Extends Encoding class to Represent hexadecimal (base-16) character encoding.

 
using System;
using System.Text;
using System.Globalization;

namespace XamlTorrent.Common
{
    /// <summary>
    /// Represents hexadecimal (base-16) character encoding.
    /// </summary>
    public class HexEncoding : Encoding
    {
        public HexEncoding()
            : base()
        {
        }

        public override int GetByteCount(char[] chars, int index, int count)
        {
            return (count / 2); // Hexadecimal uses 2 chars per byte
        }

        public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
        {
            for (int i = 0; i < charCount / 2; i++)
            {
                int lowCharIndex = (charIndex + (i * 2) + 1);
                int highCharIndex = (charIndex + (i * 2));

                byte low = AsciiToHex(chars[lowCharIndex]);
                byte high = AsciiToHex(chars[highCharIndex]);

                bytes[byteIndex + i] = (byte)(high * 0x10 + low);
            }

            return (charCount / 2);
        }

        private static byte AsciiToHex(char ch)
        {
            UInt16 c = ch;

            if (c >= 0x30 && c <= 0x39) // digit
                c -= 0x30;
            else if (c >= 0x41 && c <= 0x46) // upper-case A...F
                c -= 0x37;
            else if (c >= 0x61 && c <= 0x66) // lower-case a...f
                c -= 0x57;
            else
                throw new ArgumentOutOfRangeException("ch", "Non-hexadecimal character.");

            return (byte)c;
        }

        private static char HexToAscii(byte bt)
        {
            if (bt < 0xA) // digit
                return (char)(bt + 0x30);
            else
                return (char)(bt + 0x57);
        }

        public override int GetCharCount(byte[] bytes, int index, int count)
        {
            return (count * 2); // Hexadecimal uses 2 chars per byte
        }

        public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
        {
            for (int i = 0; i < byteCount; i++)
            {
                byte b = bytes[i];
                
                byte low = (byte)(b % 0x10);
                byte high = (byte)(b / 0x10);

                int lowCharIndex = (charIndex + (i * 2) + 1);
                int highCharIndex = (charIndex + (i * 2));

                chars[lowCharIndex] = HexToAscii(low);
                chars[highCharIndex] = HexToAscii(high);
            }

            return (byteCount * 2);
        }

        public override int GetMaxByteCount(int charCount)
        {
            return (charCount / 2); // Hexadecimal uses 2 chars per byte
        }

        public override int GetMaxCharCount(int byteCount)
        {
            return (byteCount * 2); // Hexadecimal uses 2 chars per byte
        }
    }
}

Related examples in the same category

1.	The hex dump program
2.	To specify a hexadecimal constant, begin with 0x or 0X, followed by a sequence of digits in the range 0 through 9 and a (or A) through f (or F).
3.	Hex Encoder
4.	Hex Translator
5.	Convert Hex char To Int
6.	Hex To Unicode
7.	Hex To Bytes
8.	Unicode To Hex
9.	Unicode To Hex (2)
10.	Convert a hex string into a byte array with one byte for every 2 hex characters.
11.	Convert Hex Value To Byte Array
12.	Binary To Hex
13.	Bytes To Hex String
14.	Hex String To Bytes
15.	Hex value to Binary
16.	Is hex digit
17.	Hex string to byte array and int
18.	Convert Int To Plugwise Log Hex
19.	Convert Plugwise Log Hex To Int
20.	Convert a hexadecimal string to a byte array
21.	Bytes To Hex String (2)
22.	Hex String To Bytes (2)
23.	Bytes To Hex, Hex To String
24.	Hex Encoding
25.	Hex To Int
26.	Facilities for outputting hexadecimal strings
27.	Calculates the HEX values of an array of bytes and produces a hex string
28.	Bytes To Hex

Extends Encoding class to Represent hexadecimal (base-16) character encoding. : HEX « Data Types « C# / C Sharp

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