129 lines
2.9 KiB
Plaintext
129 lines
2.9 KiB
Plaintext
Public Class DoubleLinkList(Of T)
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Private m_Head As Node(Of T)
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Private m_Tail As Node(Of T)
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Public Sub AddHead(ByVal value As T)
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Dim node As New Node(Of T)(Me, value)
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If m_Head Is Nothing Then
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m_Head = Node
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m_Tail = m_Head
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Else
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node.Next = m_Head
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m_Head = node
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End If
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End Sub
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Public Sub AddTail(ByVal value As T)
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Dim node As New Node(Of T)(Me, value)
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If m_Tail Is Nothing Then
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m_Head = node
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m_Tail = m_Head
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Else
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node.Previous = m_Tail
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m_Tail = node
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End If
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End Sub
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Public ReadOnly Property Head() As Node(Of T)
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Get
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Return m_Head
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End Get
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End Property
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Public ReadOnly Property Tail() As Node(Of T)
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Get
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Return m_Tail
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End Get
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End Property
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Public Sub RemoveTail()
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If m_Tail Is Nothing Then Return
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If m_Tail.Previous Is Nothing Then 'empty
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m_Head = Nothing
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m_Tail = Nothing
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Else
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m_Tail = m_Tail.Previous
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m_Tail.Next = Nothing
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End If
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End Sub
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Public Sub RemoveHead()
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If m_Head Is Nothing Then Return
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If m_Head.Next Is Nothing Then 'empty
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m_Head = Nothing
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m_Tail = Nothing
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Else
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m_Head = m_Head.Next
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m_Head.Previous = Nothing
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End If
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End Sub
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End Class
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Public Class Node(Of T)
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Private ReadOnly m_Value As T
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Private m_Next As Node(Of T)
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Private m_Previous As Node(Of T)
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Private ReadOnly m_Parent As DoubleLinkList(Of T)
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Public Sub New(ByVal parent As DoubleLinkList(Of T), ByVal value As T)
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m_Parent = parent
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m_Value = value
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End Sub
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Public Property [Next]() As Node(Of T)
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Get
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Return m_Next
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End Get
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Friend Set(ByVal value As Node(Of T))
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m_Next = value
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End Set
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End Property
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Public Property Previous() As Node(Of T)
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Get
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Return m_Previous
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End Get
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Friend Set(ByVal value As Node(Of T))
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m_Previous = value
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End Set
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End Property
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Public ReadOnly Property Value() As T
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Get
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Return m_Value
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End Get
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End Property
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Public Sub InsertAfter(ByVal value As T)
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If m_Next Is Nothing Then
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m_Parent.AddTail(value)
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ElseIf m_Previous Is Nothing Then
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m_Parent.AddHead(value)
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Else
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Dim node As New Node(Of T)(m_Parent, value)
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node.Previous = Me
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node.Next = Me.Next
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Me.Next.Previous = node
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Me.Next = node
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End If
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End Sub
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Public Sub Remove()
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If m_Next Is Nothing Then
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m_Parent.RemoveTail()
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ElseIf m_Previous Is Nothing Then
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m_Parent.RemoveHead()
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Else
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m_Previous.Next = Me.Next
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m_Next.Previous = Me.Previous
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End If
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End Sub
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End Class
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