_mb_strlen()
Internal compat function to mimic mb_strlen().
Only understands UTF-8 and 8bit. All other character sets will be treated as 8bit. For $encoding === UTF-8, the $str input is expected to be a valid UTF-8 byte sequence. The behavior of this function for invalid inputs is undefined.
Internal function — this function is designed to be used by the kernel itself. It is not recommended to use this function in your code.
No Hooks.
Return
Int
. String length of $str.
Usage
_mb_strlen( $str, $encoding );
- $str(string) (required)
- The string to retrieve the character length from.
- $encoding(string|null)
- Character encoding to use.
Default: null
Changelog
Since 4.2.0 | Introduced. |
_mb_strlen() mb strlen code WP 6.4.3
function _mb_strlen( $str, $encoding = null ) { if ( null === $encoding ) { $encoding = get_option( 'blog_charset' ); } /* * The solution below works only for UTF-8, so in case of a different charset * just use built-in strlen(). */ if ( ! in_array( $encoding, array( 'utf8', 'utf-8', 'UTF8', 'UTF-8' ), true ) ) { return strlen( $str ); } if ( _wp_can_use_pcre_u() ) { // Use the regex unicode support to separate the UTF-8 characters into an array. preg_match_all( '/./us', $str, $match ); return count( $match[0] ); } $regex = '/(?: [\x00-\x7F] # single-byte sequences 0xxxxxxx | [\xC2-\xDF][\x80-\xBF] # double-byte sequences 110xxxxx 10xxxxxx | \xE0[\xA0-\xBF][\x80-\xBF] # triple-byte sequences 1110xxxx 10xxxxxx * 2 | [\xE1-\xEC][\x80-\xBF]{2} | \xED[\x80-\x9F][\x80-\xBF] | [\xEE-\xEF][\x80-\xBF]{2} | \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences 11110xxx 10xxxxxx * 3 | [\xF1-\xF3][\x80-\xBF]{3} | \xF4[\x80-\x8F][\x80-\xBF]{2} )/x'; // Start at 1 instead of 0 since the first thing we do is decrement. $count = 1; do { // We had some string left over from the last round, but we counted it in that last round. --$count; /* * Split by UTF-8 character, limit to 1000 characters (last array element will contain * the rest of the string). */ $pieces = preg_split( $regex, $str, 1000 ); // Increment. $count += count( $pieces ); // If there's anything left over, repeat the loop. } while ( $str = array_pop( $pieces ) ); // Fencepost: preg_split() always returns one extra item in the array. return --$count; }