demux.h

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/* DEMUX.H */

#ifndef _DEMUX_H_
#define _DEMUX_H_

#include "al_receiving.h"
#include "channel.h"
#include "mux.h"


typedef struct {
  char name[41];       /* A label like "Remote Demux" or "Local Demux" */

  /* Params shared with corresponding MUX */
  mux_parameters *params;

  /************************************************************************** 
   * DEMUX Specific Parameters                                              *
   **************************************************************************/

  al_receiving_entity *al_receivers[MAX_AL_RECEIVERS]; /* MUX-SDU's go here */

  int num_al_receivers;

  channel *input;

  int sync_delay;                           /* will be in sync after this number of bytes */
  int in_sync;

  byte sync_reg[8];                         /* sync bytes */
  byte THRESH;                              /* bits == standard sync bits */

  byte header_reg[8];                       /* header bytes. */
  int MC;                                   /* current multiplex code */
  int PM;                                   /* packet marker bit. */

  byte mpl_reg[8];                          /* mpl bytes */
  int MPL;

  int byte_count;                           /* byte count */
 
  int goodPackets;                          /* number of good header packets */
  int badPackets;                           /* number of bad header packets */
  int bad_mpls;                             /* number of bad mpls detected */
  int mpl_counter;                          /* number of bytes remaining until
                                               need to resume byte searching */
} demux;

/* Function Prototypes */

demux *new_demux(char *name);
/*
 * This mallocs and sets up a new demux structure
 */

void close_demux(demux *d);
/*
 * This prints out packet statistics for the demux
 */

static int correlation(byte a, byte b);
/*
 * returns the number of bits the same in a and b
 */

byte shift_in(demux *d, byte b);
/*
 * This moves data through the demux
 *   Shifts in new byte b.  Returns byte shifted out.
 */

void demultiplex(demux *d);
/*
 * This reads incoming data from the channel one byte
 *   at a time and acts appropriately
 */

#endif

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