Zend: Optimize sorting single-element arrays

[LamentXU123]

Now, zend_array_sort() uses zend_array_sort_ex(), which unpacks packed arrays and temporarily increments the array refcount to protect against the comparator freeing the array.

Obviously this is useless for one-element arrays. Here, we can just use zend_hash_sort_ex instead for this case.

Some may ask what's the meaning to sort one-element array anyways. This can't be similar to what sorting zero-element array do, which is directly returning the empty array. Because the sorting functions have other things to do rather than just sort the elements.

<?php
$array = ['key' => 42];
sort($array);

var_dump($array);
// [0 => 42]

Here, we remain the original sort behavior for one-element array while making it faster because we are not actually sorting them

benchmark results:

After: 448.923 ms
Before: 905.807 ms
a roughly 50.4% enhancement in this specific case.

script:

<?php

const ITERATIONS = 20_000_000;
const RUNS = 7;

function run(int $iterations): float
{
    $array = [42];

    $start = hrtime(true);
    for ($i = 0; $i < $iterations; $i++) {
        sort($array, SORT_NUMERIC);
    }

    return (hrtime(true) - $start) / 1e6;
}

run(100_000); // Warmup

$times = [];
for ($run = 0; $run < RUNS; $run++) {
    $times[] = run(ITERATIONS);
}

sort($times, SORT_NUMERIC);
$median = $times[intdiv(RUNS, 2)];

printf(
    "single-element sort: %.3f ms (%d iterations, median of %d)\n",
    $median,
    ITERATIONS,
    RUNS,
);

[devnexen]

unless Gina beats me to it, I ll review a bit later seems good not entirely sure it s bug free