Hi,
I'm reading the header file of a PCX image and I need to convert 2 bytes
to a short. How would I go about doing this? I know that they are bytes 8
& 9 in my byte array. I'm not sure how to take those two and convert them
into a short though. In C I would just use a union and assign them
accordingly. Thanks! Ken. 8 16395
Ken,
You can use System.BitConve rter.ToInt16 to convert two bytes to a short.
The System.BitConve rter supports converting a byte array to and from most of
the normal built-in types.
Something like:
Dim s As Short
Dim bytes() As Byte
s = BitConverter.To Int16(bytes, 8)
Remember that the starting index is based 0, so the above may actually need
7.
Hope this helps
Jay
"Ken Dopierala Jr." <kd*********@wi .rr.com> wrote in message
news:%2******** *******@TK2MSFT NGP10.phx.gbl.. . Hi, I'm reading the header file of a PCX image and I need to convert 2
bytes to a short. How would I go about doing this? I know that they are bytes
8 & 9 in my byte array. I'm not sure how to take those two and convert them into a short though. In C I would just use a union and assign them accordingly. Thanks! Ken.
As a follow up, I can do this with API calls but I was wondering if there
was a .Net way to turn 2 bytes into a short, 4 bytes into an int and etcs.
Visa versa I can do it using ASCii encoding. Thanks. Ken.
"Ken Dopierala Jr." <kd*********@wi .rr.com> wrote in message
news:%2******** *******@TK2MSFT NGP10.phx.gbl.. . Hi, I'm reading the header file of a PCX image and I need to convert 2
bytes to a short. How would I go about doing this? I know that they are bytes
8 & 9 in my byte array. I'm not sure how to take those two and convert them into a short though. In C I would just use a union and assign them accordingly. Thanks! Ken.
Hi Jay,
It works sweet! Thanks! Ken.
"Jay B. Harlow [MVP - Outlook]" <Ja********@ema il.msn.com> wrote in message
news:%2******** ********@TK2MSF TNGP09.phx.gbl. .. Ken, You can use System.BitConve rter.ToInt16 to convert two bytes to a short.
The System.BitConve rter supports converting a byte array to and from most
of the normal built-in types.
Something like:
Dim s As Short Dim bytes() As Byte
s = BitConverter.To Int16(bytes, 8)
Remember that the starting index is based 0, so the above may actually
need 7.
Hope this helps Jay
"Ken Dopierala Jr." <kd*********@wi .rr.com> wrote in message news:%2******** *******@TK2MSFT NGP10.phx.gbl.. . Hi, I'm reading the header file of a PCX image and I need to convert 2 bytes to a short. How would I go about doing this? I know that they are
bytes 8 & 9 in my byte array. I'm not sure how to take those two and convert
them into a short though. In C I would just use a union and assign them accordingly. Thanks! Ken.
"Ken Dopierala Jr." <kd*********@wi .rr.com> wrote in
news:#R******** *****@TK2MSFTNG P10.phx.gbl: Hi, I'm reading the header file of a PCX image and I need to convert 2 bytes to a short. How would I go about doing this? I know that they are bytes 8 & 9 in my byte array. I'm not sure how to take those two and convert them into a short though. In C I would just use a union and assign them accordingly. Thanks! Ken.
Why don't you just define a structure that is the same as the PCX header
and just import the whole thing in one shot?
'/////
'Define the PCX header structure
Public Structure PcxHeader
Public Mfg As Byte
Public Version As Byte
Public RLE As Byte
Public Bpp As Byte
Public XMin As Short
Public YMin As Short
Public XMax As Short
Public YMax As Short
Public HDpi As Short
Public VDpi As Short
<VBFixedString( 48)> Public Palette As String
Public RFU1 As Byte
Public BitPlanes As Byte
Public VMem As Short
Public PaletteType As Short
Public HScreen As Short
Public VScreen As Short
<VBFixedString( 54)> Public RFU As String
End Structure
'This function reads it in a returns it.
Private Function GetPcxHeader(By Val vFile As String) As PcxHeader
Dim pheader As PcxHeader
Dim fHandle As Integer = FreeFile()
FileOpen(fHandl e, vFile, OpenMode.Random , OpenAccess.Read ,
OpenShare.Share d)
FileGet(fHandle , pheader)
FileClose(fHand le)
Return pheader
End Function
'////////
Chris
Chris Dunaway <du******@lunch meatsbcglobal.n et> wrote in
news:Xn******** *************** *********@207.4 6.248.16:
In my example that I posted, I used a fixed length string for the Palette
and the reserved bytes. Is there anyway to use a byte array instead?
I tried adding Public Palette(47) As Byte to the structure but it does
not allow that. I can create a parameterized constructor to initialize
the arrays, but that seems messy.
Is there any other way to specify a range of bytes in a structure? 'Define the PCX header structure Public Structure PcxHeader Public Mfg As Byte Public Version As Byte Public RLE As Byte Public Bpp As Byte Public XMin As Short Public YMin As Short Public XMax As Short Public YMax As Short Public HDpi As Short Public VDpi As Short <VBFixedString( 48)> Public Palette As String Public RFU1 As Byte Public BitPlanes As Byte Public VMem As Short Public PaletteType As Short Public HScreen As Short Public VScreen As Short <VBFixedString( 54)> Public RFU As String End Structure
Hello,
"Ken Dopierala Jr." <kd*********@wi .rr.com> schrieb: As a follow up, I can do this with API calls but I was wondering if there was a .Net way to turn 2 bytes into a short, 4 bytes into an int and etcs.
Have a look at the 'BitConverter' class.
--
Herfried K. Wagner
MVP · VB Classic, VB.NET http://www.mvps.org/dotnet
Chris Dunaway <du******@lunch meatsbcglobal.n et> wrote in
news:Xn******** *************** ***********@207 .46.248.16: Chris Dunaway <du******@lunch meatsbcglobal.n et> wrote in news:Xn******** *************** *********@207.4 6.248.16:
Is there any other way to specify a range of bytes in a structure?
Ok, I figured it out for my self. Just use the VBFixedArray attribute
instead:
Public Structure PcxHeader
Public Mfg As Byte
Public Version As Byte
Public RLE As Byte
Public Bpp As Byte
Public XMin As Short
Public YMin As Short
Public XMax As Short
Public YMax As Short
Public HDpi As Short
Public VDpi As Short
<VBFixedArray(4 7)> Public Palette() As Byte
Public RFU1 As Byte
Public BitPlanes As Byte
Public VMem As Short
Public PaletteType As Short
Public HScreen As Short
Public VScreen As Short
<VBFixedArray(5 3)> Public RFU() As Byte
End Structure
Thanks Chris!
That is very cool. Ken.
"Chris Dunaway" <du******@lunch meatsbcglobal.n et> wrote in message
news:Xn******** *************** ***********@207 .46.248.16... Chris Dunaway <du******@lunch meatsbcglobal.n et> wrote in news:Xn******** *************** ***********@207 .46.248.16:
Chris Dunaway <du******@lunch meatsbcglobal.n et> wrote in news:Xn******** *************** *********@207.4 6.248.16:
Is there any other way to specify a range of bytes in a structure?
Ok, I figured it out for my self. Just use the VBFixedArray attribute instead:
Public Structure PcxHeader Public Mfg As Byte Public Version As Byte Public RLE As Byte Public Bpp As Byte Public XMin As Short Public YMin As Short Public XMax As Short Public YMax As Short Public HDpi As Short Public VDpi As Short <VBFixedArray(4 7)> Public Palette() As Byte Public RFU1 As Byte Public BitPlanes As Byte Public VMem As Short Public PaletteType As Short Public HScreen As Short Public VScreen As Short <VBFixedArray(5 3)> Public RFU() As Byte End Structure This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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