content: /**
   * Copyright 2009 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;
  
  /**
   * @author marc
   */
  public class SyllableIterator implements Iterator<Syllable> {
  
      private final int fiPhone;
      private final byte fvPhone_0;
      private final byte fvPhone_Silence;
      private final int fiSylStart;
      private final int fiSylEnd;
      private final boolean isHalfphone;
      private final int fiLR;
      private final int fvLR_L;
      private final int fvLR_R;
      private FeatureFileReader features;
      private int fromUnitIndex;
      private int toUnitIndex;
      private int i;
      private Syllable nextSyllable = null;
  
      /**
       * Create a syllable iterator over the given feature file, starting from the given fromUnitIndex
       * and reaching up to (and including) the  given toUnitIndex
       *
       * @param features
       * @param fromUnitIndex
       * @param toUnitIndex
       */
      public SyllableIterator(FeatureFileReader features, int fromUnitIndex, int toUnitIndex) {
          this.features = features;
          this.fromUnitIndex = fromUnitIndex;
          this.toUnitIndex = toUnitIndex;
  
          FeatureDefinition featureDefinition = features.getFeatureDefinition();
          fiPhone = featureDefinition.getFeatureIndex("phone");
          fvPhone_0 = featureDefinition.getFeatureValueAsByte(fiPhone, "0");
          fvPhone_Silence = featureDefinition.getFeatureValueAsByte(fiPhone, "_");
          fiSylStart = featureDefinition.getFeatureIndex("segs_from_syl_start");
          fiSylEnd = featureDefinition.getFeatureIndex("segs_from_syl_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 = fromUnitIndex;
      }
  
      @Override
      public synchronized boolean hasNext() {
          if (nextSyllable == null) {
              prepareNextSyllable();
          }
          return nextSyllable != null;
      }
  
      @Override
      public synchronized Syllable next() {
          if (nextSyllable == null) {
              prepareNextSyllable();
          }
          if (nextSyllable == null) {
              // no more syllables
              throw new NoSuchElementException("no more syllables!");
          }
          Syllable retval = nextSyllable;
          nextSyllable = null;
          return retval;
      }
  
      @Override
      public void remove() {
          throw new UnsupportedOperationException("This iterator cannot remove syllables");
      }
  
  
      private void prepareNextSyllable() {
          if (nextSyllable != null) {
              return;
          }
          if (i > toUnitIndex) {
              return;
          }
          // if we get here, then i is the index of a unit before or at a syllable start
          while (i <= toUnitIndex && !isSyllableStart(i)) {
              i++;
          }
          if (i > toUnitIndex) {
              return;
          }
          int iSyllableStart = i;
          while (i <= toUnitIndex && !isSyllableEnd(i)) {
              i++;
          }
          if (i > toUnitIndex) {
              return;
          }
          int iSyllableEnd = i;
          nextSyllable = new Syllable(features, iSyllableStart, iSyllableEnd);
      }
  
      private boolean isSyllableStart(int index) {
          FeatureVector fv = features.getFeatureVector(index);
  
          return fv.getByteFeature(fiPhone) != fvPhone_0 // not an edge unit
                  && fv.getByteFeature(fiPhone) != fvPhone_Silence // not silence
                  && fv.getByteFeature(fiSylStart) == 0 // first segment in syllable
                  && (!isHalfphone || fv.getByteFeature(fiLR) == fvLR_L); // if halfphone, it's the left half
      }
  
      private boolean isSyllableEnd(int index) {
          FeatureVector fv = features.getFeatureVector(index);
  
          return fv.getByteFeature(fiPhone) != fvPhone_0 // not an edge unit
                  && fv.getByteFeature(fiPhone) != fvPhone_Silence // not silence
                  && fv.getByteFeature(fiSylEnd) == 0 // last segment in syllable
                  && (!isHalfphone || fv.getByteFeature(fiLR) == fvLR_R); // if halfphone, it's the right half
      }
  }
  