unit Unit1;

interface

uses

  ZLib, Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls,

  Forms, Dialogs;

type

  TForm1 = class(TForm)

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

// 两个过程都有Compress参数,这个参数用来决定进行压缩操作还是解压操作: True--压缩; false--解压.

procedure Zip(Input, Output: TStream; Compress: Boolean); overload;

function Zip(Input: string; Compress: Boolean): string; overload;

implementation

{$R *.dfm}

procedure Zip(Input, Output: TStream; Compress: Boolean);

const

  MAXBUFSIZE = 1024 * 16; //16 KB

var

  CS: TCompressionStream;

  DS: TDecompressionStream;

  Buf: array[0..MAXBUFSIZE - 1] of Byte;

  BufSize: Integer;

begin

  if Assigned(Input) and Assigned(Output) then

  begin

    if Compress then     // 压缩

    begin

      CS := TCompressionStream.Create(ZLib.clDefault, Output);

      try

        CS.CopyFrom(Input, 0); //从开始处复制

      finally

        CS.Free;

      end;

    end

    else

    begin        // 解压

      DS := TDecompressionStream.Create(Input);

      try

        BufSize := DS.Read(Buf, MAXBUFSIZE);

        while BufSize > 0 do

        begin

          Output.Write(Buf, BufSize);

          BufSize := DS.Read(Buf, MAXBUFSIZE);

        end;

      finally

        DS.Free;

      end;

    end;

  end;

end;

function Zip(Input: string; Compress: Boolean): string;

var

  InputStream, OutputStream: TStringStream;

begin

  if Input = '' then

    Exit;

  InputStream := TStringStream.Create(Input);

  try

    OutputStream := TStringStream.Create('');

    try

      Zip(InputStream, OutputStream, Compress);

      Result := OutputStream.DataString;

    finally

      OutputStream.Free;

    end;

  finally

    InputStream.Free;

  end;

end;

end.