<?php
/** php下载类,支持断点续传
*
*   Func:
*   download: 下载文件
*   setSpeed: 设置下载速度
*   getRange: 获取header中Range
*/


class Audio
{
    public $file=0;
    public $size=0;
    public $new_file=0;

    public function play()
    {
        $this->buffer();
    }

    /**
     *
     * The music download data while playing(音乐边下载数据边播放)
     * @param $data
     */
    public function buffer()
    {
        $url = 'https://mp3.baidu.com/1/top/music/40.m4a';
        $music_id = '40';
        $hostname = 'mp3.baidu.com';
        $test_type = 'm4a';
        $http_url = 'https://mp3.baidu.com/1/top/music/40.m4a';

        //The header file(头部文件)
        header("Content-Type: ". $data['suffix_type'] ."");
        header('Content-Disposition: filename='.$test_type.'');
        header('Cache-Control: no-cache');
        header('Pragma: no-cache');
        header('Content-Transfer-Encoding: chunked');
        //Content-Length
        $headers = get_headers($http_url, 1);
        foreach($headers as $key => $val) {
            switch($key) {
                case 'Content-Length':
                    header("Content-Length: {$val}");
                    break;
                default:
                    break;
            }
        }

        $port = '80';
        $fp=fsockopen($hostname,$port,$errno,$errstr);
//        set_socket_blocking($fp,false);
        stream_set_blocking($fp, false);

        if(!$fp){
           echo "$errno : $errstr<br/>";
        }else {
            $request_header="GET {$url} HTTP/1.1\r\n";
            $request_header.="Host: $hostname\r\n";
            $request_header .= "Connection: Close\r\n\r\n";

            fputs($fp,$request_header);
            $inheader = 1;

            //Download the cycle data(循环下载数据)
            while (!feof($fp)) {
                $line = fgets($fp, 1000);

                //To determine whether the header file(去除头文件)
                if ($inheader && ($line == "\n" || $line == "\r\n")) {
                     $inheader = 0;
                }

                //Data contents decryption(数据内容解密)
                if ($inheader == 0) {
                    //Decryption method(解密方式)
                    $check_dir = $this->decode($line, 1000, $music_id);
                    echo $check_dir;
                }

           }
           fclose($fp);
        }

    }

    /**
     *
     * A portion of the data decryption part(数据一部分一部分的解密)
     * @param $content
     * @param $new_content_size
     * @param $music_id
     */
    public function decode($content, $new_content_size, $music_id)
    {
        $randomData = array(122,11,246,167,217,85,180,205,77,124,152,198,246,152,170,206,196,62,169,91,42,139,103,80,155,31,22,228,196,13,66,52,131,214,228,143,73,103,3,25,84,156,170,213,239,131,185,239,222,28,112,191,220,210,177,139,75,247,89,69,122,163,120,89,24,251,144,164,89,68,71,242,233,134,171,101,231,103,159,192,96,197,31,100,66,93,106,154,59,152,117,15,10,86,200,213,132,165,162,146,221,164,161,239,199,170,62,213,155,23,5,174,118,161,118,163,47,214,211,79,145,59,21,139,214,237,78,22,208,85,150,157,53,127,250,98,47,139,241,99,211,245,189,60,189,205,170,32,132,227,19,41,252,192,234,175,101,60,64,246,0,50,82,4,245,93,131,22,167,74,236,198,164,10,157,26,247,36,233,46,233,190,142,213,184,135,165,194,136,3,251,173,212,246,52,112,85,87,134,170,220,237,214,246,25,224,74,247,118,47,165,108,159,186,215,127,240,76,89,100,49,243,57,165,134,251,63,239,252,75,27,3,49,231,94,148,212,187,142,144,215,114,52,51,225,69,201,132,12,124,211,129,131,49,26,218,27,230,204,242,159,191,63,85,102,103,244,138,43,152,159,114,124,151,53,75,95,208,48,246,97,150,90,169,142,247,86,43,169,124,70,213,245);
        $en_content = '';
        $content_size = strlen($content);
        $cc = intval(intval($this->file) + intval($content_size));

        if ($this->size == 0 && $cc == 2){ $this->size++; return ;}

        for ($i = $this->file; $i < $cc; $i++) {
            $asc_content = ord($content[$i - $this->new_file]) ^ ((($music_id * 7) + $i + $randomData[$i % 293]) & 0X00FF);
            $en_content .= chr($asc_content);
            $this->file++;
        }
        $this->new_file += strlen($en_content);

        return $en_content;
    }
}

class FileDownload{ // class start

    private $_speed = 512;   // 下载速度


    /** 下载
    * @param String  $file   要下载的文件路径
    * @param String  $name   文件名称,为空则与下载的文件名称一样
    * @param boolean $reload 是否开启断点续传
    */
    public function download($file, $name='', $reload=false){
        if(file_exists($file)){
            if($name==''){
                $name = basename($file);
            }

            $fp = fopen($file, 'rb');
            $file_size = filesize($file);
            $ranges = $this->getRange($file_size);

            header('cache-control:public');
            header('content-type:application/octet-stream');
            header('content-disposition:attachment; filename='.$name);

            if($reload && $ranges!=null){ // 使用续传
                header('HTTP/1.1 206 Partial Content');
                header('Accept-Ranges:bytes');
               
                // 剩余长度
                header(sprintf('content-length:%u',$ranges['end']-$ranges['start']));
               
                // range信息
                header(sprintf('content-range:bytes %s-%s/%s', $ranges['start'], $ranges['end'], $file_size));
               
                // fp指针跳到断点位置
                fseek($fp, sprintf('%u', $ranges['start']));
            }else{
                header('HTTP/1.1 200 OK');
                header('content-length:'.$file_size);
            }

            while(!feof($fp)){
                echo fread($fp, round($this->_speed*1024,0));
                ob_flush();
                sleep(1); // 用于测试,减慢下载速度
            }

            ($fp!=null) && fclose($fp);

        }else{
            return '';
        }
    }


    /** 设置下载速度
    * @param int $speed
    */
    public function setSpeed($speed){
        if(is_numeric($speed) && $speed>16 && $speed<4096){
            $this->_speed = $speed;
        }
    }


    /** 获取header range信息
    * @param  int   $file_size 文件大小
    * @return Array
    */
    private function getRange($file_size){
        if(isset($_SERVER['HTTP_RANGE']) && !empty($_SERVER['HTTP_RANGE'])){
            //file_put_contents('./log.log', 'xxxxccccc');
            $range = $_SERVER['HTTP_RANGE'];
            $range = preg_replace('/[\s|,].*/', '', $range);
            $range = explode('-', substr($range, 6));
            if(count($range)<2){
                $range[1] = $file_size;
            }
            $range = array_combine(array('start','end'), $range);
            if(empty($range['start'])){
                $range['start'] = 0;
            }
            if(empty($range['end'])){
                $range['end'] = $file_size;
            }
            return $range;
        }
        return null;
    }

} // class end


$Audio = new Audio();
$Audio->play();
exit;


$file = 'https://mp3.baidu.com/1/top/music/40.m4a';
$name = time().'.zip';
$obj = new FileDownload();
$flag = $obj->download($file, $name, true);
//$flag = $obj->download($file, $name, true); // 断点续传

if(!$flag){
    echo 'file not exists';
}