求vb.net中的crc32类

2008-12-27 10:31:50 171 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

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RT
网上搜索了很多，但是没一个不出问题的。

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Surpass 2008-12-27

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很好很强大
谢谢，结帖。

迈克揉索芙特 2008-12-27

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嘿手头正好有一个



Public Class CRC32

    Private Shared CRC32Table() As Integer

    Private Const BUFFER_SIZE As Integer = 1024



    Public Shared Function GetCRC32(ByVal file As String) As Integer

        Return GetCRC32(file, System.Text.Encoding.Default)

    End Function



    Public Shared Function GetCRC32(ByVal file As String, ByVal encoding As System.Text.Encoding) As Integer

        Dim sr As System.IO.StreamReader = New System.IO.StreamReader(file, encoding)

        Dim Result As Integer = GetCRC32(sr.BaseStream)

        sr.Close()

        Return Result

    End Function



    Public Shared Function GetCRC32(ByRef stream As System.IO.Stream) As Integer

        Dim crc32Result As Integer

        crc32Result = &HFFFFFFFF



        Dim buffer(BUFFER_SIZE) As Byte

        Dim readSize As Integer = BUFFER_SIZE



        Dim count As Integer = stream.Read(buffer, 0, readSize)

        Dim i As Integer

        Dim iLookup As Integer

        Dim tot As Integer = 0



        Do While (count > 0)

            For i = 0 To count - 1

                iLookup = (crc32Result And &HFF) Xor buffer(i)

                crc32Result = ((crc32Result And &HFFFFFF00) \ &H100) And &HFFFFFF

                crc32Result = crc32Result Xor CRC32Table(iLookup)

            Next i

            count = stream.Read(buffer, 0, readSize)

        Loop



        Return Not (crc32Result)

    End Function



    Shared Sub New()

        Dim dwPolynomial As Integer = &HEDB88320

        Dim i As Integer, j As Integer



        ReDim CRC32Table(256)

        Dim dwCrc As Integer



        For i = 0 To 255

            dwCrc = i

            For j = 8 To 1 Step -1

                If (dwCrc And 1) Then

                    dwCrc = ((dwCrc And &HFFFFFFFE) \ 2&) And &H7FFFFFFF

                    dwCrc = dwCrc Xor dwPolynomial

                Else

                    dwCrc = ((dwCrc And &HFFFFFFFE) \ 2&) And &H7FFFFFFF

                End If

            Next j

            CRC32Table(i) = dwCrc

        Next i

    End Sub

End Class

求vb.net中的crc32类

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