muxstuff.h

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/* MUXSTUFF.H */

#ifndef _MUXSTUFF_H_
#define _MUXSTUFF_H_

#include "mux.h"


/* Function Prototypes */

static int twotothe(int n);
/* 
 * returns 2 to the n
 */

int **make_mt_bytes(mux_table_entry *mt,
                    int mt_size,
                    int num_channels,
                    int info_bytes);
/*
 * Fills in a structure that indicates how many bytes are used
 *   for a particlar mux code given a payload length 
 */

float **make_mt_ratios(int **mt_bytes,
                       int mt_size,
                       int num_channels,
                       int info_bytes);
/*
 * Does the same as above, but for a ratio structure
 */

mux_parameters *new_mux_parameters(char *name);
/*
 * A function to query the parameters shared between a multiplexer and
 *   the corresponding demultiplexer.
 */


byte *construct_header(int mc, int pm, bch_type code, int level);
/*
 * Constructs the header.
 * NOTE: CRC is always 3 bits.
 * MC is always 4 bits.
 * pm should be either 1 or 0, nothing else.
 *
 * Bit fields look like this:
 *
 */

byte *construct_header_level2(int mc, int pm, int mpl);
/*
 * constructs concatenated header with mc, pm and mpl protected
 * by golay code
 *
 */

int deconstruct_header(byte *header,int *mc,int *pm,bch_type code,int level);
/*
 * Deconstructs the header, check crc for level 1.
 *   returns 1 if crc checks valid, 0 if not
 *
 */

void deconstruct_header_level2(byte *header,int *mc,int *pm,int *mpl);
/* 
 * deconstructs the level 2 header, described above in construct_header
 * sets mc, pm and mpl to received value
 */

byte *construct_mpl(int mpl, bch_type code);
/*
 * Creates an mpl field
 */

int deconstruct_mpl(byte *mplf, int *mpl, bch_type code);
/*
 * returns status of detection (0 if errors detected, 1 if not)
 *   at this point, only will return 1 because using for correction
 */

void swapbits(bytes *b, int a1, int a2);
/*
 * Swaps two bits.
 */

void swapbytes(bytes *b, int a1, int a2);
/*
 * Swaps bytes at a1 and a2 of (b).
 */

void interleave_header(bytes *mux_pdu, int sync_bytes, int header_bytes, int mode);
/*
 * Performs interleaving of the header throughout the area taken up by
 *   the header and the information field of the MUX-PDU.
 *
 * Swaps bits or bytes around since that is the simplest way of doing it.
 */

int mux_byte_source(mux_table_entry *mte, int x); 
/*
 * Returns the channel that octet x of the information field of a packet
 *   multiplexed with mux table entry *(mte) should come from or should
 *   return to.
 */


#endif

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