src/miner.cpp

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2013 The Bitcoin developers
   3 // Distributed under the MIT/X11 software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #include "miner.h"
   7
   8 #include "core.h"
   9 #include "main.h"
  10 #include "net.h"
  11 #include "wallet.h"
  12
  13 double dHashesPerSec = 0.0;
  14 int64_t nHPSTimerStart = 0;
  15
  16 //////////////////////////////////////////////////////////////////////////////
  17 //
  18 // BitcoinMiner
  19 //
  20
  21 int static FormatHashBlocks(void* pbuffer, unsigned int len)
  22 {
  23     unsigned char* pdata = (unsigned char*)pbuffer;
  24     unsigned int blocks = 1 + ((len + 8) / 64);
  25     unsigned char* pend = pdata + 64 * blocks;
  26     memset(pdata + len, 0, 64 * blocks - len);
  27     pdata[len] = 0x80;
  28     unsigned int bits = len * 8;
  29     pend[-1] = (bits >> 0) & 0xff;
  30     pend[-2] = (bits >> 8) & 0xff;
  31     pend[-3] = (bits >> 16) & 0xff;
  32     pend[-4] = (bits >> 24) & 0xff;
  33     return blocks;
  34 }
  35
  36 static const unsigned int pSHA256InitState[8] =
  37 {0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};
  38
  39 void SHA256Transform(void* pstate, void* pinput, const void* pinit)
  40 {
  41     SHA256_CTX ctx;
  42     unsigned char data[64];
  43
  44     SHA256_Init(&ctx);
  45
  46     for (int i = 0; i < 16; i++)
  47         ((uint32_t*)data)[i] = ByteReverse(((uint32_t*)pinput)[i]);
  48
  49     for (int i = 0; i < 8; i++)
  50         ctx.h[i] = ((uint32_t*)pinit)[i];
  51
  52     SHA256_Update(&ctx, data, sizeof(data));
  53     for (int i = 0; i < 8; i++)
  54         ((uint32_t*)pstate)[i] = ctx.h[i];
  55 }
  56
  57 //
  58 // ScanHash scans nonces looking for a hash with at least some zero bits.
  59 // It operates on big endian data.  Caller does the byte reversing.
  60 // All input buffers are 16-byte aligned.  nNonce is usually preserved
  61 // between calls, but periodically or if nNonce is 0xffff0000 or above,
  62 // the block is rebuilt and nNonce starts over at zero.
  63 //
  64 unsigned int static ScanHash_CryptoPP(char* pmidstate, char* pdata, char* phash1, char* phash, unsigned int& nHashesDone)
  65 {
  66     unsigned int& nNonce = *(unsigned int*)(pdata + 12);
  67     for (;;)
  68     {
  69         // Crypto++ SHA256
  70         // Hash pdata using pmidstate as the starting state into
  71         // pre-formatted buffer phash1, then hash phash1 into phash
  72         nNonce++;
  73         SHA256Transform(phash1, pdata, pmidstate);
  74         SHA256Transform(phash, phash1, pSHA256InitState);
  75
  76         // Return the nonce if the hash has at least some zero bits,
  77         // caller will check if it has enough to reach the target
  78         if (((unsigned short*)phash)[14] == 0)
  79             return nNonce;
  80
  81         // If nothing found after trying for a while, return -1
  82         if ((nNonce & 0xffff) == 0)
  83         {
  84             nHashesDone = 0xffff+1;
  85             return (unsigned int) -1;
  86         }
  87         if ((nNonce & 0xfff) == 0)
  88             boost::this_thread::interruption_point();
  89     }
  90 }
  91
  92 // Some explaining would be appreciated
  93 class COrphan
  94 {
  95 public:
  96     CTransaction* ptx;
  97     set<uint256> setDependsOn;
  98     double dPriority;
  99     double dFeePerKb;
 100
 101     COrphan(CTransaction* ptxIn)
 102     {
 103         ptx = ptxIn;
 104         dPriority = dFeePerKb = 0;
 105     }
 106
 107     void print() const
 108     {
 109         LogPrintf("COrphan(hash=%s, dPriority=%.1f, dFeePerKb=%.1f)\n",
 110                ptx->GetHash().ToString().c_str(), dPriority, dFeePerKb);
 111         BOOST_FOREACH(uint256 hash, setDependsOn)
 112             LogPrintf("   setDependsOn %s\n", hash.ToString().c_str());
 113     }
 114 };
 115
 116
 117 uint64_t nLastBlockTx = 0;
 118 uint64_t nLastBlockSize = 0;
 119
 120 // We want to sort transactions by priority and fee, so:
 121 typedef boost::tuple<double, double, CTransaction*> TxPriority;
 122 class TxPriorityCompare
 123 {
 124     bool byFee;
 125 public:
 126     TxPriorityCompare(bool _byFee) : byFee(_byFee) { }
 127     bool operator()(const TxPriority& a, const TxPriority& b)
 128     {
 129         if (byFee)
 130         {
 131             if (a.get<1>() == b.get<1>())
 132                 return a.get<0>() < b.get<0>();
 133             return a.get<1>() < b.get<1>();
 134         }
 135         else
 136         {
 137             if (a.get<0>() == b.get<0>())
 138                 return a.get<1>() < b.get<1>();
 139             return a.get<0>() < b.get<0>();
 140         }
 141     }
 142 };
 143
 144 CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn)
 145 {
 146     // Create new block
 147     auto_ptr<CBlockTemplate> pblocktemplate(new CBlockTemplate());
 148     if(!pblocktemplate.get())
 149         return NULL;
 150     CBlock *pblock = &pblocktemplate->block; // pointer for convenience
 151
 152     // Create coinbase tx
 153     CTransaction txNew;
 154     txNew.vin.resize(1);
 155     txNew.vin[0].prevout.SetNull();
 156     txNew.vout.resize(1);
 157     txNew.vout[0].scriptPubKey = scriptPubKeyIn;
 158
 159     // Add our coinbase tx as first transaction
 160     pblock->vtx.push_back(txNew);
 161     pblocktemplate->vTxFees.push_back(-1); // updated at end
 162     pblocktemplate->vTxSigOps.push_back(-1); // updated at end
 163
 164     // Largest block you're willing to create:
 165     unsigned int nBlockMaxSize = GetArg("-blockmaxsize", MAX_BLOCK_SIZE_GEN/2);
 166     // Limit to betweeen 1K and MAX_BLOCK_SIZE-1K for sanity:
 167     nBlockMaxSize = std::max((unsigned int)1000, std::min((unsigned int)(MAX_BLOCK_SIZE-1000), nBlockMaxSize));
 168
 169     // How much of the block should be dedicated to high-priority transactions,
 170     // included regardless of the fees they pay
 171     unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
 172     nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
 173
 174     // Minimum block size you want to create; block will be filled with free transactions
 175     // until there are no more or the block reaches this size:
 176     unsigned int nBlockMinSize = GetArg("-blockminsize", 0);
 177     nBlockMinSize = std::min(nBlockMaxSize, nBlockMinSize);
 178
 179     // Collect memory pool transactions into the block
 180     int64_t nFees = 0;
 181     {
 182         LOCK2(cs_main, mempool.cs);
 183         CBlockIndex* pindexPrev = chainActive.Tip();
 184         CCoinsViewCache view(*pcoinsTip, true);
 185
 186         // Priority order to process transactions
 187         list<COrphan> vOrphan; // list memory doesn't move
 188         map<uint256, vector<COrphan*> > mapDependers;
 189         bool fPrintPriority = GetBoolArg("-printpriority", false);
 190
 191         // This vector will be sorted into a priority queue:
 192         vector<TxPriority> vecPriority;
 193         vecPriority.reserve(mempool.mapTx.size());
 194         for (map<uint256, CTransaction>::iterator mi = mempool.mapTx.begin(); mi != mempool.mapTx.end(); ++mi)
 195         {
 196             CTransaction& tx = (*mi).second;
 197             if (tx.IsCoinBase() || !IsFinalTx(tx))
 198                 continue;
 199
 200             COrphan* porphan = NULL;
 201             double dPriority = 0;
 202             int64_t nTotalIn = 0;
 203             bool fMissingInputs = false;
 204             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 205             {
 206                 // Read prev transaction
 207                 if (!view.HaveCoins(txin.prevout.hash))
 208                 {
 209                     // This should never happen; all transactions in the memory
 210                     // pool should connect to either transactions in the chain
 211                     // or other transactions in the memory pool.
 212                     if (!mempool.mapTx.count(txin.prevout.hash))
 213                     {
 214                         LogPrintf("ERROR: mempool transaction missing input\n");
 215                         if (fDebug) assert("mempool transaction missing input" == 0);
 216                         fMissingInputs = true;
 217                         if (porphan)
 218                             vOrphan.pop_back();
 219                         break;
 220                     }
 221
 222                     // Has to wait for dependencies
 223                     if (!porphan)
 224                     {
 225                         // Use list for automatic deletion
 226                         vOrphan.push_back(COrphan(&tx));
 227                         porphan = &vOrphan.back();
 228                     }
 229                     mapDependers[txin.prevout.hash].push_back(porphan);
 230                     porphan->setDependsOn.insert(txin.prevout.hash);
 231                     nTotalIn += mempool.mapTx[txin.prevout.hash].vout[txin.prevout.n].nValue;
 232                     continue;
 233                 }
 234                 const CCoins &coins = view.GetCoins(txin.prevout.hash);
 235
 236                 int64_t nValueIn = coins.vout[txin.prevout.n].nValue;
 237                 nTotalIn += nValueIn;
 238
 239                 int nConf = pindexPrev->nHeight - coins.nHeight + 1;
 240
 241                 dPriority += (double)nValueIn * nConf;
 242             }
 243             if (fMissingInputs) continue;
 244
 245             // Priority is sum(valuein * age) / modified_txsize
 246             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 247             unsigned int nTxSizeMod = nTxSize;
 248             // In order to avoid disincentivizing cleaning up the UTXO set we don't count
 249             // the constant overhead for each txin and up to 110 bytes of scriptSig (which
 250             // is enough to cover a compressed pubkey p2sh redemption) for priority.
 251             // Providing any more cleanup incentive than making additional inputs free would
 252             // risk encouraging people to create junk outputs to redeem later.
 253             BOOST_FOREACH(const CTxIn& txin, tx.vin)
 254             {
 255                 unsigned int offset = 41U + min(110U, (unsigned int)txin.scriptSig.size());
 256                 if (nTxSizeMod > offset)
 257                     nTxSizeMod -= offset;
 258             }
 259             dPriority /= nTxSizeMod;
 260
 261             // This is a more accurate fee-per-kilobyte than is used by the client code, because the
 262             // client code rounds up the size to the nearest 1K. That's good, because it gives an
 263             // incentive to create smaller transactions.
 264             double dFeePerKb =  double(nTotalIn-GetValueOut(tx)) / (double(nTxSize)/1000.0);
 265
 266             if (porphan)
 267             {
 268                 porphan->dPriority = dPriority;
 269                 porphan->dFeePerKb = dFeePerKb;
 270             }
 271             else
 272                 vecPriority.push_back(TxPriority(dPriority, dFeePerKb, &(*mi).second));
 273         }
 274
 275         // Collect transactions into block
 276         uint64_t nBlockSize = 1000;
 277         uint64_t nBlockTx = 0;
 278         int nBlockSigOps = 100;
 279         bool fSortedByFee = (nBlockPrioritySize <= 0);
 280
 281         TxPriorityCompare comparer(fSortedByFee);
 282         std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 283
 284         while (!vecPriority.empty())
 285         {
 286             // Take highest priority transaction off the priority queue:
 287             double dPriority = vecPriority.front().get<0>();
 288             double dFeePerKb = vecPriority.front().get<1>();
 289             CTransaction& tx = *(vecPriority.front().get<2>());
 290
 291             std::pop_heap(vecPriority.begin(), vecPriority.end(), comparer);
 292             vecPriority.pop_back();
 293
 294             // Size limits
 295             unsigned int nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
 296             if (nBlockSize + nTxSize >= nBlockMaxSize)
 297                 continue;
 298
 299             // Legacy limits on sigOps:
 300             unsigned int nTxSigOps = GetLegacySigOpCount(tx);
 301             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 302                 continue;
 303
 304             // Skip free transactions if we're past the minimum block size:
 305             if (fSortedByFee && (dFeePerKb < CTransaction::nMinTxFee) && (nBlockSize + nTxSize >= nBlockMinSize))
 306                 continue;
 307
 308             // Prioritize by fee once past the priority size or we run out of high-priority
 309             // transactions:
 310             if (!fSortedByFee &&
 311                 ((nBlockSize + nTxSize >= nBlockPrioritySize) || !AllowFree(dPriority)))
 312             {
 313                 fSortedByFee = true;
 314                 comparer = TxPriorityCompare(fSortedByFee);
 315                 std::make_heap(vecPriority.begin(), vecPriority.end(), comparer);
 316             }
 317
 318             if (!view.HaveInputs(tx))
 319                 continue;
 320
 321             int64_t nTxFees = view.GetValueIn(tx)-GetValueOut(tx);
 322
 323             nTxSigOps += GetP2SHSigOpCount(tx, view);
 324             if (nBlockSigOps + nTxSigOps >= MAX_BLOCK_SIGOPS)
 325                 continue;
 326
 327             CValidationState state;
 328             if (!CheckInputs(tx, state, view, true, SCRIPT_VERIFY_P2SH))
 329                 continue;
 330
 331             CTxUndo txundo;
 332             uint256 hash = tx.GetHash();
 333             UpdateCoins(tx, state, view, txundo, pindexPrev->nHeight+1, hash);
 334
 335             // Added
 336             pblock->vtx.push_back(tx);
 337             pblocktemplate->vTxFees.push_back(nTxFees);
 338             pblocktemplate->vTxSigOps.push_back(nTxSigOps);
 339             nBlockSize += nTxSize;
 340             ++nBlockTx;
 341             nBlockSigOps += nTxSigOps;
 342             nFees += nTxFees;
 343
 344             if (fPrintPriority)
 345             {
 346                 LogPrintf("priority %.1f feeperkb %.1f txid %s\n",
 347                        dPriority, dFeePerKb, tx.GetHash().ToString().c_str());
 348             }
 349
 350             // Add transactions that depend on this one to the priority queue
 351             if (mapDependers.count(hash))
 352             {
 353                 BOOST_FOREACH(COrphan* porphan, mapDependers[hash])
 354                 {
 355                     if (!porphan->setDependsOn.empty())
 356                     {
 357                         porphan->setDependsOn.erase(hash);
 358                         if (porphan->setDependsOn.empty())
 359                         {
 360                             vecPriority.push_back(TxPriority(porphan->dPriority, porphan->dFeePerKb, porphan->ptx));
 361                             std::push_heap(vecPriority.begin(), vecPriority.end(), comparer);
 362                         }
 363                     }
 364                 }
 365             }
 366         }
 367
 368         nLastBlockTx = nBlockTx;
 369         nLastBlockSize = nBlockSize;
 370         LogPrintf("CreateNewBlock(): total size %"PRIu64"\n", nBlockSize);
 371
 372         pblock->vtx[0].vout[0].nValue = GetBlockValue(pindexPrev->nHeight+1, nFees);
 373         pblocktemplate->vTxFees[0] = -nFees;
 374
 375         // Fill in header
 376         pblock->hashPrevBlock  = pindexPrev->GetBlockHash();
 377         UpdateTime(*pblock, pindexPrev);
 378         pblock->nBits          = GetNextWorkRequired(pindexPrev, pblock);
 379         pblock->nNonce         = 0;
 380         pblock->vtx[0].vin[0].scriptSig = CScript() << OP_0 << OP_0;
 381         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
 382
 383         CBlockIndex indexDummy(*pblock);
 384         indexDummy.pprev = pindexPrev;
 385         indexDummy.nHeight = pindexPrev->nHeight + 1;
 386         CCoinsViewCache viewNew(*pcoinsTip, true);
 387         CValidationState state;
 388         if (!ConnectBlock(*pblock, state, &indexDummy, viewNew, true))
 389             throw std::runtime_error("CreateNewBlock() : ConnectBlock failed");
 390     }
 391
 392     return pblocktemplate.release();
 393 }
 394
 395 CBlockTemplate* CreateNewBlockWithKey(CReserveKey& reservekey)
 396 {
 397     CPubKey pubkey;
 398     if (!reservekey.GetReservedKey(pubkey))
 399         return NULL;
 400
 401     CScript scriptPubKey = CScript() << pubkey << OP_CHECKSIG;
 402     return CreateNewBlock(scriptPubKey);
 403 }
 404
 405 void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
 406 {
 407     // Update nExtraNonce
 408     static uint256 hashPrevBlock;
 409     if (hashPrevBlock != pblock->hashPrevBlock)
 410     {
 411         nExtraNonce = 0;
 412         hashPrevBlock = pblock->hashPrevBlock;
 413     }
 414     ++nExtraNonce;
 415     unsigned int nHeight = pindexPrev->nHeight+1; // Height first in coinbase required for block.version=2
 416     pblock->vtx[0].vin[0].scriptSig = (CScript() << nHeight << CBigNum(nExtraNonce)) + COINBASE_FLAGS;
 417     assert(pblock->vtx[0].vin[0].scriptSig.size() <= 100);
 418
 419     pblock->hashMerkleRoot = pblock->BuildMerkleTree();
 420 }
 421
 422
 423 void FormatHashBuffers(CBlock* pblock, char* pmidstate, char* pdata, char* phash1)
 424 {
 425     //
 426     // Pre-build hash buffers
 427     //
 428     struct
 429     {
 430         struct unnamed2
 431         {
 432             int nVersion;
 433             uint256 hashPrevBlock;
 434             uint256 hashMerkleRoot;
 435             unsigned int nTime;
 436             unsigned int nBits;
 437             unsigned int nNonce;
 438         }
 439         block;
 440         unsigned char pchPadding0[64];
 441         uint256 hash1;
 442         unsigned char pchPadding1[64];
 443     }
 444     tmp;
 445     memset(&tmp, 0, sizeof(tmp));
 446
 447     tmp.block.nVersion       = pblock->nVersion;
 448     tmp.block.hashPrevBlock  = pblock->hashPrevBlock;
 449     tmp.block.hashMerkleRoot = pblock->hashMerkleRoot;
 450     tmp.block.nTime          = pblock->nTime;
 451     tmp.block.nBits          = pblock->nBits;
 452     tmp.block.nNonce         = pblock->nNonce;
 453
 454     FormatHashBlocks(&tmp.block, sizeof(tmp.block));
 455     FormatHashBlocks(&tmp.hash1, sizeof(tmp.hash1));
 456
 457     // Byte swap all the input buffer
 458     for (unsigned int i = 0; i < sizeof(tmp)/4; i++)
 459         ((unsigned int*)&tmp)[i] = ByteReverse(((unsigned int*)&tmp)[i]);
 460
 461     // Precalc the first half of the first hash, which stays constant
 462     SHA256Transform(pmidstate, &tmp.block, pSHA256InitState);
 463
 464     memcpy(pdata, &tmp.block, 128);
 465     memcpy(phash1, &tmp.hash1, 64);
 466 }
 467
 468
 469 bool CheckWork(CBlock* pblock, CWallet& wallet, CReserveKey& reservekey)
 470 {
 471     uint256 hash = pblock->GetHash();
 472     uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 473
 474     if (hash > hashTarget)
 475         return false;
 476
 477     //// debug print
 478     LogPrintf("BitcoinMiner:\n");
 479     LogPrintf("proof-of-work found  \n  hash: %s  \ntarget: %s\n", hash.GetHex().c_str(), hashTarget.GetHex().c_str());
 480     pblock->print();
 481     LogPrintf("generated %s\n", FormatMoney(pblock->vtx[0].vout[0].nValue).c_str());
 482
 483     // Found a solution
 484     {
 485         LOCK(cs_main);
 486         if (pblock->hashPrevBlock != chainActive.Tip()->GetBlockHash())
 487             return error("BitcoinMiner : generated block is stale");
 488
 489         // Remove key from key pool
 490         reservekey.KeepKey();
 491
 492         // Track how many getdata requests this block gets
 493         {
 494             LOCK(wallet.cs_wallet);
 495             wallet.mapRequestCount[pblock->GetHash()] = 0;
 496         }
 497
 498         // Process this block the same as if we had received it from another node
 499         CValidationState state;
 500         if (!ProcessBlock(state, NULL, pblock))
 501             return error("BitcoinMiner : ProcessBlock, block not accepted");
 502     }
 503
 504     return true;
 505 }
 506
 507 void static BitcoinMiner(CWallet *pwallet)
 508 {
 509     LogPrintf("BitcoinMiner started\n");
 510     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 511     RenameThread("bitcoin-miner");
 512
 513     // Each thread has its own key and counter
 514     CReserveKey reservekey(pwallet);
 515     unsigned int nExtraNonce = 0;
 516
 517     try { while (true) {
 518         if (Params().NetworkID() != CChainParams::REGTEST) {
 519             // Busy-wait for the network to come online so we don't waste time mining
 520             // on an obsolete chain. In regtest mode we expect to fly solo.
 521             while (vNodes.empty())
 522                 MilliSleep(1000);
 523         }
 524
 525         //
 526         // Create new block
 527         //
 528         unsigned int nTransactionsUpdatedLast = mempool.GetTransactionsUpdated();
 529         CBlockIndex* pindexPrev = chainActive.Tip();
 530
 531         auto_ptr<CBlockTemplate> pblocktemplate(CreateNewBlockWithKey(reservekey));
 532         if (!pblocktemplate.get())
 533             return;
 534         CBlock *pblock = &pblocktemplate->block;
 535         IncrementExtraNonce(pblock, pindexPrev, nExtraNonce);
 536
 537         LogPrintf("Running BitcoinMiner with %"PRIszu" transactions in block (%u bytes)\n", pblock->vtx.size(),
 538                ::GetSerializeSize(*pblock, SER_NETWORK, PROTOCOL_VERSION));
 539
 540         //
 541         // Pre-build hash buffers
 542         //
 543         char pmidstatebuf[32+16]; char* pmidstate = alignup<16>(pmidstatebuf);
 544         char pdatabuf[128+16];    char* pdata     = alignup<16>(pdatabuf);
 545         char phash1buf[64+16];    char* phash1    = alignup<16>(phash1buf);
 546
 547         FormatHashBuffers(pblock, pmidstate, pdata, phash1);
 548
 549         unsigned int& nBlockTime = *(unsigned int*)(pdata + 64 + 4);
 550         unsigned int& nBlockBits = *(unsigned int*)(pdata + 64 + 8);
 551         unsigned int& nBlockNonce = *(unsigned int*)(pdata + 64 + 12);
 552
 553
 554         //
 555         // Search
 556         //
 557         int64_t nStart = GetTime();
 558         uint256 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 559         uint256 hashbuf[2];
 560         uint256& hash = *alignup<16>(hashbuf);
 561         while (true)
 562         {
 563             unsigned int nHashesDone = 0;
 564             unsigned int nNonceFound;
 565
 566             // Crypto++ SHA256
 567             nNonceFound = ScanHash_CryptoPP(pmidstate, pdata + 64, phash1,
 568                                             (char*)&hash, nHashesDone);
 569
 570             // Check if something found
 571             if (nNonceFound != (unsigned int) -1)
 572             {
 573                 for (unsigned int i = 0; i < sizeof(hash)/4; i++)
 574                     ((unsigned int*)&hash)[i] = ByteReverse(((unsigned int*)&hash)[i]);
 575
 576                 if (hash <= hashTarget)
 577                 {
 578                     // Found a solution
 579                     pblock->nNonce = ByteReverse(nNonceFound);
 580                     assert(hash == pblock->GetHash());
 581
 582                     SetThreadPriority(THREAD_PRIORITY_NORMAL);
 583                     CheckWork(pblock, *pwallet, reservekey);
 584                     SetThreadPriority(THREAD_PRIORITY_LOWEST);
 585
 586                     // In regression test mode, stop mining after a block is found. This
 587                     // allows developers to controllably generate a block on demand.
 588                     if (Params().NetworkID() == CChainParams::REGTEST)
 589                         throw boost::thread_interrupted();
 590
 591                     break;
 592                 }
 593             }
 594
 595             // Meter hashes/sec
 596             static int64_t nHashCounter;
 597             if (nHPSTimerStart == 0)
 598             {
 599                 nHPSTimerStart = GetTimeMillis();
 600                 nHashCounter = 0;
 601             }
 602             else
 603                 nHashCounter += nHashesDone;
 604             if (GetTimeMillis() - nHPSTimerStart > 4000)
 605             {
 606                 static CCriticalSection cs;
 607                 {
 608                     LOCK(cs);
 609                     if (GetTimeMillis() - nHPSTimerStart > 4000)
 610                     {
 611                         dHashesPerSec = 1000.0 * nHashCounter / (GetTimeMillis() - nHPSTimerStart);
 612                         nHPSTimerStart = GetTimeMillis();
 613                         nHashCounter = 0;
 614                         static int64_t nLogTime;
 615                         if (GetTime() - nLogTime > 30 * 60)
 616                         {
 617                             nLogTime = GetTime();
 618                             LogPrintf("hashmeter %6.0f khash/s\n", dHashesPerSec/1000.0);
 619                         }
 620                     }
 621                 }
 622             }
 623
 624             // Check for stop or if block needs to be rebuilt
 625             boost::this_thread::interruption_point();
 626             if (vNodes.empty() && Params().NetworkID() != CChainParams::REGTEST)
 627                 break;
 628             if (nBlockNonce >= 0xffff0000)
 629                 break;
 630             if (mempool.GetTransactionsUpdated() != nTransactionsUpdatedLast && GetTime() - nStart > 60)
 631                 break;
 632             if (pindexPrev != chainActive.Tip())
 633                 break;
 634
 635             // Update nTime every few seconds
 636             UpdateTime(*pblock, pindexPrev);
 637             nBlockTime = ByteReverse(pblock->nTime);
 638             if (TestNet())
 639             {
 640                 // Changing pblock->nTime can change work required on testnet:
 641                 nBlockBits = ByteReverse(pblock->nBits);
 642                 hashTarget = CBigNum().SetCompact(pblock->nBits).getuint256();
 643             }
 644         }
 645     } }
 646     catch (boost::thread_interrupted)
 647     {
 648         LogPrintf("BitcoinMiner terminated\n");
 649         throw;
 650     }
 651 }
 652
 653 void GenerateBitcoins(bool fGenerate, CWallet* pwallet)
 654 {
 655     static boost::thread_group* minerThreads = NULL;
 656
 657     int nThreads = GetArg("-genproclimit", -1);
 658     if (nThreads < 0) {
 659         if (Params().NetworkID() == CChainParams::REGTEST)
 660             nThreads = 1;
 661         else
 662             nThreads = boost::thread::hardware_concurrency();
 663     }
 664
 665     if (minerThreads != NULL)
 666     {
 667         minerThreads->interrupt_all();
 668         delete minerThreads;
 669         minerThreads = NULL;
 670     }
 671
 672     if (nThreads == 0 || !fGenerate)
 673         return;
 674
 675     minerThreads = new boost::thread_group();
 676     for (int i = 0; i < nThreads; i++)
 677         minerThreads->create_thread(boost::bind(&BitcoinMiner, pwallet));
 678 }
 679
 680
 681