protected override bool WriteContent(byte[] ndef_content)
{
Trace.WriteLine("Writing the NFC Forum type 2 Tag");
if (ndef_content == null)
{
return(false);
}
/* Get the new NDEF TLV to store into the Tag */
NfcTlv ndef_tlv = new NfcTlv(NDEF_MESSAGE_TLV, ndef_content);
/* Remove the Terminator TLV (if some) */
while ((_tlvs.Count > 0) && (_tlvs[_tlvs.Count - 1].T == TERMINATOR_TLV))
{
_tlvs.RemoveAt(_tlvs.Count - 1);
}
/* Where shall I put the NDEF TLV in the Tag ? */
if (_tlvs.Count == 0)
{
_tlvs.Add(ndef_tlv);
}
else
{
for (int i = 0; i < _tlvs.Count; i++)
{
if (_tlvs[i].T == NDEF_MESSAGE_TLV)
{
/* Replace this one */
_tlvs[i] = ndef_tlv;
ndef_tlv = null;
break;
}
}
if (ndef_tlv != null)
{
/* No NDEF in the Tag beforehand? Let's add it the the end */
_tlvs.Add(ndef_tlv);
}
}
CardBuffer actual_content = new CardBuffer();
for (int i = 0; i < _tlvs.Count; i++)
{
actual_content.Append(_tlvs[i].Serialize());
}
if (actual_content.Length > Capacity())
{
Trace.WriteLine("The size of the content (with its TLVs) is bigger than the tag's capacity");
return(false);
}
if ((actual_content.Length + 2) < Capacity())
{
/* Add a Terminator at the end */
Trace.WriteLine("We add a TERMINATOR TLV at the end of the Tag");
actual_content.Append((new NfcTlv(TERMINATOR_TLV, null)).Serialize());
}
/* And now write */
ushort page = 4;
for (long i = 0; i < actual_content.Length; i += 4)
{
byte[] buffer = new byte[4];
for (long j = 0; j < 4; j++)
{
if ((i + j) < actual_content.Length)
{
buffer[j] = actual_content.GetByte(i + j);
}
}
if (!WriteBinary(_channel, page, buffer))
{
return(false);
}
page++;
}
return(true);
}
protected override bool Read()
{
Trace.WriteLine("Reading the NFC Forum type 2 Tag");
ushort page = 0;
if (!Recognize(_channel, ref _formatted, ref _formattable, ref _locked))
{
return(false);
}
CardBuffer buffer = new CardBuffer();
for (page = 0; page < 256; page += 4)
{
byte[] data = ReadBinary(_channel, page, READ_4_PAGES);
if (data == null)
{
break;
}
if (page > 0)
{
bool same_as_header = true;
for (int i = 0; i < OFFSET_USER_DATA; i++)
{
if (data[i] != buffer.GetByte(i))
{
same_as_header = false;
break;
}
}
if (same_as_header)
{
break;
}
}
buffer.Append(data);
}
Trace.WriteLine("Read " + buffer.Length + "B of data from the Tag");
_raw_data = buffer.GetBytes();
_capacity = _raw_data.Length;
if (_capacity <= OFFSET_USER_DATA)
{
_capacity = 0;
return(false);
}
if (!_formatted)
{
/* Guess the capacity from the read area */
if ((_capacity > 64) && !_formatted)
{
/* Drop the 16 last bytes if they are not empty (locks on Mifare UltraLight C) */
bool locks_found = false;
for (long i = _capacity - 16; i < _capacity; i++)
{
if (_raw_data[i] != 0)
{
locks_found = true;
break;
}
}
if (locks_found)
{
Trace.WriteLine("Locks found at the end");
_capacity -= 16;
}
}
_capacity -= OFFSET_USER_DATA;
Trace.WriteLine("The Tag is not formatted, capacity=" + _capacity + "B");
}
else
{
/* Read the capacity in the CC */
_capacity = 8 * _raw_data[14];
Trace.WriteLine("The Tag is formatted, capacity read from the CC=" + _capacity + "B");
}
/* Is the tag empty ? */
_is_empty = true;
for (long i = 0; i < _capacity; i++)
{
if (_raw_data[OFFSET_USER_DATA + i] != 0)
{
_is_empty = false;
break;
}
}
if (_is_empty)
{
Trace.WriteLine("The Tag is empty");
return(true);
}
byte[] ndef_data = null;
if (!ParseUserData(buffer.GetBytes(OFFSET_USER_DATA, -1), ref ndef_data))
{
Trace.WriteLine("The parsing of the Tag failed");
return(false);
}
if (ndef_data == null)
{
Trace.WriteLine("The Tag doesn't contain a NDEF");
_is_empty = true;
return(true);
}
_is_empty = false;
Ndef[] t = Ndef.Parse(ndef_data);
if (t == null)
{
Trace.WriteLine("The NDEF is invalid or unsupported");
return(false);
}
Trace.WriteLine(t.Length + " NDEF record(s) found in the Tag");
/* This NDEF is the new content of the tag */
Content.Clear();
for (int i = 0; i < t.Length; i++)
{
Content.Add(t[i]);
}
return(true);
}