Bt种子转磁力链PHP源码

最近在研究BT种子，找了一套Bt种子转磁力链的PHP源码,下面记录一下。主要三个文件 BEncode.php  BDecode.php  test.php

把种子放到PHP同目录,种子名是filename.torrent 访问即可。

test.php

include 'BEncode.php';
include 'BDecode.php';

$torrent_content = file_get_contents('filename.torrent');

$desc = BDecode($torrent_content);
$info = $desc['info'];
$hash = strtoupper(sha1( BEncode($info) ));

sprintf('magnet:?xt=urn:btih:%s&dn=%s', $hash, $info['name']);

BEncode.php

class BEncode {
	// Dictionary keys must be sorted. foreach tends to iterate over the order
	// the array was made, so we make a new one in sorted order. <img src="http://www.cevin.me/wp-includes/images/smilies/icon_smile.gif" alt=":)" class="wp-smiley">
	function makeSorted($array) {
		// Shouldn't happen!
		if (empty($array))
			return $array;
		$i = 0;
		foreach($array as $key => $dummy)
			$keys[$i++] = stripslashes($key);
		sort($keys);
		for ($i=0; isset($keys[$i]); $i++)
			$return[addslashes($keys[$i])] = $array[addslashes($keys[$i])];
		return $return;
	}

	// Encodes strings, integers and empty dictionaries.
	// $unstrip is set to true when decoding dictionary keys
	function encodeEntry($entry, &$fd, $unstrip = false) {
		if (is_bool($entry)) {
			$fd .= 'de';
			return;
		}
		if (is_int($entry) || is_float($entry)) {
			$fd .= 'i'.$entry.'e';
			return;
		}
		if ($unstrip)
			$myentry = stripslashes($entry);
		else
			$myentry = $entry;
		$length = strlen($myentry);
		$fd .= $length.':'.$myentry;
	}

	// Encodes lists
	function encodeList($array, &$fd) {
		$fd .= 'l';
		// The empty list is defined as array();
		if (empty($array)) {
			$fd .= 'e';
			return;
		}
		for ($i = 0; isset($array[$i]); $i++)
			$this->decideEncode($array[$i], $fd);
		$fd .= 'e';
	}

	// Passes lists and dictionaries accordingly, and has encodeEntry handle
	// the strings and integers.
	function decideEncode($unknown, &$fd) {
		if (is_array($unknown)) {
			if (isset($unknown[0]) || empty($unknown))
				return $this->encodeList($unknown, $fd);
			else
				return $this->encodeDict($unknown, $fd);
		}
		$this->encodeEntry($unknown, $fd);
	}

	// Encodes dictionaries
	function encodeDict($array, &$fd) {
		$fd .= 'd';
		if (is_bool($array)) {
			$fd .= 'e';
			return;
		}
		// NEED TO SORT!
		$newarray = $this->makeSorted($array);
		foreach($newarray as $left => $right) {
			$this->encodeEntry($left, $fd, true);
			$this->decideEncode($right, $fd);
		}
		$fd .= 'e';
	}
}

function BEncode($array) {
	$string = '';
	$encoder = new BEncode;
	$encoder->decideEncode($array, $string);
	return $string;
}

BDecode.php

class BDecode {
	function numberdecode($wholefile, $offset) {
		// Funky handling of negative numbers and zero
		$negative = false;
		if ($wholefile[$offset] == '-') {
			$negative = true;
			$offset++;
		}
		if ($wholefile[$offset] == '0') {
			$offset++;
			if ($negative)
				return array(false);
			if ($wholefile[$offset] == ':' || $wholefile[$offset] == 'e')
				return array(0, ++$offset);
			return array(false);
		}
		$ret[0] = 0;
		for(;;) {
			if ($wholefile[$offset] >= '0' && $wholefile[$offset] <= '9') {
				$ret[0] *= 10;
				//Added 2005.02.21 - VisiGod
	       //Changing the type of variable from integer to double to prevent a numeric overflow   
				settype($ret[0],'double');
				//Added 2005.02.21 - VisiGod
				$ret[0] += ord($wholefile[$offset]) - ord('0');
				$offset++;
			}	else if ($wholefile[$offset] == 'e' || $wholefile[$offset] == ':') {
				// Tolerate : or e because this is a multiuse function
				$ret[1] = $offset+1;
				if ($negative) {
					if ($ret[0] == 0)
						return array(false);
					$ret[0] = - $ret[0];
				}
				return $ret;
			} else return array(false);
		}
	}

	function decodeEntry($wholefile, $offset=0) {
		if ($wholefile[$offset] == 'd')
			return $this->decodeDict($wholefile, $offset);
		if ($wholefile[$offset] == 'l')
			return $this->decodelist($wholefile, $offset);
		if ($wholefile[$offset] == 'i')
			return $this->numberdecode($wholefile, ++$offset);
		// String value: decode number, then grab substring

		$info = $this->numberdecode($wholefile, $offset);
		if ($info[0] === false)
			return array(false);
		$ret[0] = substr($wholefile, $info[1], $info[0]);
		$ret[1] = $info[1]+strlen($ret[0]);
		return $ret;
	}

	function decodeList($wholefile, $offset) {
		if ($wholefile[$offset] != 'l')
			return array(false);
		$offset++;
		$ret = array();
		for ($i=0;;$i++) {
			if ($wholefile[$offset] == 'e')
				break;
			$value = $this->decodeEntry($wholefile, $offset);
			if ($value[0] === false)
				return array(false);
			$ret[$i] = $value[0];
			$offset = $value[1];
		}
		// The empty list is an empty array. Seems fine.
		return array(0=>$ret, 1=>++$offset);
	}

	// Tries to construct an array
	function decodeDict($wholefile, $offset=0) {
		if ($wholefile[$offset] == 'l')
			return $this->decodeList($wholefile, $offset);
		if ($wholefile[$offset] != 'd')
			return false;
		$ret=array();
		$offset++;
		for (;;) {	
			if ($wholefile[$offset] == 'e')	{
				$offset++;
				break;
			}
			$left = $this->decodeEntry($wholefile, $offset);
			if (!$left[0])
				return false;
			$offset = $left[1];
			if ($wholefile[$offset] == 'd') {
				// Recurse
				$value = $this->decodedict($wholefile, $offset);
				if (!$value[0])
					return false;
				$ret[addslashes($left[0])] = $value[0];
				$offset= $value[1];
				continue;
			}
			if ($wholefile[$offset] == 'l') {
				$value = $this->decodeList($wholefile, $offset);
				if (!$value[0] && is_bool($value[0]))
					return false;
				$ret[addslashes($left[0])] = $value[0];
				$offset = $value[1];
				continue;
			}
			$value = $this->decodeEntry($wholefile, $offset);
			if ($value[0] === false)
				return false;
			$ret[addslashes($left[0])] = $value[0];
			$offset = $value[1];
		}
		return array(0=>(empty($ret)?true:$ret), 1=>$offset);
	}
}

function BDecode($wholefile) {
	$decoder = new BDecode;
	$return = $decoder->decodeEntry($wholefile);
	return $return[0];
}