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vb.net : How to Convert Byte Array to Int32 (Big-endian)
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,
Jon Skeet has a EndianBitConverter 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 [quoted text, click to view] "Charles Law" <blank@nowhere.com> wrote in message news:ODJHwi6$EHA.3988@TK2MSFTNGP11.phx.gbl... >I thought this had come up before, but I now cannot find it. > > I have a byte array, such as > > Dim a() As Byte = {1, 2, 3, 4} > > I want to convert this to an Int32 = 01020304 (hex). > > If I use BitConverter, I get 04030201. > > Is there a built-in way to do this, or am I stuck with extracting and > shifting each byte manually? > > TIA > > Charles > >
Hi Cor
I haven't really been away, just a bit quiet. I did respond to someone the other day about a serial comms issue crashing their prog, but no word yet whether it fixed the problem. [quoted text, click to view] > Maybe a crazy idea for you, however multiplying and adding? Yes, that is currently what I do, or rather what the VB6 code that I am converting does. I was just looking for a native .NET way to do it. It seems to me that there should be a switch, or extra parameter to pass that allows one to specify big or little-endianness, but I haven't spotted it. Charles [quoted text, click to view] "Cor Ligthert" <notmyfirstname@planet.nl> wrote in message news:%23c85Pk7$EHA.1524@TK2MSFTNGP09.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 >
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 [quoted text, click to view] "Herfried K. Wagner [MVP]" <hirf-spam-me-here@gmx.at> wrote in message news:uU6iyn7$EHA.1300@TK2MSFTNGP14.phx.gbl... > "Charles Law" <blank@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,
We have a long time not seen you, so welcome back, Maybe a crazy idea for you, however multiplying and adding? Cor
"Charles Law" <blank@nowhere.com> schrieb:
[quoted text, click to view] >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/>
Here's a couple of functions that I use...probably a better way to do it but
it works: Friend Function ConvIntegertoByteArray(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 ConvByteArraytoInteger(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 [quoted text, click to view] "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 > >
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 [quoted text, click to view] "Dennis" <Dennis@discussions.microsoft.com> wrote in message news:AA34156E-F28D-4F92-9C17-38DA9EFDC5E9@microsoft.com... > Here's a couple of functions that I use...probably a better way to do it > but > it works: > > Friend Function ConvIntegertoByteArray(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 ConvByteArraytoInteger(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 >> >> >>
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 [quoted text, click to view] "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message news:O38Z1$9$EHA.2012@TK2MSFTNGP15.phx.gbl... > Charles, > Jon Skeet has a EndianBitConverter 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" <blank@nowhere.com> wrote in message > news:ODJHwi6$EHA.3988@TK2MSFTNGP11.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 >> >> > >
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 [quoted text, click to view] "Charles Law" <blank@nowhere.com> wrote in message news:%23ml44gCAFHA.3852@TK2MSFTNGP10.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]" <Jay_Harlow_MVP@msn.com> wrote in message > news:O38Z1$9$EHA.2012@TK2MSFTNGP15.phx.gbl... >> Charles, >> Jon Skeet has a EndianBitConverter 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" <blank@nowhere.com> wrote in message >> news:ODJHwi6$EHA.3988@TK2MSFTNGP11.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 >>> >>> >> >> > >
Indeed. Fair point.
Thanks. Charles [quoted text, click to view] "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message news:uzZE7BWAFHA.3436@TK2MSFTNGP09.phx.gbl... > 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" <blank@nowhere.com> wrote in message > news:%23ml44gCAFHA.3852@TK2MSFTNGP10.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]" <Jay_Harlow_MVP@msn.com> wrote in message >> news:O38Z1$9$EHA.2012@TK2MSFTNGP15.phx.gbl... >>> Charles, >>> Jon Skeet has a EndianBitConverter 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" <blank@nowhere.com> wrote in message >>> news:ODJHwi6$EHA.3988@TK2MSFTNGP11.phx.gbl... >>>>I thought this had come up before, but I now cannot find it. >>>> >>>> I have a byte array, such as >>>> >>>> Dim a() As Byte = {1, 2, 3, 4} >>>> >>>> I want to convert this to an Int32 = 01020304 (hex). >>>> >>>> If I use BitConverter, I get 04030201. >>>> >>>> Is there a built-in way to do this, or am I stuck with extracting and >>>> shifting each byte manually? >>>> >>>> TIA >>>> >>>> Charles >>>> >>>> >>> >>> >> >> > >
[quoted text, click to view] "Charles Law" <blank@nowhere.com> wrote in message news:ODJHwi6$EHA.3988@TK2MSFTNGP11.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 > You could try something like this: Private Function Int32FromByteArray(ByVal BA() As Byte, ByVal SwitchEndian As Boolean) As Integer Dim outVal As Integer outVal = BitConverter.ToInt32(BA, 0) If SwitchEndian = True Then outVal = System.Net.IPAddress.NetworkToHostOrder(outVal) End If Return outVal End Function NetworkToHostOrder - Big To Little Endian HostToNetworkOrder - Little To Big Endian Although in this case it makes no difference which one you choose as the end result is the same. Gerald
Yeah, it is buried pretty deep. It also seems they have some sort of
aversion to using the word Endian, so it makes it very difficult to find. Gerald [quoted text, click to view] "Jay B. Harlow [MVP - Outlook]" <Jay_Harlow_MVP@msn.com> wrote in message news:e$q48rkAFHA.3836@tk2msftngp13.phx.gbl... > Gerald, > Thanks, I was looking for NetworkToHostOrder & HostToNetworkOrder, when > Charles first asked, I just didn't remember which System.Net class they were > on. I was thinking Socket or something else... > > Jay > > "Gerald Hernandez" <Cablewizard@spam_remove@Yahoo.com> wrote in message > news:%23NjhRqjAFHA.2792@TK2MSFTNGP15.phx.gbl... > > > > "Charles Law" <blank@nowhere.com> wrote in message > > news:ODJHwi6$EHA.3988@TK2MSFTNGP11.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 > >> > > > > You could try something like this: > > > > Private Function Int32FromByteArray(ByVal BA() As Byte, ByVal > > SwitchEndian As Boolean) As Integer > > Dim outVal As Integer > > > > outVal = BitConverter.ToInt32(BA, 0) > > If SwitchEndian = True Then > > outVal = System.Net.IPAddress.NetworkToHostOrder(outVal) > > End If > > Return outVal > > End Function > > > > NetworkToHostOrder - Big To Little Endian > > HostToNetworkOrder - Little To Big Endian > > Although in this case it makes no difference which one you choose as the > > end > > result is the same. > > > > Gerald > > > > > >
Gerald,
Thanks, I was looking for NetworkToHostOrder & HostToNetworkOrder, when Charles first asked, I just didn't remember which System.Net class they were on. I was thinking Socket or something else... Jay [quoted text, click to view] "Gerald Hernandez" <Cablewizard@spam_remove@Yahoo.com> wrote in message news:%23NjhRqjAFHA.2792@TK2MSFTNGP15.phx.gbl... > > "Charles Law" <blank@nowhere.com> wrote in message > news:ODJHwi6$EHA.3988@TK2MSFTNGP11.phx.gbl... >> I thought this had come up before, but I now cannot find it. >> >> I have a byte array, such as >> >> Dim a() As Byte = {1, 2, 3, 4} >> >> I want to convert this to an Int32 = 01020304 (hex). >> >> If I use BitConverter, I get 04030201. >> >> Is there a built-in way to do this, or am I stuck with extracting and >> shifting each byte manually? >> >> TIA >> >> Charles >> > > You could try something like this: > > Private Function Int32FromByteArray(ByVal BA() As Byte, ByVal > SwitchEndian As Boolean) As Integer > Dim outVal As Integer > > outVal = BitConverter.ToInt32(BA, 0) > If SwitchEndian = True Then > outVal = System.Net.IPAddress.NetworkToHostOrder(outVal) > End If > Return outVal > End Function > > NetworkToHostOrder - Big To Little Endian > HostToNetworkOrder - Little To Big Endian > Although in this case it makes no difference which one you choose as the > end > result is the same. > > Gerald > >
Hi Gerald
That's just the ticket. Thanks. Charles [quoted text, click to view] "Gerald Hernandez" <Cablewizard@spam_remove@Yahoo.com> wrote in message news:%23NjhRqjAFHA.2792@TK2MSFTNGP15.phx.gbl... > > "Charles Law" <blank@nowhere.com> wrote in message > news:ODJHwi6$EHA.3988@TK2MSFTNGP11.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 >> > > You could try something like this: > > Private Function Int32FromByteArray(ByVal BA() As Byte, ByVal > SwitchEndian As Boolean) As Integer > Dim outVal As Integer > > outVal = BitConverter.ToInt32(BA, 0) > If SwitchEndian = True Then > outVal = System.Net.IPAddress.NetworkToHostOrder(outVal) > End If > Return outVal > End Function > > NetworkToHostOrder - Big To Little Endian > HostToNetworkOrder - Little To Big Endian > Although in this case it makes no difference which one you choose as the > end > result is the same. > > Gerald > >
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