Example of PHP's judgment and intercepting method for mixed strings in Chinese and English

/**
  *
  * Chinese-English mixed string length judgment
  * @param unknown_type $str
  * @param unknown_type $charset
  */
function strLength($str, $charset = 'utf-8') {
  if ($charset == 'utf-8')
    $str = iconv ( 'utf-8', 'gb2312', $str );
  $num = strlen ( $str );
  $cnNum = 0;
  for($i = 0; $i < $num; $i ++) {
    if (ord ( substr ( $str, $i + 1, 1 ) ) > 127) {
      $cnNum ++;
      $i ++;
    }
  }
  $enNum = $num - ($cnNum * 2);
  $number = ($enNum / 2) + $cnNum;
  return ceil ( $number );
}

/**
  *
  * Chinese-English mixed string interception
  * @param unknown_type $sourcestr
  * @param unknown_type $cutlength
  */
function cut_str($sourcestr, $cutlength) {
  $returnstr = '';
  $i = 0;
  $n = 0;
  $str_length = strlen ( $sourcestr ); //The number of bytes of the string  while ( ($n < $cutlength) and ($i <= $str_length) ) {
    $temp_str = substr ( $sourcestr, $i, 1 );
    $ascnum = Ord ( $temp_str ); //Get the ascii code of the $i character in the string    if ($ascnum >= 224) //If ASCII bit is high and 224,    {
      $returnstr = $returnstr . substr ( $sourcestr, $i, 3 ); // According to UTF-8 encoding specification, 3 consecutive characters are counted as single characters      $i = $i + 3; //The actual Byte is counted as 3      $n ++; //String length meter 1    } elseif ($ascnum >= 192) //If ASCII bit is high and 192,    {
      $returnstr = $returnstr . substr ( $sourcestr, $i, 2 ); // According to UTF-8 encoding specification, 2 consecutive characters are counted as single characters      $i = $i + 2; //The actual Byte is counted as 2      $n ++; //String length meter 1    } elseif ($ascnum >= 65 && $ascnum <= 90) //If it is capital letters,    {
      $returnstr = $returnstr . substr ( $sourcestr, $i, 1 );
      $i = $i + 1; //The actual number of Bytes is still counted 1      $n ++; //But considering the overall beauty, capital letters are counted as high-ranking characters    } else //In other cases, including lowercase letters and half-width punctuation marks,    {
      $returnstr = $returnstr . substr ( $sourcestr, $i, 1 );
      $i = $i + 1; //The actual number of Bytes is counted 1      $n = $n + 0.5; //Lowercase letters and half-width punctuation are wide with half-high characters...    }
  }
  if ($str_length > $cutlength) {
    $returnstr = $returnstr . "..."; //Add ellipsis at the end when the length exceeds the  }
  return $returnstr;
}