Pascal (Lazarus/Delphi)

Decompress Gzip Data In-Place Using BinData

See more Gzip Examples

This example demonstrates how to use the UncompressBd method to decompress Gzip data stored in a BinData object.

The compressed .gz file is first loaded into memory. The UncompressBd method then decompresses the data in-place, meaning the original compressed bytes in the BinData object are replaced with the uncompressed data.

After decompression, the example writes the resulting data to a file. This approach is useful when working entirely in memory before saving or further processing the uncompressed data.

Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.BinData,
  Chilkat.Gzip;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  gzip: TGzip;
  bd: TBinData;

begin
  success := False;

  //  This example demonstrates how to decompress Gzip data stored in a BinData object.
  //  The decompression is done in-place, replacing the compressed data with the original data.

  gzip := TGzip.Create;
  bd := TBinData.Create;

  //  Load a .gz file into BinData:
  success := bd.LoadFile('example.txt.gz');
  if (success = False) then
    begin
      WriteLn(bd.LastErrorText);
      Exit;
    end;

  WriteLn('Compressed size (bytes): ' + bd.NumBytes);

  //  Uncompress the data in-place:
  success := gzip.UncompressBd(bd);
  if (success = False) then
    begin
      WriteLn(gzip.LastErrorText);
      Exit;
    end;

  WriteLn('Decompressed size (bytes): ' + bd.NumBytes);

  //  Save the uncompressed data to a file:
  success := bd.WriteFile('example.txt');
  if (success = False) then
    begin
      WriteLn(bd.LastErrorText);
      Exit;
    end;

  WriteLn('File successfully uncompressed to example.txt');


  gzip.Free;
  bd.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.