internal AtrChecksumToken(AtrReadStream atr)
{
this.CalculatedChecksum = AtrChecksumToken.CalculateChecksum(atr.GetPreviousBytes().GetSubArray(1));
this.CheckByte = atr.GetNextByte();
this.ChecksumValid = this.CheckByte == this.CalculatedChecksum;
}
internal AtrPreambleToken(TokenizedAtr owner, AtrReadStream atr)
{
this.owner = owner;
/* Initial character TS
* The initial character TS encodes the convention used for encoding of the ATR (and further communications until the next reset).
* In direct [resp. inverse] convention, bits with logic value ‘1’ are transferred as a High voltage (H) [resp. a Low voltage (L)];
* bits with logic value ‘0’ are transferred as L [resp. H]; and least-significant bit of each data byte is first (resp. last) in the
* physical transmission by the card.
* For direct convention, TS is (H) L H H L H H H L L H (H) and encodes the byte ‘3B’.
* For inverse convention, TS is (H) L H H L L L L L L H (H) and encodes the byte ‘3F’.
* [ (H) represents the idle (High, Mark) state of the I/O line. The 8 data bits are shown in italic.]
* In the following bytes of the ATR, bits are numbered 1st to 8th from low-order to high-order, and their value noted 0 or 1,
* regardless of the chronological order and electrical representation, defined by TS.
* TS also allows the card reader to confirm or determine the duration of bits, denoted Elementary Time Unit (ETU),
* as one third of the delay between the first and second H-to-L transition in TS. This is optional, and the principal definition of
* ETU in the ATR of standard-compliant asynchronous Smart Cards is 372 periods of the clock received by the card.
* Historical note: provision for cards that use an internal clock source and a fixed ETU of 1/9600 second during ATR existed in ISO/IEC 7816-3:1989,
* and was removed from the 1997 edition onwards.
*/
byte Ts = atr.GetNextByte();
switch (Ts)
{
case 0x3B:
this.CodingConvention = CodingConvention.Direct;
break;
case 0x3F:
this.CodingConvention = CodingConvention.Inverse;
break;
default:
throw new InvalidAtrCodingException("TS character is invalid");
}
/* Format byte T0
* The Format byte T0 encodes in its 4 low-order bits the number Y of historical bytes, in range [0..15].
* It also encodes in its 4 high-order bits the presence of at most 4 other interface bytes: TA1 (resp. TB1, TC1, TD1)
* follow, in that order, if the 5th (resp. 6th, 7th, 8th) bit of T0 is 1.
*/
byte T0 = atr.GetNextByte();
this.numberOfHistoricalCharacters = T0.GetLoNibble();
this.NextInterfaceBytesIndicator = new NextInterfaceBytesIndicator(T0, true);
this.NextInterfaceBytesIndicator.PropertyChanged += this.interfaceBytesIndicatorForNextGroup_PropertyChanged;
}
internal AtrInterfaceByteGroupToken(TokenizedAtr owner, AtrReadStream atr, NextInterfaceBytesIndicator nextInterfaceBytesIndicator)
{
this.owner = owner;
this.InterfaceBytesIndicator = nextInterfaceBytesIndicator;
this.InterfaceBytesIndicator.PropertyChanged += this.interfaceBytesIndicatorForThisGroup_PropertyChanged;
if (nextInterfaceBytesIndicator.TaExists)
{
this.ta = atr.GetNextByte();
}
if (nextInterfaceBytesIndicator.TbExists)
{
this.tb = atr.GetNextByte();
}
if (nextInterfaceBytesIndicator.TcExists)
{
this.tc = atr.GetNextByte();
}
}
internal TokenizedAtr(Atr owner, byte[] atr)
{
this.owner = owner;
AtrReadStream AtrStream = new AtrReadStream(atr);
//Read preamble
this.Preamble = new AtrPreambleToken(this, AtrStream);
//read interface byte groups
this.InterfaceByteGroups = new AtrInterfaceByteGroupTokenCollection(this);
NextInterfaceBytesIndicator NextInterfaceBytesIndicator = this.Preamble.NextInterfaceBytesIndicator;
while (NextInterfaceBytesIndicator != null)
{
AtrInterfaceByteGroupToken InterfaceByteGroup = new AtrInterfaceByteGroupToken(this, AtrStream, NextInterfaceBytesIndicator);
this.InterfaceByteGroups.AppendGroup(InterfaceByteGroup);
NextInterfaceBytesIndicator = NextInterfaceBytesIndicator.TdExists
? new NextInterfaceBytesIndicator(AtrStream.GetNextByte(), false)
: null;
}
//Read and parse historical characters
if (this.Preamble.NumberOfHistoricalCharacters > 0)
{
byte[] HistoricalCharacters = AtrStream.GetNextBytes(this.Preamble.NumberOfHistoricalCharacters);
this.HistoricalCharacters = new AtrHistoricalCharactersToken(this, HistoricalCharacters);
}
else
{
this.HistoricalCharacters = new AtrHistoricalCharactersToken(this, new byte[0]);
}
//Read checksum if needed
if (this.ChecksumRequired)
{
this.atrChecksum = new AtrChecksumToken(AtrStream);
}
//Read additional bytes
int AdditionalBytes = AtrStream.GetRemainingLength();
if (AdditionalBytes > 0)
{
this.ExtraBytes = new AtrExtraBytesToken(AtrStream, AdditionalBytes);
}
}