[PHP] – 按長度截取字串(針對UTF-8)

代碼是看看規範又抄又改,希望是完美沒錯...

 

/********************************************************************* * * Func Name : SubStrEx * * Description : *     按長度截取字串 * * * Parameters : *     $sString[string] : 字串 *     $nLength[int] : 要取長度 *     $sDot[string="..."] : 截斷符 *     $sCharset[string="UTF-8"] : 編碼 * * Returns : [bool]儲存結果 * *********************************************************************/function SubStrEx ($sString, $nLength, $sDot = "...", $sCharset = "UTF-8") {    if (strlen($sString) <= $nLength) {        return $sString;    }    $sString = str_replace(array("&", "\"", "<", ">"), array("&", "\"", "<", ">"), $sString);    $sStrcut = "";    if (strtoupper($sCharset) == "UTF-8") {        $nPos = 0;        $nWordLen = 0;        $noc = 0;  // 單位元組字元+1,多位元組+2(將非單位元組字元的長度當做是2[應該是視覺感覺吧])        while ($nPos < strlen($sString)) {            $t = ord($sString[$nPos]);            if ($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {                $nWordLen = 1;                $noc++;            } elseif (194 <= $t && $t <= 223) {                $nWordLen = 2;                $noc += 2;            } elseif (224 <= $t && $t <= 239) {                $nWordLen = 3;                $noc += 2;            } elseif (240 <= $t && $t <= 247) {                $nWordLen = 4;                $noc += 2;            } elseif (248 <= $t && $t <= 251) {                $nWordLen = 5;                $noc += 2;            } elseif ($t == 252 || $t == 253) {                $nWordLen = 6;                $noc += 2;            } else {                $nWordLen = 0;            }                        $nPos += ($nWordLen > 0) ? $nWordLen : 1;            if ($noc >= $nLength) {                break;            }        }        if ($noc > $nLength) {            $nPos -= $nWordLen;        }        $sStrcut = substr($sString, 0, $nPos);    } else {        for ($i = 0; $i < $nLength; $i++) {            $sStrcut .= ord($sString[$i]) > 127 ? $sString[$i] . $sString[++ $i] : $sString[$i];        }    }        $sStrcut = str_replace(array("&", "\"", "<", ">"), array("&", "\"", "<", ">"), $sStrcut);    return $sStrcut . $sDot;}