Checkpoints valudation, PoW reward calculation and continue working on block index.

[NovacoinLibrary.git] / Novacoin / CBlock.cs

diff --git a/Novacoin/CBlock.cs b/Novacoin/CBlock.cs
index a620d26..e8f2207 100644 (file)
--- a/Novacoin/CBlock.cs
+++ b/Novacoin/CBlock.cs
@@ -21,6 +21,7 @@ using System.Text;
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
 using System.IO;
+using System.Numerics;
 
 namespace Novacoin
 {
@@ -128,7 +129,7 @@ namespace Novacoin
 
         public bool CheckBlock(bool fCheckPOW = true, bool fCheckMerkleRoot = true, bool fCheckSig = true)
         {
-            var uniqueTX = new List<Hash256>(); // tx hashes
+            var uniqueTX = new List<uint256>(); // tx hashes
             uint nSigOps = 0; // total sigops
 
             // Basic sanity checkings
@@ -199,13 +200,13 @@ namespace Novacoin
                 }
 
                 // Check timestamp
-                if (header.nTime > NetUtils.FutureDrift(NetUtils.GetAdjustedTime()))
+                if (header.nTime > NetInfo.FutureDrift(NetInfo.GetAdjustedTime()))
                 {
                     return false;
                 }
 
                 // Check coinbase timestamp
-                if (header.nTime < NetUtils.PastDrift(vtx[0].nTime))
+                if (header.nTime < NetInfo.PastDrift(vtx[0].nTime))
                 {
                     return false;
                 }
@@ -269,9 +270,24 @@ namespace Novacoin
             return true;
         }
 
-        private bool CheckProofOfWork(ScryptHash256 hash, uint nBits)
+        private bool CheckProofOfWork(uint256 hash, uint nBits)
         {
-            // TODO: stub!
+            uint256 nTarget = new uint256();
+            nTarget.Compact = nBits;
+
+            // Check range
+            if (nTarget > NetInfo.nProofOfWorkLimit)
+            {
+                // nBits below minimum work
+                return false; 
+            }
+
+            // Check proof of work matches claimed amount
+            if (hash > nTarget)
+            {
+                //  hash doesn't match nBits
+                return false;
+            }
 
             return true;
         }
@@ -405,7 +421,7 @@ namespace Novacoin
         /// <summary>
         /// Merkle root
         /// </summary>
-        public Hash256 hashMerkleRoot
+        public uint256 hashMerkleRoot
         {
             get {
                 
@@ -413,7 +429,7 @@ namespace Novacoin
 
                 foreach (var tx in vtx)
                 {
-                    merkleTree.AddRange(Hash256.ComputeRaw256(tx));
+                    merkleTree.AddRange(CryptoUtils.ComputeHash256(tx));
                 }
 
                 int levelOffset = 0;
@@ -431,7 +447,7 @@ namespace Novacoin
                     levelOffset += nLevelSize;
                 }
 
-                return (merkleTree.Count == 0) ? new Hash256() : new Hash256(merkleTree.GetRange(merkleTree.Count-32, 32).ToArray());
+                return (merkleTree.Count == 0) ? 0 : (uint256)merkleTree.GetRange(merkleTree.Count-32, 32).ToArray();
             }
         }
 
@@ -455,6 +471,51 @@ namespace Novacoin
             
             return sb.ToString();
         }
-       }
+
+        /// <summary>
+        /// Calculate proof-of-work reward.
+        /// </summary>
+        /// <param name="nBits">Packed difficulty representation.</param>
+        /// <param name="nFees">Amount of fees.</param>
+        /// <returns>Reward value.</returns>
+        public static ulong GetProofOfWorkReward(uint nBits, ulong nFees)
+        {
+            // NovaCoin: subsidy is cut in half every 64x multiply of PoW difficulty
+            // A reasonably continuous curve is used to avoid shock to market
+            // (nSubsidyLimit / nSubsidy) ** 6 == bnProofOfWorkLimit / bnTarget
+            //
+            // Human readable form:
+            //
+            // nSubsidy = 100 / (diff ^ 1/6)
+            //
+            // Please note that we're using bisection to find an approximate solutuion
+
+            BigInteger bnSubsidyLimit = NetInfo.nMaxMintProofOfWork;
+
+            uint256 nTarget = 0;
+            nTarget.Compact = nBits;
+
+            BigInteger bnTarget = new BigInteger(nTarget);
+            BigInteger bnTargetLimit = new BigInteger(NetInfo.nProofOfWorkLimit);
+
+            BigInteger bnLowerBound = CTransaction.nCent;
+            BigInteger bnUpperBound = bnSubsidyLimit;
+
+            while (bnLowerBound + CTransaction.nCent <= bnUpperBound)
+            {
+                BigInteger bnMidValue = (bnLowerBound + bnUpperBound) / 2;
+                if (bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnMidValue * bnTargetLimit > bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnSubsidyLimit * bnTarget)
+                    bnUpperBound = bnMidValue;
+                else
+                    bnLowerBound = bnMidValue;
+            }
+
+            ulong nSubsidy = (ulong)bnUpperBound;
+            nSubsidy = (nSubsidy / CTransaction.nCent) * CTransaction.nCent;
+
+
+            return Math.Min(nSubsidy, NetInfo.nMaxMintProofOfWork) + nFees;
+        }
+    }
 }