X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=Novacoin%2FHash.cs;h=5b1d3b74335030e8b2c9ceb251352410600ae35f;hb=1f6b6ffe24de703593f20f5f881a2e797473621c;hp=804939462fdc859771610071526cbd386b44ad04;hpb=07221c9bf3606c08e8c7d49a53b2f49bde06bb5c;p=NovacoinLibrary.git

diff --git a/Novacoin/Hash.cs b/Novacoin/Hash.cs
index 8049394..5b1d3b7 100644
--- a/Novacoin/Hash.cs
+++ b/Novacoin/Hash.cs
@@ -1,63 +1,227 @@
-using System;
-using System.Security.Cryptography;
-using System.Collections.Generic;
+/**
+ *  Novacoin classes library
+ *  Copyright (C) 2015 Alex D. (balthazar.ad@gmail.com)
+
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using System.Diagnostics.Contracts;
 using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Novacoin
 {
-    public abstract class Hash
+    public abstract class Hash : IEquatable<Hash>, IComparable<Hash>
     {
         /// <summary>
-        /// Computes the SHA256 hash for the input data using the managed library.
-        /// </summary>
-        protected static SHA256Managed _hasher256 = new SHA256Managed();
-        
-        /// <summary>
         /// Array of digest bytes.
         /// </summary>
-        protected byte[] _hashBytes = null;
+        protected byte[] _hashBytes;
 
         /// <summary>
         /// Hash size, must be overriden
         /// </summary>
-        public virtual int hashSize 
+        public abstract int hashSize 
         {
             get; 
-            private set;
         }
 
-        public byte[] hashBytes
+        /// <summary>
+        /// Initializes an empty instance of the Hash class.
+        /// </summary>
+        public Hash()
         {
-            get { return _hashBytes; }
+            _hashBytes = new byte[hashSize];
         }
 
         /// <summary>
-        /// Initializes an empty instance of the Hash class.
+        /// Initializes a new instance of Hash class
         /// </summary>
-        public Hash()
+        /// <param name="bytesList">Array of bytes</param>
+        public Hash(byte[] bytes, int offset = 0)
         {
-            _hashBytes = Enumerable.Repeat<byte>(0, hashSize).ToArray();
+            if (bytes.Length - offset < hashSize)
+            {
+                throw new ArgumentException("You need to provide a sufficient amount of data to initialize new instance of hash object.");
+            }
+
+            _hashBytes = new byte[hashSize];
+            Array.Copy(bytes, offset, _hashBytes, 0, hashSize);
         }
 
         /// <summary>
-        /// Initializes a new instance of Hash class with first 20 bytes from supplied list
+        /// Initializes a new instance of Hash class as a copy of another one
         /// </summary>
-        /// <param name="bytesList">List of bytes</param>
-        public Hash(IList<byte> bytesList)
+        /// <param name="bytesList">Instance of hash class</param>
+        public Hash(Hash h)
+        {
+            _hashBytes = new byte[h.hashSize];
+            h._hashBytes.CopyTo(_hashBytes, 0);
+        }
+
+        public bool IsZero
+        {
+            get { return !_hashBytes.Any(b => b != 0); }
+        }
+
+        public static implicit operator byte[](Hash h)
+        {
+            return h._hashBytes;
+        }
+
+        public bool Equals(Hash item)
+        {
+            if ((object)item == null)
+            {
+                return false;
+            }
+            return _hashBytes.SequenceEqual((byte[])item);
+        }
+
+        public override bool Equals(object o)
+        {
+            if (o == null)
+            {
+                return false;
+            }
+
+            return _hashBytes.SequenceEqual(((Hash)o)._hashBytes);
+        }
+
+        public override int GetHashCode()
+        {
+            int hash = 17;
+            unchecked
+            {
+                foreach (var element in _hashBytes)
+                {
+                    hash = hash * 31 + element.GetHashCode();
+                }
+            }
+            return hash;
+        }
+
+        public int CompareTo(Hash item)
+        {
+            if (this > item)
+            {
+                return 1;
+            }
+            else if (this < item)
+            {
+                return -1;
+            }
+
+            return 0;
+        }
+
+        public static bool operator <(Hash a, Hash b)
+        {
+            Contract.Requires<NullReferenceException>((object)a != null && (object)b != null, "Null references are not allowed.");
+            Contract.Requires<ArgumentException>(a.hashSize == b.hashSize, "Hashes must have the same size.");
+            
+            for (int i = a.hashSize - 1; i >= 0; i--)
+            {
+                if (a._hashBytes[i] < b._hashBytes[i])
+                {
+                    return true;
+                }
+                else if (a._hashBytes[i] > b._hashBytes[i])
+                {
+                    return false;
+                }
+            }
+
+            return false;
+        }
+
+        public static bool operator <=(Hash a, Hash b)
+        {
+            Contract.Requires<NullReferenceException>((object)a != null && (object)b != null, "Null references are not allowed.");
+            Contract.Requires<ArgumentException>(a.hashSize == b.hashSize, "Hashes must have the same size.");
+
+            for (int i = a.hashSize - 1; i >= 0; i--)
+            {
+                if (a._hashBytes[i] < b._hashBytes[i])
+                {
+                    return true;
+                }
+                else if (a._hashBytes[i] > b._hashBytes[i])
+                {
+                    return false;
+                }
+            }
+
+            return false;
+        }
+
+        public static bool operator >(Hash a, Hash b)
+        {
+            Contract.Requires<NullReferenceException>((object)a != null && (object)b != null, "Null references are not allowed.");
+            Contract.Requires<ArgumentException>(a.hashSize == b.hashSize, "Hashes must have the same size.");
+
+            for (int i = a.hashSize - 1; i >= 0; i--)
+            {
+                if (a._hashBytes[i] > b._hashBytes[i])
+                {
+                    return true;
+                }
+                else if (a._hashBytes[i] < b._hashBytes[i])
+                {
+                    return false;
+                }
+            }
+
+            return false;
+        }
+
+        public static bool operator >=(Hash a, Hash b)
         {
-            _hashBytes = bytesList.Take<byte>(hashSize).ToArray<byte>();
+            Contract.Requires<NullReferenceException>((object)a != null && (object)b != null, "Null references are not allowed.");
+            Contract.Requires<ArgumentException>(a.hashSize == b.hashSize, "Hashes must have the same size.");
+
+            for (int i = a.hashSize - 1; i >= 0; i--)
+            {
+                if (a._hashBytes[i] > b._hashBytes[i])
+                {
+                    return true;
+                }
+                else if (a._hashBytes[i] < b._hashBytes[i])
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        public static bool operator ==(Hash a, Hash b)
+        {
+            Contract.Requires<NullReferenceException>((object)a != null && (object)b != null, "Null references are not allowed.");
+            Contract.Requires<ArgumentException>(a.hashSize == b.hashSize, "Hashes must have the same size.");
+
+            return a._hashBytes.SequenceEqual(b._hashBytes);
         }
 
-        public Hash(byte[] bytesArray)
+        public static bool operator !=(Hash a, Hash b)
         {
-            _hashBytes = bytesArray;
+            return !(a == b);
         }
 
         public override string ToString()
         {
-            return Interop.ToHex(_hashBytes);
+            return Interop.ToHex(Interop.ReverseBytes(_hashBytes));
         }
     }
 }