X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=Novacoin%2FCBlock.cs;h=4c878064eb6e135ca829288501bd60519560dc2d;hb=be9d844557911f95165d2c9875c4f5b2822cfc92;hp=856358f099a08c32117f35a3ff981d711700821e;hpb=308513de7625d87fa0799f3fcd2ddf28a50d6d89;p=NovacoinLibrary.git

diff --git a/Novacoin/CBlock.cs b/Novacoin/CBlock.cs
index 856358f..4c87806 100644
--- a/Novacoin/CBlock.cs
+++ b/Novacoin/CBlock.cs
@@ -17,17 +17,34 @@
  */
 
 using System;
-using System.Linq;
 using System.Text;
 using System.Collections.Generic;
-using System.Security.Cryptography;
+using System.Diagnostics.Contracts;
 
 namespace Novacoin
 {
-	/// <summary>
-	/// Represents the block. Block consists of header, transaction array and header signature.
-	/// </summary>
-	public class CBlock
+    [Serializable]
+    public class BlockException : Exception
+    {
+        public BlockException()
+        {
+        }
+
+        public BlockException(string message)
+                : base(message)
+        {
+        }
+
+        public BlockException(string message, Exception inner)
+                : base(message, inner)
+        {
+        }
+    }
+
+    /// <summary>
+    /// Represents the block. Block consists of header, transaction array and header signature.
+    /// </summary>
+    public class CBlock
 	{
 		/// <summary>
 		/// Block header.
@@ -44,6 +61,10 @@ namespace Novacoin
         /// </summary>
         public byte[] signature = new byte[0];
 
+        /// <summary>
+        /// Copy constructor.
+        /// </summary>
+        /// <param name="b">CBlock instance.</param>
         public CBlock(CBlock b)
         {
             header = new CBlockHeader(b.header);
@@ -54,25 +75,33 @@ namespace Novacoin
                 vtx[i] = new CTransaction(b.vtx[i]);
             }
 
+            signature = new byte[b.signature.Length];
             b.signature.CopyTo(signature, 0);
         }
 
         /// <summary>
         /// Parse byte sequence and initialize new block instance
         /// </summary>
-        /// <param name="blockBytes"></param>
+        /// <param name="blockBytes">Bytes sequence.</param>
 		public CBlock (byte[] blockBytes)
 		{
-            ByteQueue wBytes = new ByteQueue(blockBytes);
+            try
+            {
+                ByteQueue wBytes = new ByteQueue(ref blockBytes);
 
-            // Fill the block header fields
-            header = new CBlockHeader(wBytes.Get(80));
+                // Fill the block header fields
+                header = new CBlockHeader(wBytes.Get(80));
 
-            // Parse transactions list
-            vtx = CTransaction.ReadTransactionsList(ref wBytes);
+                // Parse transactions list
+                vtx = CTransaction.ReadTransactionsList(ref wBytes);
 
-            // Read block signature
-            signature = wBytes.Get((int)wBytes.GetVarInt());
+                // Read block signature
+                signature = wBytes.Get((int)wBytes.GetVarInt());
+            }
+            catch (Exception e)
+            {
+                throw new BlockException("Deserialization failed", e);
+            }
 		}
 
         public CBlock()
@@ -83,6 +112,156 @@ namespace Novacoin
             vtx = new CTransaction[0];
         }
 
+        public bool CheckBlock(bool fCheckPOW = true, bool fCheckMerkleRoot = true, bool fCheckSig = true)
+        {
+            var uniqueTX = new List<Hash256>(); // tx hashes
+            uint nSigOps = 0; // total sigops
+
+            // Basic sanity checkings
+            if (vtx.Length == 0 || Size > 1000000)
+            {
+                return false;
+            }
+
+            bool fProofOfStake = IsProofOfStake;
+
+            // First transaction must be coinbase, the rest must not be
+            if (!vtx[0].IsCoinBase)
+            {
+                return false;
+            }
+
+            if (!vtx[0].CheckTransaction())
+            {
+                return false;
+            }
+
+            uniqueTX.Add(vtx[0].Hash);
+            nSigOps += vtx[0].LegacySigOpCount;
+
+            if (fProofOfStake)
+            {
+                // Proof-of-STake related checkings. Note that we know here that 1st transactions is coinstake. We don't need 
+                //   check the type of 1st transaction because it's performed earlier by IsProofOfStake()
+
+                // nNonce must be zero for proof-of-stake blocks
+                if (header.nNonce != 0)
+                {
+                    return false;
+                }
+
+                // Coinbase output should be empty if proof-of-stake block
+                if (vtx[0].vout.Length != 1 || !vtx[0].vout[0].IsEmpty)
+                {
+                    return false;
+                }
+
+                // Check coinstake timestamp
+                if (header.nTime != vtx[1].nTime)
+                {
+                    return false;
+                }
+
+                // Check proof-of-stake block signature
+                if (fCheckSig && !SignatureOK)
+                {
+                    return false;
+                }
+
+                if (!vtx[1].CheckTransaction())
+                {
+                    return false;
+                }
+
+                uniqueTX.Add(vtx[1].Hash);
+                nSigOps += vtx[1].LegacySigOpCount;
+            }
+            else
+            {
+                // Check proof of work matches claimed amount
+                if (fCheckPOW && !CheckProofOfWork(header.Hash, header.nBits))
+                {
+                    return false;
+                }
+
+                // Check timestamp
+                if (header.nTime > NetUtils.FutureDrift(NetUtils.GetAdjustedTime()))
+                {
+                    return false;
+                }
+
+                // Check coinbase timestamp
+                if (header.nTime < NetUtils.PastDrift(vtx[0].nTime))
+                {
+                    return false;
+                }
+            }
+
+            // Iterate all transactions starting from second for proof-of-stake block 
+            //    or first for proof-of-work block
+            for (int i = fProofOfStake ? 2 : 1; i < vtx.Length; i++)
+            {
+                var tx = vtx[i];
+
+                // Reject coinbase transactions at non-zero index
+                if (tx.IsCoinBase)
+                {
+                    return false;
+                }
+
+                // Reject coinstake transactions at index != 1
+                if (tx.IsCoinStake)
+                {
+                    return false;
+                }
+
+                // Check transaction timestamp
+                if (header.nTime < tx.nTime)
+                {
+                    return false;
+                }
+
+                // Check transaction consistency
+                if (!tx.CheckTransaction())
+                {
+                    return false;
+                }
+
+                // Add transaction hash into list of unique transaction IDs
+                uniqueTX.Add(tx.Hash);
+
+                // Calculate sigops count
+                nSigOps += tx.LegacySigOpCount;
+            }
+
+            // Check for duplicate txids. 
+            if (uniqueTX.Count != vtx.Length)
+            {
+                return false;
+            }
+
+            // Reject block if validation would consume too much resources.
+            if (nSigOps > 50000)
+            {
+                return false;
+            }
+
+            // Check merkle root
+            if (fCheckMerkleRoot && hashMerkleRoot != header.merkleRoot)
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        private bool CheckProofOfWork(ScryptHash256 hash, uint nBits)
+        {
+            // TODO: stub!
+
+            return true;
+        }
+
         /// <summary>
         /// Is this a Proof-of-Stake block?
         /// </summary>
@@ -166,6 +345,45 @@ namespace Novacoin
         }
 
         /// <summary>
+        /// Serialized size
+        /// </summary>
+        public int Size
+        {
+            get
+            {
+                int nSize = 80 + VarInt.GetEncodedSize(vtx.Length); // CBlockHeader + NumTx
+
+                foreach (var tx in vtx)
+                {
+                    nSize += tx.Size;
+                }
+
+                nSize += VarInt.GetEncodedSize(signature.Length) + signature.Length;
+
+                return nSize;
+            }
+        }
+
+        /// <summary>
+        /// Get transaction offset inside block.
+        /// </summary>
+        /// <param name="nTx">Transaction index.</param>
+        /// <returns>Offset in bytes from the beginning of block header.</returns>
+        public int GetTxOffset(int nTx)
+        {
+            Contract.Requires<ArgumentException>(nTx >= 0 && nTx < vtx.Length, "Transaction index you've specified is incorrect.");
+
+            int nOffset = 80 + VarInt.GetEncodedSize(vtx.Length); // CBlockHeader + NumTx
+
+            for (int i = 0; i < nTx; i++)
+            {
+                nOffset += vtx[i].Size;
+            }
+
+            return nOffset;
+        }
+
+        /// <summary>
         /// Merkle root
         /// </summary>
         public Hash256 hashMerkleRoot