关于 Delphi 中 压缩与解压缩的函数

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
end;

var
Form1: TForm1;

implementation

{$R *.dfm}

uses Zlib;

//压缩函数
procedure Zip(var fs: TMemoryStream);
var
cs: TCompressionStream;
ms: TMemoryStream;
num: Integer;
begin
if not(Assigned(fs) and (fs.Size>0)) then Exit;

num := fs.Size;
ms := TMemoryStream.Create;
cs := TCompressionStream.Create(clMax, ms);
try
fs.SaveToStream(cs);
cs.Free;
//ms.Position := 0;
fs.Clear;
fs.WriteBuffer(num, sizeof(num));
fs.CopyFrom(ms, 0);
finally
ms.Free;
end;
end;

//解压函数
procedure UnZip(var fs: Tmemorystream);
var
ds: TDecompressionStream;
ms: TMemoryStream;
num: Integer;
begin
if not(Assigned(fs) and (fs.Size>0)) then Exit;

fs.Position := 0;
fs.ReadBuffer(num,sizeof(num));
ms := TMemoryStream.Create;
ds := TDecompressionStream.Create(fs);
try
ms.SetSize(num);
ds.Read(ms.Memory^, num);
//ms.Position := 0;
fs.Clear;
fs.CopyFrom(ms, 0);
finally
ds.Free;
ms.Free;
end;
end;

//压缩测试
procedure TForm1.Button1Click(Sender: TObject);
var
ms: TMemoryStream;
begin
ms := TMemoryStream.Create;
ms.LoadFromFile('c:\temp\test.txt');
Zip(ms);
ms.SaveToFile('c:\temp\test.zipx');
end;

//解压测试
procedure TForm1.Button2Click(Sender: TObject);
var
ms: TMemoryStream;
begin
ms := TMemoryStream.Create;
ms.LoadFromFile('c:\temp\test.zipx');
UnZip(ms);
ms.SaveToFile('c:\temp\test2.txt');
end;

end.

转载自：http://topic.csdn.net/u/20110329/13/c9c1062a-e55f-4559-bf30-ed440e2469bb.html