base64로 변환 (인코딩/디코딩) 하는 함수 > 기술자료

Option Explicit

Dim sBASE_64_CHARACTERS, sBASE_64_CHARACTERSansi
sBASE_64_CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
sBASE_64_CHARACTERSansi = strUnicode2Ansi(sBASE_64_CHARACTERS)


Function strUnicodeLen(asContents)
Dim asContents1 : asContents1 ="a" & asContents
Dim Len1 : Len1=Len(asContents1)
Dim K : K=0
Dim I, Asc1

For I=1 To Len1
Asc1 = asc(mid(asContents1,I,1))
IF Asc1 < 0 Then Asc1 = 65536 + Asc1
IF Asc1 > 255 Then
K = K + 2
ELSE
K = K + 1
End IF
Next

strUnicodeLen = K - 1
End Function

Function strUnicode2Ansi(asContents)
Dim Len1 : Len1 = Len(asContents)
Dim I, VarCHAR, VarASC, VarHEX, VarLOW, VarHIGH

strUnicode2Ansi = ""

For I = 1 to Len1
VarCHAR = Mid(asContents,I,1)
VarASC = Asc(VarCHAR)
IF VarASC < 0 Then VarASC = VarASC + 65536
IF VarASC > 255 Then
VarHEX = Hex(VarASC)
VarLOW = Left(VarHEX,2)
VarHIGH = Right(VarHEX,2)
strUnicode2Ansi = strUnicode2Ansi & ChrB("&H" & VarLOW ) & ChrB("&H" & VarHIGH )
Else
strUnicode2Ansi = strUnicode2Ansi & ChrB(VarASC)
End IF
Next
End Function



Function strAnsi2Unicode(asContents)
Dim Len1 : Len1 = LenB(asContents)
Dim VarCHAR, VarASC, I

strAnsi2Unicode = ""

IF Len1=0 Then Exit Function

For I=1 To Len1
VarCHAR = MidB(asContents,I,1)
VarASC = AscB(VarCHAR)
IF VarASC > 127 Then
strAnsi2Unicode = strAnsi2Unicode & Chr(AscW(MidB(asContents, I+1,1) & VarCHAR))
I = I + 1
Else
strAnsi2Unicode = strAnsi2Unicode & Chr(VarASC)
End IF
Next

End function

Function Base64encode(asContents)
Dim lnPosition
Dim lsResult
Dim Char1
Dim Char2
Dim Char3
Dim Char4
Dim Byte1
Dim Byte2
Dim Byte3
Dim SaveBits1
Dim SaveBits2
Dim lsGroupBinary
Dim lsGroup64
Dim M3, M4, Len1, Len2

Len1 =LenB(asContents)

IF Len1 < 1 Then
Base64encode = ""
Exit Function
End IF

M3=Len1 Mod 3

IF M3 > 0 Then asContents = asContents & String(3 - M3, ChrB(0))

IF m3 > 0 Then
Len1 = Len1 + (3 - M3)
Len2 = Len1 - 3
Else
Len2 = Len1
End IF

lsResult = ""

For lnPosition = 1 To Len2 Step 3
lsGroup64 = ""
lsGroupBinary = MidB(asContents, lnPosition, 3)

Byte1 = AscB(MidB(lsGroupBinary, 1, 1)) : SaveBits1 = Byte1 And 3
Byte2 = AscB(MidB(lsGroupBinary, 2, 1)) : SaveBits2 = Byte2 And 15
Byte3 = AscB(MidB(lsGroupBinary, 3, 1))

Char1 = MidB(sBASE_64_CHARACTERSansi, ((Byte1 And 252) \ 4) + 1, 1)
Char2 = MidB(sBASE_64_CHARACTERSansi, (((Byte2 And 240) \ 16) Or (SaveBits1 * 16) And &HFF) + 1, 1)
Char3 = MidB(sBASE_64_CHARACTERSansi, (((Byte3 And 192) \ 64) Or (SaveBits2 * 4) And &HFF) + 1, 1)
Char4 = MidB(sBASE_64_CHARACTERSansi, (Byte3 And 63) + 1, 1)
lsGroup64 = Char1 & Char2 & Char3 & Char4

lsResult = lsResult & lsGroup64
Next

IF M3 > 0 Then
lsGroup64 = ""
lsGroupBinary = MidB(asContents, Len2 + 1, 3)

Byte1 = AscB(MidB(lsGroupBinary, 1, 1)) : SaveBits1 = Byte1 And 3
Byte2 = AscB(MidB(lsGroupBinary, 2, 1)) : SaveBits2 = Byte2 And 15
Byte3 = AscB(MidB(lsGroupBinary, 3, 1))

Char1 = MidB(sBASE_64_CHARACTERSansi, ((Byte1 And 252) \ 4) + 1, 1)
Char2 = MidB(sBASE_64_CHARACTERSansi, (((Byte2 And 240) \ 16) Or (SaveBits1 * 16) And &HFF) + 1, 1)
Char3 = MidB(sBASE_64_CHARACTERSansi, (((Byte3 And 192) \ 64) Or (SaveBits2 * 4) And &HFF) + 1, 1)

IF M3=1 Then
lsGroup64 = Char1 & Char2 & ChrB(61) & ChrB(61)
Else
lsGroup64 = Char1 & Char2 & Char3 & ChrB(61)
End IF

lsResult = lsResult & lsGroup64
End IF

Base64encode = lsResult
End Function

Function Base64decode(asContents)
Dim lsResult
Dim lnPosition
Dim lsGroup64, lsGroupBinary
Dim Char1, Char2, Char3, Char4
Dim Byte1, Byte2, Byte3
Dim M4, Len1, Len2

Len1 = LenB(asContents)
M4 = Len1 Mod 4

IF Len1 < 1 Or M4 > 0 Then
Base64decode = ""
Exit Function
End IF

IF MidB(asContents, Len1, 1) = ChrB(61) Then M4 = 3
IF MidB(asContents, Len1-1, 1) = ChrB(61) Then M4 = 2

IF M4 = 0 Then
Len2 = Len1
Else
Len2 = Len1 - 4
End IF

For lnPosition = 1 To Len2 Step 4
lsGroupBinary = ""
lsGroup64 = MidB(asContents, lnPosition, 4)

Char1 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 1, 1)) - 1
Char2 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 2, 1)) - 1
Char3 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 3, 1)) - 1
Char4 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 4, 1)) - 1

Byte1 = ChrB(((Char2 And 48) \ 16) Or (Char1 * 4) And &HFF)
Byte2 = lsGroupBinary & ChrB(((Char3 And 60) \ 4) Or (Char2 * 16) And &HFF)
Byte3 = ChrB((((Char3 And 3) * 64) And &HFF) Or (Char4 And 63))
lsGroupBinary = Byte1 & Byte2 & Byte3

lsResult = lsResult & lsGroupBinary
Next

IF M4 > 0 Then
lsGroupBinary = ""
lsGroup64 = MidB(asContents, Len2 + 1, M4) & ChrB(65)
IF M4=2 Then
lsGroup64 = lsGroup64 & chrB(65)
End IF
Char1 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 1, 1)) - 1
Char2 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 2, 1)) - 1
Char3 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 3, 1)) - 1
Char4 = InStrB(sBASE_64_CHARACTERSansi, MidB(lsGroup64, 4, 1)) - 1

Byte1 = ChrB(((Char2 And 48) \ 16) Or (Char1 * 4) And &HFF)
Byte2 = lsGroupBinary & ChrB(((Char3 And 60) \ 4) Or (Char2 * 16) And &HFF)
Byte3 = ChrB((((Char3 And 3) * 64) And &HFF) Or (Char4 And 63))

IF M4=2 Then
lsGroupBinary = Byte1
elseIF M4=3 Then
lsGroupBinary = Byte1 & Byte2
end IF

lsResult = lsResult & lsGroupBinary
End IF

Base64decode = lsResult
End Function


'################################## 사용 샘플 ##################################
Dim ORIGNvalue : ORIGNvalue = "하완어환오라ㅓ고ㅓ엉ㅁㄹ22ㅁㅁ@@ㅇㅁㄹ;ㄴㅇaabcsdfaeerdfadf"
Dim EncodeA : EncodeA = strAnsi2Unicode(Base64encode(strUnicode2Ansi(ORIGNvalue)))
Dim DecodeA : DecodeA = strAnsi2Unicode(Base64decode(strUnicode2Ansi(EncodeA)))

response.write "------------------------------------------------------------------------<BR>"
response.write "lsResult : " & ORIGNvalue & "<BR>"
response.write "lsResult : " & EncodeA & "<BR>"
response.write "lsResult : " & DecodeA & "<BR>"
response.write "------------------------------------------------------------------------<BR>"

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