ack.h

This a framework to test new ideas in transmission technology. Actual development is a LDPC-coder in

#ifndef ACK_H__
#define ACK_H__

#define MAX_ACK 256
#define IP_BUF_LEN 0x10000

struct ack {
  // The position in the ring-buffer
  int pos;
  // The length in bytes
  int len;
  // Where to find the next ack
  int next;
  // Age in number of slots passed, if < 0, this ack is unused
  int age;
};


/**
 * @short initialise an acknowledge
 *
 * The first element of an acknowledge-array is used to do
 * some housekeeping. The len is the actual length, pos
 * is the next free ack and next is the next filled ack.
 *
 * @param a_ret where to store everything
 */
void ack_init( struct ack **a_ret );


/**
 * @short clean up an ack-list
 */
void ack_free( struct ack **a_ret );


/**
 * @short gets a free place
 *
 * Tries to find a free acknowledgement
 *
 * @return -1 for error else the index of the free place
 */
int ack_get_free( struct ack *a );


/**
 * @short insert a sorted acknowledge 
 *
 * Tries to insert an ack in the list in a sorted way.
 * The smallest elements come in first.
 */
int ack_ins_sorted( struct ack *a, int pos, int len );


/**
 * @short appends the ack to the end of the list
 */
int ack_append( struct ack *a, int pos, int len );


/**
 * @short join blocks
 *
 * This function first joins all loose blocks and then returns
 * the first ack
 *
 * @param a the ack-list
 * @return the first ack
 */
struct ack *ack_join_blocks( struct ack *a );


/*
 * @short cuts the first n bytes from the ack-list
 *
 * This is supposed to work on the rx-side of the RF, to
 * get one IP-packet. If the n-bytes correspond to exactly
 * the first packet, so it's size is only set to zero, w/o
 * removing it.
 *
 * @param a the ack-list
 * @param len the length of the packet to remove
 * @return index of where the first packet started, -1 on error
 */
int ack_cut_begin( struct ack *a, int len );


/**
 * @short delete the ack pos
 *
 * Searches for the ack with pos and deletes it
 *
 * @param a the ack-list
 * @param pos the position
 * @return 0 OK, -1 not found
 */
int ack_delete( struct ack *a, int pos );


/**
 * @short gets the first ack and deletes it
 * 
 * @param a the ack-list
 * @return the ack or NULL for error
 */
struct ack *ack_get_first( struct ack *a );


/**
 * @short returns the first ack
 * 
 * @param a the ack-list
 * @return the ack or NULL for error
 */
struct ack *ack_read_first( struct ack *a );


/**
 * @short make the acks older
 *
 * @param a the ack-list
 */
void ack_make_older( struct ack *a );


/**
 * @short returns an old ack
 *
 * Given an age, it returns the first ack found that has at
 * least this age, deletes it and returns a pointer.
 * If all acks are younger than the given age, NULL is returned.
 *
 * Care should be taken as the returned pointer may be re-used
 * on subsequent calls to ack_*.
 *
 * @param a the ack-list
 * @param age the maximal age
 * @return a pointer to an ack having at least this age or NULL
 */
struct ack *ack_delete_old( struct ack *a, int age );


#endif