/**
* @param callable|null $hashFunction
* @return Buffer
* @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) {
$binary = $hashFxn($this->transactions[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 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);
}
$binary = $tree->hash();
}
$this->setLastHash((new Buffer($binary))->flip());
return $this->getLastHash();
}
public function testWidthOfSixConstructsCorrectly()
{
$expected = '1c532ad0b8d7a2af86c321f14f722416';
$builder = new FixedSizeTree(6, $this->hasher);
$builder->set(0, 'at');
$builder->set(1, 'the');
$builder->set(2, 'end');
$builder->set(3, 'of');
$builder->set(4, 'the');
$builder->set(5, 'day');
$actual = $builder->hash();
$this->assertEquals($expected, $actual);
}
/**
* @param BlockInterface $block
* @param TransactionSerializerInterface $txSerializer
* @return Buffer
* @throws MerkleTreeEmpty
*/
public function calcMerkleRoot(BlockInterface $block, TransactionSerializerInterface $txSerializer)
{
$hashFxn = function ($value) {
return hash('sha256', hash('sha256', $value, true), true);
};
$txCount = count($block->getTransactions());
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) {
$transaction = $block->getTransaction(0);
$serialized = $txSerializer->serialize($transaction);
$binary = $hashFxn($serialized->getBinary());
} else {
// Create a fixed size Merkle Tree
$tree = new FixedSizeTree($txCount + $txCount % 2, $hashFxn);
// Compute hash of each transaction
$last = '';
foreach ($block->getTransactions() as $i => $transaction) {
$last = $txSerializer->serialize($transaction)->getBinary();
$tree->set($i, $last);
}
// Check if we need to repeat the last hash (odd number of transactions)
if (!($txCount % 2 === 0)) {
$tree->set($txCount, $last);
}
$binary = $tree->hash();
}
return (new Buffer($binary))->flip();
}
