Pascal (Lazarus/Delphi)

Compress and Decompress a String

See more Compression Examples

Demonstrates how to compress and decompress a string. 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.Compression,
  Chilkat.StringBuilder;

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

procedure RunDemo;
var
  success: Boolean;
  sb: TStringBuilder;
  i: Integer;
  compress: TCompression;
  compressedBytes: TBytes;
  compressedBase64: string;
  decompressedString: string;

begin
  success := False;

  //  This example assumes the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  sb := TStringBuilder.Create;

  for i := 1 to 20 do
    begin
      sb.Append('This is the original uncompressed string.' + #13#10);
    end;

  compress := TCompression.Create;
  compress.Algorithm := 'deflate';
  //  Indicate that the utf-8 byte representation of the string should be compressed.
  compress.Charset := 'utf-8';

  compressedBytes := compress.CompressString(sb.GetAsString());

  //  If the compressed data is desired in string format, then get the base64 representation of the bytes.
  compress.EncodingMode := 'base64';
  compressedBase64 := compress.CompressStringENC(sb.GetAsString());
  WriteLn('Compressed Bytes as Base64: ' + compressedBase64);

  //  Now decompress...
  decompressedString := compress.DecompressString(compressedBytes);
  WriteLn('The original string after decompressing from binary compressed data:');
  WriteLn(decompressedString);

  //  To decompress from Base64...
  compress.EncodingMode := 'base64';
  decompressedString := compress.DecompressStringENC(compressedBase64);
  WriteLn('The original string after decompressing from Base64:');
  WriteLn(decompressedString);


  sb.Free;
  compress.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.