Explanation of CopyMemory

[Ante]

Yes, but if this function had to be recoded w/o using copymemory, what would it look like?

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Function Makedword(Value as long) as string
if value >= 0 then
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr((value mod (256^4)) \ (256^3))
else
value=value + 2147483648#
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr(((value mod (256^4)) \ (256^3))+128)
end if
End Function


notice they are backward slashes (\), which mean integer division, not normal division

if its not the above, then add Makedword=strreverse(makedword) right below the "End if"

[Joe[x86]]

Yes, but if this function had to be recoded w/o using copymemory, what would it look like?

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Function Makedword(Value as long) as string
if value >= 0 then
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr((value mod (256^4)) \ (256^3))
else
value=value + 2147483648#
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr(((value mod (256^4)) \ (256^3))+128)
end if
End Function


notice they are backward slashes (\), which mean integer division, not normal division

if its not the above, then add Makedword=strreverse(makedword) right below the "End if"

OH DEAR GOD THAT HURT, lol.

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Function MakeDWORD(Value as Long) As String
    Dim RET as String * 4
    Mid(RET, 1, 1) = Value And &HFF000000
    Mid(RET, 2, 1) = Value And &HFF0000
    Mid(RET, 3, 1) = Value And &HFF00
    Mid(RET, 4, 1) = Value And &HFF
    MakeDWORD = RET
End Function

Note that you're doing three bad things:
1. Using return as a variable.
2. Concatenating to a string that has no contents.
3. Modifying a value passed to the function with out intention of making a ByRef return.

I don't even know what that whole if is about.

[Ante]

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Function MakeDWORD(Value as Long) As String
    Dim RET as String * 4
    Mid(RET, 1, 1) = Value And &HFF000000
    Mid(RET, 2, 1) = Value And &HFF0000
    Mid(RET, 3, 1) = Value And &HFF00
    Mid(RET, 4, 1) = Value And &HFF
    MakeDWORD = RET
End Function

that's setting values of longs into chars. for example, if the value is &H11111111, the first line will read Mid(RET, 1, 1) = &H11000000. at least add chr to convert it to string. make sure to shift it over several places

[l2k-Shadow]

FYI, neither one of those functions work.

[l)ragon]

Frozen's will also overflow at random for no reason btw, can tell you this without even testing it.
You should never use a straight out value of 256 in that manor.

[Ante]

FYI, neither one of those functions work.

does mine work if u add Makedword=strreverse(makedword) at the end of the function?

[l2k-Shadow]

FYI, neither one of those functions work.

does mine work if u add Makedword=strreverse(makedword) at the end of the function?

lol... no it overflows on the first statement you can see it from the code.

[Joe[x86]]

Oh yeah.. add Chr() to mine.

I'm so used to byte[] now.

[l2k-Shadow]

x86] link=topic=15573.msg165117#msg165117 date=1171830197]
Oh yeah.. add Chr() to mine.

I'm so used to byte[] now.

No that won't work either, you are forgetting that all variables in VB except char are signed. You'd have to do something like this to overcome that barrier (this won't work in all cases such as VB will think that &HFFFF = &HFFFFFFFF because both produce same result, -1.. therefore you'd have to have multiple functions recognizing each one, so if you must not use RtlMoveMemory, you'd best go with the Chr$(eachbyte of the DWORD) function as postead earlier):

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Function MakeDWORD(Value As Long) As String
Dim Outbuf As String, nLng As Long

    Outbuf = Chr$((Value And &HFF))
   
    nLng = (((Value And &HFF00) \ (2 ^ 8)) Mod 256)
    If nLng < 0 Then nLng = (nLng + 256)
    Outbuf = Outbuf & Chr$(nLng)
   
    nLng = (((Value And &HFF0000) \ (2 ^ 16)) Mod 256)
    If nLng < 0 Then nLng = (nLng + 256)
    Outbuf = Outbuf & Chr$(nLng)
   
    nLng = (((Value And &HFF000000) \ (2 ^ 24)) Mod 256)
    If nLng < 0 Then nLng = (nLng + 256)
    Outbuf = Outbuf & Chr$(nLng)
   
    MakeDWORD = Outbuf
End Function


[Ante]

FYI, neither one of those functions work.

does mine work if u add Makedword=strreverse(makedword) at the end of the function?

lol... no it overflows on the first statement you can see it from the code.

did u mean the if value >= 0 then line? cuz theres no place for that to overflow
i can't imagine which other line it could overflow from...every chr() has a value within it that is positive and less than 256
and the negative values are bumped into positive with that line, and put back into "negative" with the last char

[l2k-Shadow]

FYI, neither one of those functions work.

does mine work if u add Makedword=strreverse(makedword) at the end of the function?

lol... no it overflows on the first statement you can see it from the code.

did u mean the if value >= 0 then line? cuz theres no place for that to overflow
i can't imagine which other line it could overflow from...every chr() has a value within it that is positive and less than 256
and the negative values are bumped into positive with that line, and put back into "negative" with the last char

no i mean the statement after value >=0 line. it's because VB does math operations using long variables.. and (256 ^ 4) is &HFFFFFFFF which is an unsigned long, however since longs in VB are signed, overflow occurs.

[Ante]

hm...
u coulda jus doen this then

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Function Makedword(Value as long) as string
if value >= 0 then
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr(value \ (256^3)
else
value=value + 2147483648#
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr((value  \ (256^3))+128)
end if
End Function


[Imperceptus]

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[code]copy memory is really usefull, especially for filling vb types which can be build alot like cstructs

double = 8bytes
long = 4bytes
integer = 2bytes
byte = 1byte

to answer your question, without copymem that function looks like

function long2str(byval n as long) as string

  long2str = _
    chr((n and &HFF000000&) mod 256) & _
    chr((n and &H00FF0000&) mod 256) & _
    chr((n and &H0000FF00&) mod 256) & _
    chr(n and &H000000FF&)

end function[/code]

or backwards... dont know offhand, too lazy for testing!

omg this post was more then 3 months old when you replied to it. jeez.

[l2k-Shadow]

hm...
u coulda jus doen this then

Code Select Expand


Function Makedword(Value as long) as string
if value >= 0 then
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr(value \ (256^3)
else
value=value + 2147483648#
makedword = makedword & chr(value mod 256) & chr((value mod (256^2)) \ (256^1)) & chr((value mod (256^3)) \ (256^2)) & chr((value  \ (256^3))+128)
end if
End Function


Then your function produces the same result as any MakeDWORD VB function.. you get the -1 problem where &HFFFF = &HFFFFFFFF and produces ÿÿÿÿ if you input &HFFFF or &HFFFFFFFF...