/**
* @param callable|null $hashFunction
* @return string
* @throws MerkleTreeEmpty
*/
public function calculateHash(callable $hashFunction = null)
{
$hashFxn = $hashFunction ?: function ($value) {
return hash('sha256', hash('sha256', $value, true), true);
};
$txCount = count($this->transactions);
if ($txCount == 0) {
// TODO: Probably necessary. Should always have a coinbase at least.
throw new MerkleTreeEmpty('Cannot compute Merkle root of an empty tree');
}
if ($txCount == 1) {
$buffer = $hashFxn($this->transactions->getTransaction(0)->getBinary());
} else {
// Create a fixed size Merkle Tree
$tree = new FixedSizeTree($txCount + $txCount % 2, $hashFxn);
// Compute hash of each transaction
$last = '';
foreach ($this->transactions->getTransactions() as $i => $transaction) {
$last = $transaction->getBinary();
$tree->set($i, $last);
}
// Check if we need to repeat the last hash (odd number of transactions)
if (!$this->math->isEven($txCount)) {
$tree->set($txCount, $last);
}
$buffer = $tree->hash();
}
$hash = new Buffer(Buffertools::flipBytes($buffer));
$hash = $hash->getHex();
$this->setLastHash($hash);
return $this->getLastHash();
}
/**
* @param TransactionInterface|null $coinbaseTx
* @return Block
* @throws \BitWasp\Bitcoin\Exceptions\MerkleTreeEmpty
*/
public function run(TransactionInterface $coinbaseTx = null)
{
$nonce = '0';
$maxNonce = $this->math->pow(2, 32);
// Allow user supplied transactions
if ($coinbaseTx == null) {
$coinbaseTx = new Transaction();
$coinbaseTx->getInputs()->addInput(new TransactionInput('0000000000000000000000000000000000000000000000000000000000000000', 4294967295.0));
$coinbaseTx->getOutputs()->addOutput(new TransactionOutput(5000000000.0, $this->script));
}
$inputs = $coinbaseTx->getInputs();
$found = false;
$usingDiff = $this->lastBlockHeader->getBits();
$diff = new Difficulty($this->math);
$target = $diff->getTarget($usingDiff);
while (false === $found) {
// Set coinbase script, and build Merkle tree & block header.
$inputs->getInput(0)->setScript($this->getCoinbaseScriptBuf());
$transactions = new TransactionCollection(array_merge(array($coinbaseTx), $this->transactions->getTransactions()));
$merkleRoot = new MerkleRoot($this->math, $transactions);
$merkleHash = $merkleRoot->calculateHash();
$header = new BlockHeader($this->version, $this->lastBlockHeader->getBlockHash(), $merkleHash, $this->timestamp, $usingDiff, '0');
$t = microtime(true);
// Loop through all nonces (up to 2^32). Restart after modifying extranonce.
while ($this->math->cmp($header->getNonce(), $maxNonce) <= 0) {
$header->setNonce($this->math->add($header->getNonce(), '1'));
$hash = (new Parser())->writeBytes(32, Hash::sha256d($header->getBuffer()), true)->getBuffer();
if ($this->math->cmp($hash->getInt(), $target) <= 0) {
$block = new Block($this->math, $header, $transactions);
return $block;
}
if ($this->report && $this->math->cmp($this->math->mod($header->getNonce(), 100000), '0') == 0) {
$time = microtime(true) - $t;
$khash = $nonce / $time / 1000;
echo "extraNonce[{$this->extraNonce}] nonce[{$nonce}] time[{$time}] khash/s[{$khash}] \n";
}
}
// Whenever we exceed 2^32, increment extraNonce and reset $nonce
$this->extraNonce++;
$nonce = '0';
}
}
/**
* @param TransactionCollection $txs
* @return $this
*/
private function storeUtxos(TransactionCollection $txs)
{
foreach ($txs->getTransactions() as $tx) {
$this->utxoset->save($tx);
}
return $this;
}