php截取字符串函数分享_PHP

代码如下:

/**
* 方法库-截取字符串-【该函数作者未知】
* @param string $string 字符串
* @param int $length 字符长度
* @param string $dot 截取后是否添加...
* @param string $charset编码
* @return string
*/
public function cutstr($string, $length, $dot = ' ...', $charset = 'utf-8') {
if (strlen($string) <= $length) {
return $string;
}
$string = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $string);
$strcut = '';
if (strtolower($charset) == 'utf-8') {
$n = $tn = $noc = 0;
while ($n < strlen($string)) {
$t = ord($string[$n]); //ASCIIֵ
if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
$tn = 1; $n++; $noc++;
} elseif (194 <= $t && $t <= 223) {
$tn = 2; $n += 2; $noc += 2;
} elseif (224 <= $t && $t < 239) {
$tn = 3; $n += 3; $noc += 2;
} elseif (240 <= $t && $t <= 247) {
$tn = 4; $n += 4; $noc += 2;
} elseif (248 <= $t && $t <= 251) {
$tn = 5; $n += 5; $noc += 2;
} elseif ($t == 252 || $t == 253) {
$tn = 6; $n += 6; $noc += 2;
} else {
$n++;
}
if($noc >= $length) {
break;
}
}
if ($noc > $length) {
$n -= $tn;
}
$strcut = substr($string, 0, $n);
} else {
for ($i = 0; $i < $length; $i++) {
$strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];
}
}
$strcut = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $strcut);
return $strcut.$dot;
}

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