Speed up Arr::unique

[Phil-Venter]

Benchmark as proof

kv, array_unique              :  462.68 ms [ 332.00 MB] 6666667
kv, foreach isset             :  373.98 ms [ 128.00 MB] 6666667
kv, foreach !isset and        :  431.26 ms [ 128.00 MB] 6666667
kv, foreach !isset &&         :  436.31 ms [ 128.00 MB] 6666667
kv, foreach isset or          :   418.5 ms [ 128.00 MB] 6666667
kv, foreach isset ||          :  416.69 ms [ 128.00 MB] 6666667
kv, foreach                   :  420.97 ms [ 322.00 MB] 6666667
kv, for reverse               :  535.54 ms [ 448.00 MB] 6666667
kv, for reverse isset         :  596.71 ms [ 320.00 MB] 6666667

$max = 10000000;
$arr = range(1, $max, 3); 
$arr2 = range(1, $max, 2); 
$arr = array_values(array_merge($arr, $arr2));

function convert_ts($time)
{
	return round($time / 1e6, 2) . ' ms';
}

function convert_mem(int $bytes, int $decimals = 2): string
{
    $isNegative = $bytes < 0;

    $symbols = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB'];

    $bytes = \abs((float)$bytes);
    $exp   = (int)\floor(\log($bytes) / \log(1024));
    $value = ($bytes / (1024 ** \floor($exp)));

    if ($symbols[$exp] === 'B') {
        $decimals = 0;
    }

    return ($isNegative ? '-' : '') . \number_format($value, $decimals, '.', '') . ' ' . $symbols[$exp];
}


$message = 'kv, array_unique';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = array_unique($arr);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach isset';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	if (isset($temp[$val])) continue;
	$temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach !isset and';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	!isset($temp[$val]) and $temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach !isset &&';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	!isset($temp[$val]) && $temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach isset or';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	isset($temp[$val]) or $temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach isset ||';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	isset($temp[$val]) || $temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, foreach';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$temp = [];
foreach ($arr as $key => $val) {
	$temp[$val] = $key;
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, for reverse';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$keys = array_keys($arr);
$temp = [];
for ($i = count($keys) - 1; $i >= 0; $i--) {
	$temp[$arr[$keys[$i]]] = $keys[$i];
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);


$message = 'kv, for reverse isset';
$mem = -memory_get_usage(true);
$time = -hrtime(true);

$keys = array_keys($arr);
$temp = [];
for ($i = count($keys) - 1; $i >= 0; $i--) {
	if (isset($temp[$arr[$keys[$i]]])) continue;
	$temp[$arr[$keys[$i]]] = $keys[$i];
}
$temp = array_flip($temp);

$mem += memory_get_usage(true);
$time += hrtime(true);

echo sprintf('%-30s: %10s [%10s] %s', $message, convert_ts($time), convert_mem($mem), count($temp)) . PHP_EOL;
unset($temp);

[SmetDenis]

Oh, wow.

This looks really interesting. Let me check it out and I'll be back with some feedback.

[coveralls]

coverage: 92.766% (+0.02%) from 92.75%
when pulling 98a542f on Phil-Venter:patch-1
into d8a1733 on JBZoo:master.

[SmetDenis]

Thank you @Phil-Venter
Looks good. Approved and merged.