Namespace System
Namespace IO


/* ほんとはmiscに入れるかかファイルを分けたほうがいいかもしれないが一先ず実装 */
Enum FileOptions
	Asynchronous
	DeleteOnClose
	Encrypted
	None
	RandomAccess
	SequentialScan
	WriteThrough 
End Enum

Class FileStream
	Inherits Stream

	handle As HANDLE

	/*
	ファイルハンドルからこれらを取得できれば、これらは入らないが
	今のところは不明なので自前で実装するしかない
	*/
	filePath As String
	fileMode As DWord
	fileAccess As DWord
	fileShare As DWord
	fileOptions As DWord

	/* 現在は未使用 */
	/*Overlapped As OVERLAPPED*/

Public
	/* コンストラクタ.NETと同じように実装は難しい、一先ず動くものを実装したが変更が必要だと思う */
	Sub FileStream(path As String, mode As FileMode, access As FileAccess, share As FileShare, options As FileOptions)
		Dim ac As DWord
		Dim mo As DWord
		Dim sh As DWord
		Dim op As DWord

		Select Case access
			Case FileAccess.Read
				ac=GENERIC_READ
			Case FileAccess.ReadWrite
				ac=GENERIC_READ or GENERIC_WRITE
			Case FileAccess.Write
				ac=GENERIC_WRITE
		End Select

		Select Case share
			Case FileShare.DeleteFile
				sh=FILE_SHARE_DELETE
			Case FileShare.None
				sh=0
			Case FileShare.Read
				sh=FILE_SHARE_READ
			Case FileShare.ReadWrite
				sh=FILE_SHARE_READ or FILE_SHARE_WRITE
			Case FileShare.Write
				sh=FILE_SHARE_WRITE
		End Select

		Select Case mode
			Case FileMode.Append
				mo=OPEN_ALWAYS
			Case FileMode.Create
				mo=CREATE_ALWAYS
			Case FileMode.CreateNew
				mo=CREATE_NEW
			Case FileMode.Open
				mo=OPEN_EXISTING
			Case FileMode.OpenOrCreate
				mo=OPEN_ALWAYS
			Case FileMode.Truncate
				mo=TRUNCATE_EXISTING
		End Select

		Select Case options
			Case FileOptions.Asynchronous
				op=FILE_FLAG_OVERLAPPED
			Case FileOptions.DeleteOnClose
				op=FILE_FLAG_DELETE_ON_CLOSE
			Case FileOptions.Encrypted
			Case FileOptions.None
				op=0
			Case FileOptions.RandomAccess
				op=FILE_FLAG_RANDOM_ACCESS
			Case FileOptions.SequentialScan
				op=FILE_FLAG_SEQUENTIAL_SCAN
			Case FileOptions.WriteThrough
				op=FILE_FLAG_WRITE_THROUGH
		End Select

		This.handle=CreateFile(path As PSTR,ac,sh,ByVal NULL,mo,op,0)
		If This.handle=INVALID_HANDLE_VALUE Then
		'エラー処理
		'Throw ArgumentException
		'Throw IOException
		'Throw System.IO.FileNotFoundException 
			This.handle=0
			Exit Sub
		End If

		filePath = path
		fileMode = mo
		fileAccess = ac
		fileShare = sh
		fileOptions = op
	End Sub
	Sub FileStream(path As String, mode As FileMode, access As FileAccess, share As FileShare)
		FileStream(path,mode,access,share,FileOptions.None)
	End Sub
	Sub FileStream(path As String, mode As FileMode, access As FileAccess)
		FileStream(path,mode,access,FileShare.None,FileOptions.None)
	End Sub
	Sub FileStream(path As String, mode As FileMode)
		Dim access As FileAccess
		Select Case mode
			Case FileMode.Append
				access=FileAccess.Write
			Case FileMode.Create
				access=FileAccess.ReadWrite
			Case FileMode.CreateNew
				access=FileAccess.ReadWrite
			Case FileMode.Open
				access=FileAccess.ReadWrite
			Case FileMode.OpenOrCreate
				access=FileAccess.ReadWrite
			Case FileMode.Truncate
				access=FileAccess.Write
		End Select
		FileStream(path,mode,access,FileShare.None,FileOptions.None)
	End Sub

	Sub ~FileStream()
		This.Flush()
		This.Close()
	End Sub

Public
	Override Function CanRead() As Boolean
		/* ファイルが読み込みに対応しているかを返す */
		If fileAccess=GENERIC_READ/*FileAccess.Read*/ or fileAccess=GENERIC_READ or GENERIC_WRITE/*FileAccess.ReadWrite*/ Then
			Return True
		Else
			Return False
		End If
	End Function

	Override Function CanSeek() As Boolean
		/* ファイルがシークに対応しているかを返す */
		Return True
	End Function

	Override Function CanTimeout() As Boolean
		/* ファイルがタイムアウトに対応しているかを返す */
		Return False /*今のところ対応していないのでFalse*/
	End Function

	Override Function CanWrite() As Boolean
		/* ファイルが書き込みに対応しているかを返す */
		If fileAccess=GENERIC_WRITE/*FileAccess.Write*/ or fileAccess=GENERIC_READ or GENERIC_WRITE/*FileAccess.ReadWrite*/ Then
			Return True
		Else
			Return False
		End If
	End Function

	/*Handle*/

	Function IsAsync() As Boolean
		/* ファイルが非同期操作に対応しているかを返す */
		If fileOptions=FILE_FLAG_OVERLAPPED/*FileOptions.Asynchronous*/ Then
			Return True
		Else
			Return False
		End If
	End Function

	Override Function Length() As Int64
		/* ファイルのサイズの取得 */
		Dim s As LARGE_INTEGER
		s.LowPart=GetFileSize(This.handle,VarPtr(s.HighPart) As *DWord)
		memcpy(VarPtr(Length),VarPtr(s),SizeOf(LARGE_INTEGER))
	End Function

	Function Name() As String
		/* 多分文字列をコピーして返す方がいいのと思うが。。。*/
		Return filePath
	End Function
	
	Override Sub Position(value As Int64)
		/* ファイルポインタの位置の設定 */
		Dim o As LARGE_INTEGER
		memcpy(VarPtr(o),VarPtr(value),SizeOf(LARGE_INTEGER))
		If o.HighPart=0 And value<0 Then
			o.LowPart=-Abs(o.LowPart) As Long
		End If
		Dim ret As LARGE_INTEGER
		SetFilePointer(This.handle,o.LowPart,VarPtr(o.HighPart) As *DWord,FILE_CURRENT)
	End Sub
	Override Function Position() As Int64
		/* ファイルポインタの位置の取得 */
		Dim o As LARGE_INTEGER
		o.HighPart=0
		o.LowPart=0
		o.LowPart=SetFilePointer(This.handle,0,VarPtr(o.HighPart) As *DWord,FILE_CURRENT)
		memcpy(VarPtr(Position),VarPtr(o),SizeOf(LARGE_INTEGER))
	End Function

	Override Sub ReadTimeout(value As Long)
		'TODO
	End Sub
	Override Function ReadTimeout() As Long
		'TODO
	End Function

	/* Safe〜Handle系の実装は要相談！！ */
/*	Function SafeFileHandle() As SafeFileHandle
	End Function*/

	Override Sub WriteTimeout(value As Long)
		'TODO
	End Sub
	Override Function WriteTimeout() As Long
		'TODO
	End Function
	

Public
	Override Function BeginRead(ByRef buffer[] As Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
		'TODO
	End Function

	Override Function BeginWrite(ByRef buffer[] As Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
		'TODO
	End Function

	Override Sub Close()
		CloseHandle(This.handle)
	End Sub

/*	CreateObjRef*/
/*	Dispose*/

	Override Sub EndRead(ByRef asyncResult As System.IAsyncResult)
		'TODO
	End Sub

	Override Sub EndWrite(ByRef asyncResult As System.IAsyncResult)
		'TODO
	End Sub

/*	Equals*/

	Override Sub Flush()
		FlushFileBuffers(This.handle)
	End Sub

/*	Function GetAccessControl() As FileSecurity
	FileSecurityの実装がまだできてない。
	End Function*/

	Override Function GetHashCode() As Long
		Return ObjPtr(This) As Long
	End Function

/*	GetLifetimeService*/

/*	Override Function GetType() As TypeInfo
		Return Super.GetType()
	End Function*/

/*	InitializeLifetimeService*/

	Sub Lock(position As Int64, length As Int64)
		Dim p As LARGE_INTEGER
		Dim l As LARGE_INTEGER
		memcpy(VarPtr(p),VarPtr(position),SizeOf(LARGE_INTEGER))
		memcpy(VarPtr(l),VarPtr(length),SizeOf(LARGE_INTEGER))
		LockFile(This.handle,p.LowPart,p.HighPart,l.LowPart,l.HighPart)
	End Sub

	Override Function Read(ByRef buffer[] As Byte, offset As Long, count As Long) As Long
		If offset Then
			SetFilePointer(This.handle,offset,NULL,FILE_CURRENT)
		End If
		ReadFile(This.handle,buffer,count,VarPtr(Read) As *DWord,ByVal NULL)
	End Function

	Override Function ReadByte() As Long
		Dim b As Byte
		Dim ret = Read(b, 0, 1)
		If ret <> 0 Then
			Return b As Long
		Else
			Return -1
		End If
	End Function
/*	ReferenceEquals*/

	Override Function Seek(offset As Int64, origin As SeekOrigin) As Long
		Dim o As LARGE_INTEGER
		memcpy(VarPtr(o),VarPtr(offset),SizeOf(LARGE_INTEGER))
		If o.HighPart=0 And offset<0 Then
			o.LowPart=-o.LowPart
		End If
		Select Case origin
			Case SeekOrigin.Begin
				SetFilePointer(This.handle,o.LowPart,VarPtr(o.HighPart) As *DWord,FILE_BEGIN)
			Case SeekOrigin.Current
				SetFilePointer(This.handle,o.LowPart,VarPtr(o.HighPart) As *DWord,FILE_CURRENT)
			Case SeekOrigin.End
				SetFilePointer(This.handle,o.LowPart,VarPtr(o.HighPart) As *DWord,FILE_END)
		End Select
	End Function

/*	Sub SetAccessControl(fileSecurity As FileSecurity)
	FileSecurityの実装がまだできてない。
	End Sub*/

	Override Sub SetLength(value As Int64)
		Dim o As LARGE_INTEGER
		memcpy(VarPtr(o),VarPtr(value),SizeOf(LARGE_INTEGER))
		If o.HighPart=0 And value<0 Then
			o.LowPart=-o.LowPart
		End If
		If Length()=>value Then
			SetFilePointer(This.handle,o.LowPart,VarPtr(o.HighPart) As *DWord,FILE_BEGIN)
			SetEndOfFile(This.handle)
		End If
	End Sub

/*	Synchronized*/

	Override Function ToString() As String
		Return Name()
	End Function

	Sub Unlock(position As Int64, length As Int64)
		Dim p As LARGE_INTEGER
		Dim l As LARGE_INTEGER
		memcpy(VarPtr(p),VarPtr(position),SizeOf(LARGE_INTEGER))
		memcpy(VarPtr(l),VarPtr(length),SizeOf(LARGE_INTEGER))
		UnlockFile(This.handle,p.LowPart,p.HighPart,l.LowPart,l.HighPart)
	End Sub

	Override Sub Write(ByRef buffer[] As Byte, offset As Long, count As Long)
		If offset Then
			SetFilePointer(This.handle,offset,NULL,FILE_CURRENT)
		End If
		Dim ret As DWord
		WriteFile(This.handle,buffer,count,VarPtr(ret),ByVal NULL)
	End Sub

	Override Sub WriteByte(b As Byte)
		Write(b, 0, 1)
	End Sub

Protected
	/*非同期ファイル操作に必須だがどうやって実装しようか検討中*/
	Override Function CreateWaitHandle() As System.Threading.WaitHandle
'		Return Nothing
	End Function

/*	Dispose
	Finalize
	MemberwiseClone*/
End Class


End Namespace
End Namespace