X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=Novacoin%2FCBlock.cs;h=e8f220799ab111a28ca5a76f5137046dc0cb9a92;hb=624ac1021490395614a0cbee619c79860c22061a;hp=30350b71ce333e9209f74faf66c081dde341b904;hpb=4c45f0efb0bd8451c8b9a02833ce007477534751;p=NovacoinLibrary.git

diff --git a/Novacoin/CBlock.cs b/Novacoin/CBlock.cs
index 30350b7..e8f2207 100644
--- a/Novacoin/CBlock.cs
+++ b/Novacoin/CBlock.cs
@@ -20,6 +20,8 @@ using System;
 using System.Text;
 using System.Collections.Generic;
 using System.Diagnostics.Contracts;
+using System.IO;
+using System.Numerics;
 
 namespace Novacoin
 {
@@ -46,6 +48,16 @@ namespace Novacoin
     /// </summary>
     public class CBlock
 	{
+        /// <summary>
+        /// Maximum block size is 1Mb.
+        /// </summary>
+        public const uint nMaxBlockSize = 1000000;
+
+        /// <summary>
+        /// Sanity threshold for amount of sigops.
+        /// </summary>
+        public const uint nMaxSigOps = 20000;
+
 		/// <summary>
 		/// Block header.
 		/// </summary>
@@ -87,16 +99,19 @@ namespace Novacoin
 		{
             try
             {
-                ByteQueue wBytes = new ByteQueue(blockBytes);
+                var stream = new MemoryStream(blockBytes);
+                var reader = new BinaryReader(stream);
 
                 // Fill the block header fields
-                header = new CBlockHeader(wBytes.Get(80));
+                header = new CBlockHeader(ref reader);               
 
                 // Parse transactions list
-                vtx = CTransaction.ReadTransactionsList(ref wBytes);
+                vtx = CTransaction.ReadTransactionsList(ref reader);
 
                 // Read block signature
-                signature = wBytes.Get((int)wBytes.GetVarInt());
+                signature = reader.ReadBytes((int)VarInt.ReadVarInt(ref reader));
+
+                reader.Close();
             }
             catch (Exception e)
             {
@@ -114,11 +129,11 @@ 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
-            if (vtx.Length == 0 || Size > 1000000)
+            if (vtx.Length == 0 || Size > nMaxBlockSize)
             {
                 return false;
             }
@@ -241,7 +256,7 @@ namespace Novacoin
             }
 
             // Reject block if validation would consume too much resources.
-            if (nSigOps > 50000)
+            if (nSigOps > nMaxSigOps)
             {
                 return false;
             }
@@ -255,9 +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;
         }
@@ -328,20 +358,25 @@ namespace Novacoin
         /// <returns>Byte sequence</returns>
         public static implicit operator byte[] (CBlock b)
         {
-            var r = new List<byte>();
+            var stream = new MemoryStream();
+            var writer = new BinaryWriter(stream);
 
-            r.AddRange((byte[])b.header);
-            r.AddRange(VarInt.EncodeVarInt(b.vtx.LongLength)); // transactions count
+            writer.Write(b.header);
+            writer.Write(VarInt.EncodeVarInt(b.vtx.LongLength));
 
             foreach (var tx in b.vtx)
             {
-                r.AddRange((byte[])tx);
+                writer.Write(tx);
             }
 
-            r.AddRange(VarInt.EncodeVarInt(b.signature.LongLength));
-            r.AddRange(b.signature);
+            writer.Write(VarInt.EncodeVarInt(b.signature.LongLength));
+            writer.Write(b.signature);
+
+            var resultBytes = stream.ToArray();
 
-            return r.ToArray();
+            writer.Close();
+
+            return resultBytes;
         }
 
         /// <summary>
@@ -386,7 +421,7 @@ namespace Novacoin
         /// <summary>
         /// Merkle root
         /// </summary>
-        public Hash256 hashMerkleRoot
+        public uint256 hashMerkleRoot
         {
             get {
                 
@@ -394,7 +429,7 @@ namespace Novacoin
 
                 foreach (var tx in vtx)
                 {
-                    merkleTree.AddRange(Hash256.ComputeRaw256(tx));
+                    merkleTree.AddRange(CryptoUtils.ComputeHash256(tx));
                 }
 
                 int levelOffset = 0;
@@ -407,12 +442,12 @@ namespace Novacoin
                         var left = merkleTree.GetRange((levelOffset + nLeft) * 32, 32).ToArray();
                         var right = merkleTree.GetRange((levelOffset + nRight) * 32, 32).ToArray();
 
-                        merkleTree.AddRange(Hash256.ComputeRaw256(ref left, ref right));
+                        merkleTree.AddRange(CryptoUtils.ComputeHash256(ref left, ref right));
                     }
                     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();
             }
         }
 
@@ -436,6 +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;
+        }
+    }
 }