合并两个正则表达式来截断字符串中的单词

Question

I'm trying to come up with the following function that truncates string to whole words (if possible, otherwise it should truncate to chars):

function Text_Truncate($string, $limit, $more = '...')
{
    $string = trim(html_entity_decode($string, ENT_QUOTES, 'UTF-8'));

    if (strlen(utf8_decode($string)) > $limit)
    {
        $string = preg_replace('~^(.{1,' . intval($limit) . '})(?:\s.*|$)~su', '$1', $string);

        if (strlen(utf8_decode($string)) > $limit)
        {
            $string = preg_replace('~^(.{' . intval($limit) . '}).*~su', '$1', $string);
        }

        $string .= $more;
    }

    return trim(htmlentities($string, ENT_QUOTES, 'UTF-8', true));
}

Here are some tests:

// Iñtërnâtiônàlizætiøn and then the quick brown fox... (49 + 3 chars)
echo dyd_Text_Truncate('Iñtërnâtiônàlizætiøn and then the quick brown fox jumped overly the lazy dog and one day the lazy dog humped the poor fox down until she died.', 50, '...');

// Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_...  (50 + 3 chars)
echo dyd_Text_Truncate('Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_jumped_overly_the_lazy_dog and one day the lazy dog humped the poor fox down until she died.', 50, '...');

They both work as it is, however if I drop the second preg_replace() I get the following:

Iñtërnâtiônàlizætiøn_and_then_the_quick_brown_fox_jumped_overly_the_lazy_dog and one day the lazy dog humped the poor fox down until she died....

I can't use substr() because it only works on byte level and I don't have access to mb_substr() ATM, I've made several attempts to join the second regex with the first one but without success.

Please help SMS, I've been struggling with this for almost an hour.

---

EDIT: I'm sorry, I've been awake for 40 hours and I shamelessly missed this:

$string = preg_replace('~^(.{1,' . intval($limit) . '})(?:\s.*|$)?~su', '$1', $string);

Still, if someone has a more optimized regex (or one that ignores the trailing space) please share:

"Iñtërnâtiônàlizætiøn and then "
"Iñtërnâtiônàlizætiøn_and_then_"

EDIT 2: I still can't get rid of the trailing whitespace, can someone help me out?

EDIT 3: Okay, none of my edits did really work, I was being fooled by RegexBuddy - I should probably leave this to another day and get some sleep now. Off for today.

Answer 1

Perhaps I can give you a happy morning after a long night of RegExp nightmares:

'~^(.{1,' . intval($limit) . '}(?<=\S)(?=\s)|.{'.intval($limit).'}).*~su'

Boiling it down:

^      # Start of String
(       # begin capture group 1
 .{1,x} # match 1 - x characters
 (?<=\S)# lookbehind, match must end with non-whitespace 
 (?=\s) # lookahead, if the next char is whitespace, match
 |      # otherwise test this:
 .{x}   # got to x chars anyway.
)       # end cap group
.*     # match the rest of the string (since you were using replace)

You could always add the |$ to the end of (?=\\s) but since your code was already checking that the string length was longer than the $limit , I didn't feel that case would be neccesary.

Answer 2

Have you considered using wordwrap? ( http://us3.php.net/wordwrap )