Provided by: libbiblesync-dev_1.2.0-1_amd64 bug

NAME

       biblesync - multicast navigation synchronization in Bible programs

SYNOPSIS

       #include <biblesync.hh>

       typedef enum_BibleSync_mode {
           BSP_MODE_DISABLE,
           BSP_MODE_PERSONAL,
           BSP_MODE_SPEAKER,
           BSP_MODE_AUDIENCE,
           N_BSP_MODE
       } BibleSync_mode;

       typedef enum_BibleSync_xmit_status {
           BSP_XMIT_OK,
           BSP_XMIT_FAILED,
           BSP_XMIT_NO_SOCKET,
           BSP_XMIT_BAD_TYPE,
           BSP_XMIT_NO_AUDIENCE_XMIT,
           BSP_XMIT_RECEIVING,
           N_BSP_XMIT
       } BibleSync_xmit_status;

       #define BSP_ANNOUNCE   1
       #define BSP_SYNC       2
       #define BSP_BEACON     3

       typedef void (*BibleSync_navigate)(char cmd, string speakerkey,
                                          string bible, string ref, string alt,
                                          string group, string domain,
                                          string info,  string dump);

       Public interface:

       BibleSync *object = new BibleSync(string application,
                                         string version,
                                         string user);

       BibleSync_mode BibleSync::setMode(BibleSync_mode mode,
                                         BibleSync_navigate *nav_func,
                                         string passPhrase);
       BibleSync_mode BibleSync::getMode(void);
       string BibleSync::getVersion(void);
       string BibleSync::getPassphrase(void);
       BibleSync_xmit_status BibleSync::Transmit(string bible, string ref, string alt,
                                                 string group, string domain);
       static int BibleSync::Receive(void *object);
       bool BibleSync::setPrivate(bool privacy);
       void BibleSync::setBeaconCount(uint8_t count);
       void BibleSync::listenToSpeaker(bool listen, string speakerkey);

DESCRIPTION

       BibleSync  is  a  published  protocol  specification  by  which cooperating Bible programs
       navigate together.  It is implemented as a C++ class providing a  small,  clean  interface
       including  basic  setup,  take-down,  transmit,  polled  receive,  and  a bare few utility
       methods.

       The value of BibleSync is found in several examples:

       A single user may have multiple programs, or multiple computers/devices, all of  which  he
       wishes to follow along together.

       Similarly,  a  group  of  people  working  closely together, such as translators, can stay
       together as they work.

       In an instructional motif, BibleSync takes either the active or  passive  mode,  providing
       for a unidirectional navigation control.

BIBLESYNC ESSENTIALS

       BibleSync  communicates  using  local  multicast.   Three  operational modes are provided:
       Personal, Speaker, or Audience.

       In Personal mode, BibleSync operates as a peer among peers,  both  sending  and  receiving
       navigation  synchronization  on  the  shared  local  multicast  network.  Applications are
       expected to respond appropriately to navigation, and to  send  synchronization  events  of
       their own as the user moves about his Bible.

       In  Speaker  or  Audience mode, BibleSync either transmits only (Speaker) or receives only
       (Audience) navigation.  The Audience is  expected  to  follow  along  with  the  Speaker's
       direction.  The Speaker ignores incoming navigation; the Audience transmits no navigation.

       The  difference  between Personal and Speaker/Audience is thus strictly as to whether both
       sides of the conversation are active for each participant.

       On startup of the protocol, BibleSync transmits a presence announcement,  informing  other
       communication   partners   of  the  application's  participation.   BibleSync  makes  this
       announcement  available  to  the  application;  whether  the   application   shows   these
       announcements to the user is the application designer's choice.

       Thereafter,  as  appropriate  to  the  operational mode selected, BibleSync is tasked with
       polled reception of incoming navigation event packets and transmission of navigation event
       packets on the user's part.

       Transmitters  (Personal  and  Speaker  modes) issue availability beacons every 10 seconds.
       Received beacons for previously-unknown Speakers are handed up to the application.   These
       beacons  provide for receivers (Personal and Audience modes) to maintain a managed list of
       available Speakers.  Furthermore, when a transmitter ceases to issue beacons, its presence
       in  the  list  of  available  Speakers is aged out until being removed after 30 seconds of
       beacon silence.  The application is again informed when a Speaker goes dead.

       Default listening behavior is that the first  Speaker  heard  via  beacon  is  marked  for
       listening.   Other  transmitters claiming Speaker status via beacon are initially ignored,
       but their presence is made known to the application.  This provides for the application to
       maintain  a  list  from  which  the  user can select Speakers he wishes to synchronize his
       application.  It is useful for the application to provide  blanket  "listen  to  all"  and
       "listen  to  none"  functions,  as  well as per-Speaker selections, informing BibleSync of
       these choices.  In any case, this default "first Speaker only" policy can be overridden by
       the application with any other policy desired, through the use of listenToSpeaker() as the
       application designer requires.

       Synchronization events  include  5  data  elements:  The  Bible  abbreviation;  the  verse
       reference;  an  alternate  reference  (if  desired;  not  required)  which  may  allow the
       application to interpret better based on variant versification;  a  synchronization  group
       identifier; and the domain.

       The group identifier is a single digit between 1 and 9.  The specification is imprecise as
       to this parameter's use.  The initial implementation  of  BibleSync  in  Xiphos  uses  the
       synchronization  group as an indicator of the tab number in its tabbed interface: Not only
       is the Bible navigated, but the tab in which to navigate is selected.

       The domain parameter is currently fixed as "BIBLE-VERSE".  This will be put to greater use
       in future revisions of the protocol.

       BibleSync transmits no packet when the application leaves the conversation.

       Only  the  3  packet  types  BSP_ANNOUNCE,  BSP_SYNC,  and  BSP_BEACON  are defined in the
       protocol.

PUBLIC INTERFACE

   Object creation
       The application must create a single BibleSync object, identifying the application's name,
       its version, and the user.

   setMode
       setMode  identifies  how BibleSync should behave. The application must provide as well the
       navigation callback function by which BibleSync will inform the  application  of  incoming
       events;  the  callback  makes  all  the  navigation  parameters  provided in event packets
       available to the application.   setMode  returns  the  resulting  mode.   The  application
       provides  the  passphrase to be used as well; this argument defaults to "" (empty string),
       indicating that the existing passphrase should be left in place.

   getMode
       The application may request the current mode.

   getVersion
       The version string of the library itself is returned.

   getPassphrase
       Intended for use when preparing to enter any active mode, the application may request  the
       current passphrase, so as to provide a default.

   Transmit
       The  protocol  requires  all  the indicated parameters, but all have defaults in Transmit:
       KJV, Gen.1.1, empty alternate, 1, and BIBLE-VERSE.

   Receive
       This is a static method accessible from either C or C++.   It  must  be  called  with  the
       object  pointer  so  as  to  re-enter  object  context  for the private internal receiver.
       Receive() must be called regularly (i.e. polled) as long as it continues to  return  TRUE.
       When  it  returns  FALSE,  it means that the mode has changed to BSP_MODE_DISABLE, and the
       scheduled polling should stop.  See also the note below on polled reception.

   setPrivate
       In the circumstance where the user has multiple programs running on a single computer  and
       does  not want his navigation broadcast outside that single system, when in Personal mode,
       the application may also request privacy.  The effect is to set  multicast  TTL  to  zero,
       meaning that packets will not go out on the wire.

   setBeaconCount
       Beacon  transmission  occurs  during every Nth call to Receive(); the default value is 10.
       This presumes the application will call Receive() once per second. If the application will
       call  Receive()  less frequently, divide that time (say, 2 seconds) into 10 to get a value
       (5) to use with this call. Use setBeaconCount() prior  to  enabling  Personal  or  Speaker
       mode.

   listenToSpeaker
       Aside  from  default  listen behavior detailed above, the application specifically asks to
       listen or not to listen  to  specific  Speakers.   The  key  is  as  provided  during  the
       notification of a new Speaker.

RECEIVE USE CASES

       There  are  6  values  for  the  cmd  parameter  of  the nav_func.  In all cases, the dump
       parameter provides the raw content of an arriving packet.

   'A'
       Announce.  A general presence message is in alt, and  the  individual  elements  are  also
       available,  as overloaded use of the parameters: bible contains the user; ref contains the
       IP address; group contains the application name  and  version;  and  domain  contains  the
       device identification.

   'N'
       Navigation.   The  bible,  ref,  alt,  group,  and domain parameters are presented as they
       arrived.  info and dump are also available.

   'S'
       Speaker's initial recognition from beacon receipt.  Overloaded parameters are available as
       for presence announcements.

   'D'
       Dead  Speaker.  speakerkey holds the UUID key of a previously-identified application which
       is no longer a candidate for listening.

   'M'
       Mismatch.  The incoming event packet is mismatched, either against the current  passphrase
       or  for  a  navigation synchronization packet when BibleSync is in Speaker mode.  The info
       parameter begins with either "announce" or "sync", plus the user and IP address from  whom
       the  packet  came.   As  well,  in  the sync case, the regular bible, ref, alt, group, and
       domain parameters are available.  In the announce case, the presence message  is  in  alt,
       with overloaded individual parameters as previously described.

   'E'
       Error.   This  indicates network errors and malformed packets.  The application's nav_func
       is provided only the info and dump parameters.

NOTES

   Polled reception
       The application must provide a means by which to poll regularly for incoming packets.   In
       Xiphos,  which  is  built  on  GTK  and  GLib, this is readily provided by mechanisms like
       g_timeout_add(), which sets a regular interval call of the indicated function.  GLib  will
       re-schedule  the call as long as the called function returns TRUE.  When it returns FALSE,
       GLib un-schedules  the  call.   Receive()  adheres  to  this  straightforward  convention.
       Therefore,  it  is  imperative  that every time the application moves from disabled to any
       non-disabled mode, Receive is again scheduled for polled use.

       A 1-second poll interval is expected.  Brief experience during development has shown  that
       longer intervals lead to a perception of lag.

       During every Receive() call, all waiting packets are processed.

   No datalink security
       BibleSync  is a protocol defined for a friendly environment.  It offers no security in its
       current specification, and any packet sniffer such as wireshark(1) or tcpdump(8)  can  see
       the  entire conversation.  The specification makes passing reference to future encryption,
       but at this time none is implemented.

   Managed Speaker lists
       The addition of transmitter beacons was a result of initial experience showing that it can
       be  too  easy  for  a  user  to  mis-start BibleSync, or for a malicious user to interject
       himself into serious work.  The goal of beacons is to provide a means by which, on the one
       hand,  the  user  can be made aware of who is attempting to be a Speaker and, on the other
       hand, confine the set of Speakers whom  the  user  will  permit  to  make  synchronization
       changes in the application.  The simplest use of 'S' new Speaker notification events is to
       respond with listenToSpeaker(true, speakerkey) which in effect makes BibleSync  behave  as
       though there are no beacons.  More serious use of 'S'/'D' is for the application to manage
       its own sense of available Speakers, providing a means by which the user can make sensible
       selections about how to react to each Speaker's presence.  BibleSync can be told to listen
       to legitimate Speakers, and to ignore interlopers, whether intended maliciously or  merely
       due to other users' inadvertent behavior.

   Sending verse lists
       One of the better uses of BibleSync is in sharing verse lists.  Consider a relatively weak
       application, perhaps on a mobile device,  and  a  desktop-based  application  with  strong
       search  capability.  Run searches on the desktop, and send the result via BibleSync to the
       mobile app.  The ref parameter is not confined to a single reference.  In normal  citation
       syntax, the verse reference may consist of semicolon-separated references, comma-separated
       verses, and hyphen-separated ranges.  Be aware that the  specification  has  a  relatively
       short limit on packet size, so that at most a few dozen references will be sent.

   Standard reference syntax
       It  is  the  responsibility  of the application to transmit references in standard format.
       BibleSync neither validates nor converts the application's incoming bible,  ref,  and  alt
       parameters.  The specification references the BibleRef and OSIS specifications.

SEE ALSO

       http://biblesyncprotocol.wikispaces.com   (user  "General_Public",  password  "password"),
       http://semanticbible.com/bibleref/bibleref-specification.html,  socket(2),  setsockopt(2),
       select(2),  recvfrom(2),  sendto(2),  and ip(7), especially sections on IP_ADD_MEMBERSHIP,
       IP_MULTICAST_IF, IP_MULTICAST_LOOP, and IP_MULTICAST_TTL.