Problem with php smarty intercepting garbled Chinese characters? gb2312/utf-8_PHP tutorial

function smartDetectUTF8($string)
{
static $result = array();
if(! array_key_exists($key = md5($string), $result))
{
$utf8 = "
/^(?:
[x09x0Ax0Dx20-x7E] # ASCII
| [xC2-xDF][x80-xBF] # non-overlong 2-byte
| xE0[xA0-xBF][x80-xBF] # excluding overlongs
| [xE1-xECxEExEF][x80-xBF]{2} # straight 3-byte
| xED[x80-x9F][x80-xBF ] # excluding surrogates
| xF0[x90-xBF][x80-xBF]{2} # planes 1-3
| [xF1-xF3][x80-xBF]{3} # planes 4-15
| xF4[x80-x8F][x80-xBF]{2} # plane 16
)+$/xs " , $string);
}
return $result[$key];
}
function smartStrlen($string)
{
$result = 0;
$number = smartDetectUTF8($string) ? 3 : 2;
for($i = 0; $i < strlen($string); $i += $bytes)
{
$bytes = ord( substr($string, $i, 1)) > 127 ? $number : 1;
$result += $bytes > 1 ? 1.0 : 0.5;
}
return $result;
}
function smartSubstr($string, $start, $length = null)
{
$result = '';
$number = smartDetectUTF8($string) ? 3 : 2;
if($start < 0)
{
$start = max(smartStrlen($string) + $start, 0);
}
for($i = 0; $i < ; strlen($string); $i += $bytes)
{
if($start <= 0)
{
break;
}
$bytes = ord (substr($string, $i, 1)) > 127 ? $number : 1;
$start -= $bytes > 1 ? 1.0 : 0.5;
}
if(is_null($ length))
{
$result = substr($string, $i);
}
else
{
for($j = $i; $j < strlen ($string); $j += $bytes)
{
if($length <= 0)
{
break;
}
if(($bytes = ord(substr($string, $j, 1)) > 127 ? $number : 1) > 1)
{
if($length < 1.0)
{
break;
}
$result .= substr($string, $j, $bytes);
$length -= 1.0;
}
else
{
$result . = substr($string, $j, 1);
$length -= 0.5;
}
}
}
return $result;
}
function smarty_modifier_smartTruncate( $string, $length = 80, $etc = '...',
$break_words = false, $middle = false)
{
if ($length == 0)
return ' ';
if (smartStrlen($string) > $length) {
$length -= smartStrlen($etc);
if (!$break_words && !$middle) {
$string = preg_replace('/s+?(S+)?$/', '', smartSubstr($string, 0, $length+1));
}
if(!$middle) {
return smartSubstr($string, 0, $length).$etc;
} else {
return smartSubstr($string, 0, $length/2) . $etc . smartSubstr($string, -$length/2 );
}
} else {
return $string;
}
}
?>


The above code fully implements the original function of truncate It has functions and is compatible with both GB2312 and UTF-8 encoding. When judging the character length, a Chinese character is counted as 1.0 and an English character is counted as 0.5, so there will be no unevenness when intercepting substrings.