sclass CompressToInterpolatedDoubleArray {
  // raw data to compress (integers)
  int[] data;
  
  // output
  InterpolatedDoubleArray result;
  
  // internal
  new IntBuffer indices;
  new DoubleBuffer values;
  
  *(int[] *data) {}
  
  InterpolatedDoubleArray get() {
    int iData = 0;
    while (iData < data.length) {
      int startValue = data[iData];
      
      // see how far the straight line goes from iData
      DoubleRange totalSlopeRange = null;
      int jData; // our straight line ends at jData-1
      for (jData = iData+1; jData < data.length; jData++) {
        double x = data[jData], h = jData-iData;
        DoubleRange xRange = doubleRange(x-0.5, x+0.5);
        DoubleRange slopeRange = doubleRange(xRange.start/h, xRange.end/h);
        if (totalSlopeRange == null)
          totalSlopeRange = slopeRange;
        else {
          slopeRange = intersectRanges(slopeRange, totalSlopeRange);
          if (empty(slopeRange))
            break;
          else
            totalSlopeRange = slopeRange;
        }
      }
      printVars(+iData, +jData, +totalSlopeRange);
      indices.add(iData);
      values.add(data[iData]);
      iData = jData;
    }
    
    ret result = new InterpolatedDoubleArray(indices.toArrayNonNull(), values.toArrayNonNull());
  }
}