1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
<?
/**
* The decode class is simple and straightforward. The only thing to
* note is that empty dictionaries are represented by boolean trues
*/
class BencodeDecode extends Bencode {
private $Data;
private $Length;
private $Pos = 0;
public $Dec = array();
public $ExitOnError = true;
const SnipLength = 40;
/**
* Decode prepararations
*
* @param string $Arg bencoded string or path to bencoded file to decode
* @param bool $IsPath needs to be true if $Arg is a path
* @return decoded data with a suitable structure
*/
function __construct($Arg = false, $IsPath = false) {
if ($Arg === false) {
if (empty($this->Enc)) {
return false;
}
} else {
if ($IsPath === true) {
return $this->bdec_file($Arg);
}
$this->Data = $Arg;
}
return $this->decode();
}
/**
* Decodes a bencoded file
*
* @param $Path path to bencoded file to decode
* @return decoded data with a suitable structure
*/
public function bdec_file($Path = false) {
if (empty($Path)) {
return false;
}
if (!$this->Data = @file_get_contents($Path, FILE_BINARY)) {
return $this->error("Error: file '$Path' could not be opened.\n");
}
return $this->decode();
}
/**
* Decodes a string with bencoded data
*
* @param mixed $Arg bencoded data or false to decode the content of $this->Data
* @return decoded data with a suitable structure
*/
public function decode($Arg = false) {
if ($Arg !== false) {
$this->Data = $Arg;
} elseif (!$this->Data) {
$this->Data = $this->Enc;
}
if (!$this->Data) {
return false;
}
$this->Length = strlen($this->Data);
$this->Pos = 0;
$this->Dec = $this->_bdec();
if ($this->Pos < $this->Length) {
// Not really necessary, but if the torrent is invalid, it's better to warn than to silently truncate it
return $this->error();
}
return $this->Dec;
}
/**
* Internal decoding function that does the actual job
*
* @return decoded data with a suitable structure
*/
private function _bdec() {
switch ($this->Data[$this->Pos]) {
case 'i':
$this->Pos++;
$Value = substr($this->Data, $this->Pos, strpos($this->Data, 'e', $this->Pos) - $this->Pos);
if (!ctype_digit($Value) && !($Value[0] == '-' && ctype_digit(substr($Value, 1)))) {
return $this->error();
}
$this->Pos += strlen($Value) + 1;
return Int64::make($Value);
case 'l':
$Value = array();
$this->Pos++;
while ($this->Data[$this->Pos] != 'e') {
if ($this->Pos >= $this->Length) {
return $this->error();
}
$Value[] = $this->_bdec();
}
$this->Pos++;
return $Value;
case 'd':
$Value = array();
$this->Pos++;
while ($this->Data[$this->Pos] != 'e') {
$Length = substr($this->Data, $this->Pos, strpos($this->Data, ':', $this->Pos) - $this->Pos);
if (!ctype_digit($Length)) {
return $this->error();
}
$this->Pos += strlen($Length) + $Length + 1;
$Key = substr($this->Data, $this->Pos - $Length, $Length);
if ($this->Pos >= $this->Length) {
return $this->error();
}
$Value[$Key] = $this->_bdec();
}
$this->Pos++;
// Use boolean true to keep track of empty dictionaries
return empty($Value) ? true : $Value;
default:
$Length = substr($this->Data, $this->Pos, strpos($this->Data, ':', $this->Pos) - $this->Pos);
if (!ctype_digit($Length)) {
return $this->error(); // Even if the string is likely to be decoded correctly without this check, it's malformed
}
$this->Pos += strlen($Length) + $Length + 1;
return substr($this->Data, $this->Pos - $Length, $Length);
}
}
/**
* Convert everything to the correct data types and optionally escape strings
*
* @param bool $Escape whether to escape the textual data
* @param mixed $Data decoded data or false to use the $Dec property
* @return decoded data with more useful data types
*/
public function dump($Escape = true, $Data = false) {
if ($Data === false) {
$Data = $this->Dec;
}
if (Int64::is_int($Data)) {
return Int64::get($Data);
}
if (is_bool($Data)) {
return array();
}
if (is_array($Data)) {
$Output = array();
foreach ($Data as $Key => $Val) {
$Output[$Key] = $this->dump($Escape, $Val);
}
return $Output;
}
return $Escape ? htmlentities($Data) : $Data;
}
/**
* Display an error and halt the operation unless the $ExitOnError property is false
*
* @param string $ErrMsg the error message to display
*/
private function error($ErrMsg = false) {
static $ErrorPos;
if ($this->Pos === $ErrorPos) {
// The recursive nature of the class requires this to avoid duplicate error messages
return false;
}
if ($ErrMsg === false) {
printf("Malformed string. Invalid character at pos 0x%X: %s\n",
$this->Pos, str_replace(array("\r","\n"), array('',' '), htmlentities(substr($this->Data, $this->Pos, self::SnipLength))));
} else {
echo $ErrMsg;
}
if ($this->ExitOnError) {
exit();
}
$ErrorPos = $this->Pos;
return false;
}
}
|
