支持中文和其他编码的php截取字符串函数分享(截取中文字符串)

/**
* 字符串截取，支持中文和其他编码
* @static
* @access public
* @param string $str 需要转换的字符串
* @param string $start 开始位置
* @param string $length 截取长度
* @param string $charset 编码格式
* @param string $suffix 截断显示字符
* @return string
*/
function msubstr($str, $start=0, $length, $charset="utf-8", $suffix=true) {
if(function_exists("mb_substr"))
$slice = mb_substr($str, $start, $length, $charset);
elseif(function_exists('iconv_substr')) {
$slice = iconv_substr($str,$start,$length,$charset);
if(false === $slice) {
$slice = '';
}
}else{
$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 $suffix ? $slice.'…' : $slice;
}