HashUtility.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / WCF / WCF / 3.5.30729.1 / untmp / Orcas / SP / ndp / cdf / src / WCF / infocard / Service / managed / Microsoft / InfoCards / HashUtility.cs / 1 / HashUtility.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------
namespace Microsoft.InfoCards
{ 
    using System;
    using System.Collections.Generic; 
    using System.Runtime.InteropServices; 
    using System.Security;
    using System.Security.Cryptography; 
    using System.Text;
    using IDT = Microsoft.InfoCards.Diagnostics.InfoCardTrace;
    //
    // Summary: 
    //  Singleton utilty class for hashing data.
    // Remarks: 
    //  This class is currently global. Need to discuss a suitable hosting environment for it 
    // ( per user is probably appropriate )
    // 
    internal static class HashUtility
    {
        //
        // Summary: 
        //  The String identifier of the alg we use. Do we need to abstract this choice somewhere
        // 
        public const string HashAlgorithmName = "SHA256"; 

        private static object s_lock = new Object(); 

        private static SHA256Managed s_hasher = new SHA256Managed();

        // 
        // Summary:
        //  Gets the BitLength of the current hashing algorithm 
        // 
        public static Int32 HashBitLength
        { 
            get{ return s_hasher.HashSize; }
        }

 
        //
        // Summary: 
        //  Gets the Buffer Size of the current hashing algorithm 
        //
        public static Int32 HashBufferLength 
        {
            get
            {
                return HashBitLength / 8; 
            }
        } 
 
        //
        // Summary: 
        //  Hashes a given value, and write the value to the output buffer.
        //
        // Remarks:
        //  To get the size required for the output buffer, use HashBufferLength 
        //
        // Parameters: 
        //  data:       the output data buffer 
        //  dataIndex:  the index to place the hash in the output data buffer
        //  dataToHash: the input data to hash 
        //
        public static void SetHashValue( byte[] data, int dataIndex, byte[] dataToHash )
        {
            if( null == dataToHash ) 
            {
                throw IDT.ThrowHelperArgumentNull( "dataToHash" ); 
            } 

            SetHashValue( data, dataIndex, dataToHash, 0, dataToHash.Length ); 
        }

        //
        // Summary: 
        //  Hashes a given value, and write the value to the output buffer.
        // 
        // Remarks: 
        //  To get the size required for the output buffer, use HashBufferLength
        // 
        // Parameters:
        //  data:               the output data buffer
        //  dataIndex:          the index to place the hash in the output data buffer
        //  dataToHash:         the input data to hash 
        //  dataToHashIndex:    the index in the input to start hashing
        //  dataToHashSize:     the size of the data to hash. 
        // 
        public static void SetHashValue( byte[] data, int dataIndex, byte[] dataToHash, int dataToHashIndex, int dataToHashSize )
        { 

            if( null == data )
            {
                throw IDT.ThrowHelperArgumentNull( "data" ); 
            }
 
            if( dataIndex < 0 || dataIndex >= data.Length ) 
            {
                throw IDT.ThrowHelperError( new ArgumentOutOfRangeException( 
                                "dataIndex",
                                dataIndex,
                                SR.GetString( SR.StoreHashUtilityDataOutOfRange ) ) );
            } 
            if( null == dataToHash )
            { 
                throw IDT.ThrowHelperArgumentNull( "dataToHash" ); 
            }
            if( dataToHashIndex < 0 || dataToHashIndex > dataToHash.Length ) 
            {
                throw IDT.ThrowHelperError( new ArgumentOutOfRangeException(
                                "dataToHashIndex",
                                dataToHashIndex, 
                                SR.GetString( SR.StoreHashUtilityDataToHashOutOfRange ) ) );
            } 
            if( dataToHashSize < 0 || dataToHashSize > ( dataToHash.Length - dataToHashIndex ) ) 
            {
                throw IDT.ThrowHelperError( new ArgumentOutOfRangeException( 
                                "dataToHashIndex",
                                dataToHashIndex,
                                SR.GetString( SR.StoreHashUtilityDataToHashOutOfRange ) ) );
            } 

 
            byte[] newBuffer = null; 
            lock( s_lock )
            { 
                newBuffer = s_hasher.ComputeHash( dataToHash, dataToHashIndex, dataToHashSize );
            }

            // 
            // Copy this buffer to the output buffer
            // 
            Array.Copy( newBuffer, 0, data, dataIndex, newBuffer.Length ); 

            // 
            // Clear this has, as we can't ensure it will
            // be collected immediatly.
            //
            Array.Clear( newBuffer, 0, newBuffer.Length ); 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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