onethink，thinkphp，php常用公共函数

//判断电脑或手机访问

function is_mobile(){
    $user_agent = $_SERVER['HTTP_USER_AGENT'];
    $mobile_agents = Array("240x320","acer","acoon","acs-","abacho","ahong","airness","alcatel","amoi","android","anywhereyougo.com","applewebkit/525","applewebkit/532","asus","audio","au-mic","avantogo","becker","benq","bilbo","bird","blackberry","blazer","bleu","cdm-","compal","coolpad","danger","dbtel","dopod","elaine","eric","etouch","fly ","fly_","fly-","go.web","goodaccess","gradiente","grundig","haier","hedy","hitachi","htc","huawei","hutchison","inno","ipad","ipaq","ipod","jbrowser","kddi","kgt","kwc","lenovo","lg ","lg2","lg3","lg4","lg5","lg7","lg8","lg9","lg-","lge-","lge9","longcos","maemo","mercator","meridian","micromax","midp","mini","mitsu","mmm","mmp","mobi","mot-","moto","nec-","netfront","newgen","nexian","nf-browser","nintendo","nitro","nokia","nook","novarra","obigo","palm","panasonic","pantech","philips","phone","pg-","playstation","pocket","pt-","qc-","qtek","rover","sagem","sama","samu","sanyo","samsung","sch-","scooter","sec-","sendo","sgh-","sharp","siemens","sie-","softbank","sony","spice","sprint","spv","symbian","tablet","talkabout","tcl-","teleca","telit","tianyu","tim-","toshiba","tsm","up.browser","utec","utstar","verykool","virgin","vk-","voda","voxtel","vx","wap","wellco","wig browser","wii","windows ce","wireless","xda","xde","zte");
    $is_mobile = false;
    foreach ($mobile_agents as $device) {
        if (stristr($user_agent, $device)) {
            $is_mobile = true;
            break;
        }
    }
    return $is_mobile;
}

/**
 *itlife365  简单街购物平台jiandanjie
 * 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;
}

/*
  字符串转换为数组，主要用于把分隔符调整到第二个参数
  @param  string $str  要分割的字符串
  @param  string $glue 分割符
  @return array
  @author 麦当苗儿 <zuojiazi@vip.qq.com>
 */

function str2arr($str, $glue = ','){
    return explode($glue, $str);
}

/*
  数组转换为字符串，主要用于把分隔符调整到第二个参数
  @param  array  $arr  要连接的数组
  @param  string $glue 分割符
  @return string
  @author 麦当苗儿 <zuojiazi@vip.qq.com>
 */

function arr2str($arr, $glue = ','){
    return implode($glue, $arr);
}

/*
产生随机数
@param string $len 产生多少位的随机数
/

function getRand($len=5)
{
    $chars_array = array(
        "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
        "A", "B", "C", "D", "E", "F", "G",
        "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R",
        "S", "T", "U", "V", "W", "X", "Y", "Z",
    );
    $charsLen = count($chars_array) - 1;
    $outputstr = "";
    for ($i=0; $i<$len; $i++)
    {
        $outputstr .= $chars_array[mt_rand(0, $charsLen)];
    }
    return $outputstr;
}

/*
  时间戳格式化
  @param int $time
  @return string 完整的时间显示
  @author huajie <banhuajie@163.com>
 /

function time_format($time = NULL,$format='Y-m-d H:i'){
    $time = $time === NULL ? NOW_TIME : intval($time);
    return date($format, $time);
}