form1.frm

CRC的算法校验

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   3870
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5415
   LinkTopic       =   "Form1"
   ScaleHeight     =   3870
   ScaleWidth      =   5415
   StartUpPosition =   3  '窗口缺省
   Begin VB.ListBox List2 
      Height          =   1320
      Left            =   2400
      TabIndex        =   2
      Top             =   480
      Width           =   1815
   End
   Begin VB.CommandButton cmdst 
      Caption         =   "Command1"
      Height          =   495
      Left            =   2640
      TabIndex        =   1
      Top             =   3360
      Width           =   2175
   End
   Begin VB.ListBox List1 
      Height          =   3120
      Left            =   240
      TabIndex        =   0
      Top             =   360
      Width           =   1695
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Dim crc() As Byte
Dim d() As Byte

Private Sub cmdst_Click()
    Dim t As Byte
    
    If crc(0) = 0 And crc(1) = 0 Then
        For t = 1 To 6
            List1.AddItem d(t)
        Next t
    Else
        List1.AddItem "错误"
    End If
    cmdst.Enabled = False
    
        
End Sub

Private Sub Form_Load()
    Dim n, m As Byte
    Open "D:\ZL\vb\crc测试\txt.txt" For Input As 1
    
    For n = 1 To 8
        ReDim Preserve d(1 To n)
        Input #1, d(n)
    Next n
    Close 1
    crc = CRC16(d)
    For n = 0 To 1
        List2.AddItem crc(n)
    Next n
End Sub
Function CRC16(data() As Byte) As String
    Dim CRC16Lo, CRC16Hi, CL, CH, SaveLo, SaveHi As Byte
    Dim I As Integer
    Dim Flag As Integer
    CRC16Lo = &HFF
    CRC16Hi = &HFF
    CL = &H5
    CH = &H80
    For I = 1 To UBound(data)
        CRC16Lo = CRC16Lo Xor data(I)
        For Flag = 0 To 7
            SaveHi = CRC16Hi
            SaveLo = CRC16Lo
            CRC16Hi = CRC16Hi \ 2
            CRC16Lo = CRC16Lo \ 2
            If ((SaveHi And &H1) = &H1) Then
                CRC16Lo = CRC16Lo Or &H80
            End If
            If ((SaveLo And &H1) = &H1) Then
                CRC16Hi = CRC16Hi Xor CH
                CRC16Lo = CRC16Lo Xor CL
            End If
            Next Flag
        Next I
        Dim ReturnData(1) As Byte
        ReturnData(0) = CRC16Hi
        ReturnData(1) = CRC16Lo
        CRC16 = ReturnData
    End Function