I have a C# dll and want to use it in VB.NET. I'm using C# 2008 Express and VB 2008 Express. I have added a reference in a VB project to the C# dll. When I create an instane of a class in the C# dll, it gives the following error messsage: "Type 'RF.RabinFingerprint' has no constructors". How do I fix this?
My C# dll code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace RF
{
/// <summary>
/// Génère des empreintes de fichiers
/// </summary>
public static class RabinFingerprint
{
/// <summary>
/// Bit 64 of the polynomial P is always 1 and not treated directly. This is the polynomial
/// with the leading coefficient removed (lcr).
/// Represents t^64 + t^4 + t^3 + t + 1.
/// </summary>
private static readonly UInt64 p_lcr = 0x000000000000001BL;
/// <summary>
/// It's not necessary to provide definitions for such integral constant variables as long as their
/// addresses are not taken.
/// Degree of the polynomial P.
/// </summary>
private static readonly int K = 64;
/// <summary>
/// Represents t^(K-1)
/// </summary>
private static readonly UInt64 T_K_minus_1 = (UInt64)1L << (K - 1);
/// <summary>
/// Broder's paper presents four pre-computed tables because words are considered to be 32-bit.
/// In this implementation W is a 64-bit integral type. Eight tables are used.
/// Table A is i1^127 + i2^126 + ... + i8^120.
/// Table B is i1^119 + i2^118 + ... + i8^112.
/// Table C, D, ..
/// Table E is i1^95 + i2^94 + ... + i8^88. (This is table A in the paper.)
/// Table F, G, H.
/// </summary>
private static UInt64[] tableA_ = new UInt64[256]; //Assuming byte size 8.
private static UInt64[] tableB_ = new UInt64[256];
private static UInt64[] tableC_ = new UInt64[256];
private static UInt64[] tableD_ = new UInt64[256];
private static UInt64[] tableE_ = new UInt64[256];
private static UInt64[] tableF_ = new UInt64[256];
private static UInt64[] tableG_ = new UInt64[256];
private static UInt64[] tableH_ = new UInt64[256];
/// <summary>
/// Constructor
/// </summary>
static RabinFingerprint()
{
InitTables();
}
/// <summary>
/// Initialize tables
/// </summary>
private static void InitTables()
{
//This represents t^(k + i) mod P, where i is the index of the array.
//It will be used to compute the tables.
UInt64[] mods = new UInt64[K];
//Remember t^k mod P is equivalent to p_lcr.
mods[0] = p_lcr;
for (int i = 1; i < K; ++i)
{
//By property: t^i mod P = t(t^(i - 1)) mod P.
mods[i] = mods[i - 1] << 1;
//If mods[i - 1] had a term at k-1, mods[i] would have had the term k, which is not represented.
//The term k would account for exactly one more division by P. Then, the effect is the same
//as adding p_lcr to the mod.
if ((mods[i - 1] & T_K_minus_1) != 0)
mods[i] ^= p_lcr;
}
//Compute tables. A control variable is used to indicate whether the current bit should be
//considered.
for (int i = 0; i < 256; ++i)
{
int control = i;
for (int j = 0; j < 8 && control > 0; ++j)
{
// bool.Parse(Convert.ToString())
if ((control & 1) == 1) //Ok, consider bit. ((byte))
{
tableA_[i] ^= mods[j + 56];
tableB_[i] ^= mods[j + 48];
tableC_[i] ^= mods[j + 40];
tableD_[i] ^= mods[j + 32];
tableE_[i] ^= mods[j + 24];
tableF_[i] ^= mods[j + 16];
tableG_[i] ^= mods[j + 8];
tableH_[i] ^= mods[j];
}
control >>= 1;
}
}
}
/// <summary>
/// Compute hash key
/// </summary>
/// <param name="value">Value to hash</param>
/// <returns>Value</returns>
private static UInt64 ComputeTablesSum(ref UInt64 value)
{
value = tableH_[((value) & 0xFF)] ^
tableG_[((value >> 8) & 0xFF)] ^
tableF_[((value >> 16) & 0xFF)] ^
tableE_[((value >> 24) & 0xFF)] ^
tableD_[((value >> 32) & 0xFF)] ^
tableC_[((value >> 40) & 0xFF)] ^
tableB_[((value >> 48) & 0xFF)] ^
tableA_[((value >> 56) & 0xFF)];
return value; //Pass by reference to return the same w. (Convenience and efficiency.)
}
/// <summary>
/// Compute hask hey
/// </summary>
/// <param name="HashArray">Array of Ulong bytes to ahsh</param>
/// <returns>Hash key</returns>
private static UInt64 Compute(UInt64[] HashArray)
{
UInt64 w = 0L;
for (int s = 0; s < HashArray.Length; ++s)
w = ComputeTablesSum(ref w) ^ HashArray[s];
return w;
}
/// <summary>
/// Compute the fingerprint
/// </summary>
/// <param name="source">String to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(string source)
{
byte[] table = Encoding.Unicode.GetBytes(source);
UInt64[] values = new UInt64[table.LongLength];
ConvertBytes(ref table, ref values);
return Compute(values);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large text
/// </summary>
/// <param name="source">String to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(ref string source)
{
return ComputeFingerPrint(source);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large binary data
/// </summary>
/// <param name="source">Data to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(ref byte[] source)
{
UInt64[] values = new UInt64[source.LongLength];
ConvertBytes(ref source, ref values);
return Compute(values);
}
/// <summary>
/// Compute the fingerprint, you must use this method for very large binary data
/// </summary>
/// <param name="source">Data to compute</param>
/// <returns>Hash key</returns>
public static UInt64 ComputeFingerPrint(byte[] source)
{
return ComputeFingerPrint(ref source);
}
/// <summary>
/// Compute byte array to Uint64 array
/// </summary>
/// <param name="source">Table de byte source</param>
/// <param name="destination">Tableau de Uin64</param>
private static void ConvertBytes(ref byte[] source, ref UInt64[] destination)
{
for (long i = 0; i < source.LongLength; i++)
destination[i] = Convert.ToUInt64(source[i]);
}
}
}
My VB code:
Imports RF
Module Module1
Sub Main()
Dim t As New RabinFingerprint
End Sub
End Module
If you want to use instances, you need to add a non-static constructor to the C# class - currently it's only got a static constructor.
There is info on diffs between static/shared in VB.Net and C# here that could be useful in resolving this.
If you were doing this in C# you just call the class's static methods like
UInt64 result = RabinFingerprint.ComputeFIngerprint(...);
etc.
In VB.Net this looks something like this:
Dim result = RF.RabinFingerprint.ComputeFingerprint(...)
Here is an example from MSDN of what I mean. Here both Console.WriteLine and Regex.Split are static, just like your class's methods.
Dim input As String = "plum--pear"
Dim pattern As String = "-" ' Split on hyphens
Dim substrings() As String = Regex.Split(input, pattern)
For Each match As String In substrings
Console.WriteLine("'{0}'", match)
Next
' The method writes the following to the console:
' 'plum'
' ''
' 'pear'
You have no constructors because your class is declared as static
Have you tried to use it from C#?
It probably gives you the same error there.
EDIT
I have tried your code. (Jeff we need a copy source code button)
IN VB.NET. There's the following error:
Type 'RF.RabinFingerprint' has no constructors.
In C# you get the following 2 errors.
Cannot create an instance of the static class 'RF.RabinFingerprint'
Cannot declare a variable of static type 'RF.RabinFingerprint'
Actually C# shows you the real problem. As Jazz have mentioned. You should change your class to be nonstatic to work properly
EDIT2
Steve is right. If your class has been designed to be static as it appears since everything in there is static, then what has to be changed is the call to the constructor. Since the class is static you can't create an instance of your class.
There is no need to call the constructor because it will be automatically called the first time the class is used (For example when you call a method from it).
Related
I have a JsonNode to write to a file.
The JSON contains a string with a special character in it: "🐕".
It's written as "\uD83D\uDC15" and it's not exactly what I want.
JSON files support UTF-8, and "🐕" is a valid UTF-8 code point consisting of 4 bytes:
0xF0 0x9F 0x90 0xB6.
Instead I get it translated to 12 bytes, just in case I would edit it on old terminal from the 80s. I'm not interested. I actually use Visual Studio Code for editing the file.
How to force writing without such unwanted translations?
BTW, the file is deserialized correctly, the deserialized string contains valid Unicode codepoint. So - basically the application works, however I'm super curious how to change the serialization behavior.
In case someone's too curious about the code, here it is:
public virtual void Save(JsonNode node, Stream stream) {
if (node is null) return;
using var writer = new Utf8JsonWriter(stream, WriterOptions);
node.WriteTo(writer, SerializerOptions);
}
...where WriterOptions:
public JsonWriterOptions WriterOptions { get; } = new() { Indented = true, SkipValidation = true };
...and SerializerOptions:
public JsonSerializerOptions SerializerOptions { get; } = new() { WriteIndented = true };
Here's an example project showing the issue:
https://github.com/HTD/JsonNodeUtfIssue/blob/master/JsonNodeUtfIssue/Program.cs
https://dotnetfiddle.net/73RxAd
Here's my workaround. A decoding stream.
When Utf8JsonWriter writes UTF-8 bytes to the stream, my Utf8DecodeStream searches for Unicode escape sequences, decodes them to UTF-8 bytes and writes instead of original escape sequences.
It's relatively fast, because it doesn't use regular expressions, string search / replacement, string to number conversions, avoidable allocations and so on.
It operates directly on binary data (original stream's buffer). It may fail to replace a sequence when it's broken between 2 writes. In such case the file will not be damaged, just that one sequence will be left unchanged.
OK, there is one special case - if the block boundary will end breaking a long Unicode escape sequence into 2 valid 16-bit codes, it would result with invalid decoding, since 2 16-bit chars decoded to UTF-8 bytes and just concatenated won't produce the valid 32-bit UTF-8 code point.
BTW, I don't know if the Utf8JsonWriter would break writes in the middle of strings, it might write whole lines, or at least JSON tokens, so mentioned problems might never occur.
It's worth noting the class uses the escape sequence generated by Utf8JsonWriter - so, for speed, it doesn't decode sequences starting with "\U" or containing lower case hexadecimal digits. The support for different formats can easily be added.
CAUTION: The Utf8JsonWriter escapes Unicode sequences for a reason that is security. Do not decode if it might make the application vulnerable.
/// <summary>
/// Decodes the Unicode escape sequences while writing UTF-8 stream.
/// </summary>
/// <remarks>
/// This is a workaround for a <see cref="Utf8JsonWriter"/> not doing it on its own.
/// </remarks>
public class Utf8DecodeStream : Stream {
/// <summary>
/// Creates a Unicode escape sequence decoding stream over a writeable stream.
/// </summary>
/// <param name="stream">A writeable stream.</param>
public Utf8DecodeStream(Stream stream) => InnerStream = stream;
#pragma warning disable CS1591
public override bool CanRead => InnerStream.CanRead;
public override bool CanSeek => InnerStream.CanSeek;
public override bool CanWrite => InnerStream.CanWrite;
public override long Length => InnerStream.Length;
public override long Position { get => InnerStream.Position; set => InnerStream.Position = value; }
public override void Flush() => InnerStream.Flush();
public override int Read(byte[] buffer, int offset, int count) => InnerStream.Read(buffer, offset, count);
public override long Seek(long offset, SeekOrigin origin) => InnerStream.Seek(offset, origin);
public override void SetLength(long value) => InnerStream.SetLength(value);
#pragma warning restore CS1591
/// <summary>
/// Writes the buffer with the Unicode sequences decoded.
/// </summary>
/// <param name="buffer">Buffer to write.</param>
/// <param name="offset">Position in the buffer to start.</param>
/// <param name="count">Number of bytes to write.</param>
public override void Write(byte[] buffer, int offset, int count) {
bool sequenceFound = false;
while (count > 0) {
sequenceFound = false;
for (int i = offset, n = offset + count; i < n; i++) {
if (DecodeUtf8Sequence(buffer, i, out var sequence, out var bytesConsumed)) {
InnerStream.Write(buffer, offset, i - offset);
count -= i - offset;
InnerStream.Write(sequence);
offset = i + bytesConsumed;
count -= bytesConsumed;
sequenceFound = true;
break;
}
}
if (!sequenceFound) {
InnerStream.Write(buffer, offset, count);
count = 0;
}
}
}
/// <summary>
/// Tries to decode one or more subsequent Unicode escape sequences into UTF-8 bytes.
/// </summary>
/// <param name="buffer">A buffer to decode.</param>
/// <param name="index">An index to start decoding from.</param>
/// <param name="result">An array containing UTF-8 representation of the sequence.</param>
/// <param name="bytesConsumed">The length of the matched escape sequence.</param>
/// <returns>True if one or more subsequent Unicode escape sequences is found.</returns>
private static bool DecodeUtf8Sequence(byte[] buffer, int index, out byte[] result, out int bytesConsumed) {
bytesConsumed = 0;
result = Array.Empty<byte>();
List<char> parts = new(2);
while (DecodeChar(buffer, index, out var part)) {
parts.Add(part);
index += 6;
bytesConsumed += 6;
}
if (parts.Count < 1) return false;
result = Encoding.UTF8.GetBytes(parts.ToArray());
return true;
}
/// <summary>
/// Tries to decode a single Unicode escape sequence.
/// </summary>
/// <remarks>
/// "\uXXXX" format is assumed for <see cref="Utf8JsonWriter"/> output.
/// </remarks>
/// <param name="buffer">A buffer to decode.</param>
/// <param name="index">An index to start decoding from.</param>
/// <param name="result">Decoded character.</param>
/// <returns>True if a single Unicode sequnece is found at specified index.</returns>
private static bool DecodeChar(byte[] buffer, int index, out char result) {
result = (char)0;
if (index + 6 >= buffer.Length || buffer[index] != '\\' || buffer[index + 1] != 'u') return false;
int charCode = 0;
for (int i = 0; i < 4; i++)
if (!DecodeDigit(i, buffer, index + 2, ref charCode)) return false;
result = (char)charCode;
return true;
}
/// <summary>
/// Tries to decode a single hexadecimal digit from a buffer.
/// </summary>
/// <remarks>
/// Upper case is assumed for <see cref="Utf8JsonWriter"/> output.
/// </remarks>
/// <param name="n">A zero-based digit index.</param>
/// <param name="buffer">Buffer to decode.</param>
/// <param name="index">Sequence index.</param>
/// <param name="charCode">Character code reference.</param>
/// <returns>True if the buffer contains a hexadecimal digit at <paramref name="index"/> + <paramref name="n"/>.</returns>
private static bool DecodeDigit(int n, byte[] buffer, int index, ref int charCode) {
var value = buffer[index + n];
var shift = 12 - (n << 2);
if (value is >= 48 and <= 57) charCode += (value - 48) << shift;
else if (value is >= 65 and <= 70) charCode += (value - 55) << shift;
else return false;
return true;
}
/// <summary>
/// Target stream.
/// </summary>
private readonly Stream InnerStream;
}
Usage:
using var writer = new Utf8JsonWriter(new Utf8DecodeStream(stream));
Example xUnit test:
[Fact]
public void Utf8DecodeStreamTest() {
var test = Encoding.UTF8.GetBytes(#"\uD83D\uDC15 \uD83D\uDC15 \uD83D\uDC15");
using var stream = new MemoryStream();
var decoding = new Utf8DecodeStream(stream);
decoding.Write(test);
decoding.Flush();
var result = Encoding.UTF8.GetString(stream.ToArray());
Assert.Equal("🐕 🐕 🐕", result);
}
when we added paralllism elaboration on our application (dotnet service) we found some unexpected behavoir on crc calculation over text documents.
to isolate the issue i created a test case. the crc calculation fails when invoked from parallel looop. in this test case replacing parallel foreach with standard always fine. I think i've to made so change in crc32 class implementation, but i need some help to understand the right way. Thanks.
this the test method.
[TestMethod()]
public void Test_Crc_TestoDoc()
{
string query = #"select top 100 docId from sometable";
///key is document's id
///value is a couple, crc and text
Dictionary<int, Tuple<int, string>> docs = new Dictionary<int, Tuple<int, string>>();
using (SqlDataReader oSqlDataReader = Utility.ExecuteSP_Reader(query))
{
while (oSqlDataReader.Read())
{
int docId = oSqlDataReader.GetInt32(0);
///retrive the text by docId
string docText = Utility.GetDocText(docId);
///calculate and add crc in dic
int CRC = CRC32.Compute(docText);
docs.Add(docId, new Tuple<int, string>(CRC, docText));
}
oSqlDataReader.Close();
}
///calculate crc 100 times to check if the value
///is always the same for same text
for (int i = 0; i < 100; i++)
{
Parallel.ForEach(docs.Keys,(int docId) =>
{
///crc saved in dictionary
int CRC1 = docs[docId].Item1;
///text saved in dictionary
string docText = docs[docId].Item2;
///calculate crc again, crc2 must be equal to crc1 stored in dictionary
int CRC2 = CRC32.Compute(docText);
Assert.AreEqual(CRC1, CRC2, $"crc not equal, why? docId->{docId} CRC1->{CRC1} CRC2->{CRC2}");
});
}
}
crc32 class:
public class CRC32 : HashAlgorithm
{
#region CONSTRUCTORS
/// <summary>Creates a CRC32 object using the <see cref="DefaultPolynomial"/>.</summary>
public CRC32()
: this(DefaultPolynomial)
{
}
/// <summary>Creates a CRC32 object using the specified polynomial.</summary>
/// <remarks>The polynomical should be supplied in its bit-reflected form. <see cref="DefaultPolynomial"/>.</remarks>
[CLSCompliant(false)]
public CRC32(uint polynomial)
{
HashSizeValue = 32;
_crc32Table = (uint[])_crc32TablesCache[polynomial];
if (_crc32Table == null)
{
_crc32Table = CRC32._buildCRC32Table(polynomial);
_crc32TablesCache.Add(polynomial, _crc32Table);
}
Initialize();
}
// static constructor
static CRC32()
{
_crc32TablesCache = Hashtable.Synchronized(new Hashtable());
_defaultCRC = new CRC32();
}
#endregion
#region PROPERTIES
/// <summary>Gets the default polynomial (used in WinZip, Ethernet, etc.)</summary>
/// <remarks>The default polynomial is a bit-reflected version of the standard polynomial 0x04C11DB7 used by WinZip, Ethernet, etc.</remarks>
[CLSCompliant(false)]
public static readonly uint DefaultPolynomial = 0xEDB88320; // Bitwise reflection of 0x04C11DB7;
#endregion
#region METHODS
/// <summary>Initializes an implementation of HashAlgorithm.</summary>
public override void Initialize()
{
_crc = _allOnes;
}
/// <summary>Routes data written to the object into the hash algorithm for computing the hash.</summary>
protected override void HashCore(byte[] buffer, int offset, int count)
{
for (int i = offset; i < count; i++)
{
ulong ptr = (_crc & 0xFF) ^ buffer[i];
_crc >>= 8;
_crc ^= _crc32Table[ptr];
}
}
/// <summary>Finalizes the hash computation after the last data is processed by the cryptographic stream object.</summary>
protected override byte[] HashFinal()
{
byte[] finalHash = new byte[4];
ulong finalCRC = _crc ^ _allOnes;
finalHash[0] = (byte)((finalCRC >> 0) & 0xFF);
finalHash[1] = (byte)((finalCRC >> 8) & 0xFF);
finalHash[2] = (byte)((finalCRC >> 16) & 0xFF);
finalHash[3] = (byte)((finalCRC >> 24) & 0xFF);
return finalHash;
}
/// <summary>Computes the CRC32 value for the given ASCII string using the <see cref="DefaultPolynomial"/>.</summary>
public static int Compute(string asciiString)
{
_defaultCRC.Initialize();
return ToInt32(_defaultCRC.ComputeHash(asciiString));
}
/// <summary>Computes the CRC32 value for the given input stream using the <see cref="DefaultPolynomial"/>.</summary>
public static int Compute(Stream inputStream)
{
_defaultCRC.Initialize();
return ToInt32(_defaultCRC.ComputeHash(inputStream));
}
/// <summary>Computes the CRC32 value for the input data using the <see cref="DefaultPolynomial"/>.</summary>
public static int Compute(byte[] buffer)
{
_defaultCRC.Initialize();
return ToInt32(_defaultCRC.ComputeHash(buffer));
}
/// <summary>Computes the hash value for the input data using the <see cref="DefaultPolynomial"/>.</summary>
public static int Compute(byte[] buffer, int offset, int count)
{
_defaultCRC.Initialize();
return ToInt32(_defaultCRC.ComputeHash(buffer, offset, count));
}
/// <summary>Computes the hash value for the given ASCII string.</summary>
/// <remarks>The computation preserves the internal state between the calls, so it can be used for computation of a stream data.</remarks>
public byte[] ComputeHash(string asciiString)
{
byte[] rawBytes = ASCIIEncoding.ASCII.GetBytes(asciiString);
return ComputeHash(rawBytes);
}
/// <summary>Computes the hash value for the given input stream.</summary>
/// <remarks>The computation preserves the internal state between the calls, so it can be used for computation of a stream data.</remarks>
new public byte[] ComputeHash(Stream inputStream)
{
byte[] buffer = new byte[4096];
int bytesRead;
while ((bytesRead = inputStream.Read(buffer, 0, 4096)) > 0)
{
HashCore(buffer, 0, bytesRead);
}
return HashFinal();
}
/// <summary>Computes the hash value for the input data.</summary>
/// <remarks>The computation preserves the internal state between the calls, so it can be used for computation of a stream data.</remarks>
new public byte[] ComputeHash(byte[] buffer)
{
return ComputeHash(buffer, 0, buffer.Length);
}
/// <summary>Computes the hash value for the input data.</summary>
/// <remarks>The computation preserves the internal state between the calls, so it can be used for computation of a stream data.</remarks>
new public byte[] ComputeHash(byte[] buffer, int offset, int count)
{
HashCore(buffer, offset, count);
return HashFinal();
}
#endregion
#region PRIVATE SECTION
private static uint _allOnes = 0xffffffff;
private static CRC32 _defaultCRC;
private static Hashtable _crc32TablesCache;
private uint[] _crc32Table;
private uint _crc;
// Builds a crc32 table given a polynomial
private static uint[] _buildCRC32Table(uint polynomial)
{
uint crc;
uint[] table = new uint[256];
// 256 values representing ASCII character codes.
for (int i = 0; i < 256; i++)
{
crc = (uint)i;
for (int j = 8; j > 0; j--)
{
if ((crc & 1) == 1)
crc = (crc >> 1) ^ polynomial;
else
crc >>= 1;
}
table[i] = crc;
}
return table;
}
private static int ToInt32(byte[] buffer)
{
return BitConverter.ToInt32(buffer, 0);
}
#endregion
}
Probably the problem are all the "static" function.
In fact, a static function is the same for all of the instance of CRC32.
That means that while an instance is running, setting his parameter, another can write his own value over the first one.
I've implemented a number of TOTP classes now and they all generate the wrong output. Below I've posted the code I used for the most simple one.
I'd like for it to get implemented and behave just like Google Authenticator - For example like the code https://gauth.apps.gbraad.nl/#main.
So what I want to happen is that in the front end of the application a user will enter his secret "BANANAKEY123" which translates to a base32 string of "IJAU4QKOIFFUKWJRGIZQ====".
Now in the constructor below key would be "BANANAKEY123". Yet for some reason it' not generating the same OTP keys with this code as the GAuth OTP tool does.
The only two reasonable mistakes would be
var secretKeyBytes = Base32Encode(secretKey);
is wrong or that my timing function is wrong. I checked both and couldn't find the fault in any of those. So could someone please help me in the right direction? Thank you!
public class Totp
{
private readonly int digits = 6;
private readonly HMACSHA1 hmac;
private readonly HMACSHA256 hmac256;
private readonly Int32 t1 = 30;
internal int mode;
private string secret;
private const string allowedCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
public Totp(string key, int mode)
{
secret = key;
this.mode = mode;
}
// defaults to SHA-1
public Totp(string key)
{
secret = key;
this.mode = 1;
}
public Totp(string base32string, Int32 t1, int digits) : this(base32string)
{
this.t1 = t1;
this.digits = digits;
}
public Totp(string base32string, Int32 t1, int digits, int mode) : this(base32string, mode)
{
this.t1 = t1;
this.digits = digits;
}
public String getCodeString()
{
return GetCode(this.secret, GetInterval(DateTime.UtcNow));
}
private static long GetInterval(DateTime dateTime)
{
TimeSpan elapsedTime = dateTime.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return (long)elapsedTime.TotalSeconds / 30;
}
private static string GetCode(string secretKey, long timeIndex)
{
var secretKeyBytes = Base32Encode(secretKey);
HMACSHA1 hmac = new HMACSHA1(secretKeyBytes);
byte[] challenge = BitConverter.GetBytes(timeIndex);
if (BitConverter.IsLittleEndian) Array.Reverse(challenge);
byte[] hash = hmac.ComputeHash(challenge);
int offset = hash[19] & 0xf;
int truncatedHash = hash[offset] & 0x7f;
for (int i = 1; i < 4; i++)
{
truncatedHash <<= 8;
truncatedHash |= hash[offset + i] & 0xff;
}
truncatedHash %= 1000000;
return truncatedHash.ToString("D6");
}
private static byte[] Base32Encode(string source)
{
var bits = source.ToUpper().ToCharArray().Select(c =>
Convert.ToString(allowedCharacters.IndexOf(c), 2).PadLeft(5, '0')).Aggregate((a, b) => a + b);
return Enumerable.Range(0, bits.Length / 8).Select(i => Convert.ToByte(bits.Substring(i * 8, 8), 2)).ToArray();
}
}
I have been using this code for quite some time to generate Time-based OTP, hope it helps.
TotpAuthenticationService.cs
using System;
using System.Net;
using System.Security.Cryptography;
using System.Text;
namespace Wteen.Infrastructure.Services
{
/// <summary>
/// An Time Based Implementation of RFC 6238, a variation from the OTP (One Time Password) with, a default code life time of 30 seconds.
/// </summary>
public sealed class TotpAuthenticationService
{
private readonly Encoding _encoding;
private readonly int _length;
private readonly TimeSpan _timestep;
private readonly DateTime _unixEpoch;
/// <summary>
/// Create a new Instance of <see cref="TotpAuthenticationService"/>
/// </summary>
/// <param name="length">The length of the OTP</param>
/// <param name="duration">The peried of time in which the genartion of a OTP with the result with the same value</param>
public TotpAuthenticationService(int length, int duration = 30)
{
_length = length;
_encoding = new UTF8Encoding(false, true);
_timestep = TimeSpan.FromSeconds(duration);
_unixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
}
/// <summary>
/// The current time step number
/// </summary>
private ulong CurrentTimeStepNumber => (ulong)(TimeElapsed.Ticks / _timestep.Ticks);
/// <summary>
/// The number of seconds elapsed since midnight UTC of January 1, 1970.
/// </summary>
private TimeSpan TimeElapsed => DateTime.UtcNow - _unixEpoch;
/// <summary>
///
/// </summary>
/// <param name="securityToken"></param>
/// <param name="modifier"></param>
/// <returns></returns>
public int GenerateCode(byte[] securityToken, string modifier = null)
{
if (securityToken == null)
throw new ArgumentNullException(nameof(securityToken));
using (var hmacshA1 = new HMACSHA1(securityToken))
{
return ComputeTotp(hmacshA1, CurrentTimeStepNumber, modifier);
}
}
/// <summary>
/// Validating for codes generated during the current and past code generation <see cref="timeSteps"/>
/// </summary>
/// <param name="securityToken">User's secerct</param>
/// <param name="code">The code to validate</param>
/// <param name="timeSteps">The number of time steps the <see cref="code"/> could be validated for.</param>
/// <param name="channel">Possible channels could be user's email or mobile number where the code will be sent to</param>
/// <returns></returns>
public bool ValidateCode(byte[] securityToken, int code, int timeSteps, string channel = null)
{
if (securityToken == null)
throw new ArgumentNullException(nameof(securityToken));
using (var hmacshA1 = new HMACSHA1(securityToken))
{
for (var index = -timeSteps; index <= timeSteps; ++index)
if (ComputeTotp(hmacshA1, CurrentTimeStepNumber + (ulong)index, channel) == code)
return true;
}
return false;
}
private byte[] ApplyModifier(byte[] input, string modifier)
{
if (string.IsNullOrEmpty(modifier))
return input;
var bytes = _encoding.GetBytes(modifier);
var numArray = new byte[checked(input.Length + bytes.Length)];
Buffer.BlockCopy(input, 0, numArray, 0, input.Length);
Buffer.BlockCopy(bytes, 0, numArray, input.Length, bytes.Length);
return numArray;
}
private int ComputeTotp(HashAlgorithm algorithm, ulong timestepNumber, string modifier)
{
var bytes = BitConverter.GetBytes(IPAddress.HostToNetworkOrder((long)timestepNumber));
var hash = algorithm.ComputeHash(ApplyModifier(bytes, modifier));
var index = hash[hash.Length - 1] & 15;
return (((hash[index] & sbyte.MaxValue) << 24) | ((hash[index + 1] & byte.MaxValue) << 16) | ((hash[index + 2] & byte.MaxValue) << 8) | (hash[index + 3] & byte.MaxValue)) % (int)Math.Pow(10, _length);
}
}
}
I’m working on an Objective C app which receives GPS routes from a server. The routes are encoded and I have the decoding scripts written in both PHP and C#.
To my knowledge there it's not possible to compile or import the script into the Xcode project.
I have attached the two scripts below alongside a copy of the encoded GPS route.
I've studied the script a considerable amount and understand (for the most part) what is happening.) Is it feasible to port this code to Objective C? If so what would be the best approach? And how would I port the byte streams?
I'm slightly confused since I have never worked with encoding/decoding before, but any help is highly appreciated.
Encoded GPS Route
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
C# Decode Script
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
// Classes for managing IOF XML 3.0 Route element.
// IOF XML 3.0 specification: http://code.google.com/p/iofdatastandard/source/browse/trunk/IOF.xsd.
// IOF XML 3.0 example result list file with Route element: http://code.google.com/p/iofdatastandard/source/browse/trunk/Examples/ResultList1.xml.
/// <summary>
/// Class representing a route, including logic for converting to/from an IOF XML 3.0 route stored in binary format.
/// </summary>
public class IofXml30Route
{
private double? length;
private IEnumerable<IofXml30Waypoint> waypoints = new List<IofXml30Waypoint>();
/// <summary>
/// The waypoints of the route.
/// </summary>
public IEnumerable<IofXml30Waypoint> Waypoints
{
get { return waypoints; }
set { waypoints = value ?? new List<IofXml30Waypoint>(); }
}
/// <summary>
/// Writes the route in IOF XML 3.0 binary format to the specified stream.
/// </summary>
/// <param name="stream">The stream to write to.</param>
public void WriteToStream(Stream stream)
{
IofXml30Waypoint previousWaypoint = null;
foreach (var waypoint in Waypoints)
{
waypoint.WriteToStream(stream, previousWaypoint);
previousWaypoint = waypoint;
}
}
/// <summary>
/// Converts the route to IOF XML 3.0 binary format and returns it as a base64-encoded string.
/// </summary>
/// <param name="formattingOptions">The formatting options for the base64-encoded string.</param>
public string ToBase64String(Base64FormattingOptions formattingOptions = Base64FormattingOptions.None)
{
return Convert.ToBase64String(ToByteArray(), formattingOptions);
}
/// <summary>
/// Converts the route to IOF XML 3.0 binary format and returns it as a byte array.
/// </summary>
public byte[] ToByteArray()
{
using (var ms = new MemoryStream())
{
WriteToStream(ms);
return ms.ToArray();
}
}
/// <summary>
/// Reads a route in IOF XML 3.0 binary format from a stream.
/// </summary>
/// <param name="stream">The stream to read from.</param>
public static IofXml30Route FromStream(Stream stream)
{
var waypoints = new List<IofXml30Waypoint>();
while (stream.Position < stream.Length)
{
waypoints.Add(IofXml30Waypoint.FromStream(stream, waypoints.LastOrDefault()));
}
return new IofXml30Route() { Waypoints = waypoints };
}
/// <summary>
/// Reads a route in IOF XML 3.0 binary format from a base64-encoded string.
/// </summary>
/// <param name="base64String">The base64-encoded string to read from.</param>
public static IofXml30Route FromBase64String(string base64String)
{
return FromByteArray(Convert.FromBase64String(base64String));
}
/// <summary>
/// Reads a route in IOF XML 3.0 binary format from a byte array.
/// </summary>
/// <param name="bytes">The bytes to read from.</param>
public static IofXml30Route FromByteArray(byte[] bytes)
{
using (var ms = new MemoryStream(bytes))
{
return FromStream(ms);
}
}
/// <summary>
/// Gets the length of the route in meters.
/// </summary>
public double Length
{
get { return length ?? (length = CalculateLength()).Value; }
}
/// <summary>
/// Gets the start time of the route.
/// </summary>
public DateTime StartTime
{
get { return Waypoints.Any() ? Waypoints.First().Time : DateTime.MinValue; }
}
/// <summary>
/// Gets the end time of the route.
/// </summary>
public DateTime EndTime
{
get { return Waypoints.Any() ? Waypoints.Last().Time : DateTime.MinValue; }
}
/// <summary>
/// Gets the duration of the route.
/// </summary>
public TimeSpan Duration
{
get { return EndTime - StartTime; }
}
private double CalculateLength()
{
var sum = 0.0;
var wpList = Waypoints.ToList();
for(var i=1; i<Waypoints.Count(); i++)
{
sum += GetDistanceBetweenWaypoints(wpList[i - 1], wpList[i]);
}
return sum;
}
private static double GetDistanceBetweenWaypoints(IofXml30Waypoint w1, IofXml30Waypoint w2)
{
// use spherical coordinates: rho, phi, theta
const double rho = 6378200; // earth radius in metres
double sinPhi0 = Math.Sin(0.5 * Math.PI + w1.Latitude / 180.0 * Math.PI);
double cosPhi0 = Math.Cos(0.5 * Math.PI + w1.Latitude / 180.0 * Math.PI);
double sinTheta0 = Math.Sin(w1.Longitude / 180.0 * Math.PI);
double cosTheta0 = Math.Cos(w1.Longitude / 180.0 * Math.PI);
double sinPhi1 = Math.Sin(0.5 * Math.PI + w2.Latitude / 180.0 * Math.PI);
double cosPhi1 = Math.Cos(0.5 * Math.PI + w2.Latitude / 180.0 * Math.PI);
double sinTheta1 = Math.Sin(w2.Longitude / 180.0 * Math.PI);
double cosTheta1 = Math.Cos(w2.Longitude / 180.0 * Math.PI);
var x1 = rho * sinPhi0 * cosTheta0;
var y1 = rho * sinPhi0 * sinTheta0;
var z1 = rho * cosPhi0;
var x2 = rho * sinPhi1 * cosTheta1;
var y2 = rho * sinPhi1 * sinTheta1;
var z2 = rho * cosPhi1;
return DistancePointToPoint(x1, y1, z1, x2, y2, z2);
}
private static double DistancePointToPoint(double x1, double y1, double z1, double x2, double y2, double z2)
{
var sum = (x2 - x1)*(x2 - x1) + (y2 - y1)*(y2 - y1) + (z2 - z1)*(z2 - z1);
return Math.Sqrt(sum);
}
}
/// <summary>
/// Class representing a waypoint, including logic for converting to/from an IOF XML 3.0 waypoint stored in binary format.
/// </summary>
public class IofXml30Waypoint
{
private static readonly DateTime zeroTime = new DateTime(1900, 01, 01, 00, 00, 00, DateTimeKind.Utc);
private const long timeSecondsThreshold = 255;
private const long timeMillisecondsThreshold = 65535;
private const int lanLngBigDeltaLowerThreshold = -32768;
private const int lanLngBigDeltaUpperThreshold = 32767;
private const int lanLngSmallDeltaLowerThreshold = -128;
private const int lanLngSmallDeltaUpperThreshold = 127;
private const int altitudeDeltaLowerThreshold = -128;
private const int altitudeDeltaUpperThreshold = 127;
/// <summary>
/// Gets or sets the type of the waypoint; normal or interruption.
/// </summary>
public IofXml30WaypointType Type { get; set; }
/// <summary>
/// Gets or sets the time when the waypoint was recorded.
/// </summary>
public DateTime Time { get; set; }
/// <summary>
/// Gets or sets the latitude of the waypoint.
/// </summary>
public double Latitude { get; set; }
/// <summary>
/// Gets or sets the longitude of the waypoint.
/// </summary>
public double Longitude { get; set; }
/// <summary>
/// Gets or sets the altitude of the waypoint.
/// </summary>
public double? Altitude { get; set; }
/// <summary>
/// Gets or sets the the time when the waypoint was recorded in the internal storage mode.
/// </summary>
public ulong StorageTime
{
get { return (ulong)Math.Round((Time - zeroTime).TotalMilliseconds); }
set { Time = zeroTime.AddMilliseconds(value); }
}
/// <summary>
/// Gets or sets the latitude of the waypoint in the internal storage mode.
/// </summary>
public int StorageLatitude
{
get { return (int)Math.Round(Latitude * 1000000); }
set { Latitude = (double)value / 1000000; }
}
/// <summary>
/// Gets or sets the longitude of the waypoint in the internal storage mode.
/// </summary>
public int StorageLongitude
{
get { return (int)Math.Round(Longitude * 1000000); }
set { Longitude = (double)value / 1000000; }
}
/// <summary>
/// Gets or sets the altitude of the waypoint in the internal storage mode.
/// </summary>
public int? StorageAltitude
{
get { return Altitude == null ? (int?)null : (int)Math.Round(Altitude.Value * 10); }
set { Altitude = value == null ? (double?)null : (double)value / 10; }
}
/// <summary>
/// Writes the waypoint in IOF XML 3.0 binary format to a stream.
/// </summary>
/// <param name="stream">The stream to write to.</param>
/// <param name="previousWaypoint">The previous waypoint of the route, or null if this is the first waypoint.</param>
public void WriteToStream(Stream stream, IofXml30Waypoint previousWaypoint)
{
var timeStorageMode = TimeStorageMode.Full;
if (previousWaypoint != null)
{
if ((StorageTime - previousWaypoint.StorageTime) % 1000 == 0 && (StorageTime - previousWaypoint.StorageTime) / 1000 <= timeSecondsThreshold)
{
timeStorageMode = TimeStorageMode.Seconds;
}
else if (StorageTime - previousWaypoint.StorageTime <= timeMillisecondsThreshold)
{
timeStorageMode = TimeStorageMode.Milliseconds;
}
}
var positionStorageMode = PositionStorageMode.Full;
if (previousWaypoint != null &&
(StorageAltitude == null || (previousWaypoint.StorageAltitude != null && StorageAltitude - previousWaypoint.StorageAltitude >= altitudeDeltaLowerThreshold && StorageAltitude - previousWaypoint.StorageAltitude <= altitudeDeltaUpperThreshold)))
{
if (StorageLatitude - previousWaypoint.StorageLatitude >= lanLngSmallDeltaLowerThreshold && StorageLatitude - previousWaypoint.StorageLatitude <= lanLngSmallDeltaUpperThreshold &&
StorageLongitude - previousWaypoint.StorageLongitude >= lanLngSmallDeltaLowerThreshold && StorageLongitude - previousWaypoint.StorageLongitude <= lanLngSmallDeltaUpperThreshold)
{
positionStorageMode = PositionStorageMode.SmallDelta;
}
else if (StorageLatitude - previousWaypoint.StorageLatitude >= lanLngBigDeltaLowerThreshold && StorageLatitude - previousWaypoint.StorageLatitude <= lanLngBigDeltaUpperThreshold &&
StorageLongitude - previousWaypoint.StorageLongitude >= lanLngBigDeltaLowerThreshold && StorageLongitude - previousWaypoint.StorageLongitude <= lanLngBigDeltaUpperThreshold)
{
positionStorageMode = PositionStorageMode.BigDelta;
}
}
var headerByte = 0;
if (Type == IofXml30WaypointType.Interruption) headerByte |= (1 << 7);
if (timeStorageMode == TimeStorageMode.Milliseconds) headerByte |= (1 << 6);
if (timeStorageMode == TimeStorageMode.Seconds) headerByte |= (1 << 5);
if (positionStorageMode == PositionStorageMode.BigDelta) headerByte |= (1 << 4);
if (positionStorageMode == PositionStorageMode.SmallDelta) headerByte |= (1 << 3);
if (StorageAltitude != null) headerByte |= (1 << 2);
// header byte
stream.WriteByte((byte)headerByte);
// time byte(s)
switch (timeStorageMode)
{
case TimeStorageMode.Full: // 6 bytes
stream.Write(BitConverter.GetBytes(StorageTime).Reverse().ToArray(), 2, 6);
break;
case TimeStorageMode.Milliseconds: // 2 bytes
stream.Write(BitConverter.GetBytes((ushort)(StorageTime - previousWaypoint.StorageTime)).Reverse().ToArray(), 0, 2);
break;
case TimeStorageMode.Seconds: // 1 byte
stream.WriteByte((byte)((StorageTime - previousWaypoint.StorageTime) / 1000));
break;
}
// position bytes
switch (positionStorageMode)
{
case PositionStorageMode.Full: // 4 + 4 + 3 bytes
stream.Write(BitConverter.GetBytes(StorageLatitude).Reverse().ToArray(), 0, 4);
stream.Write(BitConverter.GetBytes(StorageLongitude).Reverse().ToArray(), 0, 4);
if (StorageAltitude != null) stream.Write(BitConverter.GetBytes(StorageAltitude.Value).Reverse().ToArray(), 1, 3);
break;
case PositionStorageMode.BigDelta: // 2 + 2 + 1 bytes
stream.Write(BitConverter.GetBytes((short)(StorageLatitude - previousWaypoint.StorageLatitude)).Reverse().ToArray(), 0, 2);
stream.Write(BitConverter.GetBytes((short)(StorageLongitude - previousWaypoint.StorageLongitude)).Reverse().ToArray(), 0, 2);
if (StorageAltitude != null) stream.Write(BitConverter.GetBytes((sbyte)(StorageAltitude - previousWaypoint.StorageAltitude).Value), 0, 1);
break;
case PositionStorageMode.SmallDelta: // 1 + 1 + 1 bytes
stream.Write(BitConverter.GetBytes((sbyte)(StorageLatitude - previousWaypoint.StorageLatitude)), 0, 1);
stream.Write(BitConverter.GetBytes((sbyte)(StorageLongitude - previousWaypoint.StorageLongitude)), 0, 1);
if (StorageAltitude != null) stream.Write(BitConverter.GetBytes((sbyte)(StorageAltitude - previousWaypoint.StorageAltitude).Value), 0, 1);
break;
}
}
/// <summary>
/// Reads a waypoint in IOF XML 3.0 binary format from a stream.
/// </summary>
/// <param name="stream">The stream to read from.</param>
/// <param name="previousWaypoint">The previous waypoint of the route, or null if this is the first waypoint.</param>
/// <returns></returns>
public static IofXml30Waypoint FromStream(Stream stream, IofXml30Waypoint previousWaypoint)
{
var waypoint = new IofXml30Waypoint();
// header byte
var headerByte = stream.ReadByte();
waypoint.Type = (headerByte & (1 << 7)) == 0 ? IofXml30WaypointType.Normal : IofXml30WaypointType.Interruption;
var timeStorageMode = TimeStorageMode.Full;
if ((headerByte & (1 << 6)) > 0)
{
timeStorageMode = TimeStorageMode.Milliseconds;
}
else if ((headerByte & (1 << 5)) > 0)
{
timeStorageMode = TimeStorageMode.Seconds;
}
var positionStorageMode = PositionStorageMode.Full;
if ((headerByte & (1 << 4)) > 0)
{
positionStorageMode = PositionStorageMode.BigDelta;
}
else if ((headerByte & (1 << 3)) > 0)
{
positionStorageMode = PositionStorageMode.SmallDelta;
}
var altitudePresent = (headerByte & (1 << 2)) > 0;
byte[] bytes;
int b;
// time byte(s)
switch (timeStorageMode)
{
case TimeStorageMode.Full: // 4 bytes
bytes = new byte[8];
stream.Read(bytes, 2, 6);
waypoint.StorageTime = BitConverter.ToUInt64(bytes.Reverse().ToArray(), 0);
break;
case TimeStorageMode.Milliseconds: // 2 bytes
bytes = new byte[2];
stream.Read(bytes, 0, 2);
waypoint.StorageTime = previousWaypoint.StorageTime + BitConverter.ToUInt16(bytes.Reverse().ToArray(), 0);
break;
case TimeStorageMode.Seconds: // 1 byte
b = stream.ReadByte();
waypoint.StorageTime = previousWaypoint.StorageTime + (ulong)b * 1000;
break;
}
// position bytes
switch (positionStorageMode)
{
case PositionStorageMode.Full: // 4 + 4 + 3 bytes
bytes = new byte[4];
stream.Read(bytes, 0, 4);
waypoint.StorageLatitude = BitConverter.ToInt32(bytes.Reverse().ToArray(), 0);
bytes = new byte[4];
stream.Read(bytes, 0, 4);
waypoint.StorageLongitude = BitConverter.ToInt32(bytes.Reverse().ToArray(), 0);
if (altitudePresent)
{
bytes = new byte[4];
stream.Read(bytes, 1, 3);
waypoint.StorageAltitude = BitConverter.ToInt32(bytes.Reverse().ToArray(), 0);
}
break;
case PositionStorageMode.BigDelta: // 2 + 2 + 1 bytes
bytes = new byte[2];
stream.Read(bytes, 0, 2);
waypoint.StorageLatitude = previousWaypoint.StorageLatitude + BitConverter.ToInt16(bytes.Reverse().ToArray(), 0);
bytes = new byte[2];
stream.Read(bytes, 0, 2);
waypoint.StorageLongitude = previousWaypoint.StorageLongitude + BitConverter.ToInt16(bytes.Reverse().ToArray(), 0);
if (altitudePresent)
{
b = stream.ReadByte();
waypoint.StorageAltitude = previousWaypoint.StorageAltitude + (sbyte)b;
}
break;
case PositionStorageMode.SmallDelta: // 1 + 1 + 1 bytes
b = stream.ReadByte();
waypoint.StorageLatitude = previousWaypoint.StorageLatitude + (sbyte)b;
b = stream.ReadByte();
waypoint.StorageLongitude = previousWaypoint.StorageLongitude + (sbyte)b;
if (altitudePresent)
{
b = stream.ReadByte();
waypoint.StorageAltitude = previousWaypoint.StorageAltitude + (sbyte)b;
}
break;
}
return waypoint;
}
/// <summary>
/// The storage mode for the time of a waypoint.
/// </summary>
private enum TimeStorageMode
{
/// <summary>
/// The time is stored as a 6-byte unsigned integer, and shows the number of milliseconds since January 1, 1900, 00:00:00 UTC.
/// </summary>
Full,
/// <summary>
/// The time is stored as a 2-byte unsigned integer, and shows the number of seconds since the previous waypoint's time.
/// </summary>
Seconds,
/// <summary>
/// The time is stored as a 4-byte unsigned integer, and shows the number of milliseconds since the previous waypoint's time.
/// </summary>
Milliseconds
}
/// <summary>
/// The storage mode for the position (latitude, longitude, altitude) of a waypoint.
/// </summary>
private enum PositionStorageMode
{
/// <summary>
/// The longitude and latitude are stored as microdegrees in 4-byte signed integers, and the altitude is stored as decimeters in a 3-byte signed integer.
/// </summary>
Full,
/// <summary>
/// The longitude and latitude are stored as microdegrees relative to the previous waypoint in 2-byte signed integers, and the altitude is stored as decimeters relative to the previous waypoint in a 3-byte signed integer>.
/// </summary>
BigDelta,
/// <summary>
/// The longitude and latitude are stored as microdegrees relative to the previous waypoint in 1-byte signed integers, and the altitude is stored as decimeters relative to the previous waypoint in a 1-byte signed integer.
/// </summary>
SmallDelta
}
}
/// <summary>
/// The type of waypoint.
/// </summary>
public enum IofXml30WaypointType
{
/// <summary>
/// A normal waypoint.
/// </summary>
Normal,
/// <summary>
/// A waypoint that is the last waypoint before an interruption in the route occurs.
/// </summary>
Interruption
}
PHP Decode Script
The PHP script is very similar. I can't attach due to the limit of the size of this post, however I can provide it if needed.
I have an integer that gets incremented
I then want this in hex so I do the conversion like so: myInt.ToString("X");
I then need a string in the format of 00 00 00 00 but I cannot work out a way to convert the hex string I now have into this format.
With a Linq query you can do this:
string.Join(" ", BitConverter.GetBytes(myInt).Reverse().Select(x=>x.ToString("x")));
Fun Mode On Part 1
I can use Regexes for replace! Wozza!!!
string str = Regex.Replace(
String.Format("{0:X8}", myVal),
"([0-9A-F]{2})([0-9A-F]{2})([0-9A-F]{2})([0-9A-F]{2})",
"$1 $2 $3 $4"
);
I'm writing the number in 8 digits hex format with the String.Format and then I'm inserting the spaces using a Regex. Yes, it's overkill and useless :-)
Seriously
string str = String.Format(
"{0:X2} {1:X2} {2:X2} {3:X2}",
(myVal >> 24) & 0xFF,
(myVal >> 16) & 0xFF,
(myVal >> 8) & 0xFF,
myVal & 0xFF);
Taking a piece at a time using shifts and an "&& Mask" and composing them using String.Format in Hex formatting with padding 2.
Don't use them with negative numbers, please!
Fun Mode On Part 2 (The Return of the Angry Regex)
string str = Regex.Replace(
String.Format("{0:X8}", myVal),
"([0-9A-F]{2})(?!$)",
"$1 "
);
Here we search for groups of 2 Hex digits that aren't at the end of the string and add a space after them (We could have used \B (remember to escape) instead of (?!$))
You can specify the number of hex digits using a number after the 'x' (e.g. 'x2'). A lower-case 'x' will give you lower-case hex, and visa-versa with an upper-case one.
The following methods will the the least wasteful you will find:
/// <summary>
/// Converts the specified byte array into a delimited list of hex pairs.
/// </summary>
/// <param name="values">The values.</param>
/// <param name="requiredLength">The required length (in bytes) required.</param>
/// <param name="delimiter">The delimiter.</param>
/// <returns>The binary value.</returns>
static string ToBinaryString(byte[] values, int requiredLength, string delimiter, bool allowLonger)
{
if (values == null)
return null;
if (values.Length > requiredLength)
{
if (allowLonger)
requiredLength = values.Length;
else
throw new ArgumentOutOfRangeException("values");
}
// Create the StringBuilder with the precise length of values.
var sb = new StringBuilder((2 + delimiter.Length) * requiredLength - delimiter.Length);
var padLength = requiredLength - values.Length;
for (var i = 0; i < padLength; i++)
sb.Append(sb.Length == 0 ? "" : delimiter)
.Append("00");
for (var i = 0; i < values.Length; i++)
sb.Append(sb.Length == 0 ? "" : delimiter)
.Append(values[i].ToString("x2"));
return sb.ToString();
}
/// <summary>
/// Converts the specified byte array into a delimited list of hex pairs.
/// </summary>
/// <param name="values">The values.</param>
/// <param name="delimiter">The delimiter.</param>
/// <returns>
/// The binary value.
/// </returns>
static string ToBinaryString(byte[] values, string delimiter)
{
return ToBinaryString(values, 0, delimiter, true);
}
EDIT: If you have an Int32 the following would work without unessecary allocations:
/// <summary>
/// Converts the specified <see cref="Int32"/> into a delimited list of hex pairs.
/// </summary>
/// <param name="values">The values.</param>
/// <param name="delimiter">The delimiter.</param>
/// <returns>The binary value.</returns>
static string ToBinaryString(int value, string delimeter)
{
var u = (uint)IPAddress.HostToNetworkOrder(value);
var sb = new StringBuilder((2 + delimeter.Length) * 4 - delimeter.Length);
sb.Append(((u >> 0) & 0xFF).ToString("x2")).Append(delimeter);
sb.Append(((u >> 8) & 0xFF).ToString("x2")).Append(delimeter);
sb.Append(((u >> 16) & 0xFF).ToString("x2")).Append(delimeter);
sb.Append(((u >> 24) & 0xFF).ToString("x2"));
return sb.ToString();
}