private CompressionStats Compress( IGrid grid,
ICompressor compressor,
double[] errors,
string outName,
ProgressViewModel progressBar )
{
double[] leftBorders = new double[grid.ColumnCount];
double[] rightBorders = new double[grid.ColumnCount];
var qs = new IQuantization[grid.ColumnCount];
var distrs = new IDistribution[grid.ColumnCount];
progressBar.Status = "Quantizing columns...";
Parallel.For( 0, grid.ColumnCount, column =>
{
var distr = new EmpiricalDistribution( grid, column );
leftBorders[column] = double.MaxValue;
rightBorders[column] = double.MinValue;
for ( int row = 0; row < grid.RowCount; ++row )
{
double value = grid.GetValue( row, column );
leftBorders[column] = leftBorders[column] < value ? leftBorders[column] : value;
rightBorders[column] = rightBorders[column] > value ? rightBorders[column] : value;
}
var quantizer = new Quantizer( leftBorders[column], rightBorders[column] );
var quantization = quantizer.Quantize( errors[column], distr );
lock ( _lockGuard )
{
progressBar.Progress += 1.0 / ( grid.ColumnCount + 1 );
distrs[column] = distr;
qs[column] = quantization;
}
} );
var quantizations = new List<IQuantization>( qs );
var distributions = new List<IDistribution>( distrs );
progressBar.Status = "Writing archive...";
progressBar.Progress = ( double )grid.ColumnCount / ( grid.ColumnCount + 1 );
ICompressionResult result;
using ( var stream = new FileOutputStream( outName ) )
{
result = compressor.Compress( grid, quantizations, stream );
}
progressBar.Progress = 1.0;
progressBar.TryClose( );
return new CompressionStats
{
CompressionResult = result,
Distributions = distributions,
LeftBorders = leftBorders,
RightBorders = rightBorders,
Quantizations = quantizations
};
}
public async void Compress( )
{
ICompressor compressor;
string extension;
var grid = await OpenGrid( );
if ( grid == null )
return;
ChooseCompressor( out compressor, out extension );
if ( compressor == null || extension == null )
{ MessageBox.Show( "Unknown compression scheme!", "Error", MessageBoxButton.OK, MessageBoxImage.Error ); }
var columnNames = new List<string>( );
for ( var i = 0; i < grid.ColumnCount; ++i )
{ columnNames.Add( $"Column #{i}" ); }
dynamic paramsSettings = new ExpandoObject( );
paramsSettings.Height = 200;
paramsSettings.Width = 420;
paramsSettings.SizeToContent = SizeToContent.Manual;
paramsSettings.Title = "Compression parameters";
var compParams = new CompressionParamsViewModel( columnNames );
bool? result = _manager.ShowDialog( compParams,
null,
paramsSettings );
if ( result == null || !result.Value )
{ return; }
var dialog = new SaveFileDialog
{
DefaultExt = extension,
Filter = $"Quantized and compressed grid|*.{extension}",
AddExtension = true
};
if ( dialog.ShowDialog( ) != true )
return;
var errors = ( from desc in compParams.Errors
select desc.Error ).ToArray( );
string outName = dialog.FileName;
var progressBar = new ProgressViewModel( );
dynamic settings = new ExpandoObject( );
settings.Height = 130;
settings.Width = 500;
settings.SizeToContent = SizeToContent.Manual;
_manager.ShowWindow( progressBar, null, settings );
var stats =
await Task<CompressionStats>.Factory.StartNew( ( ) => Compress( grid, compressor, errors, outName, progressBar ) );
dynamic resultSettings = new ExpandoObject( );
resultSettings.Height = 450;
resultSettings.MinHeight = 180;
resultSettings.Width = 800;
resultSettings.MinWidth = 320;
resultSettings.Title = "Report";
resultSettings.SizeToContent = SizeToContent.Manual;
_manager.ShowWindow( new CompressionResultViewModel( stats ), null, resultSettings );
}
