How to Convert Byte Array to Int32 (Big-endian)

[Charles Law]

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles

[Cor Ligthert]

Charles,

We have a long time not seen you, so welcome back,

Maybe a crazy idea for you, however multiplying and adding?

Cor

[Herfried K. Wagner [MVP]]

"Charles Law" <bl***@nowhere. com> schrieb:

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

You may want to reverse the byte array before using 'BitConverter'.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Charles Law]

Hi Cor

I haven't really been away, just a bit quiet. I did respond to someone the
other day about a serial comms issue crashing their prog, but no word yet
whether it fixed the problem.

Maybe a crazy idea for you, however multiplying and adding?
Yes, that is currently what I do, or rather what the VB6 code that I am
converting does. I was just looking for a native .NET way to do it. It seems
to me that there should be a switch, or extra parameter to pass that allows
one to specify big or little-endianness, but I haven't spotted it.

Charles
"Cor Ligthert" <no************ @planet.nl> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. .. Charles,

We have a long time not seen you, so welcome back,

Maybe a crazy idea for you, however multiplying and adding?

Cor

[Charles Law]

Hi Herfried

As I have just replied to Cor, I kind of expected a switch somewhere to
allow me to specify the endianness of the operation, but it seems to be
fixed.

I had toyed with reversing the bytes, but then I might just as well stick to
carving the array up by hand. Besides, it makes it a two-stage process, so
to avoid duplication I would need a function wrapper.

Perhaps I am just being picky, but I like to use built-in stuff wherever
possible; or maybe it's laziness ;-)

Charles
"Herfried K. Wagner [MVP]" <hi************ ***@gmx.at> wrote in message
news:uU******** ******@TK2MSFTN GP14.phx.gbl...

"Charles Law" <bl***@nowhere. com> schrieb:

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

You may want to reverse the byte array before using 'BitConverter'.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Jay B. Harlow [MVP - Outlook]]

Charles,
Jon Skeet has a EndianBitConver ter at
http://www.yoda.arachsys.com/csharp/miscutil/ that works similar to
BitConverter but either Little-Endian or Big-Endian depending on which you
pick...

Its in C#, however you should be able to use directly as a class assembly,
or easily converted to VB.NET as the source is available...

Hope this helps
Jay

"Charles Law" <bl***@nowhere. com> wrote in message
news:OD******** ******@TK2MSFTN GP11.phx.gbl...

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles

[Dennis]

Here's a couple of functions that I use...probably a better way to do it but
it works:

Friend Function ConvIntegertoBy teArray(ByVal n As Long, ByVal lg As
Integer) As Byte()
'converts an integer to a byte array of length lg
Dim m() As Byte = New Byte(lg - 1) {}
Dim i, k As Integer
Dim h As String
h = Hex(n).PadLeft( 16, "0"c)
k = 16
For i = lg - 1 To 0 Step -1
k = k - 2
m(i) = CByte("&H" & h.Substring(k, 2))
Next
Return m
End Function

Public Function ConvByteArrayto Integer(ByVal b As Byte(), Optional ByVal
ln As Integer = 0, Optional ByVal sidx As Integer = 0) As Long
Dim i As Integer
Dim j, k As Long
If ln = 0 Then ln = UBound(b) + 1
ln = sidx + ln - 1
k = 1
j = CInt(b(ln))
For i = ln - 1 To sidx Step -1
k = 256 * k
j = j + k * b(i)
Next
Return j
End Function

"Charles Law" wrote:

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles

[Charles Law]

Hi Dennis

Thanks for the reply. As I said in a couple of other replies, it is not so
much the ability to manipulate the data by hand that eludes me, but the
native .NET way, if any. I suppose I am jut trying to avoid re-inventing the
wheel if, indeed, such a wheel exists.

Charles
"Dennis" <De****@discuss ions.microsoft. com> wrote in message
news:AA******** *************** ***********@mic rosoft.com...

Here's a couple of functions that I use...probably a better way to do it
but
it works:

Friend Function ConvIntegertoBy teArray(ByVal n As Long, ByVal lg As
Integer) As Byte()
'converts an integer to a byte array of length lg
Dim m() As Byte = New Byte(lg - 1) {}
Dim i, k As Integer
Dim h As String
h = Hex(n).PadLeft( 16, "0"c)
k = 16
For i = lg - 1 To 0 Step -1
k = k - 2
m(i) = CByte("&H" & h.Substring(k, 2))
Next
Return m
End Function

Public Function ConvByteArrayto Integer(ByVal b As Byte(), Optional
ByVal
ln As Integer = 0, Optional ByVal sidx As Integer = 0) As Long
Dim i As Integer
Dim j, k As Long
If ln = 0 Then ln = UBound(b) + 1
ln = sidx + ln - 1
k = 1
j = CInt(b(ln))
For i = ln - 1 To sidx Step -1
k = 256 * k
j = j + k * b(i)
Next
Return j
End Function

"Charles Law" wrote:

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles

[Charles Law]

Hi Jay

Thanks for the link. I have had a look and I see that Jon uses, in essence,
the same approach that I have at present. I guess that is also how the .NET
little endian BitConverter method is coded under the covers, so it seems
that my best bet is just to wrap the functions I have a bit better and leave
it at that.

Cheers.

Charles
"Jay B. Harlow [MVP - Outlook]" <Ja************ @msn.com> wrote in message
news:O3******** ******@TK2MSFTN GP15.phx.gbl...

Charles,
Jon Skeet has a EndianBitConver ter at
http://www.yoda.arachsys.com/csharp/miscutil/ that works similar to
BitConverter but either Little-Endian or Big-Endian depending on which you
pick...

Its in C#, however you should be able to use directly as a class assembly,
or easily converted to VB.NET as the source is available...

Hope this helps
Jay

"Charles Law" <bl***@nowhere. com> wrote in message
news:OD******** ******@TK2MSFTN GP11.phx.gbl...

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles

[Jay B. Harlow [MVP - Outlook]]

Charles,
I would expect yours & Jon's approach to be very similar.

My point is that Jon has done all the "leg work" & created "complete"
versions of the classes. In other words Why reinvent the wheel?

Hope this helps
Jay

"Charles Law" <bl***@nowhere. com> wrote in message
news:%2******** ********@TK2MSF TNGP10.phx.gbl. ..

Hi Jay

Thanks for the link. I have had a look and I see that Jon uses, in
essence, the same approach that I have at present. I guess that is also
how the .NET little endian BitConverter method is coded under the covers,
so it seems that my best bet is just to wrap the functions I have a bit
better and leave it at that.

Cheers.

Charles
"Jay B. Harlow [MVP - Outlook]" <Ja************ @msn.com> wrote in message
news:O3******** ******@TK2MSFTN GP15.phx.gbl...

Charles,
Jon Skeet has a EndianBitConver ter at
http://www.yoda.arachsys.com/csharp/miscutil/ that works similar to
BitConverter but either Little-Endian or Big-Endian depending on which
you pick...

Its in C#, however you should be able to use directly as a class
assembly, or easily converted to VB.NET as the source is available...

Hope this helps
Jay

"Charles Law" <bl***@nowhere. com> wrote in message
news:OD******** ******@TK2MSFTN GP11.phx.gbl...

I thought this had come up before, but I now cannot find it.

I have a byte array, such as

Dim a() As Byte = {1, 2, 3, 4}

I want to convert this to an Int32 = 01020304 (hex).

If I use BitConverter, I get 04030201.

Is there a built-in way to do this, or am I stuck with extracting and
shifting each byte manually?

TIA

Charles