(Delphi) Deflate String

Compresses a string using the Deflate compression algorithm.

Download Chilkat Compression ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATCOMPRESSIONLib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
compress: TChilkatCompression;
success: Integer;
strData: String;
i: Integer;
deflatedStr: String;
strOriginal: String;

begin
compress := TChilkatCompression.Create(Self);

//  Any string argument automatically begins a 30-day trial.
success := compress.UnlockComponent('30-day trial');
if (success <> 1) then
  begin
    Memo1.Lines.Add(compress.LastErrorText);
    Exit;
  end;

compress.Algorithm := 'deflate';

//  Create a long string to deflate.
strData := 'abcdefg1122334455667788';
strData := strData + #13#10;
for i := 0 to 99 do
  begin
    strData := strData + 'abcdefg1122334455667788';
    strData := strData + #13#10;
  end;

//  Depending on the programming language, the string
//  may be Unicode.  Tell the component to convert to
//  ansi (1-byte/char) prior to compression:
compress.Charset := 'ansi';

//  Compressed data is binary, meaning that all byte values
//  from 0 to 255 are possible.  The result would not be
//  a printable string.  To receive a printable string (us-ascii),
//  the resultant compressed data should be encoded using
//  an encoding such as base64.  Set the EncodingMode
//  property to determine the output encoding:
//  (Valid choices are "base64", "hex", "url", and others)
compress.EncodingMode := 'base64';

//  Note: Base64 encoding expands the compressed data by
//  4/3rds because each 3 bytes of binary data are represented
//  by 4 printable chars.  Hex, for example, doubles the output
//  size because each byte is represented by 2 printable chars.

//  Deflate the string:

deflatedStr := compress.CompressStringENC(strData);
if (Length(deflatedStr) = 0 ) then
  begin
    Memo1.Lines.Add(compress.LastErrorText);
    Exit;
  end;

//  Display the deflated string.
//  The result will be:
//  S0xKTklNSzc0NDIyNjYxMTU1MzM3t7Dg5UoclRiVGJUYlRiVGJUYlRiVGJUYchIA
Memo1.Lines.Add(deflatedStr);

//  Decompress back to the original:

strOriginal := compress.DecompressStringENC(deflatedStr);

//  Display the uncompressed original:
Memo1.Lines.Add('--- Original ---');
Memo1.Lines.Add(strOriginal);
end;