static BEncodedDictionary DecodeDictionary(RawReader reader, bool strictDecoding)
{
int read;
BEncodedString oldkey = null;
var dictionary = new BEncodedDictionary();
while ((read = reader.ReadByte()) != -1 && read != 'e')
{
BEncodedString key = DecodeString(reader, read - '0'); // keys have to be BEncoded strings
if (oldkey != null && oldkey.CompareTo(key) > 0)
{
if (strictDecoding)
{
throw new BEncodingException(
$"Illegal BEncodedDictionary. The attributes are not ordered correctly. Old key: {oldkey}, New key: {key}");
}
}
oldkey = key;
BEncodedValue value = Decode(reader); // the value is a BEncoded value
dictionary.Add(key, value);
}
if (read != 'e') // remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
return(dictionary);
}
static BEncodedDictionary DecodeDictionary(ref ReadOnlySpan <byte> buffer, bool strictDecoding)
{
BEncodedString oldkey = null;
var dictionary = new BEncodedDictionary();
while (buffer.Length > 0)
{
if (buffer[0] == 'e')
{
buffer = buffer.Slice(1);
return(dictionary);
}
var key = DecodeString(ref buffer);
if (oldkey != null && oldkey.CompareTo(key) > 0)
{
if (strictDecoding)
{
throw new BEncodingException(
$"Illegal BEncodedDictionary. The attributes are not ordered correctly. Old key: {oldkey}, New key: {key}");
}
}
oldkey = key;
var value = Decode(ref buffer, strictDecoding);
dictionary.Add(key, value);
}
throw new BEncodingException("Invalid data found. Aborting");
}
public static (BEncodedDictionary torrent, ReadOnlyMemory <byte> infohash) DecodeTorrent(ref ReadOnlySpan <byte> buffer)
{
if (buffer[0] != 'd')
{
throw new BEncodingException($"The root value was not a BEncodedDictionary");
}
buffer = buffer.Slice(1);
ReadOnlySpan <byte> infoBuffer = default;
BEncodedString oldkey = null;
Memory <byte> infoHash = null;
var dictionary = new BEncodedDictionary();
while (buffer.Length > 0)
{
if (buffer[0] == 'e')
{
buffer = buffer.Slice(1);
return(dictionary, infoHash);
}
var key = DecodeString(ref buffer);
if (oldkey != null && oldkey.CompareTo(key) > 0)
{
throw new BEncodingException($"Illegal BEncodedDictionary. The attributes are not ordered correctly. Old key: {oldkey}, New key: {key}");
}
if (InfoKey.Equals(key))
{
infoBuffer = buffer;
}
oldkey = key;
var value = Decode(ref buffer, false);
dictionary.Add(key, value);
if (InfoKey.Equals(key))
{
using var hasher = SHA1.Create();
infoHash = new byte[hasher.HashSize / 8];
if (!hasher.TryComputeHash(infoBuffer.Slice(0, infoBuffer.Length - buffer.Length), infoHash.Span, out int written) || written != infoHash.Length)
{
throw new BEncodingException("Could not compute infohash for torrent.");
}
}
}
throw new BEncodingException("Invalid data found. Aborting");
}
static BEncodedDictionary DecodeDictionary(Stream reader, bool strictDecoding)
{
int read;
BEncodedString oldkey = null;
var dictionary = new BEncodedDictionary();
while ((read = reader.ReadByte()) != -1)
{
if (read == 'e')
{
return(dictionary);
}
if (read < '0' || read > '9')
{
throw new BEncodingException("Invalid key length");
}
var key = DecodeString(reader, read - '0'); // keys have to be BEncoded strings
if (oldkey != null && oldkey.CompareTo(key) > 0)
{
if (strictDecoding)
{
throw new BEncodingException(
$"Illegal BEncodedDictionary. The attributes are not ordered correctly. Old key: {oldkey}, New key: {key}");
}
}
oldkey = key;
var value = Decode(reader, strictDecoding); // the value is a BEncoded value
dictionary.Add(key, value);
}
throw new BEncodingException("Invalid data found. Aborting");
}
