content: /**
   * Copyright 2010 DFKI GmbH.
   * All Rights Reserved.  Use is subject to license terms.
   * <p/>
   * This file is part of MARY TTS.
   * <p/>
   * MARY TTS is free software: you can redistribute it and/or modify
   * it under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation, version 3 of the License.
   * <p/>
   * 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 Lesser General Public License for more details.
   * <p/>
   * You should have received a copy of the GNU Lesser General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package marytts.unitselection.data;
  
  import java.util.Iterator;
  import java.util.NoSuchElementException;
  
  import marytts.features.FeatureDefinition;
  import marytts.features.FeatureVector;
  
  /**
   * Iterator to provide the sentences in a given feature file, in sequence.
   *
   * @author marc
   */
  public class SentenceIterator implements Iterator<Sentence> {
  
      private final FeatureFileReader features;
      private final int fiSentenceStart;
      private final int fiSentenceEnd;
      private final int fiWordStart;
      private final int fiWordEnd;
      private final boolean isHalfphone;
      private final int fiLR;
      private final int fvLR_L;
      private final int fvLR_R;
  
      private int i;
      private int len;
      private Sentence nextSentence = null;
  
      public SentenceIterator(FeatureFileReader features) {
          this.features = features;
          FeatureDefinition featureDefinition = features.getFeatureDefinition();
          fiSentenceStart = featureDefinition.getFeatureIndex("words_from_sentence_start");
          fiSentenceEnd = featureDefinition.getFeatureIndex("words_from_sentence_end");
          fiWordStart = featureDefinition.getFeatureIndex("segs_from_word_start");
          fiWordEnd = featureDefinition.getFeatureIndex("segs_from_word_end");
          String halfphoneFeature = "halfphone_lr";
          if (featureDefinition.hasFeature(halfphoneFeature)) {
              isHalfphone = true;
              fiLR = featureDefinition.getFeatureIndex(halfphoneFeature);
              fvLR_L = featureDefinition.getFeatureValueAsByte(fiLR, "L");
              fvLR_R = featureDefinition.getFeatureValueAsByte(fiLR, "R");
          } else {
              isHalfphone = false;
              fiLR = fvLR_L = fvLR_R = 0;
          }
  
          i = 0;
          len = features.getNumberOfUnits();
      }
  
      @Override
      public synchronized boolean hasNext() {
          if (nextSentence == null) {
              prepareNextSentence();
          }
          return nextSentence != null;
      }
  
      @Override
      public synchronized Sentence next() {
          if (nextSentence == null) {
              prepareNextSentence();
          }
          if (nextSentence == null) {
              // no more sentences
              throw new NoSuchElementException("no more sentences!");
          }
          Sentence retval = nextSentence;
          nextSentence = null;
          return retval;
      }
  
      @Override
      public void remove() {
          throw new UnsupportedOperationException("This iterator cannot remove sentences");
      }
  
      /**
       * Find the next sentence in the feature file, if possible.
       */
      private void prepareNextSentence() {
          if (nextSentence != null) {
              return;
          }
          if (i >= len) {
              return;
          }
          // if we get here, then i is the index of a unit before or at a sentence start
          while (i < len && !isSentenceStart(i)) {
              i++;
          }
          if (i >= len) {
              return;
          }
          int iSentenceStart = i;
          while (i < len && !isSentenceEnd(i)) {
              i++;
          }
          if (i >= len) {
              return;
          }
          int iSentenceEnd = i;
          nextSentence = new Sentence(features, iSentenceStart, iSentenceEnd);
      }
  
  
      /**
       * Check if the given unit index is a sentence start
       *
       * @param index the unit index
       */
      private boolean isSentenceStart(int index) {
          FeatureVector fv = features.getFeatureVector(index);
  
          return fv.getByteFeature(fiSentenceStart) == 0 // first word in sentence
                  && fv.getByteFeature(fiWordStart) == 0 // first segment in word
                  && (!isHalfphone || fv.getByteFeature(fiLR) == fvLR_L); // for halfphones, it's the left half
      }
  
      /**
       * Check if the given unit index is a sentence end
       *
       * @param index the unit index
       */
      private boolean isSentenceEnd(int index) {
          FeatureVector fv = features.getFeatureVector(index);
  
          return fv.getByteFeature(fiSentenceEnd) == 0 // last word in sentence
                  && fv.getByteFeature(fiWordEnd) == 0 // last segment in word
                  && (!isHalfphone || fv.getByteFeature(fiLR) == fvLR_R); // for halfphones, it's the right half
      }
  
  
  }
  