原型
_mb_strlen( $str, $encoding = null )
源文件
路径:wp-includes/compat.php
<?php
...
| [xF1-xF3][x80-xBF]{3}
| xF4[x80-x8F][x80-xBF]{2}
)/x';
// Start with 1 element instead of 0 since the first thing we do is pop.
$chars = array( '' );
do {
// We had some string left over from the last round, but we counted it in that last round.
array_pop( $chars );
/*
* 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, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY );
$chars = array_merge( $chars, $pieces );
// If there's anything left over, repeat the loop.
} while ( count( $pieces ) > 1 && $str = array_pop( $pieces ) );
return join( '', array_slice( $chars, $start, $length ) );
}
if ( ! function_exists( 'mb_strlen' ) ) :
/**
* Compat function to mimic mb_strlen().
*
* @ignore
* @since 4.2.0
*
* @see _mb_strlen()
*
* @param string $str The string to retrieve the character length from.
* @param string|null $encoding Optional. Character encoding to use. Default null.
* @return int String length of `$str`.
*/
function mb_strlen( $str, $encoding = null ) {
return _mb_strlen( $str, $encoding );
}
endif;
/**
* Internal compat function to mimic mb_strlen().
...
?>
其他
英文文档:https://developer.wordpress.org/reference/functions/_mb_strlen/