Truncate a multibyte String to n chars

Question

I am trying to get this method in a String Filter working: ``` public function truncate($string, $chars = 50, $terminator = ' …'); ``` I'd expect this ``` $in = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWYXZ1234567890"; $out = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUV …"; ``` and also this ``` $in = "âãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿĀāĂăĄąĆćĈĉĊċČčĎďĐđĒēĔĕĖėĘęĚěĜĝ"; $out = "âãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿĀāĂăĄąĆćĈĉĊċČčĎďĐđ …"; ``` That is `$chars` minus the chars of the `$terminator` string. In addition, the filter is supposed to cut at the first word boundary below the `$chars` limit, e.g. ``` $in = "Answer to the Ultimate Question of Life, the Universe, and Everything."; $out = "Answer to the Ultimate Question of Life, the …"; ``` I am pretty certain this should work with these steps - substract amount of chars in terminator from maximum chars - validate that string is longer than the calculated limit or return it unaltered - find the last space character in string below c…

Accepted Answer

Try this:

```
function truncate($string, $chars = 50, $terminator = ' …') {
    $cutPos = $chars - mb_strlen($terminator);
    $boundaryPos = mb_strrpos(mb_substr($string, 0, mb_strpos($string, ' ', $cutPos)), ' ');
    return mb_substr($string, 0, $boundaryPos === false ? $cutPos : $boundaryPos) . $terminator;
}
```

But you need to make sure that your internal encoding is properly set.

Truncate a multibyte String to n chars

Solution

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