source: trunk/Include/Classes/System/IO/MemoryStream.ab@ 445

NameSpace System
NameSpace IO

Class MemoryStream
    Inherits Stream

Public
    /*
    0に初期化される拡張可能な容量を使用して初期化
    */
    Sub MemoryStream()
        This.writable = True
        This.Resizable = True
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,0)
        This.StreamLength = 0
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(capacity As Long)
        This.writable = True
        This.Resizable = True
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,capacity)
        This.StreamLength = capacity
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(buffer As *Byte, length As Long)
        This.writable = True
        This.Resizable = False
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,length)
        MoveMemory(This.p,buffer,length)
        This.StreamLength = length
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(buffer As *Byte, length As Long, writable As Boolean)
        This.writable = writable
        This.Resizable = False
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,length)
        MoveMemory(This.p,buffer,length)
        This.StreamLength = length
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(buffer As *Byte, index As Long, count As Long)
        This.writable = True
        This.Resizable = False
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,count)
        MoveMemory(This.p,VarPtr(buffer[index]),count)
        This.StreamLength = count
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(buffer As *Byte, index As Long, count As Long, writable As Boolean)
        This.writable = writable
        This.Resizable = False
        This.visible = False
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,count)
        MoveMemory(This.p,VarPtr(buffer[index]),count)
        This.StreamLength = count
        This.CurrentPosition = 0
    End Sub
    Sub MemoryStream(buffer As *Byte, index As Long, count As Long, writable As Boolean, visible As Boolean)
        This.writable = writable
        This.Resizable = False
        This.visible = visible
        This.handle = HeapCreate(0,0,0)
        This.p = HeapAlloc(This.handle,HEAP_ZERO_MEMORY,count)
        MoveMemory(This.p,VarPtr(buffer[index]),count)
        This.StreamLength = count
        This.CurrentPosition = 0
    End Sub
    Sub ~MemoryStream()
        This.Close()
    End Sub

Public
    Override Function CanRead() As Boolean
        If This.p Then
            Return True
        Else
            Return False
        End If
    End Function

    Override Function CanSeek() As Boolean
        If This.p Then
            Return True
        Else
            Return False
        End If
    End Function

    Override Function CanWrite() As Boolean
        If This.p Then
            Return This.writable
        Else
            Return False
        End If
    End Function

    /*
    メモリの容量であってストリームの長さではない
    メモリはヒープからブロック単位で確保されるので
    指定したストリーム長より大きくなることがある
    また、配列として扱う場合の配列長となる
    */
    Virtual Function Capacity() As Long
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        Return HeapSize(This.handle,0,This.p)
    End Function

    Virtual Sub Capacity(value As Long)
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If value < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If value < This.StreamLength Then Debug'Throw New ArgumentOutOfRangeException
        This.p = HeapReAlloc(This.handle,HEAP_ZERO_MEMORY,This.p,value)
    End Sub

    /*
    こちらは容量とは別のストリーム長
    実際のデータの長さはこちら
    */
    Override Function Length() As Int64
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        Return This.StreamLength
    End Function

    /*
    ストリームの現在位置を取得または設定
    */
    Override Sub Position(value As Int64)
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If value < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If value > Int32.MaxValue() Then Debug'Throw New ArgumentOutOfRangeException
        This.CurrentPosition = value As Long
    End Sub

    Override Function Position() As Int64
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        Return This.CurrentPosition As Int64
    End Function

    Override Sub Flush()
    End Sub

/*  Virtual Function GetBuffer() As Array<Byte>
        If visible = False Then Return NULL
        Return p
    End Function*/

    Override Function Read(buffer As *Byte, offset As Long, count As Long) As Long
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If buffer = 0 Then Debug 'Throw New ArgumentNullException
        If offset < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If count < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If (This.StreamLength - (This.CurrentPosition + count)) < 0 Then
            count + = (This.StreamLength - (This.CurrentPosition + count))
        ElseIf count < 1 Then
            Return 0
        End If
        MoveMemory(VarPtr(buffer[offset]),VarPtr(This.p[This.CurrentPosition]),count)
        This.CurrentPosition + = count
        Return count
    End Function

    Override 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

    Override Function Seek(offset As Int64, origin As SeekOrigin) As Int64
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If offset > Int32.MaxValue() Then Debug'Throw New ArgumentOutOfRangeException
        Select Case origin
            Case SeekOrigin.Begin
                If offset < 0 Then Debug 'Throw New IOException
                This.CurrentPosition = offset As Long
            Case SeekOrigin.Current
                Beep(440,10)
                If (This.CurrentPosition + offset) < 0 Then Debug 'Throw New IOException
                This.CurrentPosition += offset As Long
            Case SeekOrigin.End
                If (This.StreamLength + offset) < 0 Then Debug 'Throw New IOException
                This.CurrentPosition = (This.StreamLength + offset) As Long
            Case Else
                Debug 'Throw New ArgumentException
        End Select
        Return This.CurrentPosition As Int64
    End Function

    Override Sub SetLength(value As Int64)
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If This.writable = False Then Debug 'Throw New NotSupportedException
        If This.Resizable = False Then Debug 'Throw New NotSupportedException
        If value < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If value > Int32.MaxValue() Then Debug'Throw New ArgumentOutOfRangeException
        This.p = HeapReAlloc(This.handle,HEAP_ZERO_MEMORY,This.p,value As Long)
        This.StreamLength = value As Long
    End Sub

    Override Sub Write(buffer As *Byte, offset As Long, count As Long)
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If This.writable = False Then Debug'Throw New NotSupportedException
        If buffer = 0 Then Debug 'Throw New ArgumentNullException
        If offset < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If count < 0 Then Debug'Throw New ArgumentOutOfRangeException
        If count > (This.StreamLength - This.CurrentPosition) Then 
            If This.Resizable = False Then
                Debug 'Throw New NotSupportedException
            Else
                If count > (This.Capacity() - This.CurrentPosition) Then 
                    This.p = HeapReAlloc(This.handle,HEAP_ZERO_MEMORY,This.p,This.CurrentPosition+count)
                End If
                This.StreamLength = This.CurrentPosition+count
            End If
        End If
        MoveMemory(VarPtr(This.p[This.CurrentPosition]),VarPtr(buffer[offset]),count)
        This.CurrentPosition + = count
    End Sub

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

/*  Virtual Function ToArray() As List<Byte>
        TODO:
    End Function*/

    Virtual Sub WriteTo(stream As Stream)
        If This.p = 0 Then Debug'Throw New ObjectDisposedException
        If ActiveBasic.IsNothing(stream) Then Debug 'Throw New ArgumentNullException("path")
        stream.Write(This.p,0,This.Capacity())
    End Sub

Protected
    Override Sub Dispose(disposing As Boolean)
        HeapFree(This.handle,0,InterlockedExchangePointer(ByVal VarPtr(This.p) As VoidPtr,NULL) As VoidPtr)
        HeapDestroy(InterlockedExchangePointer(ByVal VarPtr(This.handle) As VoidPtr,NULL) As HANDLE)
    End Sub

    /* status */
    writable As Boolean
    Resizable As Boolean
    visible As Boolean

    StreamLength As Long
    CurrentPosition As Long

Private
    handle As HANDLE
    p As *Byte
End Class

End NameSpace 'IO
End NameSpace 'System