Multi-byte safe wordwrap() function for UTF-8

Question

PHP\'s wordwrap() function doesn\'t work correctly for multi-byte strings like UTF-8.

There are a few examples of mb safe functions in the comments, but with some di

Answer 1

Custom word boundaries

Unicode text has many more potential word boundaries than 8-bit encodings, including 17 space separators, and the full width comma. This solution allows you to customize a list of word boundaries for your application.

Better performance

Have you ever benchmarked the mb_* family of PHP built-ins? They don't scale well at all. By using a custom nextCharUtf8(), we can do the same job, but orders of magnitude faster, especially on large strings.

 $width) {
      if ($line) {
        $lines[] = $line;
        $lineLen = 0;
        $line = '';
      }
    }
    $line .= $chunk;
    $lineLen += $len;
  }
  if ($line) {
    $lines[] = $line;
  }
  return implode($break, $lines);
}

function nextCharUtf8(&$string, &$pointer)
{
  // EOF
  if (!isset($string[$pointer])) {
    return null;
  }

  // Get the byte value at the pointer
  $char = ord($string[$pointer]);

  // ASCII
  if ($char < 128) {
    return $string[$pointer++];
  }

  // UTF-8
  if ($char < 224) {
    $bytes = 2;
  } elseif ($char < 240) {
    $bytes = 3;
  } elseif ($char < 248) {
    $bytes = 4;
  } elseif ($char == 252) {
    $bytes = 5;
  } else {
    $bytes = 6;
  }

  // Get full multibyte char
  $str = substr($string, $pointer, $bytes);

  // Increment pointer according to length of char
  $pointer += $bytes;

  // Return mb char
  return $str;
}