HashAlgorithm.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / HashAlgorithm.cs / 1 / HashAlgorithm.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// HashAlgorithm.cs 
//
 
namespace System.Security.Cryptography {
    using System.IO;

    [System.Runtime.InteropServices.ComVisible(true)] 
    public abstract class HashAlgorithm : 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, Environment.GetResourceString("ObjectDisposed_Generic")); 
                if (State != 0)
                    throw new CryptographicUnexpectedOperationException(Environment.GetResourceString("Cryptography_HashNotYetFinalized")); 
                return (byte[]) HashValue.Clone();
            }
        }
 
        //
        // public methods 
        // 

        static public HashAlgorithm Create() { 
            return Create("System.Security.Cryptography.HashAlgorithm");
        }

        static public HashAlgorithm Create(String hashName) { 
            return (HashAlgorithm) CryptoConfig.CreateFromName(hashName);
        } 
 
        public byte[] ComputeHash(Stream inputStream) {
            if (m_bDisposed) 
                throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic"));

            // 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, Environment.GetResourceString("ObjectDisposed_Generic"));
 
            // 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) { 
            if (m_bDisposed) 
                throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic"));
 
            // 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"));
 
            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 
        public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset) { 
            if (m_bDisposed)
                throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic")); 

            // 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")); 
 
            // 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; 
        }
 
        public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount) { 
            if (m_bDisposed)
                throw new ObjectDisposedException(null, Environment.GetResourceString("ObjectDisposed_Generic")); 

            // 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")); 
 
            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 

        /// 
        void IDisposable.Dispose() {
            Dispose(true); 
            GC.SuppressFinalize(this);
        } 
 
        public void Clear() {
            ((IDisposable) this).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();
    }
}

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