blocks.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.

/*****************************************************************************/
// File: blocks.cpp [scope = CORESYS/COMPRESSED]
// Version: Kakadu, V2.2
// Author: David Taubman
// Last Revised: 20 June, 2001
/*****************************************************************************/
// Copyright 2001, David Taubman, The University of New South Wales (UNSW)
// The copyright owner is Unisearch Ltd, Australia (commercial arm of UNSW)
// Neither this copyright statement, nor the licensing details below
// may be removed from this file or dissociated from its contents.
/*****************************************************************************/
// Licensee: Book Owner
// License number: 99999
// The Licensee has been granted a NON-COMMERCIAL license to the contents of
// this source file, said Licensee being the owner of a copy of the book,
// "JPEG2000: Image Compression Fundamentals, Standards and Practice," by
// Taubman and Marcellin (Kluwer Academic Publishers, 2001).  A brief summary
// of the license appears below.  This summary is not to be relied upon in
// preference to the full text of the license agreement, which was accepted
// upon breaking the seal of the compact disc accompanying the above-mentioned
// book.
// 1. The Licensee has the right to Non-Commercial Use of the Kakadu software,
//    Version 2.2, including distribution of one or more Applications built
//    using the software, provided such distribution is not for financial
//    return.
// 2. The Licensee has the right to personal use of the Kakadu software,
//    Version 2.2.
// 3. The Licensee has the right to distribute Reusable Code (including
//    source code and dynamically or statically linked libraries) to a Third
//    Party, provided the Third Party possesses a license to use the Kakadu
//    software, Version 2.2, and provided such distribution is not for
//    financial return.
/******************************************************************************
Description:
   Implements a part of the compressed data management machinery, in
relation to code-blocks.  Includes packet header parsing and construction.
Note that the internal representation employed for code-block state
information has been carefully paired down to a point where it would be
difficult to implement packet operations with substantially less
memory.
******************************************************************************/

#include <string.h>
#include <assert.h>
#include "kdu_elementary.h"
#include "kdu_messaging.h"
#include "kdu_compressed.h"
#include "compressed_local.h"

/* ========================================================================= */
/*                                kdu_block                                  */
/* ========================================================================= */

/*****************************************************************************/
/*                          kdu_block::kdu_block                             */
/*****************************************************************************/

kdu_block::kdu_block()
{
  transpose = vflip = hflip = false;
  pass_lengths = NULL; pass_slopes = NULL; max_passes = 0;
  byte_buffer = NULL;  max_bytes = 0;
  sample_buffer = NULL; max_samples = 0;
  context_buffer = NULL; max_contexts = 0;
  cpu_iterations = 0;
  cpu_time = 0;
  cpu_unique_samples = 0;
  resilient = fussy = false;
}

/*****************************************************************************/
/*                          kdu_block::~kdu_block                            */
/*****************************************************************************/

kdu_block::~kdu_block()
{
  if (pass_lengths != NULL)
    delete[] pass_lengths;
  if (pass_slopes != NULL)
    delete[] pass_slopes;
  if (byte_buffer != NULL)
    delete[] (byte_buffer-1);
  if (sample_buffer != NULL)
    delete[] sample_buffer;
  if (context_buffer != NULL)
    delete[] context_buffer;
}

/*****************************************************************************/
/*                        kdu_block::set_max_passes                          */
/*****************************************************************************/

void
  kdu_block::set_max_passes(int new_passes, bool copy_existing)
{
  if (max_passes >= new_passes)
    return;
  if (max_passes == 0)
    copy_existing = false;
  if (copy_existing)
    {
      int *new_pass_lengths = new int[new_passes];
      kdu_uint16 *new_pass_slopes = new kdu_uint16[new_passes];
      for (int n=0; n < max_passes; n++)
        {
          new_pass_lengths[n] = pass_lengths[n];
          new_pass_slopes[n] = pass_slopes[n];
        }
      delete[] pass_lengths;
      delete[] pass_slopes;
      pass_lengths = new_pass_lengths;
      pass_slopes = new_pass_slopes;
    }
  else
    {
      if (pass_lengths != NULL)
        delete[] pass_lengths;
      if (pass_slopes != NULL)
        delete[] pass_slopes;
      pass_lengths = new int[new_passes];
      pass_slopes = new kdu_uint16[new_passes];
    }
  max_passes = new_passes;
}

/*****************************************************************************/
/*                        kdu_block::set_max_bytes                           */
/*****************************************************************************/

void
  kdu_block::set_max_bytes(int new_bytes, bool copy_existing)
{
  if (max_bytes >= new_bytes)
    return;
  if (max_bytes == 0)
    copy_existing = false;
  if (copy_existing)
    {
      kdu_byte *new_buf = (new kdu_byte[new_bytes+1])+1;
      memcpy(new_buf,byte_buffer,max_bytes);
      delete[] (byte_buffer-1);
      byte_buffer = new_buf;
    }
  else
    {
      if (byte_buffer != NULL)
        delete[] (byte_buffer-1);
      byte_buffer = (new kdu_byte[new_bytes+1])+1;
    }
  max_bytes = new_bytes;
}

/*****************************************************************************/
/*                        kdu_block::set_max_samples                         */
/*****************************************************************************/

void
  kdu_block::set_max_samples(int new_samples)
{
  if (max_samples >= new_samples)
    return;
  if (sample_buffer != NULL)
    delete[] sample_buffer;
  sample_buffer = new kdu_int32[new_samples];
  max_samples = new_samples;
}

/*****************************************************************************/
/*                       kdu_block::set_max_contexts                         */
/*****************************************************************************/

void
  kdu_block::set_max_contexts(int new_contexts)
{
  if (max_contexts >= new_contexts)
    return;
  if (context_buffer != NULL)
    delete[] context_buffer;
  context_buffer = new kdu_int32[new_contexts];
  max_contexts = new_contexts;
}


/* ========================================================================= */
/*                                  kd_block                                 */
/* ========================================================================= */

/*****************************************************************************/
/*                             kd_block::cleanup                             */
/*****************************************************************************/

void
  kd_block::cleanup(kd_precinct_band *pband)
{
  kd_codestream *codestream = pband->subband->codestream;
  kd_code_buffer *tmp;

  while ((tmp=first_buf) != NULL)
    {
      first_buf = tmp->next;
      codestream->buf_server->release(tmp);
    }
}

/*****************************************************************************/
/*                       kd_block::parse_packet_header                       */
/*****************************************************************************/

int
  kd_block::parse_packet_header(kd_header_in &head,
                                 kd_buf_server *buf_server,
                                 int layer_idx)
{
  // Parse inclusion information first.

  temp_length = 0;
  if (beta == 0)
    { // Not yet included. Tag tree decoding for `layer_w'.
      assert(layer_wbar == layer_w);
      kd_block *scan, *prev, *next;

      // Walk up to the root node in the tree.
      scan=this; prev=NULL;
      while ((next=scan->up_down) != NULL)
        { scan->up_down=prev; prev=scan; scan=next; }
      scan->up_down = prev;

      // Walk back down the tree, performing the decoding steps.
      kdu_uint16 wbar_min = 0;
      kdu_uint16 threshold = (kdu_uint16)(layer_idx+1);
      prev = NULL;
      while (scan != NULL)
        {
          if (scan->layer_wbar < wbar_min)
            { scan->layer_wbar = wbar_min; scan->layer_w = wbar_min; }
          while ((scan->layer_w == scan->layer_wbar) &&
                 (scan->layer_wbar < threshold))
            {
              scan->layer_wbar++;
              if (head.get_bit() == 0)
                scan->layer_w++;
            }
          wbar_min = scan->layer_w;
          next=scan->up_down; scan->up_down=prev; prev=scan; scan=next;
        }
      if (layer_wbar == layer_w)
        return 0; // Nothing included yet.
      if (layer_w != (kdu_uint16) layer_idx)
        throw KDU_EXCEPTION_ILLEGAL_LAYER;
    }
  else
    { // Already included.
      if (head.get_bit() == 0)
        return 0;
    }

  // If we get here, the code-block does contribute to the current layer.

  bool discard_block = (num_passes == 255);

  if (beta == 0)
    { // First time contribution.  Need to get MSB's and set up buffering.
      while (msbs_w == msbs_wbar)
        { // Run tag tree decoder.
          kd_block *scan, *prev, *next;

          // Walk up to the root note in the tree.
          scan=this; prev=NULL;
          while ((next=scan->up_down) != NULL)
            { scan->up_down=prev; prev=scan; scan=next; }
          scan->up_down = prev;

          // Walk back down the tree, performing the decoding steps.
          kdu_byte wbar_min = 0;
          kdu_byte threshold = msbs_wbar+1;
          prev = NULL;
          while (scan != NULL)
            {
              if (scan->msbs_wbar < wbar_min)
                { scan->msbs_wbar = wbar_min; scan->msbs_w = wbar_min; }
              while ((scan->msbs_w == scan->msbs_wbar) &&
                     (scan->msbs_wbar < threshold))
                {
                  scan->msbs_wbar++;
                  if (head.get_bit() == 0)
                    scan->msbs_w++;
                }
              wbar_min = scan->msbs_w;
              next=scan->up_down; scan->up_down=prev; prev=scan; scan=next;
            }
        }

      num_bytes = 0;
      beta = 3;
      assert(pass_idx == 0);
      if (!discard_block)
        start_buffering(buf_server);
    }

  if (!discard_block)
    { // Record the layer index for this new contribution.
      put_byte((kdu_byte)(layer_idx>>8),buf_server);
      put_byte((kdu_byte) layer_idx,buf_server);
    }

  // Decode number of passes.

  int new_passes = 1;
  new_passes += head.get_bit();
  if (new_passes >= 2)
    {
      new_passes += head.get_bit();
      if (new_passes >= 3)
        {
          new_passes += head.get_bits(2);
          if (new_passes >= 6)
            {
              new_passes += head.get_bits(5);
              if (new_passes >= 37)
                new_passes += head.get_bits(7);
            }
        }
    }

  // Finally, decode the length information.

  while (head.get_bit())
    {
      if (beta == 255)
        throw KDU_EXCEPTION_PRECISION;
      beta++;
    }

  bool bypass_term = ((((int) modes) & Cmodes_BYPASS) != 0);
  bool all_term = ((((int) modes) & Cmodes_RESTART) != 0);
  if (all_term)
    bypass_term = false;

  int segment_passes, segment_bytes;
  int length_bits;
  int idx = pass_idx;
  while (new_passes > 0)
    {
      if (all_term)
        segment_passes = 1;
      else if (bypass_term)
        {
          if (idx < 10)
            segment_passes = 10-idx;
          else if (((idx-10) % 3) == 0)
            segment_passes = 2;
          else
            segment_passes = 1;
          if (segment_passes > new_passes)
            segment_passes = new_passes;
        }
      else
        segment_passes = new_passes;
      for (length_bits=0; (1<<length_bits) <= segment_passes; length_bits++);
      length_bits--;
      length_bits += beta;
      segment_bytes = head.get_bits(length_bits);
      if ((segment_bytes >= (1<<15)) ||
          (segment_bytes >= ((1<<16) - (int) temp_length)))
        throw KDU_EXCEPTION_PRECISION;
      temp_length += segment_bytes;
      idx += segment_passes;
      new_passes -= segment_passes;
      if (new_passes > 0)
        segment_bytes |= (1<<15); // Continuation flag.
      if (!discard_block)
        { // Record the number of bytes and the number of passes in the segment
          put_byte((kdu_byte)(segment_bytes>>8),buf_server);
          put_byte((kdu_byte) segment_bytes,buf_server);
          put_byte((kdu_byte) segment_passes,buf_server);
        }
    }

  pass_idx = (kdu_byte) idx;
  if (!discard_block)
    num_passes = pass_idx;
  return temp_length;
}