Wordpress custom smart excerpt

getTheLimitedExcerpt.php

<?php
/**
 * Limits an excerpt to the given number of characters
 * @param integer $limit in words
 * @param boolean $allowUnfilteredManualExcerpt Gives the manual excerpt priority
 * @return string
 */
function getTheLimitedExcerpt($limit = 30, $allowUnfilteredManualExcerpt = false)
{
    global $post;
    //first select the excerpt
    $manualExcerpt = $post->post_excerpt;
    if (strlen($manualExcerpt) > 0) {
        if ($allowUnfilteredManualExcerpt) {
            return $manualExcerpt;
        }
        $excerpt = $manualExcerpt;
    } else {
        $excerpt = get_the_excerpt();
    }
   
    $words = explode(' ', $excerpt);
   
    //then limit the excerpt
    if ($limit > 1 && count($words) > $limit) {
        $excerpt = implode(' ', array_slice($words, 0, $limit - 1)) . '...';
    }
    return $excerpt;
}