HashAlgorithm.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Cryptography / HashAlgorithm.cs / 1305376 / HashAlgorithm.cs
                        
                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
// [....]
// 
 
//
// HashAlgorithm.cs 
//

namespace System.Security.Cryptography {
    using System.IO; 
    using System.Diagnostics.Contracts;
 
    [System.Runtime.InteropServices.ComVisible(true)] 
    public abstract class HashAlgorithm : IDisposable, ICryptoTransform {
        protected int HashSizeValue; 
        protected internal byte[] HashValue;
        protected int State = 0;

        private bool m_bDisposed = false; 

        protected HashAlgorithm() {} 
 
        //
        // public properties 
        //

        public virtual int HashSize {
            get { return HashSizeValue; } 
        }
 
        public virtual byte[] Hash { 
            get {
                if (m_bDisposed) 
                    throw new ObjectDisposedException(null);
                if (State != 0)
                    throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_HashNotYetFinalized"));
                return (byte[]) HashValue.Clone(); 
            }
        } 
 
        //
        // public methods 
        //

        [System.Security.SecuritySafeCritical]  // auto-generated
        static public HashAlgorithm Create() { 
            return Create("System.Security.Cryptography.HashAlgorithm");
        } 
 
        [System.Security.SecuritySafeCritical]  // auto-generated
        static public HashAlgorithm Create(String hashName) { 
            return (HashAlgorithm) CryptoConfig.CreateFromName(hashName);
        }

        public byte[] ComputeHash(Stream inputStream) { 
            if (m_bDisposed)
                throw new ObjectDisposedException(null); 
 
            // Default the buffer size to 4K.
            byte[] buffer = new byte[4096]; 
            int bytesRead;
            do {
                bytesRead = inputStream.Read(buffer, 0, 4096);
                if (bytesRead > 0) { 
                    HashCore(buffer, 0, bytesRead);
                } 
            } while (bytesRead > 0); 

            HashValue = HashFinal(); 
            byte[] Tmp = (byte[]) HashValue.Clone();
            Initialize();
            return(Tmp);
        } 

        public byte[] ComputeHash(byte[] buffer) { 
            if (m_bDisposed) 
                throw new ObjectDisposedException(null);
 
            // Do some validation
            if (buffer == null) throw new ArgumentNullException("buffer");

            HashCore(buffer, 0, buffer.Length); 
            HashValue = HashFinal();
            byte[] Tmp = (byte[]) HashValue.Clone(); 
            Initialize(); 
            return(Tmp);
        } 

        public byte[] ComputeHash(byte[] buffer, int offset, int count) {
            // Do some validation
            if (buffer == null) 
                throw new ArgumentNullException("buffer");
            if (offset < 0) 
                throw new ArgumentOutOfRangeException("offset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum")); 
            if (count < 0 || (count > buffer.Length))
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue")); 
            if ((buffer.Length - count) < offset)
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen"));
            Contract.EndContractBlock();
 
            if (m_bDisposed)
                throw new ObjectDisposedException(null); 
 
            HashCore(buffer, offset, count);
            HashValue = HashFinal(); 
            byte[] Tmp = (byte[]) HashValue.Clone();
            Initialize();
            return(Tmp);
        } 

        // ICryptoTransform methods 
 
        // we assume any HashAlgorithm can take input a byte at a time
        public virtual int InputBlockSize { 
            get { return(1); }
        }

        public virtual int OutputBlockSize { 
            get { return(1); }
        } 
 
        public virtual bool CanTransformMultipleBlocks {
            get { return(true); } 
        }

        public virtual bool CanReuseTransform {
            get { return(true); } 
        }
 
        // We implement TransformBlock and TransformFinalBlock here 
        [System.Security.SecuritySafeCritical]  // auto-generated
        public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset) { 
            // Do some validation, we let BlockCopy do the destination array validation
            if (inputBuffer == null)
                throw new ArgumentNullException("inputBuffer");
            if (inputOffset < 0) 
                throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            if (inputCount < 0 || (inputCount > inputBuffer.Length)) 
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue")); 
            if ((inputBuffer.Length - inputCount) < inputOffset)
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen")); 
            Contract.EndContractBlock();

            if (m_bDisposed)
                throw new ObjectDisposedException(null); 

            // Change the State value 
            State = 1; 
            HashCore(inputBuffer, inputOffset, inputCount);
            if ((outputBuffer != null) && ((inputBuffer != outputBuffer) || (inputOffset != outputOffset))) 
                Buffer.BlockCopy(inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
            return inputCount;
        }
 
        [System.Security.SecuritySafeCritical]  // auto-generated
        public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount) { 
            // Do some validation 
            if (inputBuffer == null)
                throw new ArgumentNullException("inputBuffer"); 
            if (inputOffset < 0)
                throw new ArgumentOutOfRangeException("inputOffset", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum"));
            if (inputCount < 0 || (inputCount > inputBuffer.Length))
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidValue")); 
            if ((inputBuffer.Length - inputCount) < inputOffset)
                throw new ArgumentException(Environment.GetResourceString("Argument_InvalidOffLen")); 
            Contract.EndContractBlock(); 

            if (m_bDisposed) 
                throw new ObjectDisposedException(null);

            HashCore(inputBuffer, inputOffset, inputCount);
            HashValue = HashFinal(); 
            byte[] outputBytes = new byte[inputCount];
            if (inputCount != 0) 
                Buffer.InternalBlockCopy(inputBuffer, inputOffset, outputBytes, 0, inputCount); 
            // reset the State value
            State = 0; 
            return outputBytes;
        }

        // IDisposable methods 

        // To keep mscorlib compatibility with Orcas, CoreCLR's HashAlgorithm has an explicit IDisposable 
        // implementation. Post-Orcas the desktop has an implicit IDispoable implementation. 
#if FEATURE_CORECLR
        void IDisposable.Dispose() 
#if false
        { }
#endif // false
#else 
        [System.Security.SecuritySafeCritical]  // auto-generated
        public void Dispose() 
#endif // FEATURE_CORECLR 
        {
            Dispose(true); 
            GC.SuppressFinalize(this);
        }

        public void Clear() { 
            (this as IDisposable).Dispose();
        } 
 
        protected virtual void Dispose(bool disposing) {
            if (disposing) { 
                if (HashValue != null)
                    Array.Clear(HashValue, 0, HashValue.Length);
                HashValue = null;
                m_bDisposed = true; 
            }
        } 
 
        //
        // abstract public methods 
        //

        public abstract void Initialize();
 
        protected abstract void HashCore(byte[] array, int ibStart, int cbSize);
 
        protected abstract byte[] HashFinal(); 
    }
} 

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