VB 2015 - Check on Function for conversion between Int32 and UInt32

Question

Hi,

in a software written in VB2015 ( I must modify ) I found a Function that converts an input Int32 value into an UInt32 value.

The original purpose was to use an SQL INT Field ( 4 Bytes ) to store an UInt32 value ( 4 Bytes ).

This is the original Function "ConvertToUInt32" :

    Public Function ConvertToUInt32(ByVal ValInt As Int32,
                                    ByRef ValUInt32Ret As UInt32,
                                    ByRef pErrorMsg As String) As Boolean

        Try
            Dim ValUInt32 As UInt32 = 0
            Dim ArrBytes As Byte() = BitConverter.GetBytes(ValInt)
            ValUInt32 = ArrBytes(3)
            ValUInt32 <<= 24
            ValUInt32Ret = ValUInt32
            ValUInt32 = ArrBytes(2)
            ValUInt32 <<= 16
            ValUInt32Ret += ValUInt32
            ValUInt32 = ArrBytes(1)
            ValUInt32 <<= 8
            ValUInt32Ret += ValUInt32
            ValUInt32Ret += ArrBytes(0)
            Return True
        Catch ex As Exception
            pErrorMsg = "ERROR ConvertToUInt32 Array Bytes : " & ex.Message
            Return False
        End Try

    End Function

And this is the Function "GetUInt32FromInt32" I wrote myself to replace the first one :

    Public Function GetUInt32FromInt32(ByVal pInt32 As Int32) As UInt32

        If pInt32 >= 0 Then
            Return Convert.ToUInt32(pInt32)
        Else
            Return Convert.ToUInt32(UInt32.MaxValue + pInt32 + 1)
        End If

    End Function

I've made some tests with this code :

        Dim SBTest As New System.Text.StringBuilder
        Dim valueInt32 As Int32 = Convert.ToInt32(txt_valueint32.Text)
        Dim valueUInt32 As UInt32
        Dim errorMsg As String = String.Empty

        SBTest.AppendLine("valueInt32 = " & valueInt32.ToString)

        If ConvertToUInt32(valueInt32,
                           valueUInt32,
                           errorMsg) = True Then
            SBTest.AppendLine("ConvertToUInt32() valueUInt32 = " & valueUInt32.ToString)
        Else
            SBTest.AppendLine("Conversion FAILED for " & valueInt32.ToString & " : " & errorMsg)
        End If

        valueUInt32 = GetUInt32FromInt32(valueInt32)
        SBTest.AppendLine("GetUInt32FromInt32() valueUInt32 = " & valueUInt32.ToString)

        Clipboard.SetText(SBTest.ToString)

And the results are always the same for both :

valueInt32 = 0
ConvertToUInt32() valueUInt32 = 0
GetUInt32FromInt32() valueUInt32 = 0

valueInt32 = 254
ConvertToUInt32() valueUInt32 = 254
GetUInt32FromInt32() valueUInt32 = 254

valueInt32 = -1
ConvertToUInt32() valueUInt32 = 4294967295
GetUInt32FromInt32() valueUInt32 = 4294967295

valueInt32 = -254
ConvertToUInt32() valueUInt32 = 4294967042
GetUInt32FromInt32() valueUInt32 = 4294967042

valueInt32 = 2147483647 ( Int32 MAX )
ConvertToUInt32() valueUInt32 = 2147483647
GetUInt32FromInt32() valueUInt32 = 2147483647

valueInt32 = -2147483648 ( Int32 MIN )
ConvertToUInt32() valueUInt32 = 2147483648
GetUInt32FromInt32() valueUInt32 = 2147483648

The questions are :

1. Are these two Functions equivalent in your opinion ?
2. Do you think I could get the same operation with another simpler method ? How ?

Thaks to anyone able to help.

Answer 1

This function seems to work too:

Public Function GetUInt32FromInt32(ByVal pInt32 As Int32) As UInt32

    Return BitConverter.ToUInt32(BitConverter.GetBytes(pInt32), 0)

End Function

Answer 2

Thanks Viorel-1.

I also tested the two Functions with all values ( took just 2 minutes ) and I'll take your solution :

        Dim valueUInt32_A As UInt32 
        Dim valueUInt32_B As UInt32 
        Dim errorMsg As String = String.Empty

        For i As Int32 = Int32.MinValue To Int32.MaxValue - 1
            If ConvertToUInt32(i,
                               valueUInt32_A,
                               errorMsg) = True Then
                valueUInt32_B = GetUInt32FromInt32(i)
                If valueUInt32_A <> valueUInt32_B Then
                    errorMsg = "i = " & i.ToString & " --> valueUInt32_A " & valueUInt32_A.ToString & " <> " &
                                                          "valueUInt32_B " & valueUInt32_B.ToString
                    MessageBox.Show(errorMsg,
                                    "ERROR",
                                    MessageBoxButtons.OK,
                                    MessageBoxIcon.Exclamation)
                    Exit For
                End If
            Else
                MessageBox.Show(errorMsg,
                                "ERROR",
                                MessageBoxButtons.OK,
                                MessageBoxIcon.Exclamation)
                Exit For
            End If
        Next

        MessageBox.Show("TEST OK",
                        "OK",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Information)