source: trunk/ab5.0/ablib/src/Classes/System/IO/Stream.ab@ 609

Namespace System
Namespace IO

Class Stream
    Implements IDisposable

Protected
    Sub Stream()
    End Sub
Public
    Sub ~Stream()
        This.Dispose(False)
    End Sub
Public
    Abstract Function CanRead() As Boolean
    Abstract Function CanSeek() As Boolean

    Virtual Function CanTimeout() As Boolean
        Return False
    End Function

    Abstract Function CanWrite() As Boolean
    Abstract Function Length() As QWord
    Abstract Sub Position(value As QWord)
    Abstract Function Position() As QWord

    Virtual Sub ReadTimeout(value As Long)
        Throw New InvalidOperationException("Stream does not support Timeout.")
    End Sub

    Virtual Function ReadTimeout() As Long
        Throw New InvalidOperationException("Stream does not support Timeout.")
    End Function

    Virtual Sub WriteTimeout(value As Long)
        Throw New InvalidOperationException("Stream does not support Timeout.")
    End Sub

    Virtual Function WriteTimeout() As Long
        Throw New InvalidOperationException("Stream does not support Timeout.")
    End Function

Public
    Virtual Function BeginRead(buffer As *Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
        Dim r = Read(buffer,offset,count)
        Return New Detail.SyncStreamResultImpl(r, state)
    End Function
    Virtual Function BeginWrite(buffer As *Byte, offset As Long, count As Long, callback As AsyncCallback, state As Object) As System.IAsyncResult
        Write(buffer,offset,count)
        Return New Detail.SyncStreamResultImpl(0, state)
    End Function
    Sub Close()
        Dispose(True)
    End Sub
    Sub Dispose()
        Dispose(True)
    End Sub
    Virtual Function EndRead(asyncResult As System.IAsyncResult) As Long
        Dim ar = asyncResult As Detail.IAsyncStreamResult
        EndRead = ar.WaitAndGetResult
    End Function
    Virtual Sub EndWrite(asyncResult As System.IAsyncResult)
    End Sub
    Abstract Sub Flush()
    Abstract Function Read(buffer As *Byte, offset As Long, count As Long) As Long

    Virtual Function ReadByte() As Long
        Dim b As Byte
        Dim ret = Read(VarPtr(b), 0, 1)
        If ret <> 0 Then
            Return b
        Else
            Return -1
        End If
    End Function

    Abstract Function Seek(offset As Int64, origin As SeekOrigin) As Int64
    Abstract Sub SetLength(value As QWord)
    Abstract Sub Write(buffer As *Byte, offset As Long, count As Long)
    Virtual Sub WriteByte(b As Byte)
        Write(VarPtr(b), 0, 1)
    End Sub

    Static Function Null() As Stream
        '（Constではなく）読み取り専用にはこうするしかないはず。
        If ActiveBasic.IsNothing(null) Then
            null = New Detail.NullStream
        End If
        Null = null
    End Function
Protected
    Virtual Sub Dispose(disposing As Boolean)
    End Sub

Private
    Static null = Nothing As Stream
End Class

Namespace Detail

/*!
@brief ヌルストリーム
@date 2008/08/21
@auther Egtra
*/
Class NullStream
    Inherits Stream
Public
    Override Function CanRead() As Boolean
        CanRead = True
    End Function

    Override Function Read(buffer As *Byte, offset As Long, count As Long) As Long
        Read = 0
    End Function

    Override Function ReadByte() As Long
        ReadByte = -1
    End Function

    Override Function CanWrite() As Boolean
        CanWrite = True
    End Function

    Override Sub Write(buffer As *Byte, offset As Long, count As Long)
    End Sub

    Override Sub WriteByte(b As Byte)
    End Sub

    Override Sub Flush()
    End Sub

    Override Function CanSeek() As Boolean
        CanSeek = True
    End Function

    Override Function Length() As QWord
        Length = 0
    End Function

    Override Sub Position(value As QWord)
    End Sub

    Override Function Position() As QWord
        Position = 0
    End Function

    Override Function Seek(offset As Int64, origin As SeekOrigin) As Int64
        Seek = 0
    End Function

    Override Sub SetLength(value As QWord)
    End Sub
End Class

End Namespace

End Namespace
End Namespace