base64算法，是不是不支持汉字啊？？

[mendel]

这样逆算后得到的是空值？？

dim a,b,c
a="中国"
b=base64encode(a)
c=base64decode(b)

[mendel]

现在找到了加密中文的办法，在ASP中测试通过，但是为什么在VB中失败呢？
代码如下：



Function strUnicodeLen(asContents)
'计算unicode字符串的Ansi编码的长度
asContents1 = "a" & asContents
len1 = Len(asContents1)
k = 0
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)
'将Unicode编码的字符串，转换成Ansi编码的字符串
strUnicode2Ansi = ""
len1 = Len(asContents)
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)
'将Ansi编码的字符串，转换成Unicode编码的字符串
strAnsi2Unicode = ""
len1 = LenB(asContents)
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)
'将Ansi编码的字符串进行Base64编码
'asContents应当是ANSI编码的字符串（二进制的字符串也可以）
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 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))
'补足位数是为了便于计算

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_CHARACTERS, ((Byte1 And 252) \ 4) + 1, 1)
Char2 = MidB(sBASE_64_CHARACTERS, (((Byte2 And 240) \ 16) Or (SaveBits1 * 16) And &HFF) + 1, 1)
Char3 = MidB(sBASE_64_CHARACTERS, (((Byte3 And 192) \ 64) Or (SaveBits2 * 4) And &HFF) + 1, 1)
Char4 = MidB(sBASE_64_CHARACTERS, (Byte3 And 63) + 1, 1)
lsGroup64 = Char1 & Char2 & Char3 & Char4

lsResult = lsResult & lsGroup64
Next

'处理最后剩余的几个字符
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_CHARACTERS, ((Byte1 And 252) \ 4) + 1, 1)
Char2 = MidB(sBASE_64_CHARACTERS, (((Byte2 And 240) \ 16) Or (SaveBits1 * 16) And &HFF) + 1, 1)
Char3 = MidB(sBASE_64_CHARACTERS, (((Byte3 And 192) \ 64) Or (SaveBits2 * 4) And &HFF) + 1, 1)

If M3 = 1 Then
lsGroup64 = Char1 & Char2 & ChrB(61) & ChrB(61) '用=号补足位数
Else
lsGroup64 = Char1 & Char2 & Char3 & ChrB(61) '用=号补足位数
End If

lsResult = lsResult & lsGroup64
End If

Base64encode = lsResult

End Function


Function Base64decode(asContents)
'将Base64编码字符串转换成Ansi编码的字符串
'asContents应当也是ANSI编码的字符串（二进制的字符串也可以）
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
'字符串长度应当是4的倍数
Base64decode = ""
Exit Function
End If

'判断最后一位是不是 = 号
'判断倒数第二位是不是 = 号
'这里m4表示最后剩余的需要单独处理的字符个数
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_CHARACTERS, MidB(lsGroup64, 1, 1)) - 1
Char2 = InStrB(sBASE_64_CHARACTERS, MidB(lsGroup64, 2, 1)) - 1
Char3 = InStrB(sBASE_64_CHARACTERS, MidB(lsGroup64, 3, 1)) - 1
Char4 = InStrB(sBASE_64_CHARACTERS, 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

'处理最后剩余的几个字符
If M4 > 0 Then
lsGroupBinary = ""
lsGroup64 = MidB(asContents, len2 + 1, M4) & ChrB(65) 'chr(65)=A，转换成值为0
If M4 = 2 Then '补足4位，是为了便于计算
lsGroup64 = lsGroup64 & ChrB(65)
End If
Char1 = InStrB(sBASE_64_CHARACTERS, MidB(lsGroup64, 1, 1)) - 1
Char2 = InStrB(sBASE_64_CHARACTERS, MidB(lsGroup64, 2, 1)) - 1
Char3 = InStrB(sBASE_64_CHARACTERS, MidB(lsGroup64, 3, 1)) - 1
Char4 = InStrB(sBASE_64_CHARACTERS, 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

Private Sub Command1_Click()
Text1.Text = Base64encode("中国")
End Sub

Private Sub Form_Load()
sBASE_64_CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
sBASE_64_CHARACTERS = strUnicode2Ansi(sBASE_64_CHARACTERS)
End Sub


出错信息为：

实时错误“5”
无效的过程调用或参数。

也就是这行出错：
If M3 > 0 Then asContents = asContents & String(3 - M3, ChrB(0))
'补足位数是为了便于计算







是什么问题啊？谢谢

[rainstormmaster]

Function Base64decode(asContents)
'将Base64编码字符串转换成Ansi编码的字符串
'asContents应当也是ANSI编码的字符串（二进制的字符串也可以）

"中国"不是ANSI编码的字符串，要用strconv转一下，类似这样：
s = StrConv(s, vbFromUnicode)

[mendel]

我把代码加到base64encode中，出错了，提示如下：

实时错误“5”
无效的过程调用或参数。

也就是这行出错：

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



我已经在BASE64ENCODE过程中加上了
asContents = StrConv(asContents,vbFromUnicode)

[rainstormmaster]

在调用时转一下就可以了，自定义函数不用修改

[mendel]

我这样改了，但是结果不对，是空白的：

Dim aaa
aaa = Base64encode(StrConv("中国", vbFromUnicode))
Text1.Text = Base64decode(StrConv(aaa, vbFromUnicode))


为什么呢？

[mendel]

请大家帮个忙，分不够我再加！谢谢

[mendel]

你好 rainstormmaster(rainstormmaster) ，我按你的方法，可是还是错的~

Dim aaa
aaa = Base64encode(StrConv("中国", vbFromUnicode))
Text1.Text = aaa


出错提示还是那个“实时错误5“

[mendel]

你好，RAINSTORMMASTER，请问这个语句要加在什么地方呢？谢谢