=head1 NAME

Chipcard::PCSC - Smart card reader interface library

=head1 SYNOPSIS

 my $hContext = new Chipcard::PCSC();

 @ReadersList = $hContext->ListReaders ();

 $hContext->GetStatusChange(\@readers_states, $timeout);

 $apdu = Chipcard::PCSC::array_to_ascii(@apdu);

 @apdu = Chipcard::PCSC::ascii_to_array($apdu);

 $hContext = undef;

=head1 DESCRIPTION

The PCSC module implements the Chipcard::PCSC class. Objects of this
class are used to communicate with the PCSC-lite daemon (see F<pcscd(1)>
for more information).

PC/SC represents an abstraction layer to smart card readers. It provides
a communication layer with a wide variety of smart card readers through
a standardized API.

A PCSC object can be used to communicate with more than one reader
through Chipcard::PCSC::Card objects. Please read
L<Chipcard::PCSC::Card> for extended information on how to talk to a
smart card reader.

A PCSC object uses the following property:
C<$pcsc_object-E<gt>{hContext}> the context returned by the pcsc library

=head1 CONSTRUCTORS

The following methods can be used to construct a PCSC object:

=over 4

=item *
 B<$hContext = new Chipcard::PCSC($scope, $remote_host);>

=over 4

=item *

C<$scope> is the scope of the connection to the PC/SC daemon. It can be
any of the following:

 $Chipcard::PCSC::SCARD_SCOPE_USER     (not used by PCSClite);
 $Chipcard::PCSC::SCARD_SCOPE_TERMINAL (not used by PCSClite);
 $Chipcard::PCSC::SCARD_SCOPE_SYSTEM   Services on the local machine;
 $Chipcard::PCSC::SCARD_SCOPE_GLOBAL   Services on a remote host.

=item *

C<$remote_host> is the host name of the remote machine to contact. It is
only used when C<$scope> is equal to
C<$Chipcard::PCSC::SCARD_SCOPE_GLOBAL>. A null value means F<localhost>.

=back

=item *
 B<$hContext = new Chipcard::PCSC($scope);>

This method is equivalent to:

 $hContext = new Chipcard::PCSC($scope, 0);

=item *
 B<$hContext = new Chipcard::PCSC();>

This method is equivalent to:

 $hContext = new Chipcard::PCSC($Chipcard::PCSC::SCARD_SCOPE_SYSTEM, 0);

=back

=head1 CONSTRUCTION FAILURE

Chipcard::PCSC constructors return an C<undef> value when the object can
not be created. C<$Chipcard::PCSC::errno> can be used to get more
information about the error.  (See section L<ERROR HANDLING> below for
more information)

=head1 Chipcard::PCSC METHODS

Here is a list of all the methods that can be used with a PCSC object.

=over 4

=item *
 B<hContext-E<gt>ListReaders( $group );>

This method returns the available readers in the given C<$group>. If
omitted, C<$group> defaults to a null value meaning "all groups". Please
note that as of this writing, C<$group> can safely be omitted as it is
not used by PCSClite.

The return value upon successful completion is an array of strings: one
string by available reader. If an error occurred, the undef value is
returned and C<$Chipcard::PCSC::errno> should be used to get more
information about the error.  (See section L<ERROR HANDLING> below for
more information). The following example describes the use of
L<ListReaders>:

 $hContext = new Chipcard::PCSC();
 die ("Can't create the PCSC object: $Chipcard::PCSC::errno\n")
 	unless (defined $hContext);

 @ReadersList = $hContext->ListReaders ();
 die ("Can't get readers' list: $Chipcard::PCSC::errno\n")
 	unless (defined($ReadersList[0]));

 $, = "\n  ";
 print @ReadersList . "\n";

=item *
 B<$hContext-E<gt>GetStatusChange(\@readers_states, $timeout);>

The method C<$hContext-E<gt>GetStatusChange(\@readers_states, $timeout)>
uses a reference to a list of hashes. 

 # create the list or readers to watch
 map { push @readers_states, ({'reader_name'=>"$_"}) } @ReadersList;

 @StatusResult = $hContext->GetStatusChange(\@readers_states);

The keys of the hash are: 'reader_name', 'current_state', 'event_state'
and 'ATR'.

To detect a status change you have to first get the status and then copy
the 'event_state' in the 'current_state'. The method will return when
both states are different or a timeout occurs.

 @StatusResult = $hContext->GetStatusChange(\@readers_states);
 foreach $reader (@readers_states)
 {
   $reader->{current_state} = $reader->{event_state};
 }
 @StatusResult = $hContext->GetStatusChange(\@readers_states);

=item *
 B<$hContext-E<gt>GetStatusChange(\@readers_states);>

This method is equivalent to:

 $hContext->GetStatusChange(\@readers_states, 0xFFFFFFFF);

The timeout is set to infinite.

=item *
 B<$apdu_ref = Chipcard::PCSC::ascii_to_array($apdu);>

The method C<Chipcard::PCSC::Card::Transmit()> uses references to arrays
as in and out parameters. The C<Chipcard::PCSC::ascii_to_array()> is used
to transform an APDU in ASCII format to a reference to an array in the
good format.

Example:

 $SendData = Chipcard::PCSC::ascii_to_array("00 A4 01 00 02 01 00");

=item *
 B<$apdu = Chipcard::PCSC::array_to_ascii($apdu_ref);>

This method is used to convert the result of a
C<Chipcard::PCSC::Card::Transmit()> into ASCII format.

Example:

 $RecvData = $hCard->Transmit($SendData);
 print Chipcard::PCSC::array_to_ascii($RecvData);

=back

=head1 ERROR HANDLING

All functions from PCSC objects save the return value in a global
variable called C<$Chipcard::PCSC::errno>. This variable therefore holds
the latest status of PCSC.

It is a double-typed magical variable that behaves just like C<$!>. This
means that it both holds a numerical value describing the error and the
corresponding string.  The numerical value may change from a system to
another as it depends on the PCSC library...

Here is a small example of how to use it:

 $hContext = new Chipcard::PCSC();
 die ("Can't create the PCSC object: $Chipcard::PCSC::errno\n")
     unless (defined $hContext);

In case the last call was successful, C<$Chipcard::PCSC::errno> contains
the C<SCARD_S_SUCCESS> status. Here is a list of all possible error
codes.  They are defined as read-only variables with in the PCSC module:

 $Chipcard::PCSC::SCARD_S_SUCCESS
 $Chipcard::PCSC::SCARD_E_CANCELLED
 $Chipcard::PCSC::SCARD_E_CANT_DISPOSE
 $Chipcard::PCSC::SCARD_E_CARD_UNSUPPORTED
 $Chipcard::PCSC::SCARD_E_DUPLICATE_READER
 $Chipcard::PCSC::SCARD_E_INSUFFICIENT_BUFFER
 $Chipcard::PCSC::SCARD_E_INVALID_ATR
 $Chipcard::PCSC::SCARD_E_INVALID_HANDLE
 $Chipcard::PCSC::SCARD_E_INVALID_PARAMETER
 $Chipcard::PCSC::SCARD_E_INVALID_TARGET
 $Chipcard::PCSC::SCARD_E_INVALID_VALUE
 $Chipcard::PCSC::SCARD_E_NO_MEMORY
 $Chipcard::PCSC::SCARD_E_NO_SERVICE
 $Chipcard::PCSC::SCARD_E_NO_SMARTCARD
 $Chipcard::PCSC::SCARD_E_NOT_READY
 $Chipcard::PCSC::SCARD_E_NOT_TRANSACTED
 $Chipcard::PCSC::SCARD_E_PCI_TOO_SMALL
 $Chipcard::PCSC::SCARD_E_PROTO_MISMATCH
 $Chipcard::PCSC::SCARD_E_READER_UNAVAILABLE
 $Chipcard::PCSC::SCARD_E_READER_UNSUPPORTED
 $Chipcard::PCSC::SCARD_E_SERVICE_STOPPED
 $Chipcard::PCSC::SCARD_E_SHARING_VIOLATION
 $Chipcard::PCSC::SCARD_E_SYSTEM_CANCELLED
 $Chipcard::PCSC::SCARD_E_TIMEOUT
 $Chipcard::PCSC::SCARD_E_UNKNOWN_CARD
 $Chipcard::PCSC::SCARD_E_UNKNOWN_READER
 $Chipcard::PCSC::SCARD_E_UNSUPPORTED_FEATURE

 $Chipcard::PCSC::SCARD_W_REMOVED_CARD
 $Chipcard::PCSC::SCARD_W_RESET_CARD
 $Chipcard::PCSC::SCARD_W_UNPOWERED_CARD
 $Chipcard::PCSC::SCARD_W_UNRESPONSIVE_CARD
 $Chipcard::PCSC::SCARD_W_UNSUPPORTED_CARD

PCSClite users will also be able to use the following (PCSClite
specific) codes:

 $Chipcard::PCSC::SCARD_INSERTED
 $Chipcard::PCSC::SCARD_REMOVED
 $Chipcard::PCSC::SCARD_RESET
 $Chipcard::PCSC::SCARD_SCOPE_GLOBAL

In addition, the wrapper defines:

 $Chipcard::PCSC::SCARD_P_ALREADY_CONNECTED
 $Chipcard::PCSC::SCARD_P_NOT_CONNECTED

=head1 SEE ALSO

F<pcscd(1)> manpage has useful information about PC/SC lite.
L<Chipcard::PCSC::Card> manpage gives information about how to
communicate with a reader and the smart card inside it.

=head1 COPYRIGHT

(C) Lionel VICTOR & Ludovic ROUSSEAU, 2001-2004, GNU GPL
(C) Ludovic ROUSSEAU, 2005-2008, GNU GPL

=head1 AUTHORS / ACKNOWLEDGEMENT

 Lionel VICTOR <lionel.victor@unforgettable.com>
               <lionel.victor@free.fr>

 Ludovic ROUSSEAU <ludovic.rousseau@free.fr>

=cut