atempt at time parsing in php

parse-time.php

<?php
/**
 * Parse various time formats into standard H:i:s format (e.g. "2:30pm" -> "14:30:00").
 *
 * @param string  $timeString     Time to parse
 * @param boolean $includeSeconds Optionally include seconds, default = true
 *
 * @return string|null Null if unable to parse time
 */
function parseTime($timeString, $includeSeconds = true) {
    $timePattern = '/^\s*(?<hour>[01]?[0-9]|2[0-3])(?::(?<min>[0-5][0-9]))?(?::(?<sec>[0-5][0-9]))?\s*(?<meridiem>[ap](?:\.?m\.?)?)?\s*$/i';
    if (preg_match($timePattern, $timeString, $matches) === 1) {
        $hour = (int) $matches['hour'];
        $min = isset($matches['min']) ? (int) $matches['min'] : 0;
        if ($hour < 12 && isset($matches['meridiem']) && ($matches['meridiem'][0] === 'p' || $matches['meridiem'][0] === 'P')) {
            $hour += 12;
        }
        $str = str_pad($hour, 2, '0', STR_PAD_LEFT) . ':' . str_pad($min, 2, '0', STR_PAD_LEFT);
        if ($includeSeconds) {
            $sec = isset($matches['sec']) ? (int) $matches['sec'] : 0;
            $str .= ':' . str_pad($sec, 2, '0', STR_PAD_LEFT);
        }

        return $str;
    }

    return null;
}

/**
 * Convert time string to minutes since midnight.
 *
 * @param string  $timeString     Time to parse
 * @param boolean $includeSeconds Optionally include seconds and return as float, default = false
 *
 * @return int|float|null Null if unable to parse time
 */
function timeToMinutes($timeString, $includeSeconds = false) {
    $time = parseTime($timeString, $includeSeconds);
    if (isset($time)) {
        $parts = explode(':', $time);

        return ($parts[0] * 60) + $parts[1] + ($includeSeconds ? ($parts[2] / 60) : 0);
    }

    return null;
}

assert('null === timeToMinutes("foo")');
assert('90 === timeToMinutes("01:30")');
assert('90 === timeToMinutes("1:30a")');
assert('90 === timeToMinutes("1:30 am")');
assert('90 === timeToMinutes("1:30 AM")');
assert('120 === timeToMinutes("2")');
assert('120 === timeToMinutes("2a")');
assert('840 === timeToMinutes("2p")');
assert('870 === timeToMinutes("14:30")');
assert('870 === timeToMinutes("2:30p")');
assert('870 === timeToMinutes("2:30 p.m.")');
assert('870.25 === timeToMinutes("2:30:15p", true)');