/// <summary>
/// Decodes a BEncodedString from the supplied StreamReader
/// </summary>
/// <param name="reader">The StreamReader containing the BEncodedString</param>
internal override void DecodeInternal(RawReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("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(string.Format("Invalid data found at {0}. Aborting", reader.Position));
}
if (!int.TryParse(length, out letterCount))
{
throw new BEncodingException(string.Format("Invalid BEncodedString. Length was '{0}' instead of a number", length));
}
this.textBytes = new byte[letterCount];
if (reader.Read(textBytes, 0, letterCount) != letterCount)
{
throw new BEncodingException("Couldn't decode string");
}
}
private void DecodeInternal(RawReader reader, bool strictDecoding)
{
BEncodedString key = null;
BEncodedValue value = null;
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'))
{
key = (BEncodedString)BEncodedValue.Decode(reader); // keys have to be BEncoded strings
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;
value = BEncodedValue.Decode(reader); // the value is a BEncoded value
dictionary.Add(key, value);
}
if (reader.ReadByte() != 'e') // remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
}
/// <summary>
/// Decodes a BEncodedList from the given StreamReader
/// </summary>
/// <param name="reader"></param>
internal 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(BEncodedValue.Decode(reader));
}
if (reader.ReadByte() != 'e') // Remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
}
/// <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 DecodeTorrent(RawReader reader)
{
BEncodedString key = null;
BEncodedValue value = null;
BEncodedDictionary torrent = new BEncodedDictionary();
if (reader.ReadByte() != 'd')
{
throw new BEncodingException("Invalid data found. Aborting"); // Remove the leading 'd'
}
while ((reader.PeekByte() != -1) && (reader.PeekByte() != 'e'))
{
key = (BEncodedString)BEncodedValue.Decode(reader); // keys have to be BEncoded strings
if (reader.PeekByte() == 'd')
{
value = new BEncodedDictionary();
if (key.Text.ToLower().Equals("info"))
{
((BEncodedDictionary)value).DecodeInternal(reader, true);
}
else
{
((BEncodedDictionary)value).DecodeInternal(reader, false);
}
}
else
{
value = BEncodedValue.Decode(reader); // the value is a BEncoded value
}
torrent.dictionary.Add(key, value);
}
if (reader.ReadByte() != 'e') // remove the trailing 'e'
{
throw new BEncodingException("Invalid data found. Aborting");
}
return(torrent);
}
/// <summary>
/// Decodes a BEncoded number from the supplied RawReader
/// </summary>
/// <param name="reader">RawReader containing a BEncoded Number</param>
internal override void DecodeInternal(RawReader reader)
{
int sign = 1;
if (reader == null)
{
throw new ArgumentNullException("reader");
}
if (reader.ReadByte() != 'i') // remove the leading 'i'
{
throw new BEncodingException("Invalid data found. Aborting.");
}
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;
}
/// <summary>
/// Decode BEncoded data in the given RawReader
/// </summary>
/// <param name="reader">The RawReader containing the BEncoded data</param>
/// <returns>BEncodedValue containing the data that was in the stream</returns>
public static BEncodedValue Decode(RawReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
BEncodedValue data;
switch (reader.PeekByte())
{
case ('i'): // Integer
data = new BEncodedNumber();
break;
case ('d'): // Dictionary
data = new BEncodedDictionary();
break;
case ('l'): // List
data = new BEncodedList();
break;
case ('1'): // String
case ('2'):
case ('3'):
case ('4'):
case ('5'):
case ('6'):
case ('7'):
case ('8'):
case ('9'):
case ('0'):
data = new BEncodedString();
break;
default:
throw new BEncodingException(string.Format("Could not find what value to decode at {0}", reader.Position));
}
data.DecodeInternal(reader);
return(data);
}