Android Question Bit.And 0xFF can't function

[52manhua]

I have checked all this afternoon, can't figure out the reason.

Here is my test code :

    Dim key(9) As Byte
     key=Array As Byte(-24,43,-53,67,78,82,91,245,218,190)
          Dim mstr="dsfsdfsdfsdf"
          Dim k As Int=0,j As Int=0
       
          For i = 0 To key.Length-1
            If key(i)<0 Then
                Log("err" & " " & i & key(i))
                key(i)=Bit.And(0xFF,key(i))     
                Log("c " & key(i))
            End If
         
            k = key(i) / mstr.Length
            j = key(i) Mod mstr.Length
            Log("k=" & k & "j=" & j & "i=" & i & "key(i)=" & key(i))         
          Next

As you see, I want to change the Key(i) always to be the Positive value, but failed ~
Any help is Welcome ,Thank you!

 

[sorex]

why don't you use abs() ?

 

[52manhua]

why don't you use abs() ?

It's part of a encrypt .

I must get the right byte value~

 

[sorex]

you wrote that you want the positive value of key(i) and abs(key(i)) is giving you that.

what goes wrong then?

 

[52manhua]

you wrote that you want the positive value of key(i) and abs(key(i)) is giving you that.

what goes wrong then?

OK, Maybe there is some expression problem, to be right, I need the 0xFF & val value, not just positive value

As the title says, I want to use 0xFF and to do this, but can't work ~ so be it.

 

[sorex]

but 0xff of a byte is the byte value.

 

[52manhua]

OK, Maybe there is some expression problem, to be right, I need the 0xFF & val value, not just positive value

Thanks for mention that,

but 0xff of a byte is the byte value.

To be exactly, I want change a vb6 program to b4a ,then I found b4a value is signed ,someone say use 0xFF can change it
Then I get this result.
what's right way to change it to vb6 style byte ?

 

[sorex]

if the value is -10 do you want it to be 10 or still -10?

or do you want to keep adding values and then do the and FF ?

 

[sorex]

try this

Log(    Bit.ToHexString(-10+256)    )

gives you the expected 0XF6 and not 0xFFFFFFF6

altho it doesn't matter when you store it back into that byte array.

 

[52manhua]

try this

Log(    Bit.ToHexString(-10+256)    )

gives you the expected 0XF6 and not 0xFFFFFFF6

altho it doesn't matter when you store it back into that byte array.

Thank you fo your help!

After all, I find the way to change the encrypt/decode program,
It's a Character encoding problem, I change the character to gb2312,
Use the int value replace origin byte variable, no negative, & 0xFF works right~
the word runs right ...
THX