form1.frm

一个利用VB实现的CRC32程序

VERSION 5.00
Object = "{F9043C88-F6F2-101A-A3C9-08002B2F49FB}#1.2#0"; "comdlg32.ocx"
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3090
   ClientLeft      =   60
   ClientTop       =   450
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3090
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   WindowState     =   2  'Maximized
   Begin VB.CommandButton Command1 
      Caption         =   "计算CRC"
      Height          =   615
      Left            =   3600
      TabIndex        =   4
      Top             =   960
      Width           =   1695
   End
   Begin VB.TextBox Text1 
      Height          =   2535
      Left            =   3360
      MultiLine       =   -1  'True
      ScrollBars      =   2  'Vertical
      TabIndex        =   2
      Text            =   "Form1.frx":0000
      Top             =   2160
      Width           =   3015
   End
   Begin MSComDlg.CommonDialog CDlg_File 
      Left            =   1200
      Top             =   360
      _ExtentX        =   847
      _ExtentY        =   847
      _Version        =   393216
   End
   Begin VB.TextBox Txt_CJ 
      Height          =   3015
      Left            =   840
      MultiLine       =   -1  'True
      ScrollBars      =   2  'Vertical
      TabIndex        =   1
      Top             =   1800
      Width           =   2055
   End
   Begin VB.CommandButton readtable 
      Caption         =   "读取CRC32表"
      Height          =   615
      Left            =   840
      TabIndex        =   0
      Top             =   960
      Width           =   1815
   End
   Begin VB.Label Label2 
      Caption         =   "输入的字符串及生成CRC码："
      Height          =   375
      Left            =   3480
      TabIndex        =   3
      Top             =   1800
      Width           =   2535
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit

Dim Table_CRC(0 To 255) As Long           '生成表



Public Function CRC32(aData() As Byte, ByVal aSize As Long) As Long
    Dim i As Long, t1 As Long, t2 As Long, nAccum As Long
    
        nAccum = 0

            For i = 0 To aSize - 1
            t1 = (nAccum And &H7FFFFF) * &H100
            t2 = (nAccum) / &H1000000
            nAccum = t1 Xor (Table_CRC((t2 Xor aData(i)) And &HFF))
            Next i

        CRC32 = nAccum
End Function

Private Sub Command1_Click()

Dim str1, str2 As String, i As Integer
Dim data(0 To 10) As Byte, t As Byte, k, j As Integer

k = 0
j = 0

           For i = 0 To 9
           data(i) = i + 48
           Next i

           t = data(k)
           data(k) = data(j)
           data(j) = t

            
            

Text1.Text = CRC32(data(), 10)


End Sub


Private Sub readtable_Click()
'==================================导入CRC32表的数据

   
    Dim i As Long, j As Long, k As Long
    Dim str1 As String, str2 As String, str3 As String, str4 As String
    Dim File_No As Integer, strData
    
    
        str1 = App.Path
        str2 = "数据文件(*.txt)|*.txt"

            With CDlg_File
            .InitDir = str1
            .FileName = ""
            .DialogTitle = "打开"
            .CancelError = False
            .Filter = str2
            .Flags = &H1004
            .ShowOpen
                If Len(.FileName) = 0 Then
                Exit Sub
                End If
            str3 = .FileName
            End With
    
        On Error Resume Next
        
'--------------------------------------------------------
     File_No = FreeFile(1)
        Open str3 For Input As #File_No
        
        str4 = ""
         For i = 0 To 255
        Line Input #File_No, str1
        strData = Split(str1, ",")
        str2 = strData(0)
        Table_CRC(i) = strData(1)
        
            str4 = str4 + str2 + "  " + Str(Table_CRC(i)) + vbCrLf
         Next i
        Txt_CJ.Text = str4
  Close #File_No
End Sub