将MBF Single和Double转换为IEEE

Question

跟进可用：有更多细节的后续行动，请参阅Convert MBF to IEEE。

我有一些仍在使用的遗留数据，读取二进制文件不是问题，数字格式是。所有浮点数都以MBF格式保存（单和双）。我找到了a topic about that on the MSDN boards，但那个只处理单值。我也希望尽可能远离API调用。

有没有人有双打的解决方案？

编辑：以防有人需要它，这是VB.NET代码（它符合Option Strict）我最终（随意将其转换为C＃并编辑）：

''' <summary>Converts a MBF Single to an IEEE Single</summary>
''' <param name="src">The MBF Single value</param>
''' <returns>The converted IEEE Single value</returns>
''' <remarks>Here can find some further information about this topic: http://en.wikipedia.org/wiki/Microsoft_Binary_Format http://support.microsoft.com/kb/140520</remarks>
Public Shared Function MTIS(ByVal src As Single) As Single
    Return MTIS(BitConverter.GetBytes(src), 0)
End Function

''' <summary>Converts a MBF Single to an IEEE Single</summary>
''' <param name="src">The source array</param>
''' <param name="startIndex">The start index at which the Single starts</param>
''' <returns>The converted IEEE Single value</returns>
''' <remarks>Here can find some further information about this topic: http://en.wikipedia.org/wiki/Microsoft_Binary_Format http://support.microsoft.com/kb/140520</remarks>
Public Shared Function MTIS(ByVal src() As Byte, ByVal startIndex As Integer) As Single
    Dim mbf(3) As Byte
    Dim ieee(3) As Byte

    Array.Copy(src, startIndex, mbf, 0, 4)

    If mbf(3) <> 0 Then
        Dim sign As Byte = mbf(2) And ToByte(&H80)
        Dim exp As Byte = mbf(3) - ToByte(2) ' -1-128-127 '

        ieee(3) = ieee(3) Or sign
        ieee(3) = ieee(3) Or exp >> 1
        ieee(2) = ieee(2) Or exp << 7
        ieee(2) = ieee(2) Or mbf(2) And ToByte(&H7F)
        ieee(1) = mbf(1)
        ieee(0) = mbf(0)
    End If

    Return BitConverter.ToSingle(ieee, 0)
End Function


''' <summary>Converts a MBF Double to a IEEE Double</summary>
''' <param name="src">The MBF Double value</param>
''' <returns>The converted IEEE Double value</returns>
''' <remarks>Here can find some further information about this topic: http://en.wikipedia.org/wiki/Microsoft_Binary_Format http://support.microsoft.com/kb/140520</remarks>
Public Shared Function MTID(ByVal src As Double) As Double
    Return MTID(BitConverter.GetBytes(src), 0)
End Function

''' <summary>Converts a MBF Double to a IEEE Double</summary>
''' <param name="src">The source array</param>
''' <param name="startIndex">The start index at which the Double starts</param>
''' <returns>The converted IEEE Double value</returns>
''' <remarks>Here can find some further information about this topic: http://en.wikipedia.org/wiki/Microsoft_Binary_Format http://support.microsoft.com/kb/140520</remarks>
Public Shared Function MTID(ByVal src() As Byte, ByVal startIndex As Integer) As Double
    Dim mbf(7) As Byte
    Dim ieee(7) As Byte

    Array.Copy(src, startIndex, mbf, 0, 8)

    If mbf(7) <> 0 Then
        Dim sign As Byte = mbf(6) And ToByte(&H80)
        Dim exp As Int16 = mbf(7) - 128S - 1S + 1023S

        ieee(7) = ieee(7) Or sign
        ieee(7) = ieee(7) Or ToByte(exp >> 4 And &HFF)
        ieee(6) = ieee(6) Or ToByte(exp << 4 And &HFF)

        For i As Integer = 6 To 1 Step -1
            mbf(i) <<= 1
            mbf(i) = mbf(i) Or mbf(i - 1) >> 7
        Next
        mbf(0) <<= 1

        For i As Integer = 6 To 1 Step -1
            ieee(i) = ieee(i) Or mbf(i) >> 4
            ieee(i - 1) = ieee(i - 1) Or mbf(i) << 4
        Next
        ieee(0) = ieee(0) Or mbf(0) >> 4
    End If

    Return BitConverter.ToDouble(ieee, 0)
End Function

Answer 1

在this Wiki页面上，可以找到几个不同代码示例的链接，用于在C，C ++和Python中执行此操作。

其中一个或多个应该相对容易转换为适合您的语言。

Answer 2

Microsoft已发布了一篇关于此的知识库文章，其中包括一个P / Invokable DLL，您可以使用它来进行从MBF到IEEE的转换。

它的存档副本是available here。