X-Git-Url: https://git.novaco.in/?a=blobdiff_plain;f=Novacoin%2FStakeModifier.cs;h=882a699486564ed6c1f6c5992322bfe37fc8bc45;hb=04ac3ad40812b5ff686f16e182a10a78b9816bf4;hp=2448497b4c0c21af4fbeb2bc22001bab92978362;hpb=12f67828e449407a93bdb3202066003a48a8c276;p=NovacoinLibrary.git

diff --git a/Novacoin/StakeModifier.cs b/Novacoin/StakeModifier.cs
index 2448497..882a699 100644
--- a/Novacoin/StakeModifier.cs
+++ b/Novacoin/StakeModifier.cs
@@ -1,14 +1,33 @@
-using System;
+/**
+*  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.Collections.Generic;
 using System.Diagnostics.Contracts;
 using System.IO;
 using System.Linq;
-using System.Numerics;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace Novacoin
 {
+    /// <summary>
+    /// Stake modifier calculation. Doesn't work properly, for now.
+    /// </summary>
     public class StakeModifier
     {
         /// <summary>
@@ -98,7 +117,7 @@ namespace Novacoin
         /// Get stake modifier selection interval (in seconds)
         /// </summary>
         /// <returns></returns>
-        static long GetStakeModifierSelectionInterval()
+        internal static long GetStakeModifierSelectionInterval()
         {
             long nSelectionInterval = 0;
             for (int nSection = 0; nSection < 64; nSection++)
@@ -118,14 +137,14 @@ namespace Novacoin
         /// <param name="nStakeModifierPrev">Previous value of stake modifier.</param>
         /// <param name="selectedCursor">Selection result.</param>
         /// <returns></returns>
-        static bool SelectBlockFromCandidates(List<Tuple<uint, uint256>> sortedByTimestamp, Dictionary<uint256, CBlockStoreItem> mapSelectedBlocks, long nSelectionIntervalStop, long nStakeModifierPrev, ref CBlockStoreItem selectedCursor)
+        internal static bool SelectBlockFromCandidates(List<Tuple<uint, uint256>> sortedByTimestamp, Dictionary<uint256, CBlockStoreItem> mapSelectedBlocks, long nSelectionIntervalStop, long nStakeModifierPrev, ref CBlockStoreItem selectedCursor)
         {
             bool fSelected = false;
             uint256 hashBest = 0;
             selectedCursor = null;
             foreach (var item in sortedByTimestamp)
             {
-                CBlockStoreItem cursor = CBlockStore.Instance.GetCursor(item.Item2);
+                CBlockStoreItem cursor = CBlockStore.Instance.GetMapCursor(item.Item2);
 
                 if (cursor == null)
                 {
@@ -147,7 +166,7 @@ namespace Novacoin
                 // compute the selection hash by hashing its proof-hash and the
                 // previous proof-of-stake modifier
 
-                uint256 hashProof = cursor.IsProofOfStake ? (uint256)cursor.hashProofOfStake : selectedBlockHash;
+                var hashProof = cursor.IsProofOfStake ? (uint256)cursor.hashProofOfStake : selectedBlockHash;
                 uint256 hashSelection;
 
                 var s = new MemoryStream();
@@ -194,7 +213,7 @@ namespace Novacoin
         /// additional bits in the stake modifier, even after generating a chain of
         /// blocks.
         /// </summary>
-        bool ComputeNextStakeModifier(CBlockStoreItem cursorCurrent, ref long nStakeModifier, ref bool fGeneratedStakeModifier)
+        public static bool ComputeNextStakeModifier(CBlockStoreItem cursorCurrent, ref long nStakeModifier, ref bool fGeneratedStakeModifier)
         {
             nStakeModifier = 0;
             fGeneratedStakeModifier = false;
@@ -261,7 +280,7 @@ namespace Novacoin
                 }
 
                 // write the entropy bit of the selected block
-                nStakeModifierNew |= ((cursor.StakeEntropyBit) << nRound);
+                nStakeModifierNew |= (((long)cursor.StakeEntropyBit) << nRound);
 
                 // add the selected block from candidates to selected list
                 mapSelectedBlocks.Add(cursor.Hash, cursor);
@@ -276,10 +295,13 @@ namespace Novacoin
         /// The stake modifier used to hash for a stake kernel is chosen as the stake
         /// modifier about a selection interval later than the coin generating the kernel
         /// </summary>
-        static bool GetKernelStakeModifier(uint256 hashBlockFrom, ref long nStakeModifier, ref uint nStakeModifierHeight, ref uint nStakeModifierTime)
+        static bool GetKernelStakeModifier(uint256 hashBlockFrom, out long nStakeModifier, out uint nStakeModifierHeight, out uint nStakeModifierTime)
         {
             nStakeModifier = 0;
-            var cursorFrom = CBlockStore.Instance.GetCursor(hashBlockFrom);
+            nStakeModifierTime = 0;
+            nStakeModifierHeight = 0;
+
+            var cursorFrom = CBlockStore.Instance.GetMapCursor(hashBlockFrom);
             if (cursorFrom == null)
             {
                 return false; // Block not indexed
@@ -311,41 +333,41 @@ namespace Novacoin
             return true;
         }
 
-        bool GetKernelStakeModifier(uint256 hashBlockFrom, ref long nStakeModifier)
+        public static bool GetKernelStakeModifier(uint256 hashBlockFrom, out long nStakeModifier)
         {
             uint nStakeModifierHeight = 0;
             uint nStakeModifierTime = 0;
 
-            return GetKernelStakeModifier(hashBlockFrom, ref nStakeModifier, ref nStakeModifierHeight, ref nStakeModifierTime);
+            return GetKernelStakeModifier(hashBlockFrom, out nStakeModifier, out nStakeModifierHeight, out nStakeModifierTime);
         }
 
-        bool CheckStakeKernelHash(uint nBits, CBlock blockFrom, uint nTxPrevOffset, CTransaction txPrev, COutPoint prevout, uint nTimeTx, ref uint256 hashProofOfStake, ref uint256 targetProofOfStake)
+        public static bool CheckStakeKernelHash(uint nBits, uint256 hashBlockFrom, uint nTimeBlockFrom, uint nTxPrevOffset, CTransaction txPrev, COutPoint prevout, uint nTimeTx, out uint256 hashProofOfStake, out uint256 targetProofOfStake)
         {
+            hashProofOfStake = targetProofOfStake = 0;
+
             if (nTimeTx < txPrev.nTime)
             {
                 return false; // Transaction timestamp violation
             }
 
-            uint nTimeBlockFrom = blockFrom.header.nTime;
             if (nTimeBlockFrom + nStakeMinAge > nTimeTx) // Min age requirement
             {
                 return false; // Min age violation
             }
 
-            uint256 nTargetPerCoinDay = new uint256();
+            uint256 nTargetPerCoinDay = 0;
             nTargetPerCoinDay.Compact = nBits;
 
             ulong nValueIn = txPrev.vout[prevout.n].nValue;
-            uint256 hashBlockFrom = blockFrom.header.Hash;
-            BigInteger bnCoinDayWeight = (long)nValueIn * GetWeight(txPrev.nTime, nTimeTx) / (long)CTransaction.nCoin / (24 * 60 * 60);
+            uint256 nCoinDayWeight = new uint256(nValueIn) * GetWeight(txPrev.nTime, nTimeTx) / CTransaction.nCoin / (24 * 60 * 60);
 
-            targetProofOfStake = (bnCoinDayWeight * new BigInteger(nTargetPerCoinDay)).ToByteArray();
+            targetProofOfStake = nCoinDayWeight * nTargetPerCoinDay;
 
             // Calculate hash
-            long nStakeModifier = 0;
-            uint nStakeModifierHeight = 0;
-            uint nStakeModifierTime = 0;
-            if (!GetKernelStakeModifier(hashBlockFrom, ref nStakeModifier, ref nStakeModifierHeight, ref nStakeModifierTime))
+            long nStakeModifier;
+            uint nStakeModifierTime;
+            uint nStakeModifierHeight;
+            if (!GetKernelStakeModifier(hashBlockFrom, out nStakeModifier, out nStakeModifierHeight, out nStakeModifierTime))
             {
                 return false;
             }
@@ -371,7 +393,7 @@ namespace Novacoin
         }
 
         // Get time weight using supplied timestamps
-        static long GetWeight(long nIntervalBeginning, long nIntervalEnd)
+        static ulong GetWeight(ulong nIntervalBeginning, ulong nIntervalEnd)
         {
             // Kernel hash weight starts from 0 at the 30-day min age
             // this change increases active coins participating the hash and helps
@@ -381,5 +403,92 @@ namespace Novacoin
 
             return Math.Min(nIntervalEnd - nIntervalBeginning - nStakeMinAge, nStakeMaxAge);
         }
+
+        internal static uint GetStakeModifierChecksum(ref CBlockStoreItem itemTemplate)
+        {
+            Contract.Assert(itemTemplate.prev != null || (uint256)itemTemplate.Hash == NetInfo.nHashGenesisBlock);
+
+            // Hash previous checksum with flags, hashProofOfStake and nStakeModifier
+            MemoryStream ss = new MemoryStream();
+            BinaryWriter writer = new BinaryWriter(ss);
+
+            if (itemTemplate.prev != null)
+            {
+                writer.Write(itemTemplate.prev.nStakeModifierChecksum);
+            }
+
+            writer.Write((uint)itemTemplate.BlockTypeFlag);
+
+            if (itemTemplate.IsProofOfStake)
+            {
+                writer.Write(itemTemplate.hashProofOfStake);
+            }
+            else
+            {
+                writer.Write(new uint256(0));
+            }
+            writer.Write(itemTemplate.nStakeModifier);
+
+            uint256 hashChecksum = CryptoUtils.ComputeHash256(ss.ToArray());
+            writer.Close();
+
+            hashChecksum >>= (256 - 32);
+
+            return (uint)hashChecksum.Low64;
+        }
+
+        public static bool CheckProofOfStake(CTransaction tx, uint nBits, out uint256 hashProofOfStake, out uint256 targetProofOfStake)
+        {
+            hashProofOfStake = targetProofOfStake = 0;
+
+            if (!tx.IsCoinStake)
+            {
+                return false; // called on non-coinstake
+            }
+
+            // Kernel (input 0) must match the stake hash target per coin age (nBits)
+            CTxIn txin = tx.vin[0];
+
+            // Read block header
+
+            long nBlockPos;
+            CBlock block;
+            if (!CBlockStore.Instance.GetBlockByTransactionID(txin.prevout.hash, out block, out nBlockPos))
+            {
+                return false; // unable to read block of previous transaction
+            }
+
+            long nTxPos = 0;
+            CTransaction txPrev = null;
+
+            // Iterate through vtx array
+            for (var i = 0; i < block.vtx.Length; i++)
+            {
+                if (block.vtx[i].Hash == txin.prevout.hash)
+                {
+                    txPrev = block.vtx[i];
+                    nTxPos = nBlockPos + block.GetTxOffset(i);
+
+                    break;
+                }
+            }
+
+            if (txPrev == null)
+            {
+                return false; // No such transaction found in the block
+            }
+
+            if (!ScriptCode.VerifyScript(txin.scriptSig, txPrev.vout[txin.prevout.n].scriptPubKey, tx, 0, (int)scriptflag.SCRIPT_VERIFY_P2SH, 0))
+            {
+                return false; // vin[0] signature check failed
+            }
+
+            if (!CheckStakeKernelHash(nBits, block.header.Hash, block.header.nTime, (uint)(nTxPos - nBlockPos), txPrev, txin.prevout, tx.nTime, out hashProofOfStake, out targetProofOfStake))
+            {
+                return false; // check kernel failed on coinstake 
+            }
+
+            return true;
+        }
     }
 }