
  /* This is the only place where we need to be particularly careful
     about mapping apparent dimensions through geometric transformations.
     The reason is that high-pass subband coordinates are notionally based
     on an origin +1/2 a subband sample spacing beyond the origin of the
     real coordinate system.  To flip these subbands, it is not sufficient to
     negate the coordinates of each constituent sample; we must also
     subtract 1. */
{
  kdu_coords band_idx = state->band_idx;
  result = state->region;
  state->codestream->to_apparent(result);
  if (state->codestream->transpose)
    band_idx.transpose();
  if (state->codestream->hflip && band_idx.x)
    result.pos.x--;
  if (state->codestream->vflip && band_idx.y)
    result.pos.y--;
}

/*****************************************************************************/
/*                       kdu_subband::get_valid_blocks                       */
/*****************************************************************************/

void
  kdu_subband::get_valid_blocks(kdu_dims &indices)
{
  indices = state->region_indices;
  state->codestream->to_apparent(indices);
}

/*****************************************************************************/
/*                        kdu_subband::get_block_size                        */
/*****************************************************************************/

void
  kdu_subband::get_block_size(kdu_coords &nominal_size, kdu_coords &first_size)
{
  kdu_dims indices;
  kdu_coords first_idx;
  kdu_dims first_dims;
  
  nominal_size = state->block_partition.size;
  get_valid_blocks(indices);
  first_idx = indices.pos;
  state->codestream->from_apparent(first_idx);
  first_dims = state->block_partition;
  first_dims.pos.x += first_idx.x*first_dims.size.x;
  first_dims.pos.y += first_idx.y*first_dims.size.y;
  first_dims &= state->region;
  assert((!first_dims) || (first_dims.area() > 0));
  first_size = first_dims.size;
  if (state->codestream->transpose)
    {
      nominal_size.transpose();
      first_size.transpose();
    }
}

/*****************************************************************************/
/*                          kdu_subband::open_block                          */
/*****************************************************************************/

kdu_block *
  kdu_subband::open_block(kdu_coords block_idx, int *return_tpart)
{
  state->codestream->from_apparent(block_idx);
  block_idx -= state->region_indices.pos;
  assert((block_idx.x >= 0) && (block_idx.y >= 0) &&
         (block_idx.x < state->region_indices.size.x) &&
         (block_idx.y < state->region_indices.size.y));
  block_idx += state->region_indices.pos; // Back to absolute indices.

  // First find the precinct to which this block belongs and the block index
  // within that precinct.

  kdu_coords precinct_idx = block_idx;
  precinct_idx.x >>= state->log2_blocks_per_precinct.x;
  precinct_idx.y >>= state->log2_blocks_per_precinct.y;

  // Create the precinct if necessary.

  kd_resolution *res = state->resolution;
  precinct_idx -= res->precinct_indices.pos;
  assert((precinct_idx.x >= 0) && (precinct_idx.y >= 0) &&
         (precinct_idx.x < res->precinct_indices.size.x) &&
         (precinct_idx.y < res->precinct_indices.size.y));
  int precinct_num =
    precinct_idx.x + precinct_idx.y*res->precinct_indices.size.x;
  kd_precinct *precinct = res->precinct_refs[precinct_num];
  assert(precinct != KD_EXPIRED_PRECINCT);
  if (precinct == NULL)
    {
      precinct = new kd_precinct(res,precinct_idx);
      assert(precinct == res->precinct_refs[precinct_num]);
    }

  // Load the precinct if necessary.

  kd_codestream *codestream = res->codestream;
  kd_tile *tile = res->tile_comp->tile;
  if (codestream->in != NULL)
    {
      while ((!tile->exhausted) &&
             (precinct->next_layer_idx < precinct->num_layers))
        {
          if ((tile != codestream->active_tile) &&
              !tile->read_tile_part_header())
            {
              assert(!tile->closed); // Otherwise, we could delete ourself.
              tile->finished_reading();
              break; // Can't read any more information for this tile.
            }
          kd_precinct *seq = tile->sequencer->next_in_sequence();
          if ((seq == NULL) || !seq->read_packet())
            tile->read_tile_part_header();
        }
    }

  // Initialize the block structure.

  kdu_dims band_dims = state->block_partition;
  band_dims.pos.x += block_idx.x*band_dims.size.x;
  band_dims.pos.y += block_idx.y*band_dims.size.y;
  band_dims &= state->dims;
  assert(band_dims.area() > 0);

  kd_precinct_band *pband = precinct->bands + state->which_band;
  block_idx -= pband->block_indices.pos;
  assert((block_idx.x >= 0) && (block_idx.y >= 0) &&
         (block_idx.x < pband->block_indices.size.x) &&
         (block_idx.y < pband->block_indices.size.y));

  kdu_block *result = codestream->shared_block;
  codestream->shared_block = NULL;
  assert(result != NULL);
  result->precinct = precinct;
  result->which_block = block_idx.x + block_idx.y*pband->block_indices.size.x;
  kd_block *block = pband->blocks + result->which_block;

  // Set up the common fields (common to input and output codestream objects).

  result->size = band_dims.size;
  result->region = band_dims & state->region;
  result->region.pos -= band_dims.pos;
  result->modes = state->resolution->tile_comp->modes;
  result->orientation = state->which_band;
  result->K_max_prime = state->K_max_prime;

  // Retrieve compressed data, if necessary.

  if (codestream->in != NULL)
    block->retrieve_data(result,tile->num_apparent_layers);
  else if (!block->empty())
    { kdu_error e; e << "Attempting to open the same code-block more than "
      "once for writing!"; }

  if (return_tpart != NULL)
    *return_tpart = precinct->resolution->tile_comp->tile->next_tpart-1;

  return result;
}

/*****************************************************************************/
/*                          kdu_subband::close_block                         */
/*****************************************************************************/

void
  kdu_subband::close_block(kdu_block *result)
{
  kd_precinct *precinct = result->precinct;
  assert(precinct != NULL);
  assert(state->codestream->shared_block == NULL);
  state->codestream->shared_block = result;
  result->precinct = NULL;

  kd_precinct_band *pband = precinct->bands + state->which_band;
  kd_block *block = pband->blocks + result->which_block;
  assert(precinct->num_outstanding_blocks > 0);
  if (state->codestream->in != NULL)
    { // Release the block storage.
      if (!state->codestream->persistent)
        {
          block->cleanup(pband);
          precinct->num_outstanding_blocks--;
          if (precinct->num_outstanding_blocks == 0)
            delete precinct;
        }
      return;
    }

  // If we get here, we have an output block.

  bool trim_storage = false;
  if (state->codestream->stats != NULL)
    trim_storage = state->codestream->stats->update(result);
  assert(block->empty());
  block->store_data(result,state->codestream->buf_server);
  precinct->num_outstanding_blocks--;
  if (trim_storage)
    state->codestream->trim_compressed_data();
}

/*****************************************************************************/
/*               kdu_subband::get_conservative_slope_threshold               */
/*****************************************************************************/

kdu_uint16
  kdu_subband::get_conservative_slope_threshold()
{
  kd_codestream *codestream = state->codestream;
  kdu_uint16 result = 1;
  if (codestream->stats != NULL)
    result = codestream->stats->get_conservative_slope_threshold();
  if (codestream->min_slope_threshold > result)
    result = codestream->min_slope_threshold;
  return result;
}


/* ========================================================================= */
/*                                kd_precinct                                */
/* ========================================================================= */

/*****************************************************************************/
/*                        kd_precinct::kd_precinct                           */
/*****************************************************************************/

kd_precinct::kd_precinct(kd_resolution *resolution, kdu_coords pos_idx)
{
  kd_tile_comp *comp = resolution->tile_comp;
  kd_tile *tile = comp->tile;
  kdu_dims dims, region;

  resolution->codestream->var_structure_new(sizeof(*this));
  this->resolution = resolution;
  this->pos_idx = pos_idx;
  num_layers = tile->num_layers;
  next_layer_idx = 0;
  corrupted = false;
  assert((pos_idx.x < resolution->precinct_indices.size.x) &&
         (pos_idx.y < resolution->precinct_indices.size.y));
  int p = pos_idx.x + resolution->precinct_indices.size.x*pos_idx.y;
  resolution->precinct_refs[p] = this;
  pos_idx += resolution->precinct_indices.pos;
  dims = resolution->precinct_partition;
  dims.pos.x += pos_idx.x*dims.size.x;
  dims.pos.y += pos_idx.y*dims.size.y;
  dims &= resolution->dims;
  region = dims & resolution->region;

  bool discard = false;
  bool persistent = resolution->codestream->persistent;
  if ((!persistent) &&
      ((!region) || (resolution->res_level > comp->apparent_dwt_levels) ||
       (comp->cnum < tile->first_apparent_component) ||
       (comp->cnum >=
        (tile->first_apparent_component+tile->num_apparent_components))))
    {
      assert((dims.size.x>0) && (dims.size.y>0));
      discard = true; // Mark all code-blocks in precinct for discarding.
    }
  
  // Initialize the precinct-bands.

  num_outstanding_blocks = 0;
  total_block_nodes = 0;
  int num_block_nodes;
  for (int b=resolution->min_band; b <= resolution->max_band; b++)
    {
      kd_precinct_band *pb = bands+b;
      kd_subband *subband = resolution->bands+b;
      pb->subband = subband;
      kdu_dims pband_dims =
        (b==LL_BAND)?dims:get_band_dims(dims,subband->band_idx);
      pb->block_indices =
        get_partition_indices(subband->block_partition,pband_dims);
      num_outstanding_blocks += pb->block_indices.area();
      pb->blocks = kd_block::build_tree(pb->block_indices.size,
                                        &num_block_nodes);
      total_block_nodes += num_block_nodes;

      /* Finally, scan through the leaf nodes of the `blocks' array setting
         up the `modes' field and setting `num_passes' to indicate whether
         or not each block's contents can be discarded. */

      // Get location and size of first code-block in the partition which
      // intersects with current precinct-band.
      kdu_dims block_dims = subband->block_partition;
      block_dims.pos.x += block_dims.size.x * pb->block_indices.pos.x;
      block_dims.pos.y += block_dims.size.y * pb->block_indices.pos.y;
      kdu_coords min = block_dims.pos; // So we can keep coming back here.
      kd_block *block = pb->blocks;
      int x, y;
      for (y=0, block_dims.pos.y=min.y;
           y < pb->block_indices.size.y;
           y++, block_dims.pos.y += block_dims.size.y)
        for (x=0, block_dims.pos.x=min.x;
             x < pb->block_indices.size.x;
             x++, block_dims.pos.x += block_dims.size.x, block++)
          {
            block->set_modes(resolution->tile_comp->modes);
            if ((!persistent) && (discard || !(block_dims & subband->region)))
              block->set_discard();
          }
    }
  resolution->codestream->var_structure_new(sizeof(kd_block)*total_block_nodes);
  packet_bytes = NULL; // Create this array if and when we need it.
}

/*****************************************************************************/
/*                        kd_precinct::~kd_precinct                          */
/*****************************************************************************/

kd_precinct::~kd_precinct()
{
  resolution->codestream->var_structure_delete(sizeof(*this));
  for (int b=resolution->min_band; b <= resolution->max_band; b++)
    {
      kd_precinct_band *pb = bands+b;
      if (pb->blocks != NULL)
        {
          int num_blocks = pb->block_indices.area();
          for (int n=0; n < num_blocks; n++)
            pb->blocks[n].cl