php：一个截取指定长度的方法
PHP语言:<wbr></wbr>根据中文裁减字符串function cutstr($string,$length, $dot = ' ...') {
<wbr><wbr>if (strlen($string) <= $length) {</wbr></wbr>
<wbr><wbr><wbr><wbr>return$string;</wbr></wbr></wbr></wbr>
<wbr><wbr>}</wbr></wbr>
<wbr><wbr>$pre = chr(1);</wbr></wbr>
<wbr><wbr>$end = chr(1);</wbr></wbr>
<wbr><wbr>$string = str_replace(array('&','"', '<', '>'),array($pre . '&'. $end, $pre . '"' . $end, $pre . '<' .$end, $pre . '>' . $end), $string);</wbr></wbr>
<wbr><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>$strcut = '';</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>if (strtolower(CHARSET) == 'utf-8'){</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>$n = $tn =$noc = 0;</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>while ($n< strlen($string)) {</wbr></wbr></wbr></wbr></span><br><wbr><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>$t =ord($string[$n]);</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>if ($t == 9 || $t == 10 || (32<= $t && $t <= 126)) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 1;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n++;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc++;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} elseif (194 <= $t&& $t <= 223) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} elseif (224 <= $t&& $t <= 239) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 3;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n += 3;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} elseif (240 <= $t&& $t <= 247) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 4;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n += 4;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} elseif (248 <= $t&& $t <= 251) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 5;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n += 5;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} elseif ($t == 252 || $t ==253) {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$tn = 6;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n += 6;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$noc += 2;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>} else {</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>$n++;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></span><br><wbr><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>if ($noc >= $length){</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr><wbr><wbr>break;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>if ($noc> $length) {</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>$n -= $tn;</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>$strcut =substr($string, 0, $n);</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>} else {</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>for ($i =0; $i < $length; $i++) {</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr><wbr><wbr>$strcut .= ord($string[$i])> 127 ? $string[$i] . $string[++$i] : $string[$i];</wbr></wbr></wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>}</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>$strcut = str_replace(array($pre . '&' .$end, $pre . '"' . $end, $pre . '<' . $end, $pre . '>' .$end), array('&', '"','<', '>'), $strcut);</wbr></wbr></span><br><wbr><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>$pos = strrpos($strcut, chr(1));</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>if ($pos !== false) {</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr><wbr><wbr>$strcut =substr($strcut, 0, $pos);</wbr></wbr></wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>}</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);"><wbr><wbr>return $strcut . $dot;</wbr></wbr></span><br><span style="color: rgb(32, 32, 32);">}</span></wbr></wbr></wbr></wbr>
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