使用php实现截取指定长度

  PHP语言: 根据中文裁减字符串

  

复制代码 代码如下:

  function cutstr($string,$length, $dot = ' ...') {

  if (strlen($string) <= $length) {

  return$string;

  }

  $pre = chr(1);

  $end = chr(1);

  $string = str_replace(array('&','"', '<', '>'),array($pre . '&'. $end, $pre . '"' . $end, $pre . '<' .$end, $pre . '>' . $end), $string);

  $strcut = '';

  if (strtolower(CHARSET) == 'utf-8'){

  $n = $tn =$noc = 0;

  while ($n< strlen($string)) {

  $t =ord($string[$n]);

  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];

  }

  }

  $strcut = str_replace(array($pre . '&' .$end, $pre . '"' . $end, $pre . '<' . $end, $pre . '>' .$end), array('&', '"','<', '>'), $strcut);

  $pos = strrpos($strcut, chr(1));

  if ($pos !== false) {

  $strcut =substr($strcut, 0, $pos);

  }

  return $strcut . $dot;

  }