Changeset 609

Timestamp:

Aug 22, 2008, 11:57:39 AM (16 years ago)

Author:

イグトランス (egtra)

Message:

Stream.Nullを追加

File:

• trunk/ab5.0/ablib/src/Classes/System/IO/Stream.ab (modified) (2 diffs)

trunk/ab5.0/ablib/src/Classes/System/IO/Stream.ab

@@ -1 +1 @@
 Namespace System
 Namespace IO
-
 
 Class Stream
@@ -82 +81 @@
         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