source code
<?hh
/* The Computer Language Benchmarks Game
http://benchmarksgame.alioth.debian.org/
contributed by Peter Baltruschat
modified by Levi Cameron
multiprocessing by Yuriy Moskalchuk
*/
function createTree($depth)
{
if (!$depth) {
return [null, null];
}
$depth--;
return [
createTree($depth),
createTree($depth)
];
}
function checkTree($treeNode)
{
return 1
+ ($treeNode[0][0] === null ? 1 : checkTree($treeNode[0]))
+ ($treeNode[1][0] === null ? 1 : checkTree($treeNode[1]));
}
$minDepth = 4;
$n = ($argc == 2) ? $argv[1] : 1;
$maxDepth = max($minDepth + 2, $n);
$stretchDepth = $maxDepth + 1;
$stretchTree = createTree($stretchDepth);
echo "stretch tree of depth $stretchDepth\t check: ", checkTree($stretchTree), PHP_EOL;
unset($stretchTree);
$longLivedTree = createTree($maxDepth);
function startWorker($depth, $iter, $n, $size, $shmId)
{
$pid = pcntl_fork();
if ($pid) {
return $pid;
} else {
$check = 0;
for ($i = 1; $i <= $iter; ++$i) {
$t = createTree($depth);
$check += checkTree($t);
unset($t);
}
$result = "$iter\t trees of depth $depth\t check: $check\n";
shmop_write($shmId, $result, $size * ($n - 1));
exit(0);
}
}
$iterations = 1 << ($maxDepth);
$depthIterations = [$minDepth => $iterations];
do {
$minDepth += 2;
if ($minDepth <= $maxDepth) {
$iterations >>= 2;
$depthIterations[$minDepth] = $iterations;
}
} while ($minDepth <= $maxDepth);
$size = 128;
$shmId = shmop_open(ftok(__FILE__, 'b'), 'c', 0644, $size * (count($depthIterations) + 1));
$PIDs = [];
$n = 0;
foreach ($depthIterations as $d => $i) {
$PIDs[] = startWorker($d, $i, ++$n, $size, $shmId);
}
foreach ($PIDs as $PID) {
pcntl_waitpid($PID, $status);
}
foreach (range(1, count($depthIterations)) as $n) {
echo trim(shmop_read($shmId, $size * ($n - 1), $size)), PHP_EOL;
}
shmop_delete($shmId);
echo "long lived tree of depth $maxDepth\t check: ", checkTree($longLivedTree), PHP_EOL;