bss::doc::pod3::bss(3)					       BSS library functions					    bss::doc::pod3::bss(3)

NAME

       bss - Bundle Streaming Service library

SYNOPSIS

	   #include "bss.h"

	   typedef int (*RTBHandler)(time_t time, unsigned long count, char *buffer, int bufLength);

	   [see description for available functions]

DESCRIPTION

       The BSS library supports the streaming of data over delay-tolerant networking (DTN) bundles.  The intent of the library is to enable
       applications that pass streaming data received in transmission time order (i.e., without time regressions) to an application-specific
       "display" function -- notionally for immediate real-time display -- but to store all received data (including out-of-order data) in a
       private database for playback under user control.  The reception and real-time display of in-order data is performed by a background
       thread, leaving the application's main (foreground) thread free to respond to user commands controlling playback or other application-
       specific functions.

       The application-specific "display" function invoked by the background thread must conform to the RTBHandler type definition.  It must
       return 0 on success, -1 on any error that should terminate the background thread.  Only on return from this function will the background
       thread proceed to acquire the next BSS payload.

       All data acquired by the BSS background thread is written to a BSS database comprising three files: table, list, and data.  The name of the
       database is the root name that is common to the three files, e.g., db3.tbl, db3.lst, db3.dat would be the three files making up the db3 BSS
       database.  All three files of the selected BSS database must reside in the same directory of the file system.

       Several replay navigation functions in the BSS library require that the application provide a navigation state structure of type bssNav as
       defined in the bss.h header file.  The application is not reponsible for populating this structure; it's strictly for the private use of
       the BSS library.

       int bssOpen(char *bssName, char *path, char *eid)
	   Opens access to a BSS database, to enable data playback.  bssName identifies the specific BSS database that is to be opened.  path
	   identifies the directory in which the database resides.  eid is ignored.  On any failure, returns -1.  On success, returns zero.

       int bssStart(char *bssName, char *path, char *eid, char *buffer, int bufLen, RTBHandler handler)
	   Starts a BSS data acquisition background thread.  bssName identifies the BSS database into which data will be acquired.  path
	   identifies the directory in which that database resides.  eid is used to open the BP endpoint at which the delivered BSS bundle payload
	   contents will be acquired.  buffer identifies a data acquisition buffer, which must be provided by the application, and bufLen
	   indicates the length of that buffer; received bundle payloads in excess of this length will be discarded.  handler identifies the
	   display function to which each in-order bundle payload will be passed.  On any failure, returns -1.	On success, returns zero.

       int bssRun(char *bssName, char *path, char *eid, char *buffer, int bufLen, RTBHandler handler)
	   A convenience function that performs both bssOpen() and bssStart().	On any failure, returns -1.  On success, returns zero.

       void bssClose()
	   Terminates data playback access to the most recently opened BSS database.

       void bssStop()
	   Terminates the most recently initiated BSS data acquisition background thread.

       void bssExit()
	   A convenience function that performs both bssClose() and bssStop().

       long bssRead(bssNav nav, char *data, int dataLen)
	   Copies the data at the current playback position in the database, as indicated by nav, into data; if the length of the data is in
	   excess of dataLen then an error condition is asserted (i.e., -1 is returned).  Note that bssRead() cannot be successfully called until
	   nav has been populated, nominally by a preceding call to bssSeek(), bssNext(), or bssPrev().  Returns the length of data read, or -1 on
	   any error.

       long bssSeek(bssNav *nav, time_t time, time_t *curTime, unsigned long *count)
	   Sets the current playback position in the database, in nav, to the data received in the bundle with the earliest creation time that was
	   greater than or equal to time.  Populates nav and also returns the creation time and bundle ID count of that bundle in curTime and
	   count.  Returns the length of data at this location, or -1 on any error.

       long bssSeek_read(bssNav *nav, time_t time, time_t *curTime, unsigned long *count, char *data, int dataLen)
	   A convenience function that performs bssSeek() followed by an immediate bssRead() to return the data at the new playback position.
	   Returns the length of data read, or -1 on any error.

       long bssNext(bssNav *nav, time_t *curTime, unsigned long *count)
	   Sets the playback position in the database, in nav, to the data received in the bundle with the earliest creation time and ID count
	   greater than that of the bundle at the current playback position.  Populates nav and also returns the creation time and bundle ID count
	   of that bundle in curTime and count.  Returns the length of data at this location (if any), -2 on reaching end of list, or -1 on any
	   error.

       long bssNext_read(bssNav *nav, time_t *curTime, unsigned long *count, char *data, int dataLen)
	   A convenience function that performs bssNext() followed by an immediate bssRead() to return the data at the new playback position.
	   Returns the length of data read, -2 on reaching end of list, or -1 on any error.

       long bssPrev(bssNav *nav, time_t *curTime, unsigned long *count)
	   Sets the playback position in the database, in nav, to the data received in the bundle with the latest creation time and ID count
	   earlier than that of the bundle at the current playback position.  Populates nav and also returns the creation time and bundle ID count
	   of that bundle in curTime and count.  Returns the length of data at this location (if any), -2 on reaching end of list, or -1 on any
	   error.

       long bssPrev_read(bssNav *nav, time_t *curTime, unsigned long *count, char *data, int dataLen)
	   A convenience function that performs bssPrev() followed by an immediate bssRead() to return the data at the new playback position.
	   Returns the length of data read, -2 on reaching end of list, or -1 on any error.

SEE ALSO

       bp(3)

perl v5.14.2							    2012-05-25						    bss::doc::pod3::bss(3)