VB.Net实现PDU中的UCS2编码和解码

UCS2编码也就是两字节的Unicode编码，Unicode编码除了UCS2外还有UCS4规范，VB.Net中将汉字转换成UCS2编码方法很简单，可以直接调用System.Text.Encoding.Unicode.GetBytes方法就可以实现，比如System.Text.Encoding.Unicode.GetBytes(“程”)就可以得到“程”的UCS2编码0B 7A,不过在PDU中UCS2编码的字节顺序和这样取到字节顺序是相反的，PDU的顺序是7A0B，因此还需要将System.Text.Encoding.Unicode.GetBytes取到的字节位置进行一下交换。具体代码如下：

    'UCS2编码
    Public Function Encoder_UCS2(ByVal s As String) As Byte()
        '取Unicode编码Byte数组
        Dim arr() As Byte = System.Text.Encoding.Unicode.GetBytes(s)
        Dim tmp As Byte

        '换位
        For xx As Integer = 0 To arr.Length - 2 Step 2
            tmp = arr(xx)
            arr(xx) = arr(xx + 1)
            arr(xx + 1) = tmp
        Next

        Encoder_UCS2 = arr
        Erase arr
    End Function

    'UCS2解码
    Public Function Decoder_UCS2(ByVal s As Byte()) As String
        Dim tmp As Byte

        '换位
        For xx As Integer = 0 To s.Length - 2 Step 2
            tmp = s(xx)
            s(xx) = s(xx + 1)
            s(xx + 1) = tmp
        Next

        Decoder_UCS2 = System.Text.Encoding.Unicode.GetString(s)
    End Function