/**

 *

 * 中英混合字符串长度判断

 * @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);

}

/**

 *

 * 中英混合的字符串截取

 * @param unknown_type $sourcestr

 * @param unknown_type $cutlength

 */

function cut_str($sourcestr, $cutlength)

{

    $returnstr = '';

    $i = 0;

    $n = 0;

    $str_length = strlen($sourcestr); //字符串的字节数

    while (($n < $cutlength) and ($i <= $str_length)) {

        $temp_str = substr($sourcestr, $i, 1);

        $ascnum = Ord($temp_str); //得到字符串中第$i位字符的ascii码

        if ($ascnum >= 224) //如果ASCII位高与224，

        {

            $returnstr = $returnstr . substr($sourcestr, $i, 3); //根据UTF-8编码规范，将3个连续的字符计为单个字符

            $i = $i + 3; //实际Byte计为3

            $n++; //字串长度计1

        } elseif ($ascnum >= 192) //如果ASCII位高与192，

        {

            $returnstr = $returnstr . substr($sourcestr, $i, 2); //根据UTF-8编码规范，将2个连续的字符计为单个字符

            $i = $i + 2; //实际Byte计为2

            $n++; //字串长度计1

        } elseif ($ascnum >= 65 && $ascnum <= 90) //如果是大写字母，

        {

            $returnstr = $returnstr . substr($sourcestr, $i, 1);

            $i = $i + 1; //实际的Byte数仍计1个

            $n++; //但考虑整体美观，大写字母计成一个高位字符

        } else //其他情况下，包括小写字母和半角标点符号，

        {

            $returnstr = $returnstr . substr($sourcestr, $i, 1);

            $i = $i + 1; //实际的Byte数计1个

            $n = $n + 0.5; //小写字母和半角标点等与半个高位字符宽...

        }

    }

    if ($str_length > $cutlength) {

        $returnstr = $returnstr . "..."; //超过长度时在尾处加上省略号

    }

    return $returnstr;

}

/**

 * PHP实现中文字串截取无乱码的方法

 * @param $string

 * @param $start

 * @param $length

 * @return string

 */

function GBsubstr($string, $start, $length)

{

    if (strlen($string) > $length) {

        $str = null;

        $len = $start + $length;

        for ($i = $start; $i < $len; $i++) {

            if (ord(substr($string, $i, 1)) > 0xa0) {

                $str .= substr($string, $i, 2);

                $i++;

            } else {

                $str .= substr($string, $i, 1);

            }

        }

        return $str . '...';

    } else {

        return $string;

    }

}

function substr_text($str, $start = 0, $length, $charset = "utf-8", $suffix = "")

{

    if (function_exists("mb_substr")) {

        return mb_substr($str, $start, $length, $charset) . $suffix;

    } elseif (function_exists('iconv_substr')) {

        return iconv_substr($str, $start, $length, $charset) . $suffix;

    }

    $re['utf-8'] = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";

    $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";

    $re['gbk'] = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";

    $re['big5'] = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";

    preg_match_all($re[$charset], $str, $match);

    $slice = join("", array_slice($match[0], $start, $length));

    return $slice . $suffix;

}