syn.h

linux环境下用纯c写的RTP协议的通用开发库

/*-------------------------------------------------------------------------
 * syn.h - tseq, tsgt, tslt, tsmax, tsmin
 *-------------------------------------------------------------------------
 */

#ifndef SYN_H
#define SYN_H

#include <rtp.h>
#include <pthread.h>
#include <semaphore.h>
#include <hash.h>
#include <time.h>

/* Macros to compare timestamps */
#define SYN_TSWINDOW (1 << ((sizeof(mediatime_t) * 8) - 1))
#define tseq(x, y) (x == y)
#define tsgt(x, y) (x > y ? (x - y < SYN_TSWINDOW ? TRUE : FALSE) : (y - x < SYN_TSWINDOW ? FALSE : TRUE))
#define tslt(x, y) (tsgt(y, x))
#define tsmax(x, y) (tsgt(x, y) ? x : y)
#define tsmin(x, y) (tslt(x, y) ? x : y)

/* Read constants */
#define SYN_CONTINUE                1
#define SYN_NODATA		   -2
#define SYN_BUFFERING		   -3

#define SYN_READ_FLUSH		    0x1	/* Skip stale data */
#define SYN_READ_BLOCK		    0x2

/* Constants for synsynchronize */
#define SYN_EXTERNALAHEAD          -2
#define SYN_NOTADJUSTED             1
#define SYN_ADJUSTED                2

/* Commands for synctl */
#define SYN_CTL_GETRTPSESSION       1
#define SYN_CTL_ADDSYNCFD           2
#define SYN_CTL_REMSYNCFD           3
#define SYN_CTL_STREAM_SETREADFLAGS 4
#define SYN_CTL_STREAM_GETREADFLAGS 5
#define SYN_CTL_STREAM_ISBUFFERING  6
#define SYN_CTL_STREAM_GETCLKRT     7
#define SYN_CTL_STREAM_GETTYPE      8
#define SYN_CTL_STREAM_GETLASTREAD  9
#define SYN_CTL_STREAM_GETPARAM     10
#define SYN_CTL_STREAM_GETLEEWAY    11	/* microsec */
#define SYN_CTL_STREAM_SETLEEWAY    12	/* microsec */
#define SYN_CTL_STREAM_GETJITTHRESH 13
#define SYN_CTL_STREAM_SETJITTHRESH 14
#define SYN_CTL_STREAM_GETBUFSPAN   15

/* Constants for synsession */
#define SYN_SSRCHTSZ		    11
#define SYN_DFLTEVENTBUFSZ	    1024
#define SYN_DFLTEVENTBUFCNT	    32
#define SYN_DEFAULT_LEEWAY	    10000 /* microsec */
#define SYN_FDCNT		    10
#define SYN_BADFD                  -1

struct synsession {
  pthread_mutex_t       ssn_mutex;
  pthread_cond_t        ssn_cond;
  struct ht		*ssn_ssrcs;	/* hashtable ssrc -> synstream **/
  struct eventqueue	ssn_events; /* event queue for internal use	*/
  struct session	*ssn_session;	/* associated RTP layer session	*/

  pthread_t		ssn_eventthr;	/* thread to run event loop	*/
  int                   ssn_eventthrstat;
  pthread_mutex_t       ssn_eventthrmutex;

  pthread_t             ssn_recvthr;
  int                   ssn_recvthrstat;
  pthread_mutex_t       ssn_recvthrmutex;

  pthread_mutex_t	ssn_getstreammutex;
  int			ssn_syncfds[SYN_FDCNT];/* FDs to other synch sessions	*/
};

/* Stream types */
#define SYN_STREAMTYPE_PACKET	0
#define SYN_STREAMTYPE_SAMPLE	1
#define SYN_STREAMTYPE_FRAME	2

/* structure to hold state for receive stream */
struct synstream {
  int			sstm_type;	/* type of stream (e.g. sample)	*/
  ssrc_t		sstm_ssrc;	/* stream's synchronization src */  
  int			sstm_readflags;	/* stream's readflags		*/
  bool			sstm_buffering;	/* stream is still buffering	*/
  bool			sstm_zombie;	/* marked for removal if true	*/
  int			sstm_clkrt;	/* stream's clock rate		*/
  int			sstm_refcnt;	/* to prevent bad pointers	*/
  pthread_cond_t	sstm_readcond;	/* cond var for blocking read	*/
  pthread_mutex_t	sstm_readmutex;	/* mutex associated with above	*/
  mediatime_t		sstm_lastread;	/* timestamp of last data read	*/
  struct timespec	sstm_clkx;	/* local time stamp		*/
  mediatime_t		sstm_clky;	/* equivelant media time stamp	*/
  mediatime_t		sstm_leeway;	/* how early data can be retn'd	*/
  struct timespec	sstm_leewayts;	/* leeway in timespec format	*/
  mediatime_t           sstm_jitthresh; /* jitter buffer (media ticks)  */
  void *		sstm_parameters;/* type-dependant parameters	*/
};
  
/* structure for passing synsynchto args between processes */
struct synsyncargs {
  char			sa_cname[256];
  struct timespec	sa_ntp;
  struct timespec	sa_localtime;
};

/* API Calls */  
struct synsession *synopen(struct in_addr, int, int, int);
int synclose(struct synsession *);
int synstreamon(struct synsession *, ssrc_t, int, int, mediatime_t, void *);
int synstreamoff(struct synsession *, ssrc_t);
int synrebuffer(struct synsession *, ssrc_t);
int synctl(struct synsession *, int, char *, ssrc_t);
int synsources(struct synsession *, ssrc_t *, int);
int synread(struct synsession *, ssrc_t, struct timespec *, mediatime_t *, char *, int, void *);

/* Internal functions */
int synbufspan(struct synsession *, struct synstream *, mediatime_t *, mediatime_t *);
struct synstream *syngetstream(struct synsession *, ssrc_t);
int synreleasestream(struct synsession *, struct synstream *);
void syneventloop(struct synsession *);
int synprocessevent(struct synsession *, struct event *, int);
void synstreamdestroy(struct synstream *);
int synnewdata(struct synsession *, ssrc_t);
int synreadnextpacket(struct synsession *, struct synstream *, struct rtpln **);
int synreadwait(struct synsession *, struct synstream *, struct rtpln *, mediatime_t, struct timespec, mediatime_t, struct timespec *);

/* synchronization functions */
void synsyncrecvthr(struct synsession *);
int synsyncrecv(struct synsession *, int);
int synsynchronize(struct synsession *, char *);
int synsyncto(struct synsession *, struct cnamelist *, struct timespec *, struct timespec *);
#endif