lcd-image-converter/classes/compression/rlecompressor.cpp

/*
 * LCD Image Converter. Converts images and fonts for embedded applications.
 * Copyright (C) 2012 riuson
 * mailto: riuson@gmail.com
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/
 */

#include "rlecompressor.h"

#include <QQueue>
#include <QVector>

#include "rlesequence.h"
// #include <QDebug>

namespace Utils
{
namespace Compression
{

RleCompressor::RleCompressor(QObject* parent) : QObject(parent) {}

void RleCompressor::compress(QVector<quint32>* input, Parsing::Conversion::Options::DataBlockSize dataSize,
                             QVector<quint32>* output, quint32 minimumOfEquals)
{
  output->clear();

  QVector<RleSequence*> sequencesSource;

  this->collectSequences(input, &sequencesSource);

  QVector<RleSequence*> sequencesCombined;
  this->combineSequences(&sequencesSource, minimumOfEquals, &sequencesCombined);

  for (int i = 0; i < sequencesCombined.size(); i++) {
    RleSequence* seq = sequencesCombined.at(i);
    this->flushSequence(seq, dataSize, output);
  }

  qDeleteAll(sequencesSource);
  qDeleteAll(sequencesCombined);
}

void RleCompressor::collectSequences(const QVector<quint32>* input, QVector<RleSequence*>* sequences)
{
  RleSequence* temp = new RleSequence();
  temp->append(input->at(0));
  quint32 index = 1;

  while (index < (quint32)input->size()) {
    quint32 value = input->at(index);

    // if new value not equals to last sequence
    if (temp->last() != value) {
      // save last sequence
      sequences->append(temp);
      // and create new
      temp = new RleSequence();
    }

    temp->append(value);
    index++;
  }

  sequences->append(temp);
}

void RleCompressor::combineSequences(const QVector<RleSequence*>* inputSequences, quint32 minimumOfEquals,
                                     QVector<RleSequence*>* outputSequences)
{
  RleSequence* temp = new RleSequence();

  for (int i = 0; i < inputSequences->size(); i++) {
    RleSequence* seq = inputSequences->at(i);

    // if number of equals values >= minimal
    if (seq->size() >= minimumOfEquals) {
      // save previous
      outputSequences->append(temp);

      // copy and save
      temp = new RleSequence(seq);
      outputSequences->append(temp);

      // create new
      temp = new RleSequence();
    } else {
      temp->append(seq);
    }
  }

  outputSequences->append(temp);
}

quint32 RleCompressor::getMaxSize(Parsing::Conversion::Options::DataBlockSize dataSize)
{
  quint32 result;

  switch (dataSize) {
    case Parsing::Conversion::Options::DataBlockSize::Data8:
      result = 0x7f;
      break;

    case Parsing::Conversion::Options::DataBlockSize::Data16:
      result = 0x7fff;
      break;

    case Parsing::Conversion::Options::DataBlockSize::Data24:
      result = 0x7fffff;
      break;

    case Parsing::Conversion::Options::DataBlockSize::Data32:
      result = 0x7fffffff;
      break;

    default:
      result = 127;
      break;
  }

  return result;
}

void RleCompressor::flushSequence(const RleSequence* sequence, Parsing::Conversion::Options::DataBlockSize dataSize,
                                  QVector<quint32>* output)
{
  if (sequence->size() > 0) {
    quint32 size = this->getMaxSize(dataSize);

    // if all equals
    if (sequence->allEquals()) {
      // qDebug() << "all equals";
      // qDebug() << " count: " << queue->size();
      // qDebug() <<  " of : " << output->last();
      for (quint32 shift = 0; shift < sequence->size(); shift += size) {
        int partSize = qMin(size, sequence->size() - shift);
        this->flushSequencePart(sequence, shift, partSize, output);
      }
    } else { // if all non-equals
      // qDebug() << "all non-equals";
      // qDebug() << " count: " << -queue->size();
      for (quint32 shift = 0; shift < sequence->size(); shift += size) {
        int partSize = qMin(size, sequence->size() - shift);
        this->flushSequencePart(sequence, shift, partSize, output);
      }
    }
  }
}

void RleCompressor::flushSequencePart(const RleSequence* sequence, quint32 start, quint32 length,
                                      QVector<quint32>* output)
{
  if (sequence->allEquals()) {
    output->append(length);
    output->append(sequence->at(start));
  } else {
    output->append(-length);

    for (quint32 i = 0; i < length; i++) {
      output->append(sequence->at(start + i));
    }
  }
}

} // namespace Compression
} // namespace Utils