This PHP function, subStringByLastNBSP, is designed to extract a substring from a given input string while ensuring that the resulting substring does not exceed a specified maximum length ($max). It also considers a minimum length ($min) that the substring should have before attempting to find the last non-breaking space character (' ') within t…

subStringByLastNBSP.php

<?php
/**
 * Extracts a substring from a given string, ensuring it does not exceed a maximum length,
 * and ends at the last occurrence of a non-breaking space character (' ') within the specified range.
 *
 * @param string $string      The input string to extract the substring from.
 * @param int    $max         The maximum length of the substring.
 * @param int    $min         The minimum length of the substring before considering the last non-breaking space.
 * @param string $endstring   Optional: The string to append to the extracted substring.
 *
 * @return string The extracted substring.
 */

function subStringByLastNBSP($string, $max, $min, $endstring = "") {
    // Check if the input string is already shorter than or equal to the maximum length.
    if (mb_strlen($string) <= $max) {
        return $string;
    }
    
    // Extract the substring up to the maximum length.
    $str = mb_substr($string, 0, $max, "utf8");
    
    // Extract a sub-substring starting from the minimum length.
    $son = mb_substr($str, $min, $max, "utf8");
    
    // Find the position of the last space character (' ') within the sub-substring.    
    $say = mb_strpos($son, " ", 0, "utf8");
    
    // Calculate the new length based on the last space position and the minimum length.    
    $say = $say + $min;
    
    // Truncate the substring to the new calculated length and append the optional endstring.    
    $str = mb_substr($str, 0, $say, "utf8");
    $str .= $endstring;

    return ($str);
}