Snippet that closes unclosed HTML tags in HTML extract (useful when HTML string is trimmed by some specific length)

close-cutoff-text.php

<?php
function closeCutoff($text)
{
    static $closing = [
        'img', 'br', 'input', 'hr', 'area', 'base', 'basefont', 'col',
        'frame', 'isindex', 'link', 'meta', 'param'
    ];
    $skip = [];
    $add = [];
    preg_match_all('/<\s*(\/?)\s*(\w+)/i', $text, $matches, PREG_SET_ORDER);
    foreach (array_reverse($matches) as list($full, $close, $tag)) {
        $tag = strtolower($tag);
        if (in_array($tag, $closing)) continue; // self closing tag
        if ($close) $skip[] = $tag;
        else {
            if (end($skip) == $tag) array_pop($skip);
            else $add[] = "</$tag>";
        }
    }
    return implode('', $add);
}