return false;
}
-// Scan given input for kernel solution
-bool ScanInputForStakeKernelHash(CTransaction &tx, uint32_t nOut, uint32_t nBits, uint32_t nSearchInterval, std::pair<uint256, uint32_t> &solution)
+// Precompute hashing state for static part of kernel
+void GetKernelMidstate(uint64_t nStakeModifier, uint32_t nBlockTime, uint32_t nTxOffset, uint32_t nInputTxTime, uint32_t nOut, SHA256_CTX &ctx)
{
- CTxDB txdb("r");
-
- CBlock block;
- CTxIndex txindex;
-
- // Load transaction index item
- if (!txdb.ReadTxIndex(tx.GetHash(), txindex))
- return false;
-
- // Read block header
- if (!block.ReadFromDisk(txindex.pos.nFile, txindex.pos.nBlockPos, false))
- return false;
-
- uint64_t nStakeModifier = 0;
- if (!GetKernelStakeModifier(block.GetHash(), nStakeModifier))
- return false;
-
- uint32_t nTime = GetTime();
- // Only count coins meeting min age requirement
- if (nStakeMinAge + block.nTime > nTime)
- nTime += (nStakeMinAge + block.nTime - nTime);
-
- // Transaction offset inside block
- uint32_t nTxOffset = txindex.pos.nTxPos - txindex.pos.nBlockPos;
- int64_t nValueIn = tx.vout[nOut].nValue;
+ // Build static part of kernel
+ CDataStream ssKernel(SER_GETHASH, 0);
+ ssKernel << nStakeModifier;
+ ssKernel << nBlockTime << nTxOffset << nInputTxTime << nOut;
+ CDataStream::const_iterator it = ssKernel.begin();
+
+ // Init sha256 context and update it
+ // with first 24 bytes of kernel
+ SHA256_Init(&ctx);
+ SHA256_Update(&ctx, (unsigned char*)&it[0], 8 + 16);
+}
+// Scan given midstate for solution
+bool ScanMidstateForward(SHA256_CTX &ctx, uint32_t nBits, uint32_t nInputTxTime, int64_t nValueIn, std::pair<uint32_t, uint32_t> &SearchInterval, std::pair<uint256, uint32_t> &solution)
+{
CBigNum bnTargetPerCoinDay;
bnTargetPerCoinDay.SetCompact(nBits);
CBigNum bnMaxTargetPerCoinDay = bnTargetPerCoinDay * CBigNum(nValueIn) * nStakeMaxAge / COIN / (24 * 60 * 60);
uint256 maxTarget = bnMaxTargetPerCoinDay.getuint256();
+ SHA256_CTX ctxCopy = ctx;
+
// Search forward in time from the given timestamp
// Stopping search in case of shutting down
- for (unsigned int n=0; n<nSearchInterval && !fShutdown; n++)
+ for (uint32_t nTimeTx=SearchInterval.first; nTimeTx<SearchInterval.second && !fShutdown; nTimeTx++)
{
- uint32_t nTimeTx = nTime + n;
+ // Complete first hashing iteration
+ uint256 hash1;
+ SHA256_Update(&ctxCopy, (unsigned char*)&nTimeTx, 4);
+ SHA256_Final((unsigned char*)&hash1, &ctxCopy);
- // Build kernel
- CDataStream ss(SER_GETHASH, 0);
- ss << nStakeModifier;
- ss << block.nTime << nTxOffset << tx.nTime << nOut << nTimeTx;
+ // Restore context
+ ctxCopy = ctx;
- // Calculate kernel hash
- uint256 hashProofOfStake = Hash(ss.begin(), ss.end());
+ // Finally, calculate kernel hash
+ uint256 hashProofOfStake;
+ SHA256((unsigned char*)&hash1, sizeof(hashProofOfStake), (unsigned char*)&hashProofOfStake);
// Skip if hash doesn't satisfy the maximum target
if (hashProofOfStake > maxTarget)
continue;
- CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)tx.nTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
+ CBigNum bnCoinDayWeight = CBigNum(nValueIn) * GetWeight((int64_t)nInputTxTime, (int64_t)nTimeTx) / COIN / (24 * 60 * 60);
CBigNum bnTargetProofOfStake = bnCoinDayWeight * bnTargetPerCoinDay;
if (bnTargetProofOfStake >= CBigNum(hashProofOfStake))