content: /**
   * Copyright 2004-2006 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.util.data;
  
  /**
   * @author Marc Schr&ouml;der
   */
  public class BlockwiseDoubleDataSource extends BufferedDoubleDataSource {
      protected int blockSize;
  
      /**
       * @param inputSource
       */
      public BlockwiseDoubleDataSource(DoubleDataSource inputSource, int blockSize) {
          super(inputSource);
          this.blockSize = blockSize;
      }
  
      /**
       * Attempt to get more data from the input source. If less than this can be read,
       * the possible amount will be read, but canReadMore() will return false afterwards.
       *
       * @param minLength the amount of data to get from the input source
       * @return true if the requested amount could be read, false if none or less data could be read.
       */
      @Override
      protected boolean readIntoBuffer(int minLength) {
          if (bufferSpaceLeft() < minLength) {
              // current buffer cannot hold the data requested;
              // need to make it larger
              increaseBufferSize(minLength + currentlyInBuffer());
          } else if (buf.length - writePos < minLength) {
              compact(); // create a contiguous space for the new data
          }
          // Now we have a buffer that can hold at least minLength new data points
          int readSum = 0;
          // read blocks:
  
          while (readSum < minLength && hasMoreData()) {
              prepareBlock();
              int blockSize = getBlockSize();
              if (buf.length < writePos + blockSize) {
                  increaseBufferSize(writePos + blockSize);
              }
              int read = readBlock(buf, writePos);
              if (read == 0) {
                  break; // cannot read any more blocks
              }
              writePos += read;
              readSum += read;
          }
          if (dataProcessor != null) {
              dataProcessor.applyInline(buf, writePos - readSum, readSum);
          }
          return readSum >= minLength;
  
      }
  
      /**
       * Provide the size of the next block. This implementation returns the fixed
       * blocksize given in the constructor.
       * Subclasses may want to override this method.
       */
      protected int getBlockSize() {
          return blockSize;
      }
  
      /**
       * Prepare a block of data for output. This method is called before readBlock() is called.
       * This implementation does nothing.
       * Subclasses will want to override this method.
       */
      protected void prepareBlock() {
      }
  
      /**
       * Read a block of data. This method is called after prepareBlock() is called.
       * This implementation simply reads getBlockSize()
       * data from the inputSource given in the constructor.
       * Subclasses will want to override this method.
       *
       * @param target
       * @param pos
       * @return number of values written into target from position pos
       */
      protected int readBlock(double[] target, int pos) {
          return inputSource.getData(target, pos, getBlockSize());
      }
  
  
  }
  
  