How are you?
I wrote a program manipulating big binary chains (string variables). This said manipulation requires me to store my chains in a variable so I can use them as numbers. The only variable type that I have found big enough to store such lengthy numbers is BigInteger (we are talking 1.0E100+).
I would like to use something like:
val = BigInteger.Parse(bin, 2)
But the second parameter needed is a NumberStyles object, which can only refer to a NumberStyles.HexNumber.
Is there a simple/optimal way to do this?
Thank you very much. :)
This converts a binary string to BigInteger in 8 bit chunks. It assumes that the binary string represents a positive number.
Private Function BinToBI(ByRef binstr As String) As BigInteger
Dim t As New List(Of Byte)
Dim s As String
Dim idx As Integer = binstr.Length
Do While idx > 0
'get 8 bits
If idx >= 8 Then
s = binstr.Substring(idx - 8, 8)
Else
s = binstr.Substring(0, idx).PadLeft(8, "0"c)
End If
'convert to byte and add to list
Dim b As Byte = Convert.ToByte(s, 2)
t.Add(b)
idx -= 8
Loop
'force to positive
If t(t.Count - 1) >= 128 Then
t.Add(0)
End If
Dim rv As New BigInteger(t.ToArray)
Return rv
End Function
for testing
Dim d As Double = 1.0E+101
Debug.WriteLine(d.ToString("n2"))
Dim bi As BigInteger
' Dim bin As String = "1111111111111111111111111111111" 'Integer.MaxValue
' Dim bin As String = "111111111111111111111111111111111111111111111111111111111111111" 'Long.MaxValue
Dim bin As String = "1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111110"
bi = BinToBI(bin)
Debug.WriteLine(bi.ToString("n2"))
This was not well tested but should give you some ideas.
Related
As shown here: https://gregstoll.com/~gregstoll/floattohex/
I need to convert a 32 bit float to a little endian hex (click the swap endiness button before converting). I've managed to do this in python by converting to big endian then reordering, but I have no idea how to approach this issue in VB as I'm entirely new to the language. Using the Hex inbuilt function returns 19a, which i assume means its not correctly evaluating my input as a single.
I've found a recommended solution here but cant get it working:
https://www.tek-tips.com/faqs.cfm?fid=6404
Any suggestions would be great, thanks in advance.
There are a number of ways you could do this - the most obvious being the Copy Memory API. Some time ago, a pretty neat solution was published here: Extracting bits from a float in vba which avoided the need for the API
Basically, you'd just need a couple of short functions:
Option Explicit
Type SingleType
Value As Single
End Type
Type FourBytesType
Value(3) As Byte
End Type
Private Function SingleToBytes(f As Single) As Variant
Dim sngType As SingleType
Dim bytesType As FourBytesType
sngType.Value = f
LSet bytesType = sngType
SingleToBytes = bytesType.Value
End Function
Private Function BytesToHex(bytes As Variant) As String
Dim result As String
Dim i As Long
For i = LBound(bytes) To UBound(bytes)
result = result & IIf(bytes(i) < 16, "0", "") & Hex(bytes(i))
Next
BytesToHex = result
End Function
If you wanted to test Endianness and reverse the array, then something like the following, which kind of uses a Byte Order Mark, could be added. I haven't tested it on a big-endian processor but I think it'd work:
Private Function IsLittleEndianProcessor() As Boolean
Const BOM As Single = 1
Const MSB As Byte = 63
Dim bytes() As Byte
Dim n As Long
bytes = SingleToBytes(BOM)
n = UBound(bytes)
IsLittleEndianProcessor = (bytes(n) = MSB)
End Function
Private Function ChangeEndianness(bytes As Variant) As Variant
Dim result() As Byte
Dim n As Long, m As Long
ReDim result(UBound(bytes))
m = UBound(bytes)
For n = LBound(bytes) To UBound(bytes)
result(m) = bytes(n)
m = m - 1
Next
ChangeEndianness = result
End Function
I'm not actually sure how you want the hex string displayed but you could step backwards through the array to write the hex if needed. Sample test would be:
Public Sub TestMe()
Dim bytes As Variant
Dim output As String
bytes = SingleToBytes(3.1415)
If Not IsLittleEndianProcessor Then
bytes = ChangeEndianness(bytes)
End If
output = BytesToHex(bytes)
Debug.Print output
End Sub
My question is simple, i need to convert the first three bits of a byte to a integer (Enum) value. However the things i try i always get a 0 back. This is wat the document says:
Bit 0-3: These bits indicate the connection state.
Value 0 to 14 indicate the connection state. Value 3 = Connected
Now the response i get (from a serial device) is a encoded byte stream of ASCII hex values, so i first need to convert it from a hex string to byte array and then get the bits from it. This is my code so far:
Dim strResonse As String = "0C03" 'This should result in a connection state value of 3
Dim ConState(2) As Byte
ConState = HexStringToByteArray(strResonse)
Dim int As Integer = ConState(1) << 1 And ConState(1) << 2 And ConState(1) << 3
Debug.Print(int.ToString)
Private Function HexStringToByteArray(ByVal shex As String) As Byte()
Dim B As Byte() = Enumerable.Range(0, shex.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(shex.Substring(x, 2), 16)).ToArray()
Return Enumerable.Range(0, shex.Length).Where(Function(x) x Mod 2 = 0).[Select](Function(x) Convert.ToByte(shex.Substring(x, 2), 16)).ToArray()
End Function
It would be easier to use bit operation
Dim connectionState As Integer
Dim response As Integer = &HC03
' Get the first 4 bits. 15 in binary is 1111
connectionState = response And 15
If your input is really a string, there a built-in way to convert to integer.
Dim response As Integer = Convert.ToInt32("C03", 16)
If you really want to get an array, I suggest you use the built in method.
Dim allBits As Byte() = BitConverter.GetBytes(response)
There also the BitArray class that can be handy.
I have a byte array need to convert to integer, and this array only have one value. I tried Bitconverter, convert.ToInt32 both are not working for me. my code as follows:
Dim a As new Byte() ={&H1C} ' the value range is {&H01} to {&HFF}
Dim key As integer = BitConverter.ToInt32(a,1)
I need the result with key = 28, which convert function I should use?
Thank you very much.
BitConverter.ToInt32 needs 4 bytes to work with, so you just need to put your one byte value into a 4 byte array. Allowing for the endianness, something like this:
Dim a() As Byte = { &H1C }
Dim b(3) As Byte
If BitConverter.IsLittleEndian Then
b(0) = a(0)
Else
b(3) = a(0)
End If
Dim key As Integer = BitConverter.ToInt32(b, 0)
You are not converting an array of values, but rather a single array element.
That said, there is no need to call a conversion function to convert a single Byte to an Integer. Just assign the value.
Dim key As Integer = a(0)
I have two strings:
Dim Original_Hex_Bytes as string = "616572646E61"
Dim Patched_Hex_Bytes as string = "616E64726561"
Then I have a binary file and I need to search for the Original_Hex_Bytes and replace them with Patched_Hex_Bytes; I don't konw the offset where begin to write new bytes :(
How can I do this?
If needed, I also know how to convert Hex strings in bytes, I use this:
Private Function Hex_To_Bytes(ByVal strinput As String) As Byte()
Dim i As Integer = 0
Dim x As Integer = 0
Dim bytes(strinput.Length / 2) As Byte
Do While (strinput.Length > i + 1)
Dim lngDecimal As Long = Convert.ToInt32(strinput.Substring(i, 2), 16)
bytes(x) = Convert.ToByte(lngDecimal)
i += 2
x += 1
Loop
Return bytes
End Function
You can use BinaryReader and BinaryWriter classes to achieve this.
But in this case, as you do not know the file structure, need to read the entire file and sweep it in search of bytes array and will be easier to use ASCII strings as aerdna and andrea.
When you know the structure of a file is more appropriate to work with data structure to manipulate its contents.
I wish to convert text to base 4 (AGCT), by first converting it to binary (I've done this bit) and then break it into 2 bit pairs.
can someone help me turn this into code using vb.net syntax?
if (length of binary String is an odd number) add a zero to the front (leftmost position) of the String. Create an empty String to add translated digits to. While the original String of binary is not empty { Translate the first two digits only of the binary String into a base-4 digit, and add this digit to the end (rightmost) index of the new String. After this, remove the same two digits from the binary string and repeat if it is not empty. }
in this context:
Dim Base2Convert As String = ""
For Each C As Char In Result.Text
Dim s As String = System.Convert.ToString(AscW(C), 2).PadLeft(8, "0")
Base2Convert &= s
Next
Result.Text = Base2Convert
Dim Base4Convert As String = ""
For Each C As Char In Result.Text
'//<ADD THE STATEMENT ABOVE AS CODE HERE>//
Base4Convert &= s
Next
Result.Text = Base4Convert
.NET does not support conversion to non-standard base, such as 4, so this will not work:
Dim base4number As String = Convert.ToString(base10number, 4)
From MSDN:
[...] base of the return value [...] must be 2, 8, 10, or 16.
But you can write your own conversion function, or take the existing one off the web:
Public Function IntToStringFast(value As Integer, baseChars As Char()) As String
Dim i As Integer = 32
Dim buffer(i - 1) As Char
Dim targetBase As Integer = baseChars.Length
Do
buffer(System.Threading.Interlocked.Decrement(i)) =
baseChars(value Mod targetBase)
value = value \ targetBase
Loop While value > 0
Dim result As Char() = New Char(32 - i - 1) {}
Array.Copy(buffer, i, result, 0, 32 - i)
Return New String(result)
End Function
Used this answer. Converted with developer fusion from C# + minor adjustments. Example:
Dim base2number As String = "11110" 'Decimal 30
Dim base10number As Integer = Convert.ToInt32(base2number, 2)
Dim base4number As String = IntToStringFast(base10number, "0123")
Console.WriteLine(base4number) 'outputs 132
Notice that you don't need base 2 there as an intermediate value, you can convert directly from base 10. If in doubt, whether it worked correctly or not, here is a useful resource:
Number base converter
Converting the number to base first and then to base 4 doesn’t make a lot of sense, since directly converting to base 4 is the same algorithm anyway. In fact, representation of a number in any base requires the same general algorithm:
Public Shared Function Representation(number As Integer, digits As String) As String
Dim result = ""
Dim b = digits.Length
Do
result = digits(number Mod b) & result
number \= b
Loop While number > 0
Return result
End Function
Now you can verify that Representation(i, decimal) does the same as i.ToString():
Dim decimalDigits = "0123456789"
For i = 0 To 30 Step 3
Console.WriteLine("{0}, {1}", i.ToString(), Representation(i, decimalDigits))
Next
It’s worth noting that i.ToString() converts i to decimal base because this is the base we, humans, are mostly using. But there is nothing special about decimal, and in fact internally, i is not a decimal number: its representation in computer memory is binary.
For conversion to any other base, just pass a different set of digits to the method. In your case, that’d be "ACGT":
Console.WriteLine(Representation(i, "ACGT"))
Hexadecimal also works:
Console.WriteLine(Representation(i, "0123456789ABCDEF"))
And, just to repeat it because it’s such a nice mathematical property: so does any other base with at least two distinct digits.