[fpc-pascal] How to use TCompressionStream?

[Felipe Monteiro de Carvalho]

Hello,

I am trying to use TCompressionStream to compress a string. But the
destination stream is empty. Here is by code, thanks:

program stringcompressor;

{$apptype console}

uses
  Classes, SysUtils, zstream;

var
  Compressor: TCompressionStream;
  Source: TStringStream;
  Dest: TMemoryStream;
  i: Integer;
begin
  Source := TStringStream.Create('The string to be compressed');
  Dest := TMemoryStream.Create();
  Compressor := TCompressionStream.Create(clDefault, Dest);
  try
    Compressor.CopyFrom(Source, Source.Size);

    Write('The result is: ');
    Dest.Position := 0;
    for i := 0 to Dest.Size - 1 do
      IntToHex(Dest.ReadByte, 2);
    WriteLn('');
  finally
    Compressor.Free;
    Dest.Free;
    Source.Free;
  end;
end.