常用的php函数库

 以后慢慢补充

/**
 * 函数：格式化字节大小
 * @param  number $size      字节数
 * @param  string $delimiter 数字和单位分隔符
 * @return string            格式化后的带单位的大小
 */
function format_bytes($size, $delimiter = '') {
    $units = array('B', 'KB', 'MB', 'GB', 'TB', 'PB');
    for ($i = 0; $size >= 1024 && $i < 5; $i++) $size /= 1024;
    return round($size, 2) . $delimiter . $units[$i];
}

/**
 * 随机字符
 * @param number $length 长度
 * @param string $type 类型
 * @param number $convert 转换大小写
 * @return string
 */
function random($length=6, $type='string', $convert=0){
    $config = array(
        'number'=>'1234567890',
        'letter'=>'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ',
        'string'=>'abcdefghjkmnpqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ23456789',
        'all'=>'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890'
    );

    if(!isset($config[$type])) $type = 'string';
    $string = $config[$type];

    $code = '';
    $strlen = strlen($string) -1;
    for($i = 0; $i < $length; $i++){
        $code .= $string{mt_rand(0, $strlen)};
    }
    if(!empty($convert)){
        $code = ($convert > 0)? strtoupper($code) : strtolower($code);
    }
    return $code;
}

/**
 * 获取客户端IP地址
 * @param integer $type 返回类型 0 返回IP地址 1 返回IPV4地址数字
 * @param boolean $adv 是否进行高级模式获取（有可能被伪装）
 * @return mixed
 */
function get_client_ip($type = 0,$adv=false) {
    $type       =  $type ? 1 : 0;
    static $ip  =   NULL;
    if ($ip !== NULL) return $ip[$type];
    if($adv){
        if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
            $arr    =   explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
            $pos    =   array_search('unknown',$arr);
            if(false !== $pos) unset($arr[$pos]);
            $ip     =   trim($arr[0]);
        }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
            $ip     =   $_SERVER['HTTP_CLIENT_IP'];
        }elseif (isset($_SERVER['REMOTE_ADDR'])) {
            $ip     =   $_SERVER['REMOTE_ADDR'];
        }
    }elseif (isset($_SERVER['REMOTE_ADDR'])) {
        $ip     =   $_SERVER['REMOTE_ADDR'];
    }
    // IP地址合法验证
    $long = sprintf("%u",ip2long($ip));
    $ip   = $long ? array($ip, $long) : array('0.0.0.0', 0);
    return $ip[$type];
}

/**
 * 判断是否SSL协议
 * @return boolean
 */
function is_ssl() {
    if(isset($_SERVER['HTTPS']) && ('1' == $_SERVER['HTTPS'] || 'on' == strtolower($_SERVER['HTTPS']))){
        return true;
    }elseif(isset($_SERVER['SERVER_PORT']) && ('443' == $_SERVER['SERVER_PORT'] )) {
        return true;
    }
    return false;
}