Hex.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Util / Hex.cs / 1305376 / Hex.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*
 * Hex.cs 
// 
// [....]
 * 
 * Operations to convert to and from Hex
 *
 */
 
namespace System.Security.Util
{ 
    using System; 
    using System.Security;
    using System.Diagnostics.Contracts; 
    internal static class Hex
    {
        // converts number to hex digit. Does not do any range checks.
        static char HexDigit(int num) { 
            return (char)((num < 10) ? (num + '0') : (num + ('A' - 10)));
        } 
 
        public  static String EncodeHexString(byte[] sArray)
        { 
            String result = null;

            if(sArray != null) {
                char[] hexOrder = new char[sArray.Length * 2]; 

                int digit; 
                for(int i = 0, j = 0; i < sArray.Length; i++) { 
                    digit = (int)((sArray[i] & 0xf0) >> 4);
                    hexOrder[j++] = HexDigit(digit); 
                    digit = (int)(sArray[i] & 0x0f);
                    hexOrder[j++] = HexDigit(digit);
                }
                result = new String(hexOrder); 
            }
            return result; 
        } 

        internal static string EncodeHexStringFromInt(byte[] sArray) { 
            String result = null;
            if(sArray != null) {
                char[] hexOrder = new char[sArray.Length * 2];
 
                int i = sArray.Length;
                int digit, j=0; 
                while (i-- > 0) { 
                    digit = (sArray[i] & 0xf0) >> 4;
                    hexOrder[j++] = HexDigit(digit); 
                    digit = sArray[i] & 0x0f;
                    hexOrder[j++] = HexDigit(digit);
                }
                result = new String(hexOrder); 
            }
            return result; 
        } 

        public static int ConvertHexDigit(Char val) 
        {
            if (val <= '9' && val >= '0')
                return (val - '0');
            else if (val >= 'a' && val <= 'f') 
                return ((val - 'a') + 10);
            else if (val >= 'A' && val <= 'F') 
                return ((val - 'A') + 10); 
            else
                throw new ArgumentException( Environment.GetResourceString( "ArgumentOutOfRange_Index" ) ); 
        }


        public static byte[] DecodeHexString(String hexString) 
        {
            if (hexString == null) 
                throw new ArgumentNullException( "hexString" ); 
            Contract.EndContractBlock();
 
            bool spaceSkippingMode = false;

            int i = 0;
            int length = hexString.Length; 

            if ((length >= 2) && 
                (hexString[0] == '0') && 
                ( (hexString[1] == 'x') ||  (hexString[1] == 'X') ))
            { 
                length = hexString.Length - 2;
                i = 2;
            }
 
            // Hex strings must always have 2N or (3N - 1) entries.
 
            if (length % 2 != 0 && length % 3 != 2) 
            {
                throw new ArgumentException( Environment.GetResourceString( "Argument_InvalidHexFormat" ) ); 
            }

            byte[] sArray;
 
            if (length >=3 && hexString[i + 2] == ' ')
            { 
                spaceSkippingMode = true; 

                // Each hex digit will take three spaces, except the first (hence the plus 1). 
                sArray = new byte[length / 3 + 1];
            }
            else
            { 
                // Each hex digit will take two spaces
                sArray = new byte[length / 2]; 
            } 

            int digit; 
            int rawdigit;
            for (int j = 0; i < hexString.Length; i += 2, j++) {
                rawdigit = ConvertHexDigit(hexString[i]);
                digit = ConvertHexDigit(hexString[i+1]); 
                sArray[j] = (byte) (digit | (rawdigit << 4));
                if (spaceSkippingMode) 
                    i++; 
            }
            return(sArray); 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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