C#：将 COMP-3 压缩十进制转换为人类可读的值

Question

我有一系列来自大型机的 ASCII 平面文件，由 C# 应用程序处理。 引入了带有压缩十进制 (COMP-3) 字段的新提要，该字段需要转换为数值。

文件通过 FTP 使用 ASCII 传输模式进行传输。 我担心二进制字段可能包含被解释为非常低的 ASCII 代码或控制字符而不是值 - 或者更糟糕的是，可能会在 FTP 过程中丢失。

更重要的是，这些字段被读取为字符串。 我可能可以灵活地解决这部分（即某种流），但业务会给我带来阻力。

要求是“从十六进制转换为 ASCII”，但显然这并没有产生正确的值。 任何帮助，将不胜感激; 它不必是特定于语言的，只要您可以解释转换过程的逻辑即可。

Answer 1

我一直在观看许多论坛上关于将 Comp-3 BCD 数据从“遗留”大型机文件转换为可在 C# 中使用的内容的帖子。 首先，我想说的是，我对其中一些帖子收到的回复不太感兴趣，尤其是那些本质上说“你为什么用这些与 C#/C++ 无关的帖子来打扰我们”以及“如果您需要有关某种 COBOL 约定的答案，为什么不去访问面向 COBOL 的站点”。 对我来说，这完全是胡说八道，因为（不幸的是）软件开发人员在未来的许多年里都需要了解如何处理现实世界中存在的一些遗留问题。 因此，即使我因以下代码而在这篇文章中受到猛烈抨击，我也将与您分享我必须处理的有关 COMP-3/EBCDIC 转换的真实世界经验（是的，我就是那个谈论“的人”软盘、纸带、光盘包等... - 我自 1979 年以来一直是一名软件工程师”）。

首先 - 了解您从 IBM 等遗留大型机系统读取的任何文件都将以 EBCDIC 格式向您呈现数据，并且为了将任何该数据转换为您可以处理的 C#/C++ 字符串必须使用正确的代码页转换才能将数据转换为 ASCII 格式。 如何处理此问题的一个很好的示例是：

StreamReader readFile = new StreamReader(path, Encoding.GetEncoding(037); // 037 = EBCDIC 到 ASCII 转换。

这将确保您从此流中读取的任何内容都将被转换转换为 ASCII，并且可以以字符串格式使用。这包括 COBOL 声明的“分区十进制”（图 9）和“文本”（图 X）字段。但是，这不一定将 COMP-3 字段转换为正确的“读入 char[] 或 byte[] 数组时相当于“binary”。为此，这是正确翻译该代码页的唯一方法（即使使用 UTF-8、UTF-16、默认或其他）代码页，您将要像这样打开文件：

FileStream fileStream = new FileStream(path, FIleMode.Open, FIleAccess.Read, FileShare.Read);

，“FileShare.Read”选项是“可选”的。

当然 您已经隔离了要转换为十进制值的字段（如果需要，然后随后转换为 ASCII 字符串），您可以使用以下代码 - 这基本上是从 MicroSoft“UnpackDecimal”帖子中窃取的，您可以访问：

http:// www.microsoft.com/downloads/details.aspx?familyid=0e4bba52-cc52-4d89-8590-cda297ff7fbd&displaylang=en

我已经隔离了（我认为）这个逻辑中最重要的部分并将其整合起来一分为二的方法，你可以做你想做的事。 出于我的目的，我选择将其保留为返回 Decimal 值，然后我可以按照我想要的方式进行操作。 基本上，该方法称为“unpack”，并向其传递一个 byte[] 数组（不超过 12 个字节）和一个 int 形式的标度，即您希望在 Decimal 值中返回的小数位数。 我希望这对你和我一样有用。

    private Decimal Unpack(byte[] inp, int scale)
    {
        long lo = 0;
        long mid = 0;
        long hi = 0;
        bool isNegative;

        // this nybble stores only the sign, not a digit.  
        // "C" hex is positive, "D" hex is negative, and "F" hex is unsigned. 
        switch (nibble(inp, 0))
        {
            case 0x0D:
                isNegative = true;
                break;
            case 0x0F:
            case 0x0C:
                isNegative = false;
                break;
            default:
                throw new Exception("Bad sign nibble");
        }
        long intermediate;
        long carry;
        long digit;
        for (int j = inp.Length * 2 - 1; j > 0; j--)
        {
            // multiply by 10
            intermediate = lo * 10;
            lo = intermediate & 0xffffffff;
            carry = intermediate >> 32;
            intermediate = mid * 10 + carry;
            mid = intermediate & 0xffffffff;
            carry = intermediate >> 32;
            intermediate = hi * 10 + carry;
            hi = intermediate & 0xffffffff;
            carry = intermediate >> 32;
            // By limiting input length to 14, we ensure overflow will never occur

            digit = nibble(inp, j);
            if (digit > 9)
            {
                throw new Exception("Bad digit");
            }
            intermediate = lo + digit;
            lo = intermediate & 0xffffffff;
            carry = intermediate >> 32;
            if (carry > 0)
            {
                intermediate = mid + carry;
                mid = intermediate & 0xffffffff;
                carry = intermediate >> 32;
                if (carry > 0)
                {
                    intermediate = hi + carry;
                    hi = intermediate & 0xffffffff;
                    carry = intermediate >> 32;
                    // carry should never be non-zero. Back up with validation
                }
            }
        }
        return new Decimal((int)lo, (int)mid, (int)hi, isNegative, (byte)scale);
    }

    private int nibble(byte[] inp, int nibbleNo)
    {
        int b = inp[inp.Length - 1 - nibbleNo / 2];
        return (nibbleNo % 2 == 0) ? (b & 0x0000000F) : (b >> 4);
    }

如果您有任何问题，请将它们发布在这里 - 因为我怀疑我会像其他选择发布与今天的问题相关的问题的人一样受到“攻击”......

谢谢，
约翰——长老。

Answer 2

首先，您必须消除由 ASCII 传输模式引起的行尾 (EOL) 转换问题。 当 BCD 值恰好对应于 EOL 字符时，您担心数据损坏是完全正确的。 这个问题最糟糕的方面是它很少发生且出乎意料。

最好的解决办法就是将传输模式改为BIN。 这是合适的，因为您正在传输的数据是二进制的。 如果无法使用正确的 FTP 传输模式，您可以在代码中消除 ASCII 模式损坏。 您所要做的就是将 \r\n 对转换回 \n。 如果我是你，我会确保这经过充分测试。

一旦解决了 EOL 问题，COMP-3 转换就非常简单了。 我在 MS 知识库中找到了这篇文章，其中包含 BASIC 示例代码。 请参阅下面的此代码的 VB.NET 端口。

由于您正在处理 COMP-3 值，因此您正在读取的文件格式几乎肯定具有固定的记录大小和固定的字段长度。 如果我是你，我会在你进一步讨论之前先了解文件格式规范。 您应该使用 BinaryReader 来处理此数据。 如果有人在这一点上反驳，我就会走开。 让他们找其他人来纵容他们的愚蠢吧。

下面是 BASIC 示例代码的 VB.NET 移植。 我还没有对此进行测试，因为我无权访问 COMP-3 文件。 如果这不起作用，我会参考原始的 MS 示例代码以获取指导，或参考此问题的其他答案中的参考资料。

Imports Microsoft.VisualBasic

Module Module1

'Sample COMP-3 conversion code
'Adapted from http://support.microsoft.com/kb/65323
'This code has not been tested

Sub Main()

    Dim Digits%(15)       'Holds the digits for each number (max = 16).
    Dim Basiceqv#(1000)   'Holds the Basic equivalent of each COMP-3 number.

    'Added to make code compile
    Dim MyByte As Char, HighPower%, HighNibble%
    Dim LowNibble%, Digit%, E%, Decimal%, FileName$


    'Clear the screen, get the filename and the amount of decimal places
    'desired for each number, and open the file for sequential input:
    FileName$ = InputBox("Enter the COBOL data file name: ")
    Decimal% = InputBox("Enter the number of decimal places desired: ")

    FileOpen(1, FileName$, OpenMode.Binary)

    Do Until EOF(1)   'Loop until the end of the file is reached.
        Input(1, MyByte)
        If MyByte = Chr(0) Then     'Check if byte is 0 (ASC won't work on 0).
            Digits%(HighPower%) = 0       'Make next two digits 0. Increment
            Digits%(HighPower% + 1) = 0   'the high power to reflect the
            HighPower% = HighPower% + 2   'number of digits in the number
            'plus 1.
        Else
            HighNibble% = Asc(MyByte) \ 16      'Extract the high and low
            LowNibble% = Asc(MyByte) And &HF    'nibbles from the byte. The
            Digits%(HighPower%) = HighNibble%  'high nibble will always be a
            'digit.
            If LowNibble% <= 9 Then                   'If low nibble is a
                'digit, assign it and
                Digits%(HighPower% + 1) = LowNibble%   'increment the high
                HighPower% = HighPower% + 2            'power accordingly.
            Else
                HighPower% = HighPower% + 1 'Low nibble was not a digit but a
                Digit% = 0                  '+ or - signals end of number.

                'Start at the highest power of 10 for the number and multiply
                'each digit by the power of 10 place it occupies.
                For Power% = (HighPower% - 1) To 0 Step -1
                    Basiceqv#(E%) = Basiceqv#(E%) + (Digits%(Digit%) * (10 ^ Power%))
                    Digit% = Digit% + 1
                Next

                'If the sign read was negative, make the number negative.
                If LowNibble% = 13 Then
                    Basiceqv#(E%) = Basiceqv#(E%) - (2 * Basiceqv#(E%))
                End If

                'Give the number the desired amount of decimal places, print
                'the number, increment E% to point to the next number to be
                'converted, and reinitialize the highest power.
                Basiceqv#(E%) = Basiceqv#(E%) / (10 ^ Decimal%)
                Print(Basiceqv#(E%))
                E% = E% + 1
                HighPower% = 0
            End If
        End If
    Loop

    FileClose()   'Close the COBOL data file, and end.
End Sub

End Module

Answer 3

如果我在这里偏离基地，我很抱歉，但也许我粘贴在这里的代码示例可以帮助您。 这来自 VBRocks...

Imports System
Imports System.IO
Imports System.Text
Imports System.Text.Encoding



'4/20/07 submission includes a line spacing addition when a control character is used:
'   The line spacing is calculated off of the 3rd control character.
'
'   Also includes the 4/18 modification of determining end of file.

'4/26/07 submission inclues an addition of 6 to the record length when the 4th control
'   character is an 8.  This is because these records were being truncated.


'Authored by Gary A. Lima, aka. VBRocks



''' <summary>
''' Translates an EBCDIC file to an ASCII file.
''' </summary>
''' <remarks></remarks>
Public Class EBCDIC_to_ASCII_Translator

#Region " Example"

    Private Sub Example()
        'Set your source file and destination file paths
        Dim sSourcePath As String = "c:\Temp\MyEBCDICFile"
        Dim sDestinationPath As String = "c:\Temp\TranslatedFile.txt"

        Dim trans As New EBCDIC_to_ASCII_Translator()

        'If your EBCDIC file uses Control records to determine the length of a record, then this to True
        trans.UseControlRecord = True

        'If the first record of your EBCDIC file is filler (junk), then set this to True
        trans.IgnoreFirstRecord = True

        'EBCDIC files are written in block lengths, set your block length (Example:  134, 900, Etc.)
        trans.BlockLength = 900

        'This method will actually translate your source file and output it to the specified destination file path
        trans.TranslateFile(sSourcePath, sDestinationPath)


        'Here is a alternate example:
        'No Control record is used
        'trans.UseControlRecord = False

        'Translate the whole file, including the first record
        'trans.IgnoreFirstRecord = False

        'Set the block length
        'trans.BlockLength = 134

        'Translate...
        'trans.TranslateFile(sSourcePath, sDestinationPath)



        '*** Some additional methods that you can use are:

        'Trim off leading characters from left side of string (position 0 to...)
        'trans.LTrim = 15

        'Translate 1 EBCDIC character to an ASCII character
        'Dim strASCIIChar as String = trans.TranslateCharacter("S")

        'Translate an EBCDIC character array to an ASCII string
        'trans.TranslateCharacters(chrEBCDICArray)

        'Translates an EBCDIC string to an ASCII string
        'Dim strASCII As String = trans.TranslateString("EBCDIC String")


    End Sub

#End Region    'Example

    'Translate characters from EBCDIC to ASCII

    Private ASCIIEncoding As Encoding = Encoding.ASCII
    Private EBCDICEncoding As Encoding = Encoding.GetEncoding(37)  'EBCDIC

    'Block Length:  Can be fixed (Ex:  134). 
    Private miBlockLength As Integer = 0
    Private mbUseControlRec As Boolean = True        'If set to False, will return exact block length
    Private mbIgnoreFirstRecord As Boolean = True    'Will Ignore first record if set to true  (First record may be filler)
    Private miLTrim As Integer = 0

    ''' <summary>
    ''' Translates SourceFile from EBCDIC to ASCII.  Writes output to file path specified by DestinationFile parameter.
    ''' Set the BlockLength Property to designate block size to read.
    ''' </summary>
    ''' <param name="SourceFile">Enter the path of the Source File.</param>
    ''' <param name="DestinationFile">Enter the path of the Destination File.</param>
    ''' <remarks></remarks>
    Public Sub TranslateFile(ByVal SourceFile As String, ByVal DestinationFile As String)

        Dim iRecordLength As Integer     'Stores length of a record, not including the length of the Control Record (if used)
        Dim sRecord As String = ""         'Stores the actual record
        Dim iLineSpace As Integer = 1    'LineSpace:  1 for Single Space, 2 for Double Space, 3 for Triple Space...

        Dim iControlPosSix As Byte()      'Stores the 6th character of a Control Record (used to calculate record length)
        Dim iControlRec As Byte()          'Stores the EBCDIC Control Record (First 6 characters of record)
        Dim bEOR As Boolean                'End of Record Flag
        Dim bBOF As Boolean = True      'Beginning of file
        Dim iConsumedChars As Integer = 0     'Stores the number of consumed characters in the current block
        Dim bIgnoreRecord As Boolean = mbIgnoreFirstRecord   'Ignores the first record if set.

        Dim ControlArray(5) As Char         'Stores Control Record (first 6 bytes)
        Dim chrArray As Char()              'Stores characters just after read from file

        Dim sr As New StreamReader(SourceFile, EBCDICEncoding)
        Dim sw As New StreamWriter(DestinationFile)

        'Set the RecordLength to the RecordLength Property (below)
        iRecordLength = miBlockLength

        'Loop through entire file
        Do Until sr.EndOfStream = True

            'If using a Control Record, then check record for valid data.
            If mbUseControlRec = True Then
                'Read the Control Record (first 6 characters of the record)
                sr.ReadBlock(ControlArray, 0, 6)

                'Update the value of consumed (read) characters
                iConsumedChars += ControlArray.Length

                'Get the bytes of the Control Record Array
                iControlRec = EBCDICEncoding.GetBytes(ControlArray)

                'Set the line spacing  (position 3 divided by 64)
                '   (64 decimal = Single Spacing; 128 decimal = Double Spacing)
                iLineSpace = iControlRec(2) / 64


                'Check the Control record for End of File
                'If the Control record has a 8 or 10 in position 1, and a 1 in postion 2, then it is the end of the file
                If (iControlRec(0) = 8 OrElse iControlRec(0) = 10) AndAlso _
                    iControlRec(1) = 1 Then

                    If bBOF = False Then
                        Exit Do

                    Else
                        'The Beginning of file flag is set to true by default, so when the first
                        '   record is encountered, it is bypassed and the bBOF flag is set to False
                        bBOF = False

                    End If    'If bBOF = Fals

                End If    'If (iControlRec(0) = 8 OrElse



                'Set the default value for the End of Record flag to True
                '   If the Control Record has all zeros, then it's True, else False
                bEOR = True

                'If the Control record contains all zeros, bEOR will stay True, else it will be set to False
                For i As Integer = 0 To 5
                    If iControlRec(i) > 0 Then
                        bEOR = False

                        Exit For

                    End If    'If iControlRec(i) > 0

                Next    'For i As Integer = 0 To 5

                If bEOR = False Then
                    'Convert EBCDIC character to ASCII
                    'Multiply the 6th byte by 6 to get record length
                    '   Why multiply by 6?  Because it works.
                    iControlPosSix = EBCDICEncoding.GetBytes(ControlArray(5))

                    'If the 4th position of the control record is an 8, then add 6
                    '    to the record length to pick up remaining characters.
                    If iControlRec(3) = 8 Then
                        iRecordLength = CInt(iControlPosSix(0)) * 6 + 6

                    Else
                        iRecordLength = CInt(iControlPosSix(0)) * 6

                    End If

                    'Add the length of the record to the Consumed Characters counter
                    iConsumedChars += iRecordLength

                Else
                    'If the Control Record had all zeros in it, then it is the end of the Block.

                    'Consume the remainder of the block so we can continue at the beginning of the next block.
                    ReDim chrArray(miBlockLength - iConsumedChars - 1)
                    'ReDim chrArray(iRecordLength - iConsumedChars - 1)

                    'Consume (read) the remaining characters in the block.  
                    '   We are not doing anything with them because they are not actual records.
                    'sr.ReadBlock(chrArray, 0, iRecordLength - iConsumedChars)
                    sr.ReadBlock(chrArray, 0, miBlockLength - iConsumedChars)

                    'Reset the Consumed Characters counter
                    iConsumedChars = 0

                    'Set the Record Length to 0 so it will not be processed below.
                    iRecordLength = 0

                End If    ' If bEOR = False

            End If    'If mbUseControlRec = True



            If iRecordLength > 0 Then
                'Resize our array, dumping previous data.  Because Arrays are Zero (0) based, subtract 1 from the Record length.
                ReDim chrArray(iRecordLength - 1)

                'Read the specfied record length, without the Control Record, because we already consumed (read) it.
                sr.ReadBlock(chrArray, 0, iRecordLength)

                'Copy Character Array to String Array, Converting in the process, then Join the Array to a string
                sRecord = Join(Array.ConvertAll(chrArray, New Converter(Of Char, String)(AddressOf ChrToStr)), "")

                'If the record length was 0, then the Join method may return Nothing
                If IsNothing(sRecord) = False Then

                    If bIgnoreRecord = True Then
                        'Do nothing - bypass record

                        'Reset flag
                        bIgnoreRecord = False

                    Else
                        'Write the line out, LTrimming the specified number of characters.
                        If sRecord.Length >= miLTrim Then
                            sw.WriteLine(sRecord.Remove(0, miLTrim))

                        Else
                            sw.WriteLine(sRecord.Remove(0, sRecord.Length))

                        End If    ' If sRecord.Length >= miLTrim

                        'Write out the number of blank lines specified by the 3rd control character.
                        For i As Integer = 1 To iLineSpace - 1
                            sw.WriteLine("")

                        Next    'For i As Integer = 1 To iLineSpace

                    End If    'If bIgnoreRecord = True


                    'Obviously, if we have read more characters from the file than the designated size of the block,
                    '   then subtract the number of characters we have read into the next block from the block size.
                    If iConsumedChars > miBlockLength Then
                        'If iConsumedChars > iRecordLength Then
                        iConsumedChars = iConsumedChars - miBlockLength
                        'iConsumedChars = iConsumedChars - iRecordLength

                    End If

                End If    'If IsNothing(sRecord) = False

            End If    'If iRecordLength > 0

            'Allow computer to process  (works in a class module, not in a dll)
            'Application.DoEvents()

        Loop

        'Destroy StreamReader (sr)
        sr.Close()
        sr.Dispose()

        'Destroy StreamWriter (sw)
        sw.Close()
        sw.Dispose()

    End Sub



    ''' <summary>
    ''' Translates 1 EBCDIC Character (Char) to an ASCII String
    ''' </summary>
    ''' <param name="chr"></param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Private Function ChrToStr(ByVal chr As Char) As String
        Dim sReturn As String = ""

        'Convert character into byte
        Dim EBCDICbyte As Byte() = EBCDICEncoding.GetBytes(chr)

        'Convert EBCDIC byte to ASCII byte
        Dim ASCIIByte As Byte() = Encoding.Convert(EBCDICEncoding, ASCIIEncoding, EBCDICbyte)

        sReturn = Encoding.ASCII.GetString(ASCIIByte)

        Return sReturn

    End Function



    ''' <summary>
    ''' Translates an EBCDIC String to an ASCII String
    ''' </summary>
    ''' <param name="sStringToTranslate"></param>
    ''' <returns>String</returns>
    ''' <remarks></remarks>
    Public Function TranslateString(ByVal sStringToTranslate As String) As String
        Dim i As Integer = 0
        Dim sReturn As New System.Text.StringBuilder()

        'Loop through the string and translate each character
        For i = 0 To sStringToTranslate.Length - 1
            sReturn.Append(ChrToStr(sStringToTranslate.Substring(i, 1)))

        Next

        Return sReturn.ToString()


    End Function



    ''' <summary>
    ''' Translates 1 EBCDIC Character (Char) to an ASCII String
    ''' </summary>
    ''' <param name="sCharacterToTranslate"></param>
    ''' <returns>String</returns>
    ''' <remarks></remarks>
    Public Function TranslateCharacter(ByVal sCharacterToTranslate As Char) As String

        Return ChrToStr(sCharacterToTranslate)

    End Function



    ''' <summary>
    ''' Translates an EBCDIC Character (Char) Array to an ASCII String
    ''' </summary>
    ''' <param name="sCharacterArrayToTranslate"></param>
    ''' <returns>String</returns>
    ''' <remarks>Remarks</remarks>
    Public Function TranslateCharacters(ByVal sCharacterArrayToTranslate As Char()) As String
        Dim sReturn As String = ""

        'Copy Character Array to String Array, Converting in the process, then Join the Array to a string
        sReturn = Join(Array.ConvertAll(sCharacterArrayToTranslate, _
                            New Converter(Of Char, String)(AddressOf ChrToStr)), "")

        Return sReturn

    End Function


    ''' <summary>
    ''' Block Length must be set.  You can set the BlockLength for specific block sizes (Ex:  134).
    ''' Set UseControlRecord = False for files with specific block sizes (Default is True)
    ''' </summary>
    ''' <value>0</value>
    ''' <returns>Integer</returns>
    ''' <remarks></remarks>
    Public Property BlockLength() As Integer
        Get
            Return miBlockLength

        End Get
        Set(ByVal value As Integer)
            miBlockLength = value

        End Set
    End Property



    ''' <summary>
    ''' Determines whether a ControlKey is used to calculate RecordLength of valid data
    ''' </summary>
    ''' <value>Default value is True</value>
    ''' <returns>Boolean</returns>
    ''' <remarks></remarks>
    Public Property UseControlRecord() As Boolean
        Get
            Return mbUseControlRec

        End Get
        Set(ByVal value As Boolean)
            mbUseControlRec = value

        End Set
    End Property



    ''' <summary>
    ''' Ignores first record if set (Default is True)
    ''' </summary>
    ''' <value>Default is True</value>
    ''' <returns>Boolean</returns>
    ''' <remarks></remarks>
    Public Property IgnoreFirstRecord() As Boolean
        Get
            Return mbIgnoreFirstRecord

        End Get

        Set(ByVal value As Boolean)
            mbIgnoreFirstRecord = value

        End Set
    End Property



    ''' <summary>
    ''' Trims the left side of every string the specfied number of characters.  Default is 0.
    ''' </summary>
    ''' <value>Default is 0.</value>
    ''' <returns>Integer</returns>
    ''' <remarks></remarks>
    Public Property LTrim() As Integer
        Get
            Return miLTrim

        End Get

        Set(ByVal value As Integer)
            miLTrim = value

        End Set
    End Property


End Class

Answer 4

如果原始数据采用 EBCDIC 格式，则您的 COMP-3 字段已出现乱码。 FTP 进程已将 COMP-3 字段中的字节值从 EBCDIC 转换为 ASCII，这不是您想要的。 要纠正此问题，您可以：

1) 使用 BINARY 模式进行传输，以便获得原始 EBCDIC 数据。 然后，将 COMP-3 字段转换为数字，并将记录上的任何其他 EBCDIC 文本转换为 ASCII。 压缩字段将每个数字存储在半字节中，下半字节作为符号（F 为正值，其他值（通常为 D 或 E）为负值）。 将 123.4 存储在 PIC 999.99 USAGE COMP-3 中将是 X'01234F'（三个字节），将 -123 存储在同一字段中将是 X'01230D'。

2) 让发送者将该字段转换为 USAGE IS DISPLAY SIGN IS LEADING（或 TRAILING）数字字段。 这会将数字存储为 EBCDIC 数字字符串，并将符号作为单独的负号 (-) 或空白字符。 所有数字和符号在 FTP 传输上都正确转换为相应的 ASCII。

Answer 5

EBCDIC 转换的一些有用链接：

转换表 - 对于检查压缩十进制字段中的某些值很有用：
http://www.simotime.com/asc2ebc1.htm

msdn 中的代码页列表：
http://msdn.microsoft.com/en-us /library/dd317756(VS.85).aspx

以及一段在 C# 中转换字节数组字段的代码：

// 500 is the code page for IBM EBCDIC International 
System.Text.Encoding enc = new System.Text.Encoding(500);
string value = enc.GetString(byteArrayField);

Answer 6

EBCDIC 或 ASCII 中的打包字段相同。 不要对它们运行 EBCDIC 到 ASCII 的转换。 在 .Net 中，将它们转储到 byte[] 中。

您使用按位掩码和移位来打包/解包。
-- 但按位运算仅适用于 .Net 中的整数类型，因此您需要跳过一些环节！

优秀的 COBOL 或 C 艺术家可以为您指明正确的方向。

找到一位老家伙并支付你的会费（大约三杯啤酒就可以了）。

Answer 7

“ASCII 传输类型”将文件作为常规文本文件传输。 因此，当我们以 ASCII 传输类型传输打包的十进制或二进制数据文件时，文件会损坏。 “二进制传输类型”将以二进制模式传输数据，将文件作为二进制数据而不是文本数据处理。 所以这里我们必须使用Binary传输类型。
参考：https://www.codeproject.com/Tips/673240/ EBCDIC-to-ASCII-Converter

文件准备好后，下面是将压缩十进制转换为人类可读十进制的代码。

    using System;
    using System.Collections.Generic;
    using System.IO;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;

   namespace ConsoleApp2
   {
    class Program
    {
        static void Main(string[] args)
        {
            var path = @"C:\FileName.BIN.dat";
            var templates = new List<Template>
            {
                new Template{StartPos=1,CharLength=4,Type="AlphaNum"},
                new Template{StartPos=5,CharLength=1,Type="AlphaNum"},
                new Template{StartPos=6,CharLength=8,Type="AlphaNum"},
                new Template{StartPos=14,CharLength=1,Type="AlphaNum"},
                new Template{StartPos=46,CharLength=4,Type="Packed",DecimalPlace=2},
                new Template{StartPos=54,CharLength=5,Type="Packed",DecimalPlace=0},
                new Template{StartPos=60,CharLength=4,Type="Packed",DecimalPlace=2},
                new Template{StartPos=64,CharLength=1,Type="AlphaNum"}
            };

            var allBytes = File.ReadAllBytes(path);
            for (int i = 0; i < allBytes.Length; i += 66)
            {
                var IsLastline = (allBytes.Length - i) < 66;
                var lineLength = IsLastline ? 64 : 66;
                byte[] lineBytes = new byte[lineLength];
                Array.Copy(allBytes, i, lineBytes, 0, lineLength);


                var outArray = new string[templates.Count];
                int index = 0;
                foreach (var temp in templates)
                {
                    byte[] amoutBytes = new byte[temp.CharLength];
                    Array.Copy(lineBytes, temp.StartPos - 1, amoutBytes, 0, 
    temp.CharLength);
                    var final = "";
                    if (temp.Type == "Packed")
                    {
                        final = Unpack(amoutBytes, temp.DecimalPlace).ToString();
                    }
                    else
                    {
                        final = ConvertEbcdicString(amoutBytes);
                    }

                    outArray[index] = final;
                    index++;

                }

                Console.WriteLine(string.Join(" ", outArray));

            }

            Console.ReadLine();
        }


        private static string ConvertEbcdicString(byte[] ebcdicBytes)
        {
            if (ebcdicBytes.All(p => p == 0x00 || p == 0xFF))
            {
                //Every byte is either 0x00 or 0xFF (fillers)
                return string.Empty;
            }

            Encoding ebcdicEnc = Encoding.GetEncoding("IBM037");
            string result = ebcdicEnc.GetString(ebcdicBytes); // convert EBCDIC Bytes -> 
    Unicode string
            return result;
        }

        private static Decimal Unpack(byte[] inp, int scale)
        {
            long lo = 0;
            long mid = 0;
            long hi = 0;
            bool isNegative;

            // this nybble stores only the sign, not a digit.  
            // "C" hex is positive, "D" hex is negative, AlphaNumd "F" hex is unsigned. 
            var ff = nibble(inp, 0);
            switch (ff)
            {
                case 0x0D:
                    isNegative = true;
                    break;
                case 0x0F:
                case 0x0C:
                    isNegative = false;
                    break;
                default:
                    throw new Exception("Bad sign nibble");
            }
            long intermediate;
            long carry;
            long digit;
            for (int j = inp.Length * 2 - 1; j > 0; j--)
            {
                // multiply by 10
                intermediate = lo * 10;
                lo = intermediate & 0xffffffff;
                carry = intermediate >> 32;
                intermediate = mid * 10 + carry;
                mid = intermediate & 0xffffffff;
                carry = intermediate >> 32;
                intermediate = hi * 10 + carry;
                hi = intermediate & 0xffffffff;
                carry = intermediate >> 32;
                // By limiting input length to 14, we ensure overflow will never occur

                digit = nibble(inp, j);
                if (digit > 9)
                {
                    throw new Exception("Bad digit");
                }
                intermediate = lo + digit;
                lo = intermediate & 0xffffffff;
                carry = intermediate >> 32;
                if (carry > 0)
                {
                    intermediate = mid + carry;
                    mid = intermediate & 0xffffffff;
                    carry = intermediate >> 32;
                    if (carry > 0)
                    {
                        intermediate = hi + carry;
                        hi = intermediate & 0xffffffff;
                        carry = intermediate >> 32;
                        // carry should never be non-zero. Back up with validation
                    }
                }
            }
            return new Decimal((int)lo, (int)mid, (int)hi, isNegative, (byte)scale);
        }

        private static int nibble(byte[] inp, int nibbleNo)
        {
            int b = inp[inp.Length - 1 - nibbleNo / 2];
            return (nibbleNo % 2 == 0) ? (b & 0x0000000F) : (b >> 4);
        }

        class Template
        {
            public string Name { get; set; }
            public string Type { get; set; }
            public int StartPos { get; set; }
            public int CharLength { get; set; }
            public int DecimalPlace { get; set; }
        }
    }
   }

Answer 8

文件必须以二进制形式传输。 这是一种更短的方法：

using System.Linq;

namespace SomeNamespace
{
    public static class SomeExtensionClass
    {
        /// <summary>
        /// computes the actual decimal value from an IBM "Packed Decimal" 9(x)v9 (COBOL) format
        /// </summary>
        /// <param name="value">byte[]</param>
        /// <param name="precision">byte; decimal places, default 2</param>
        /// <returns>decimal</returns>
        public static decimal FromPackedDecimal(this byte[] value, byte precision = 2)
        {
            if (value.Length < 1)
            {
                throw new System.InvalidOperationException("Cannot unpack empty bytes.");
            }
            double power = System.Math.Pow(10, precision);
            if (power > long.MaxValue)
            {
                throw new System.InvalidOperationException(
                    $"Precision too large for valid calculation: {precision}");
            }
            string hex = System.BitConverter.ToString(value).Replace("-", "");
            var bytes = Enumerable.Range(0, hex.Length)
                     .Select(x => System.Convert.ToByte($"0{hex.Substring(x, 1)}", 16))
                     .ToList();
            long place = 1;
            decimal ret = 0;
            for (int i = bytes.Count - 2; i > -1; i--)
            {
                ret += (bytes[i] * place);
                place *= 10;
            }
            ret /= (long)power;
            return (bytes.Last() & (1 << 7)) != 0 ? ret * -1 : ret;
        }
    }
}