a problem with copymem API

[Antony Clements]

i am using the following code

private var1 as Long
private var2 as Long
private var3 as Long

ReDim bytearray(0 To 3)
ReDim bytearray2(0 To 3)

For a = 0 To 3
bytearray(a) = Asc(Mid(DataSou rce, b, 1))
bytearray2(a) = Asc(Mid(DataSou rce2, c, 1))
b = b + 1
c = c + 1
Next a

var1 = IVbytearray(0) & IVbytearray(1) & IVbytearray(2) & IVbytearray(3)
var2 = IVbytearray2(0) & IVbytearray2(1) & IVbytearray2(2) & IVbytearray2(3)

CopyMemory var1, var1 Xor var2, 4
CopyMemory var1, var1 Xor var3, 4

an overflow error is sometimes thrown up in the copymemory api, how do i fix
it?

[J French]

On Thu, 15 Feb 2007 10:27:25 +1100, "Antony Clements"
<an************ *@optusnet.com. auwrote:

>i am using the following code

private var1 as Long
private var2 as Long
private var3 as Long

ReDim bytearray(0 To 3)
ReDim bytearray2(0 To 3)

For a = 0 To 3
bytearray(a) = Asc(Mid(DataSou rce, b, 1))
bytearray2(a) = Asc(Mid(DataSou rce2, c, 1))
b = b + 1
c = c + 1
Next a

var1 = IVbytearray(0) & IVbytearray(1) & IVbytearray(2) & IVbytearray(3)
var2 = IVbytearray2(0) & IVbytearray2(1) & IVbytearray2(2) & IVbytearray2(3)

CopyMemory var1, var1 Xor var2, 4
CopyMemory var1, var1 Xor var3, 4

an overflow error is sometimes thrown up in the copymemory api, how do i fix
it?

I can't make any sense of this code
- you don't use & for building a Long out of Bytes

If you described what you are trying to do, then maybe we can come up
with a suggestion.

[Antony Clements]

i modified the code after i posted this, it no longer throws up an error but
it still doesn't work correctly.

dim var1 var2 and var3 as long

ReDim IVbytearray(0 To 7)
ReDim IVbytearray2(0 To 7)

bytearray() = Mid(stream1, b, 8)
bytearray2() = Mid(stream2, c, 8) 'a messagebox here proves that at this
point, the data held in bytearray() is different than the data held in
bytearray2()

var1 = bytearray()
var2 = bytearray2() 'this is where the problem is as var2 returns the same
value as var1 even though the value in bytearray() is different to the value
in bytearray2().

Call CopyMemory(var1 , var1 Xor var2, 8)
Call CopyMemory(var1 , var1 Xor var3, 8)
now here is the problem. even though the data source for bytearray() and
bytearray2() are different, for some reason or other they both have the same
value. var2 needs to be a value from the second data source. i hope this is
a clear indication of what i am trying to do.

"J French" <er*****@nowher e.ukwrote in message
news:45******** ******@news.bto penworld.com...

On Thu, 15 Feb 2007 10:27:25 +1100, "Antony Clements"
<an************ *@optusnet.com. auwrote:

>>i am using the following code

private var1 as Long
private var2 as Long
private var3 as Long

ReDim bytearray(0 To 3)
ReDim bytearray2(0 To 3)

For a = 0 To 3
bytearray(a) = Asc(Mid(DataSou rce, b, 1))
bytearray2(a) = Asc(Mid(DataSou rce2, c, 1))
b = b + 1
c = c + 1
Next a

var1 = IVbytearray(0) & IVbytearray(1) & IVbytearray(2) & IVbytearray(3)
var2 = IVbytearray2(0) & IVbytearray2(1) & IVbytearray2(2) &
IVbytearray2( 3)

CopyMemory var1, var1 Xor var2, 4
CopyMemory var1, var1 Xor var3, 4

an overflow error is sometimes thrown up in the copymemory api, how do i
fix
it?

I can't make any sense of this code
- you don't use & for building a Long out of Bytes

If you described what you are trying to do, then maybe we can come up
with a suggestion.

[Dean Earley]

Antony Clements wrote:

i modified the code after i posted this, it no longer throws up an error but
it still doesn't work correctly.

dim var1 var2 and var3 as long

ReDim IVbytearray(0 To 7)
ReDim IVbytearray2(0 To 7)

These are redundant as they are replaced in the next block.

bytearray() = Mid(stream1, b, 8)
bytearray2() = Mid(stream2, c, 8) 'a messagebox here proves that at this
point, the data held in bytearray() is different than the data held in
bytearray2()

This copies a UNICODE string into the byte array.
This will be 16 bytes, every other one being a null character.

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

var1 = bytearray()
var2 = bytearray2() 'this is where the problem is as var2 returns the same
value as var1 even though the value in bytearray() is different to the value
in bytearray2().

From the code below, you can't join them up like this.
You will need to do the arithmetic manually (shifting and adding) or
copymemory from the byte array to a long.
Bear in mind that you can only fit 4 bytes in a long...

Call CopyMemory(var1 , var1 Xor var2, 8)
Call CopyMemory(var1 , var1 Xor var3, 8)

Be VERY careful as longs are still only 4 bytes.
you WILL be corrupting memory with this code.

now here is the problem. even though the data source for bytearray() and
bytearray2() are different, for some reason or other they both have the same
value. var2 needs to be a value from the second data source. i hope this is
a clear indication of what i am trying to do.

It still doesn't explain what you have and what results you want at the
end...

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems

[Dean Earley]

Dean Earley wrote:

Antony Clements wrote:

>bytearray() = Mid(stream1, b, 8)
bytearray2() = Mid(stream2, c, 8) 'a messagebox here proves that at
this point, the data held in bytearray() is different than the data
held in bytearray2()

This copies a UNICODE string into the byte array.
This will be 16 bytes, every other one being a null character.

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

This does assume a normal ANSI string. It will be longer if you have non
ANSI data in your string

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems

[Antony Clements]

if stream1 has a value of 1a2b3c4d i want bytearray() to return the asc
value of the string. the only way i know how to do this is take each
character convert to ascii and then place in a string and then place the
string in bytearray(). i'm looking for a simpler way. var1 and var2 are
always returning the value of 1306840 regardless. bytearray() will return
1a2b3c4d. i am copying the bytearray variables to long variables. the
problem will be solved once var1 and var2 are correct values.

"Dean Earley" <de*********@ic ode.co.ukwrote in message
news:45******** *************** @news.zen.co.uk ...

Antony Clements wrote:

>i modified the code after i posted this, it no longer throws up an error
but it still doesn't work correctly.

dim var1 var2 and var3 as long

ReDim IVbytearray(0 To 7)
ReDim IVbytearray2(0 To 7)

These are redundant as they are replaced in the next block.

>bytearray() = Mid(stream1, b, 8)
bytearray2() = Mid(stream2, c, 8) 'a messagebox here proves that at this
point, the data held in bytearray() is different than the data held in
bytearray2()

This copies a UNICODE string into the byte array.
This will be 16 bytes, every other one being a null character.

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

>var1 = bytearray()
var2 = bytearray2() 'this is where the problem is as var2 returns the
same value as var1 even though the value in bytearray() is different to
the value in bytearray2().

From the code below, you can't join them up like this.
You will need to do the arithmetic manually (shifting and adding) or
copymemory from the byte array to a long.
Bear in mind that you can only fit 4 bytes in a long...

>Call CopyMemory(var1 , var1 Xor var2, 8)
Call CopyMemory(var1 , var1 Xor var3, 8)

Be VERY careful as longs are still only 4 bytes.
you WILL be corrupting memory with this code.

>now here is the problem. even though the data source for bytearray() and
bytearray2() are different, for some reason or other they both have the
same value. var2 needs to be a value from the second data source. i hope
this is a clear indication of what i am trying to do.

It still doesn't explain what you have and what results you want at the
end...

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems

[Antony Clements]

the data is from the full ascii range
"Dean Earley" <de*********@ic ode.co.ukwrote in message
news:45******** **************@ news.zen.co.uk. ..

Dean Earley wrote:

>Antony Clements wrote:

>>bytearray() = Mid(stream1, b, 8)
bytearray2( ) = Mid(stream2, c, 8) 'a messagebox here proves that at this
point, the data held in bytearray() is different than the data held in
bytearray2( )

This copies a UNICODE string into the byte array.
This will be 16 bytes, every other one being a null character.

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

This does assume a normal ANSI string. It will be longer if you have non
ANSI data in your string

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems

[Antony Clements]

i eralilse what i said i'm trying to do is quite vague. the purpose of the
code is the core of a stream cipher where they key is defined as

key = var1 xor var2 xor var3 where var3 is (2147483647 * rnd). what happens
next is cipherbyte = chr((messagebyt e xor key) mod 256)

>Call CopyMemory(var1 , var1 Xor var2, 8)
Call CopyMemory(var1 , var1 Xor var3, 8)

does actually work as written.

the problem is that var1 and var2 are always the same constant no matter
what the source is.

"Dean Earley" <de*********@ic ode.co.ukwrote in message
news:45******** *************** @news.zen.co.uk ...

Antony Clements wrote:

>i modified the code after i posted this, it no longer throws up an error
but it still doesn't work correctly.

dim var1 var2 and var3 as long

ReDim IVbytearray(0 To 7)
ReDim IVbytearray2(0 To 7)

These are redundant as they are replaced in the next block.

>bytearray() = Mid(stream1, b, 8)
bytearray2() = Mid(stream2, c, 8) 'a messagebox here proves that at this
point, the data held in bytearray() is different than the data held in
bytearray2()

This copies a UNICODE string into the byte array.
This will be 16 bytes, every other one being a null character.

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

>var1 = bytearray()
var2 = bytearray2() 'this is where the problem is as var2 returns the
same value as var1 even though the value in bytearray() is different to
the value in bytearray2().

From the code below, you can't join them up like this.
You will need to do the arithmetic manually (shifting and adding) or
copymemory from the byte array to a long.
Bear in mind that you can only fit 4 bytes in a long...

>Call CopyMemory(var1 , var1 Xor var2, 8)
Call CopyMemory(var1 , var1 Xor var3, 8)

Be VERY careful as longs are still only 4 bytes.
you WILL be corrupting memory with this code.

>now here is the problem. even though the data source for bytearray() and
bytearray2() are different, for some reason or other they both have the
same value. var2 needs to be a value from the second data source. i hope
this is a clear indication of what i am trying to do.

It still doesn't explain what you have and what results you want at the
end...

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems

[J French]

On Fri, 16 Feb 2007 09:46:04 +1100, "Antony Clements"
<an************ *@optusnet.com. auwrote:

>if stream1 has a value of 1a2b3c4d i want bytearray() to return the asc
value of the string. the only way i know how to do this is take each
character convert to ascii and then place in a string and then place the
string in bytearray(). i'm looking for a simpler way. var1 and var2 are
always returning the value of 1306840 regardless. bytearray() will return
1a2b3c4d. i am copying the bytearray variables to long variables. the
problem will be solved once var1 and var2 are correct values.

I still don't follow what you are trying to do.

It looks as if you want to compute some sort of 32 bit number from an
8 character String.

[Dean Earley]

Antony Clements wrote:

if stream1 has a value of 1a2b3c4d i want bytearray() to return the asc
value of the string. the only way i know how to do this is take each
character convert to ascii and then place in a string and then place the
string in bytearray().

As I said...

If you want each character as an item in the array, then you want:
bytearray = StrConv(string, vbFromUnicode)

From a string of "1a2b3c4d", this will give you an 8 item array
containing: 49, 97, 50, 98, 51, 99, 52, 100,

IF however, you want the 32bit equivalent of that hex encoded string (if
it is hex) then you will need to manually split it on every two
characters and pass it through val("&H" & hexvalue) and store each part
in the array.

--
Dean Earley (de*********@ic ode.co.uk)
i-Catcher Development Team

iCode Systems