Hex Encoding : HEX « Data Types « C# / C Sharp
Hex Encoding
using System;
using System.Text;
namespace MOM.Utility
{
/// <summary>
/// Summary description for HexEncoding.
/// </summary>
public class HexEncoding
{
public HexEncoding()
{
//
// TODO: Add constructor logic here
//
}
public static int GetByteCount(string hexString)
{
int numHexChars = 0;
char c;
// remove all none A-F, 0-9, characters
for (int i=0; i<hexString.Length; i++)
{
c = hexString[i];
if (IsHexDigit(c))
numHexChars++;
}
// if odd number of characters, discard last character
if (numHexChars % 2 != 0)
{
numHexChars--;
}
return numHexChars / 2; // 2 characters per byte
}
/// <summary>
/// Creates a byte array from the hexadecimal string. Each two characters are combined
/// to create one byte. First two hexadecimal characters become first byte in returned array.
/// Non-hexadecimal characters are ignored.
/// </summary>
/// <param name="hexString">string to convert to byte array</param>
/// <param name="discarded">number of characters in string ignored</param>
/// <returns>byte array, in the same left-to-right order as the hexString</returns>
public static byte[] GetBytes(string hexString, out int discarded)
{
discarded = 0;
string newString = "";
char c;
// remove all none A-F, 0-9, characters
for (int i=0; i<hexString.Length; i++)
{
c = hexString[i];
if (IsHexDigit(c))
newString += c;
else
discarded++;
}
// if odd number of characters, discard last character
if (newString.Length % 2 != 0)
{
discarded++;
newString = newString.Substring(0, newString.Length-1);
}
int byteLength = newString.Length / 2;
byte[] bytes = new byte[byteLength];
string hex;
int j = 0;
for (int i=0; i<bytes.Length; i++)
{
hex = new String(new Char[] {newString[j], newString[j+1]});
bytes[i] = HexToByte(hex);
j = j+2;
}
return bytes;
}
public static string ToString(byte[] bytes)
{
string hexString = "";
for (int i=0; i<bytes.Length; i++)
{
hexString += bytes[i].ToString("X2");
}
return hexString;
}
/// <summary>
/// Determines if given string is in proper hexadecimal string format
/// </summary>
/// <param name="hexString"></param>
/// <returns></returns>
public static bool InHexFormat(string hexString)
{
bool hexFormat = true;
foreach (char digit in hexString)
{
if (!IsHexDigit(digit))
{
hexFormat = false;
break;
}
}
return hexFormat;
}
/// <summary>
/// Returns true is c is a hexadecimal digit (A-F, a-f, 0-9)
/// </summary>
/// <param name="c">Character to test</param>
/// <returns>true if hex digit, false if not</returns>
public static bool IsHexDigit(Char c)
{
int numChar;
int numA = Convert.ToInt32('A');
int num1 = Convert.ToInt32('0');
c = Char.ToUpper(c);
numChar = Convert.ToInt32(c);
if (numChar >= numA && numChar < (numA + 6))
return true;
if (numChar >= num1 && numChar < (num1 + 10))
return true;
return false;
}
/// <summary>
/// Converts 1 or 2 character string into equivalant byte value
/// </summary>
/// <param name="hex">1 or 2 character string</param>
/// <returns>byte</returns>
private static byte HexToByte(string hex)
{
if (hex.Length > 2 || hex.Length <= 0)
throw new ArgumentException("hex must be 1 or 2 characters in length");
byte newByte = byte.Parse(hex, System.Globalization.NumberStyles.HexNumber);
return newByte;
}
}
}
