<?php
/* The Computer Language Benchmarks Game
   https://salsa.debian.org/benchmarksgame-team/benchmarksgame/

   contributed by Peter Baltruschat
   modified by Levi Cameron
   multiprocessing by Yuriy Moskalchuk
*/

function createTree($depth)
{
    echo '';
    if (!$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]));
}


function startWorker($depth, $iter, $n, $size, $shmId)
{
    $pid = pcntl_fork();
    if ($pid) {
        return $pid;
    } else {
        var_dump($iter, $n);
        echo str_repeat('----', 16).PHP_EOL;
        $check = 0;
        for ($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);
    }
}

function main()
{
    global $argc, $argv;
    $minDepth = 4;
    $n = ($argc == 3) ? $argv[2] : 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);

    $iterations = 1 << ($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;
}