unit Unit1;
interface
uses
Windows, Messages, SysUtils, StrUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, zlib, Zlibconst;
type
TForm1 = class(TForm)
dlgOpen1: TOpenDialog;
edt1: TEdit;
btn1: TButton;
btn2: TButton;
btn3: TButton;
procedure btn1Click(Sender: TObject);
procedure btn2Click(Sender: TObject);
procedure btn3Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
procedure CompressIt(var CompressedStream: TMemoryStream; const CompressionLevel: TCompressionLevel);
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure CompressIt(var CompressedStream: TMemoryStream; const CompressionLevel: TCompressionLevel);
// 参数是传递的流和压缩方式
var
SourceStream: TCompressionStream;
DestStream: TMemoryStream;
Count: int64; //注意，此处修改了,原来是int
begin
//获得流的原始尺寸
Count := CompressedStream.Size;
DestStream := TMemoryStream.Create;
SourceStream := TCompressionStream.Create(CompressionLevel, DestStream);
try
//SourceStream中保存着原始的流
CompressedStream.SaveToStream(SourceStream);
//将原始流进行压缩， DestStream中保存着压缩后的流
SourceStream.Free;
CompressedStream.Clear;
//写入原始图像的尺寸
CompressedStream.WriteBuffer(Count, SizeOf(Count));
//写入经过压缩的流
CompressedStream.CopyFrom(DestStream, 0);
finally
DestStream.Free;
end;
end;
procedure UnCompressit(const CompressedStream: TMemoryStream; var UnCompressedStream: TMemoryStream);
//参数 压缩过的流，解压后的流
var
SourceStream: TDecompressionStream;
DestStream: TMemoryStream;
Buffer: PChar;
Count: int64;
begin
//从被压缩的图像流中读出原始的尺寸
CompressedStream.ReadBuffer(Count, SizeOf(Count));
//根据尺寸大小为将要读入的原始流分配内存块
GetMem(Buffer, Count);
DestStream := TMemoryStream.Create;
SourceStream := TDecompressionStream.Create(CompressedStream);
try
//将被压缩的流解压缩，然后存入 Buffer内存块中
SourceStream.ReadBuffer(Buffer^, Count);
//将原始流保存至 DestStream流中
DestStream.WriteBuffer(Buffer^, Count);
DestStream.Position := 0; //复位流指针
//从 DestStream流中载入图像流
UnCompressedStream.LoadFromStream(DestStream);
finally
FreeMem(Buffer);
DestStream.Free;
end;
end;
procedure TForm1.btn1Click(Sender: TObject);
begin
dlgOpen1.Execute;
edt1.Text := dlgOpen1.FileName;
end;
procedure TForm1.btn2Click(Sender: TObject);
//把指定文件压缩然后保存为另外一个压缩包，
//呵呵，我使用的时候是把后缀改成cab,可以唬一些人吧？
var
SM: TMemoryStream;
begin
SM := TMemoryStream.Create;
try
Sm.LoadFromFile(edt1.Text);
SM.Position := 0;
Compressit(sm, clDefault);
sm.SaveToFile(edt1.Text + '.cab');
finally
SM.Free;
end;
end;
procedure TForm1.btn3Click(Sender: TObject);
//把指定的压缩包解成原来的文件。
var
SM, DM: TMemoryStream;
begin
SM := TMemoryStream.Create;
DM := TMemoryStream.Create;
try
Sm.LoadFromFile(edt1.Text);
SM.Position := 0;
UnCompressit(sm, dm);
dm.Position := 0;
dm.SaveToFile(LeftStr(edt1.Text, Length(edt1.Text) - 4));
finally
SM.Free;
DM.Free;
end;
end;
end.
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