复杂的结构化存取(三) : 存取函数

今天写了四个小函数, 拿来与大家共享:

Dir2Doc: 把文件夹下的所有文件(不包括子文件夹)保存成一个复合文件;

Doc2Dir: Dir2Doc 的反操作;

ZipDir2Doc: 同 Dir2Doc, 只是同时执行了压缩;

UnZipDoc2Dir: ZipDir2Doc 的反操作.

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函数及测试代码(分别在 Delphi 2007 和 Delphi 2009 下测试通过):

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses ActiveX, Zlib; {函数用到的单元}

{把指定文件夹下的文件保存到一个复合文件}
function Dir2Doc(SourcePath, DestFile: string): Boolean;
const
  Mode = STGM_CREATE or STGM_WRITE or STGM_SHARE_EXCLUSIVE;
var
  sr: TSearchRec;
  Stg: IStorage;
  Stm: IStream;
  ms: TMemoryStream;
begin
  Result := False;
  SourcePath := ExcludeTrailingPathDelimiter(SourcePath);        {去掉最后一个 '\'}
  if not DirectoryExists(SourcePath) then Exit;                  {如果源路径不存在则退出}

  if not DirectoryExists(ExtractFileDir(DestFile)) then          {假如目标目录不存在}
    if not ForceDirectories(ExtractFileDir(DestFile)) then Exit; {就创建, 若创建失败退出.}

  {如果目标路径不存在则退出}

  StgCreateDocfile(PWideChar(WideString(DestFile)), Mode, 0, Stg); {建立复合文件根路径}

  if FindFirst(SourcePath + '\*.*', faAnyFile, sr) = 0 then
  begin
    repeat
      if sr.Name[1] = '.' then Continue; {如果是'.' 或 '..' (当前目录或上层目录)则忽略}
      if (sr.Attr and faDirectory) <> faDirectory then
      begin
        Stg.CreateStream(PWideChar(WideString(sr.Name)), Mode, 0, 0, Stm);
        ms := TMemoryStream.Create;
        ms.LoadFromFile(SourcePath + '\' + sr.Name);
        ms.Position := 0;
        Stm.Write(ms.Memory, ms.Size, nil);
        ms.Free;
      end;
    until (FindNext(sr) <> 0);
  end;
  Result := True;
end;

{上一个 Dir2Doc 函数的反操作}
function Doc2Dir(SourceFile, DestPath: string): Boolean;
const
  Mode = STGM_READ or STGM_SHARE_EXCLUSIVE;
var
  Stg: IStorage;
  Stm: IStream;
  StatStg: TStatStg;
  EnumStatStg: IEnumStatStg;
  ms: TMemoryStream;
  i: Integer;
begin
  Result := False;
  if not FileExists(SourceFile) then Exit;       {如果文件不存在退出}
  if not DirectoryExists(DestPath) then          {如果目标目录不存在}
    if not ForceDirectories(DestPath) then Exit; {就创建, 若创建失败退出}

  DestPath := ExcludeTrailingPathDelimiter(DestPath); {去掉最后一个 '\'}

  StgOpenStorage(PWideChar(WideString(SourceFile)), nil, Mode, nil, 0, Stg);
  Stg.EnumElements(0, nil, 0, EnumStatStg);

  while True do
  begin
    EnumStatStg.Next(1, StatStg, @i);
    if (i = 0) or (StatStg.dwType = 1) then Break; {dwType = 1 时是文件夹}
    Stg.OpenStream(StatStg.pwcsName, nil, Mode, 0, Stm);
    ms := TMemoryStream.Create;
    ms.SetSize(StatStg.cbSize);
    Stm.Read(ms.Memory, ms.Size, nil);
    ms.SaveToFile(DestPath + '\' + StatStg.pwcsName);
    ms.Free;
  end;
  Result := True;
end;

{把指定文件夹下的文件压缩到一个复合文件}
function ZipDir2Doc(SourcePath, DestFile: string): Boolean;
const
  Mode = STGM_CREATE or STGM_WRITE or STGM_SHARE_EXCLUSIVE;
var
  sr: TSearchRec;
  Stg: IStorage;
  Stm: IStream;
  ms1,ms2: TMemoryStream;
  zip: TCompressionStream;
  num: Int64;
begin
  Result := False;
  SourcePath := ExcludeTrailingPathDelimiter(SourcePath);        {去掉最后一个 '\'}
  if not DirectoryExists(SourcePath) then Exit;                  {如果源路径不存在则退出}
  if not DirectoryExists(ExtractFileDir(DestFile)) then          {假如目标目录不存在}
    if not ForceDirectories(ExtractFileDir(DestFile)) then Exit; {就创建, 若创建失败退出.}

  StgCreateDocfile(PWideChar(WideString(DestFile)), Mode, 0, Stg); {建立复合文件根路径}

  if FindFirst(SourcePath + '\*.*', faAnyFile, sr) = 0 then
  begin
    repeat
      if sr.Name[1] = '.' then Continue; {如果是'.' 或 '..' (当前目录或上层目录)则忽略}
      if (sr.Attr and faDirectory) <> faDirectory then
      begin
        Stg.CreateStream(PWideChar(WideString(sr.Name)), Mode, 0, 0, Stm);
        ms1 := TMemoryStream.Create;
        ms2 := TMemoryStream.Create;
        ms1.LoadFromFile(SourcePath + '\' + sr.Name);

        num := ms1.Size;
        ms2.Write(num, SizeOf(num));
        zip := TCompressionStream.Create(clMax, ms2);
        ms1.SaveToStream(zip);
        zip.Free;

        ms2.Position := 0;
        Stm.Write(ms2.Memory, ms2.Size, nil);

        ms1.Free;
        ms2.Free;
      end;
    until (FindNext(sr) <> 0);
  end;
  Result := True;
end;

{上一个 ZipDir2Doc 函数的反操作}
function UnZipDoc2Dir(SourceFile, DestPath: string): Boolean;
const
  Mode = STGM_READ or STGM_SHARE_EXCLUSIVE;
var
  Stg: IStorage;
  Stm: IStream;
  StatStg: TStatStg;
  EnumStatStg: IEnumStatStg;
  ms1,ms2: TMemoryStream;
  i: Integer;
  num: Int64;
  UnZip: TDecompressionStream;
begin
  Result := False;
  if not FileExists(SourceFile) then Exit;    {如果文件不存在退出}
  if not DirectoryExists(DestPath) then          {如果目标目录不存在}
    if not ForceDirectories(DestPath) then Exit; {就创建, 若创建失败退出}

  DestPath := ExcludeTrailingPathDelimiter(DestPath); {去掉最后一个 '\'}

  StgOpenStorage(PWideChar(WideString(SourceFile)), nil, Mode, nil, 0, Stg);
  Stg.EnumElements(0, nil, 0, EnumStatStg);

  while True do
  begin
    EnumStatStg.Next(1, StatStg, @i);
    if (i = 0) or (StatStg.dwType = 1) then Break; {dwType = 1 时是文件夹}
    Stg.OpenStream(StatStg.pwcsName, nil, Mode, 0, Stm);
    ms1 := TMemoryStream.Create;
    ms1.SetSize(StatStg.cbSize);
    Stm.Read(ms1.Memory, ms1.Size, nil);
    ms1.Position := 0;
    ms1.ReadBuffer(num, SizeOf(num));
    ms2 := TMemoryStream.Create;
    ms2.SetSize(num);

    UnZip := TDecompressionStream.Create(ms1);
    ms2.Position := 0;
    UnZip.Read(ms2.Memory^, num);
    UnZip.Free;

    ms2.SaveToFile(DestPath + '\' + StatStg.pwcsName);
    ms1.Free;
    ms2.Free;
  end;
  Result := True;
end;

{测试 Dir2Doc}
procedure TForm1.Button1Click(Sender: TObject);
const
  TestPath = 'C:\Documents and Settings\All Users\Documents\My Pictures\示例图片';
  TestFile = 'C:\Temp\pic1.dat';
begin
  if Dir2Doc(TestPath, TestFile) then
    ShowMessage('ok');
end;

{测试 Doc2Dir}
procedure TForm1.Button2Click(Sender: TObject);
const
  TestPath = 'C:\Temp\pic1';
  TestFile = 'C:\Temp\pic1.dat';
begin
  if Doc2Dir(TestFile, TestPath) then
    ShowMessage('ok');
end;

{测试 ZipDir2Doc}
procedure TForm1.Button3Click(Sender: TObject);
const
  TestPath = 'C:\Documents and Settings\All Users\Documents\My Pictures\示例图片';
  TestFile = 'C:\Temp\pic2.dat';
begin
  if ZipDir2Doc(TestPath, TestFile) then
    ShowMessage('ok');
end;

{测试 UnZipDoc2Dir}
procedure TForm1.Button4Click(Sender: TObject);
const
  TestPath = 'C:\Temp\pic2';
  TestFile = 'C:\Temp\pic2.dat';
begin
  if UnZipDoc2Dir(TestFile, TestPath) then
    ShowMessage('ok');
end;

end.