/// <summary>
/// Special decoding method for torrent files - allows dictionary attributes to be out of order for the
/// overall torrent file, but imposes strict rules on the info dictionary.
/// </summary>
/// <returns></returns>
public static BEncodedDictionary DecodeMetadata(RawReader reader)
{
BEncodedDictionary metadata = new BEncodedDictionary();
if (reader.ReadByte() != 'd')
{
throw new BEncodingException("Invalid data found. Aborting"); // Remove the leading 'd'
}
while ((reader.PeekByte() != -1) && (reader.PeekByte() != 'e'))
{
BEncodedString key = (BEncodedString)Decode(reader);
BEncodedValue value;
if (reader.PeekByte() == 'd')
{
value = new BEncodedDictionary();
((BEncodedDictionary)value).DecodeInternal(reader, key.Text.ToLower().Equals("info"));
}
else
{
value = Decode(reader); // the value is a BEncoded value
}
metadata._dictionary.Add(key, value);
}
if (reader.ReadByte() != 'e') // remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
return(metadata);
}
private void DecodeInternal(RawReader reader, bool strictDecoding)
{
BEncodedString oldkey = null;
if (reader.ReadByte() != 'd')
{
throw new BEncodingException("Invalid data found. Aborting"); // Remove the leading 'd'
}
while ((reader.PeekByte() != -1) && (reader.PeekByte() != 'e'))
{
BEncodedString key = (BEncodedString)Decode(reader);
if ((oldkey != null) && (oldkey.CompareTo(key) > 0))
{
if (strictDecoding)
{
throw new BEncodingException(string.Format("Illegal BEncodedDictionary. The attributes are not ordered correctly. Old key: {0}, New key: {1}", oldkey, key));
}
}
oldkey = key;
BEncodedValue value = Decode(reader);
_dictionary.Add(key, value);
}
if (reader.ReadByte() != 'e') // remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
}
/// <summary>
/// Decodes a BEncodedString from the supplied StreamReader
/// </summary>
/// <param name="reader">The StreamReader containing the BEncodedString</param>
protected override void DecodeInternal(RawReader reader)
{
if (reader == null)
{
throw new ArgumentNullException(nameof(reader));
}
int letterCount;
string length = string.Empty;
while ((reader.PeekByte() != -1) && (reader.PeekByte() != ':')) // read in how many characters
{
length += (char)reader.ReadByte(); // the string is
}
if (reader.ReadByte() != ':') // remove the ':'
{
throw new BEncodingException("Invalid data found. Aborting");
}
if (!int.TryParse(length, out letterCount))
{
throw new BEncodingException(
string.Format("Invalid BEncodedString. Length was '{0}' instead of a number", length));
}
TextBytes = new byte[letterCount];
if (reader.Read(TextBytes, 0, letterCount) != letterCount)
{
throw new BEncodingException("Couldn't decode string");
}
}
/// <summary>
/// Decodes a BEncodedList from the given StreamReader
/// </summary>
/// <param name="reader"></param>
protected override void DecodeInternal(RawReader reader)
{
if (reader.ReadByte() != 'l') // Remove the leading 'l'
{
throw new BEncodingException("Invalid data found. Aborting");
}
while ((reader.PeekByte() != -1) && (reader.PeekByte() != 'e'))
{
_list.Add(Decode(reader));
}
if (reader.ReadByte() != 'e') // Remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
}
/// <summary>
/// Decodes a BEncoded number from the supplied RawReader
/// </summary>
/// <param name="reader">RawReader containing a BEncoded Number</param>
protected override void DecodeInternal(RawReader reader)
{
if (reader == null)
{
throw new ArgumentNullException(nameof(reader));
}
if (reader.ReadByte() != 'i') // remove the leading 'i'
{
throw new BEncodingException("Invalid data found. Aborting.");
}
int sign = 1;
if (reader.PeekByte() == '-')
{
sign = -1;
reader.ReadByte();
}
int letter;
while (((letter = reader.PeekByte()) != -1) && (letter != 'e'))
{
if ((letter < '0') || (letter > '9'))
{
throw new BEncodingException("Invalid number found.");
}
Number = Number * 10 + (letter - '0');
reader.ReadByte();
}
if (reader.ReadByte() != 'e') //remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting.");
}
Number *= sign;
}
