(Delphi DLL) Compress and Decompress Base64

Imagine we have data represented as a base64 string. This example demonstrates how to decode, compress, and re-encode to smaller base64 representing the compressed data.

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, BinData, Compression;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
strBase64: PWideChar;
compress: HCkCompression;
binDat: HCkBinData;
compressedBase64: PWideChar;
decompressedBase64: PWideChar;

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

strBase64 := 'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K';

compress := CkCompression_Create();
CkCompression_putAlgorithm(compress,'deflate');

binDat := CkBinData_Create();
// Load the base64 data into a BinData object.
// This decodes the base64. The decoded bytes will be contained in the BinData.
CkBinData_AppendEncoded(binDat,strBase64,'base64');

// Compress the BinData.
CkCompression_CompressBd(compress,binDat);

// Get the compressed data in base64 format:
compressedBase64 := CkBinData__getEncoded(binDat,'base64');
Memo1.Lines.Add('compressed base64:');
Memo1.Lines.Add(compressedBase64);

// The compressed base64 is: C8lIVSgszUzOVkgqyi/PU0jLr1DIKs0tSE1RyC9LLVIoAcrnJFZVKqTkp+vxcoUMYeW8XAA=

// Now decompress:
CkBinData_Clear(binDat);
CkBinData_AppendEncoded(binDat,compressedBase64,'base64');
CkCompression_DecompressBd(compress,binDat);

decompressedBase64 := CkBinData__getEncoded(binDat,'base64');
Memo1.Lines.Add('decompressed base64:');
Memo1.Lines.Add(decompressedBase64);

// The output is the original data:
// VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NClRoZSBxdWljayBicm93biBmb3gganVtcGVkIG92ZXIgdGhlIGxhenkgZG9nLg0KVGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cuDQpUaGUgcXVpY2sgYnJvd24gZm94IGp1bXBlZCBvdmVyIHRoZSBsYXp5IGRvZy4NCg0K

CkCompression_Dispose(compress);
CkBinData_Dispose(binDat);

end;