sclass SlidingWindow implements IAudioSample {
  // general params
  double sampleRate;
  int channels;
  
  // length of window
  int length;       // in samples per channel
  
  // start of window
  double start;
  
  // at which index in data array is our first value?
  int boundaryIndex; // in data
  
  // Here they are: the partial sums of the 16 bit audio samples
  // in an array of 6-byte integers. Channels are stored interleaved.
  HalfLongs data;

  public double sampleRate() { ret sampleRate; }
  public int channels() { ret channels; }
  public double length() { ret length; }
  
  // result is in the range -32768*(end-start) to 32767*(end-start)
  public double sampleSum(int channel, double start, double end) {
    // We could do linear interpolation here if we weren't so basic.
    int a = ifloor(start), b = ifloor(end);
    ret getEntry(channel, b-1)-getEntry(channel, a-1);
  }
  
  // Get an entry of the sum table - allow for out-of-bounds
  // requests (those just default to silence).
  long getEntry(int channel, int i) {
    if (i < 0) ret 0;
    i = min(i, length-1);
    ret data.get(i*channels+channel);
  }
  
  // perform the integration of the raw audio data
  *(L<short[]> samples, int *channels, double *sampleRate) {
    length = lengthLevel2_shortArrays(samples);
    data = new HalfLongs(length*channels);
    long[] sums = new[channels];
    int iSample = 0, iChunk = 0, iInArray = 0;
    short[] chunk = null;
    for i to length:
      for c to channels: {
        if (chunk == null || iInArray >= chunk.length) {
          chunk = samples.get(iChunk++);
          iInArray = 0;
        }
        data.set(iSample++, sums[c] += chunk[iInArray++]);
      }
  }
}