CODEWITHSUNDEEP
c#joininteger
SYB
SYB

Reputation: 173

C# join 2 Int16 into Int32

I ran into a dead-end for what I think should be a simple solution. Basically, I have:

List<Uint16> header = new List<UInt16>();

Then I populate it with data but later I need to join a couple of elements into Int32 and I have no idea what is the best way to do it. Are there any .NET calls I can make to join these two into Uint32?

Thanks

Upvotes: 0

Views: 4194

Answers (5)

Simorider
Simorider

Reputation: 1

Function get_DWord(ByVal D1 As Short, ByVal D2 As Short) As Integer
    Dim Bits As String = Convert.ToString(D1, 16)
    Dim length As Integer = Bits.Length
    If length < 4 Then
        For I As Integer = 0 To 4 - length
            Bits = "0" & Bits
        Next
    End If
    Dim Bits2 As String = Convert.ToString(D2, 16)
    Dim No As Integer = Convert.ToInt32(Bits2 & Bits, 2)
    Return No
End Function

Upvotes: 0

phoxis
phoxis

Reputation: 61950

I think we also need to take care of the endianness of the system.

Stored value: 0x00000001

In memory representation:

       Memory Address

  Low                   High
   0       1      2      3
+------+------+------+------+
|  00  |  00  |  00  |  01  |      Big Endian Representation
+------+------+------+------+      stores the least significant byte
                                   in higher memory address. So we get
                                   0 in lower address.
  Low                   High
   0       1      2      3
+------+------+------+------+
|  01  | 00   |  00  |  00  |      Little Endian Representation
+------+------+------+------+      stores the least significant byte
                                   in lower memory address.

Therefore if we need to paste two uint16 then first we need to understand the byte ordering.

uint16 val1, val2;

val1
+------+------+                       +------+------+
|  b1  |  b2  |             OR        |  b2  |  b1  |
+------+------+                       +------+------+

    (paste)                               (paste)

val2
+------+------+                       +------+------+
|  b3  |  b4  |             OR        |  b4  |  b3  |
+------+------+                       +------+------+

===============================+===============================
paste(val1,val2)               | paste(val2,val1)
   0      1      2      3      |    0      1      2      3
+------+------+------+------+  | +------+------+------+------+
|  b1  |  b2  |  b3  |  b4  |  | |  b4  |  b3  |  b2  |  b1  |
+------+------+------+------+  | +------+------+------+------+
     val1           val2       |      val2           val1
         LITTLE Endian                     BIG Endian

Therefore the byte ordering needs to be considered.

To check if the Endinness of the system you can use

endian = (((char *)&x)[0]) ? 0 : 1;

Where 0 is Little and 1 is Big. (I am not explaining this here).

Depending on this output you can use the paste function to get the uint16s pasted.

For completeness sake I am writing the paste function.

uint32 paste (uint16 n1, uint16 n2)
{
  return ((uint32) n1 << 16)| (uint) n2;
}

Upvotes: 1

Jessica
Jessica

Reputation: 490

If by join them you mean use one Uint16 as the lowest 16 bits of a 32 bit Uint and the other as the highest 16 bits then you can use bit-wise arithmetic and shifting. Something like:

Uint16 u1;
Uint16 u2;
Uint32 = (Uint32)u1 << 16 | (Uint32)u2;

Upvotes: 0

user1968030
user1968030

Reputation:

You can use Bitwise Operators:

    uint num = (uint)((header.ElementAt(0) << 16) | header.ElementAt(1));

Upvotes: 2

itsme86
itsme86

Reputation: 19526

You can use bit shifting to do it:

var num = (uint)((header.ElementAt(0) << 16) | header.ElementAt(1));

That's assuming the element at 0 is most significant.

Upvotes: 7

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