Extract JSON objects from a a string faster than use regular expressions.

json_extract.php

/**
 * Extract all JSON objects (doens't work with JSON arrays) from a string.
 * 
 * This method is the alternative to '/\{(?:[^{}]|(?R))*}/m' regular expression but faster
 * according to https://3v4l.org/4WtGX VS https://3v4l.org/N9oRi
 *
 */
function jsonExtract(string $str) : array
    {
        $numBrackets = $initStr = $foundAt = -1;
        $strings     = [];

        foreach (str_split($str) as $k => $chr) {
            switch ($chr) {
                case '{':
                    $numBrackets++;

                    if ($initStr === -1) {
                        $initStr = $k;
                    }
                    break;

                case '}':
                    if ($initStr >= 0) {
                        $numBrackets--;

                        if ($numBrackets === -1 && $foundAt > -1) {
                            $strings[] = substr($str, $foundAt, $k - $foundAt + 1);
                            $numBrackets = $initStr = $foundAt = -1;
                        }
                    }
                    break;

                case '"':
                    if ($numBrackets > -1 && $foundAt === -1) {
                        $foundAt = $initStr;
                    }
                    break;
            }
        }

        return $strings;
    }