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'출저 : http://www.planet-source-code.com/vb/scripts/ShowCode.asp?txtCodeId=12638&lngWId=1
'CRC Checksum Class
'------------------------------------
'
'A very fast solution to calculate the
'CRC Checksum (at the moment CRC16 and
'CRC32 values) with the help of some
'pre-compiled assembler code
'
'(c) 2000, Fredrik Qvarfort
'
Option Explicit
Public Enum CRCAlgorithms
CRC16
CRC32
End Enum
Private m_Algorithm As Boolean
Private m_CRC16 As Long
Private m_CRC16Asm() As Byte
Private m_CRC16Init As Boolean
Private m_CRC16Table(0 To 255) As Long
Private m_CRC32 As Long
Private m_CRC32Asm() As Byte
Private m_CRC32Init As Boolean
Private m_CRC32Table(0 To 255) As Long
Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal Msg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
Public Function AddBytes(ByteArray() As Byte) As Variant
Dim ByteSize As Long
'We need to add a simple error trapping
'here because if the bytearray is not
'dimensioned we want it to just skip
'the assembler code call below
On Local Error GoTo NoData
'Precalculate the size of the byte array
ByteSize = UBound(ByteArray) - LBound(ByteArray) + 1
'No error trapping needed, if something
'goes bad below something is definitely
'fishy with your computer
On Local Error GoTo 0
'Run the pre-compiled assembler code
'for the current selected algorithm
Select Case m_Algorithm
Case CRC16
Call CallWindowProc(VarPtr(m_CRC16Asm(0)), VarPtr(m_CRC16), VarPtr(ByteArray(LBound(ByteArray))), VarPtr(m_CRC16Table(0)), ByteSize)
Case CRC32
Call CallWindowProc(VarPtr(m_CRC32Asm(0)), VarPtr(m_CRC32), VarPtr(ByteArray(LBound(ByteArray))), VarPtr(m_CRC32Table(0)), ByteSize)
End Select
NoData:
'Return the current CRC value
AddBytes = Value
End Function
Public Function AddString(Text As String) As Variant
'Convert the string into a byte array
'and send it to the function that can
'handle bytearrays
AddString = AddBytes(StrConv(Text, vbFromUnicode))
End Function
Public Property Let Algorithm(New_Value As CRCAlgorithms)
'Set the new algorithm
m_Algorithm = New_Value
'Make sure we have initialized the
'current selected algorithm
Select Case m_Algorithm
Case CRC16
If (Not m_CRC16Init) Then Call InitializeCRC16
Case CRC32
If (Not m_CRC32Init) Then Call InitializeCRC32
End Select
'Make sure we reset the data of the
'current selected algorithm
Call Clear
End Property
Public Property Get Algorithm() As CRCAlgorithms
Algorithm = m_Algorithm
End Property
Public Function CalculateBytes(ByteArray() As Byte) As Variant
'Reset the current CRC calculation
Call Clear
'Calculate the CRC from the bytearray
'and return the current CRC value
CalculateBytes = AddBytes(ByteArray)
End Function
Public Function CalculateFile(Filename As String) As Variant
On Error GoTo eR
Dim Filenr As Integer
Dim ByteArray() As Byte
'Make sure the file contains data
'to avoid errors later below
If (FileLen(Filename) = 0) Then Exit Function
'Open the file in binary mode, read
'the data into a bytearray and then
'close the file
Filenr = FreeFile
Open Filename For Binary As #Filenr
ReDim ByteArray(0 To LOF(Filenr) - 1)
Get #Filenr, , ByteArray()
Close #Filenr
'Now send the bytearray to the function
'that can calculate a CRC from it
CalculateFile = CalculateBytes(ByteArray)
Exit Function
eR:
CalculateFile = "1"
End Function
Public Function CalculateString(Text As String)
'Convert the string into a bytearray
'and send it to the function that
'calculates the CRC from a bytearray
CalculateString = CalculateBytes(StrConv(Text, vbFromUnicode))
End Function
Public Property Get Value() As Variant
Select Case m_Algorithm
Case CRC16
Value = (m_CRC16 And 65535)
Case CRC32
Value = (Not m_CRC32)
End Select
End Property
Public Property Let Value(New_Value As Variant)
Select Case m_Algorithm
Case CRC16
m_CRC16 = New_Value
Case CRC32
m_CRC32 = New_Value
End Select
End Property
Private Sub InitializeCRC16()
Dim i As Long
Dim j As Long
Dim k As Long
Dim CRC As Long
Dim sASM As String
'Create the fixed lookup-table, this
'is calculated because it won't take
'long and is only done once
For i = 0 To 255
k = i * 256
CRC = 0
For j = 0 To 7
If (((CRC Xor k) And 32768) = 32768) Then
CRC = (CRC * 2) Xor &H1021
Else
CRC = (CRC * 2)
End If
k = k * 2
Next
m_CRC16Table(i) = CRC '(CRC And 65535)
Next
'Create a bytearray to hold the
'precompiled assembler code
sASM = "5589E55756505351528B45088B008B750C8B7D108B4D1431DB8A1E30E3668B149F30C66689D0464975EF25FFFF00008B4D0889015A595B585E5F89EC5DC21000"
ReDim m_CRC16Asm(0 To Len(sASM) \ 2 - 1)
For i = 1 To Len(sASM) Step 2
m_CRC16Asm(i \ 2) = Val("&H" & Mid$(sASM, i, 2))
Next
'Mark the CRC16 algorithm as initialized
m_CRC16Init = True
End Sub
Public Sub Clear()
'Here can be sloppy and reset both
'crc variables (this procedure will
'be more advanced when adding more
'checksums algorithms..)
m_CRC16 = 0
m_CRC32 = &HFFFFFFFF
End Sub
Private Sub InitializeCRC32()
Dim i As Long
Dim sASM As String
m_CRC32Table(0) = &H0
m_CRC32Table(1) = &H77073096
m_CRC32Table(2) = &HEE0E612C
m_CRC32Table(3) = &H990951BA
m_CRC32Table(4) = &H76DC419
m_CRC32Table(5) = &H706AF48F
m_CRC32Table(6) = &HE963A535
m_CRC32Table(7) = &H9E6495A3
m_CRC32Table(8) = &HEDB8832
m_CRC32Table(9) = &H79DCB8A4
m_CRC32Table(10) = &HE0D5E91E
m_CRC32Table(11) = &H97D2D988
m_CRC32Table(12) = &H9B64C2B
m_CRC32Table(13) = &H7EB17CBD
m_CRC32Table(14) = &HE7B82D07
m_CRC32Table(15) = &H90BF1D91
m_CRC32Table(16) = &H1DB71064
m_CRC32Table(17) = &H6AB020F2
m_CRC32Table(18) = &HF3B97148
m_CRC32Table(19) = &H84BE41DE
m_CRC32Table(20) = &H1ADAD47D
m_CRC32Table(21) = &H6DDDE4EB
m_CRC32Table(22) = &HF4D4B551
m_CRC32Table(23) = &H83D385C7
m_CRC32Table(24) = &H136C9856
m_CRC32Table(25) = &H646BA8C0
m_CRC32Table(26) = &HFD62F97A
m_CRC32Table(27) = &H8A65C9EC
m_CRC32Table(28) = &H14015C4F
m_CRC32Table(29) = &H63066CD9
m_CRC32Table(30) = &HFA0F3D63
m_CRC32Table(31) = &H8D080DF5
m_CRC32Table(32) = &H3B6E20C8
m_CRC32Table(33) = &H4C69105E
m_CRC32Table(34) = &HD56041E4
m_CRC32Table(35) = &HA2677172
m_CRC32Table(36) = &H3C03E4D1
m_CRC32Table(37) = &H4B04D447
m_CRC32Table(38) = &HD20D85FD
m_CRC32Table(39) = &HA50AB56B
m_CRC32Table(40) = &H35B5A8FA
m_CRC32Table(41) = &H42B2986C
m_CRC32Table(42) = &HDBBBC9D6
m_CRC32Table(43) = &HACBCF940
m_CRC32Table(44) = &H32D86CE3
m_CRC32Table(45) = &H45DF5C75
m_CRC32Table(46) = &HDCD60DCF
m_CRC32Table(47) = &HABD13D59
m_CRC32Table(48) = &H26D930AC
m_CRC32Table(49) = &H51DE003A
m_CRC32Table(50) = &HC8D75180
m_CRC32Table(51) = &HBFD06116
m_CRC32Table(52) = &H21B4F4B5
m_CRC32Table(53) = &H56B3C423
m_CRC32Table(54) = &HCFBA9599
m_CRC32Table(55) = &HB8BDA50F
m_CRC32Table(56) = &H2802B89E
m_CRC32Table(57) = &H5F058808
m_CRC32Table(58) = &HC60CD9B2
m_CRC32Table(59) = &HB10BE924
m_CRC32Table(60) = &H2F6F7C87
m_CRC32Table(61) = &H58684C11
m_CRC32Table(62) = &HC1611DAB
m_CRC32Table(63) = &HB6662D3D
m_CRC32Table(64) = &H76DC4190
m_CRC32Table(65) = &H1DB7106
m_CRC32Table(66) = &H98D220BC
m_CRC32Table(67) = &HEFD5102A
m_CRC32Table(68) = &H71B18589
m_CRC32Table(69) = &H6B6B51F
m_CRC32Table(70) = &H9FBFE4A5
m_CRC32Table(71) = &HE8B8D433
m_CRC32Table(72) = &H7807C9A2
m_CRC32Table(73) = &HF00F934
m_CRC32Table(74) = &H9609A88E
m_CRC32Table(75) = &HE10E9818
m_CRC32Table(76) = &H7F6A0DBB
m_CRC32Table(77) = &H86D3D2D
m_CRC32Table(78) = &H91646C97
m_CRC32Table(79) = &HE6635C01
m_CRC32Table(80) = &H6B6B51F4
m_CRC32Table(81) = &H1C6C6162
m_CRC32Table(82) = &H856530D8
m_CRC32Table(83) = &HF262004E
m_CRC32Table(84) = &H6C0695ED
m_CRC32Table(85) = &H1B01A57B
m_CRC32Table(86) = &H8208F4C1
m_CRC32Table(87) = &HF50FC457
m_CRC32Table(88) = &H65B0D9C6
m_CRC32Table(89) = &H12B7E950
m_CRC32Table(90) = &H8BBEB8EA
m_CRC32Table(91) = &HFCB9887C
m_CRC32Table(92) = &H62DD1DDF
m_CRC32Table(93) = &H15DA2D49
m_CRC32Table(94) = &H8CD37CF3
m_CRC32Table(95) = &HFBD44C65
m_CRC32Table(96) = &H4DB26158
m_CRC32Table(97) = &H3AB551CE
m_CRC32Table(98) = &HA3BC0074
m_CRC32Table(99) = &HD4BB30E2
m_CRC32Table(100) = &H4ADFA541
m_CRC32Table(101) = &H3DD895D7
m_CRC32Table(102) = &HA4D1C46D
m_CRC32Table(103) = &HD3D6F4FB
m_CRC32Table(104) = &H4369E96A
m_CRC32Table(105) = &H346ED9FC
m_CRC32Table(106) = &HAD678846
m_CRC32Table(107) = &HDA60B8D0
m_CRC32Table(108) = &H44042D73
m_CRC32Table(109) = &H33031DE5
m_CRC32Table(110) = &HAA0A4C5F
m_CRC32Table(111) = &HDD0D7CC9
m_CRC32Table(112) = &H5005713C
m_CRC32Table(113) = &H270241AA
m_CRC32Table(114) = &HBE0B1010
m_CRC32Table(115) = &HC90C2086
m_CRC32Table(116) = &H5768B525
m_CRC32Table(117) = &H206F85B3
m_CRC32Table(118) = &HB966D409
m_CRC32Table(119) = &HCE61E49F
m_CRC32Table(120) = &H5EDEF90E
m_CRC32Table(121) = &H29D9C998
m_CRC32Table(122) = &HB0D09822
m_CRC32Table(123) = &HC7D7A8B4
m_CRC32Table(124) = &H59B33D17
m_CRC32Table(125) = &H2EB40D81
m_CRC32Table(126) = &HB7BD5C3B
m_CRC32Table(127) = &HC0BA6CAD
m_CRC32Table(128) = &HEDB88320
m_CRC32Table(129) = &H9ABFB3B6
m_CRC32Table(130) = &H3B6E20C
m_CRC32Table(131) = &H74B1D29A
m_CRC32Table(132) = &HEAD54739
m_CRC32Table(133) = &H9DD277AF
m_CRC32Table(134) = &H4DB2615
m_CRC32Table(135) = &H73DC1683
m_CRC32Table(136) = &HE3630B12
m_CRC32Table(137) = &H94643B84
m_CRC32Table(138) = &HD6D6A3E
m_CRC32Table(139) = &H7A6A5AA8
m_CRC32Table(140) = &HE40ECF0B
m_CRC32Table(141) = &H9309FF9D
m_CRC32Table(142) = &HA00AE27
m_CRC32Table(143) = &H7D079EB1
m_CRC32Table(144) = &HF00F9344
m_CRC32Table(145) = &H8708A3D2
m_CRC32Table(146) = &H1E01F268
m_CRC32Table(147) = &H6906C2FE
m_CRC32Table(148) = &HF762575D
m_CRC32Table(149) = &H806567CB
m_CRC32Table(150) = &H196C3671
m_CRC32Table(151) = &H6E6B06E7
m_CRC32Table(152) = &HFED41B76
m_CRC32Table(153) = &H89D32BE0
m_CRC32Table(154) = &H10DA7A5A
m_CRC32Table(155) = &H67DD4ACC
m_CRC32Table(156) = &HF9B9DF6F
m_CRC32Table(157) = &H8EBEEFF9
m_CRC32Table(158) = &H17B7BE43
m_CRC32Table(159) = &H60B08ED5
m_CRC32Table(160) = &HD6D6A3E8
m_CRC32Table(161) = &HA1D1937E
m_CRC32Table(162) = &H38D8C2C4
m_CRC32Table(163) = &H4FDFF252
m_CRC32Table(164) = &HD1BB67F1
m_CRC32Table(165) = &HA6BC5767
m_CRC32Table(166) = &H3FB506DD
m_CRC32Table(167) = &H48B2364B
m_CRC32Table(168) = &HD80D2BDA
m_CRC32Table(169) = &HAF0A1B4C
m_CRC32Table(170) = &H36034AF6
m_CRC32Table(171) = &H41047A60
m_CRC32Table(172) = &HDF60EFC3
m_CRC32Table(173) = &HA867DF55
m_CRC32Table(174) = &H316E8EEF
m_CRC32Table(175) = &H4669BE79
m_CRC32Table(176) = &HCB61B38C
m_CRC32Table(177) = &HBC66831A
m_CRC32Table(178) = &H256FD2A0
m_CRC32Table(179) = &H5268E236
m_CRC32Table(180) = &HCC0C7795
m_CRC32Table(181) = &HBB0B4703
m_CRC32Table(182) = &H220216B9
m_CRC32Table(183) = &H5505262F
m_CRC32Table(184) = &HC5BA3BBE
m_CRC32Table(185) = &HB2BD0B28
m_CRC32Table(186) = &H2BB45A92
m_CRC32Table(187) = &H5CB36A04
m_CRC32Table(188) = &HC2D7FFA7
m_CRC32Table(189) = &HB5D0CF31
m_CRC32Table(190) = &H2CD99E8B
m_CRC32Table(191) = &H5BDEAE1D
m_CRC32Table(192) = &H9B64C2B0
m_CRC32Table(193) = &HEC63F226
m_CRC32Table(194) = &H756AA39C
m_CRC32Table(195) = &H26D930A
m_CRC32Table(196) = &H9C0906A9
m_CRC32Table(197) = &HEB0E363F
m_CRC32Table(198) = &H72076785
m_CRC32Table(199) = &H5005713
m_CRC32Table(200) = &H95BF4A82
m_CRC32Table(201) = &HE2B87A14
m_CRC32Table(202) = &H7BB12BAE
m_CRC32Table(203) = &HCB61B38
m_CRC32Table(204) = &H92D28E9B
m_CRC32Table(205) = &HE5D5BE0D
m_CRC32Table(206) = &H7CDCEFB7
m_CRC32Table(207) = &HBDBDF21
m_CRC32Table(208) = &H86D3D2D4
m_CRC32Table(209) = &HF1D4E242
m_CRC32Table(210) = &H68DDB3F8
m_CRC32Table(211) = &H1FDA836E
m_CRC32Table(212) = &H81BE16CD
m_CRC32Table(213) = &HF6B9265B
m_CRC32Table(214) = &H6FB077E1
m_CRC32Table(215) = &H18B74777
m_CRC32Table(216) = &H88085AE6
m_CRC32Table(217) = &HFF0F6A70
m_CRC32Table(218) = &H66063BCA
m_CRC32Table(219) = &H11010B5C
m_CRC32Table(220) = &H8F659EFF
m_CRC32Table(221) = &HF862AE69
m_CRC32Table(222) = &H616BFFD3
m_CRC32Table(223) = &H166CCF45
m_CRC32Table(224) = &HA00AE278
m_CRC32Table(225) = &HD70DD2EE
m_CRC32Table(226) = &H4E048354
m_CRC32Table(227) = &H3903B3C2
m_CRC32Table(228) = &HA7672661
m_CRC32Table(229) = &HD06016F7
m_CRC32Table(230) = &H4969474D
m_CRC32Table(231) = &H3E6E77DB
m_CRC32Table(232) = &HAED16A4A
m_CRC32Table(233) = &HD9D65ADC
m_CRC32Table(234) = &H40DF0B66
m_CRC32Table(235) = &H37D83BF0
m_CRC32Table(236) = &HA9BCAE53
m_CRC32Table(237) = &HDEBB9EC5
m_CRC32Table(238) = &H47B2CF7F
m_CRC32Table(239) = &H30B5FFE9
m_CRC32Table(240) = &HBDBDF21C
m_CRC32Table(241) = &HCABAC28A
m_CRC32Table(242) = &H53B39330
m_CRC32Table(243) = &H24B4A3A6
m_CRC32Table(244) = &HBAD03605
m_CRC32Table(245) = &HCDD70693
m_CRC32Table(246) = &H54DE5729
m_CRC32Table(247) = &H23D967BF
m_CRC32Table(248) = &HB3667A2E
m_CRC32Table(249) = &HC4614AB8
m_CRC32Table(250) = &H5D681B02
m_CRC32Table(251) = &H2A6F2B94
m_CRC32Table(252) = &HB40BBE37
m_CRC32Table(253) = &HC30C8EA1
m_CRC32Table(254) = &H5A05DF1B
m_CRC32Table(255) = &H2D02EF8D
'Create a bytearray to hold the
'precompiled assembler code
sASM = "5589E557565053518B45088B008B750C8B7D108B4D1431DB8A1E30C3C1E80833049F464975F28B4D088901595B585E5F89EC5DC21000"
ReDim m_CRC32Asm(0 To Len(sASM) \ 2 - 1)
For i = 1 To Len(sASM) Step 2
m_CRC32Asm(i \ 2) = Val("&H" & Mid$(sASM, i, 2))
Next
'Mark the CRC32 algorithm as initialized
m_CRC32Init = True
End Sub
Private Sub Class_Initialize()
'The default algorithm is CRC32
Algorithm = CRC32
End Sub
