String segmentation utf-8 (supports Chinese, Japanese, Korean, etc., efficient,)

Because mb_substr and mb_strlen are too inefficient, this code is used.

Not original, the main principle is based on the encoding characteristics of UTF-8
0xxxxxxx
110xxxxx 10xxxxxx
1110xxxx 10xxxxxx 10xxxxxx
11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
to get the character boundary, thereby determining the number of bytes occupied by a word, and processing it into an array.


It is convenient for users who frequently operate characters. This function is 10 times more efficient than mb_substr. I once wrote an "N million banned word replacement class". During the development process of this type, I compared the efficiency of the two in detail. , this function clearly wins.

function str_split_utf8($str) {
 // place each character of the string into and array
 $split = 1;
 $array = array(); $len = strlen($str);
 for ( $ i = 0; $i < $len; ){
 $value = ord($str[$i]);
 if($value > 0x7F){
 if($value >= 0xC0 && $value < ;= 0xDF)
 $split = 2;
 elseif($value >= 0xE0 && $value <= 0xEF)
 $split = 3;
 elseif($value >= 0xF0 && $value <= 0xF7)
 $split = 4;
 elseif($value >= 0xF8 && $value <= 0xFB)
 $split = 5;
 elseif($value >= 0xFC)
 $split = 6;

 } else {
 $split = 1;
 }
 $key = '';
 for ( $j = 0; $j < $split; ++$j, ++$i ) {
 $key .= $str[$ i];
 }
 $array[] = $key;
 }
 return $array;
}