int getPaletteIndex(int rgb) 
  {      
    ColorRecord rec;

    for ( int itable = rgb % hTable.length;    
          (rec = hTable[itable]) != null && rec.rgb != rgb;
          itable = ++itable % hTable.length
        ) 
      ;

    if (rec != null)
      return rec.ipalette;
      
    return -1;    
  }