php wordwrap cut parameter when dealing with weird characters

Question

I have a problem when using the wordwrap() function in php with for example chinese characters. When the $cut parameter in the wordwrap function is set to true, it ruins the string by inserting question marks.

Is there a solution to this?

Answer 1

The native wordwrap function is not safe to use for unicode. Here's a mb_wordwrap by Sam B.:

<?php
/**
 * Multibyte capable wordwrap
 *
 * @param string $str
 * @param int $width
 * @param string $break
 * @return string
 */
function mb_wordwrap($str, $width=74, $break="\r\n")
{
    // Return short or empty strings untouched
    if(empty($str) || mb_strlen($str, 'UTF-8') <= $width)
        return $str;

    $br_width  = mb_strlen($break, 'UTF-8');
    $str_width = mb_strlen($str, 'UTF-8');
    $return = '';
    $last_space = false;

    for($i=0, $count=0; $i < $str_width; $i++, $count++)
    {
        // If we're at a break
        if (mb_substr($str, $i, $br_width, 'UTF-8') == $break)
        {
            $count = 0;
            $return .= mb_substr($str, $i, $br_width, 'UTF-8');
            $i += $br_width - 1;
            continue;
        }

        // Keep a track of the most recent possible break point
        if(mb_substr($str, $i, 1, 'UTF-8') == " ")
        {
            $last_space = $i;
        }

        // It's time to wrap
        if ($count > $width)
        {
            // There are no spaces to break on!  Going to truncate :(
            if(!$last_space)
            {
                $return .= $break;
                $count = 0;
            }
            else
            {
                // Work out how far back the last space was
                $drop = $i - $last_space;

                // Cutting zero chars results in an empty string, so don't do that
                if($drop > 0)
                {
                    $return = mb_substr($return, 0, -$drop);
                }

                // Add a break
                $return .= $break;

                // Update pointers
                $i = $last_space + ($br_width - 1);
                $last_space = false;
                $count = 0;
            }
        }

        // Add character from the input string to the output
        $return .= mb_substr($str, $i, 1, 'UTF-8');
    }
    return $return;
}
?>