text: #ifndef _DCCP_LI_HIST_
  #define _DCCP_LI_HIST_
  /*
   *  Copyright (c) 2007   The University of Aberdeen, Scotland, UK
   *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
   *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
   *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
   *
   *  This program is free software; you can redistribute it and/or modify it
   *  under the terms of the GNU General Public License as published by the Free
   *  Software Foundation; either version 2 of the License, or (at your option)
   *  any later version.
   */
  #include <linux/ktime.h>
  #include <linux/list.h>
  #include <linux/slab.h>
  
  /*
   * Number of loss intervals (RFC 4342, 8.6.1). The history size is one more than
   * NINTERVAL, since the `open' interval I_0 is always stored as the first entry.
   */
  #define NINTERVAL	8
  #define LIH_SIZE	(NINTERVAL + 1)
  
  /**
   *  tfrc_loss_interval  -  Loss history record for TFRC-based protocols
   *  @li_seqno:		Highest received seqno before the start of loss
   *  @li_ccval:		The CCVal belonging to @li_seqno
   *  @li_is_closed:	Whether @li_seqno is older than 1 RTT
   *  @li_length:		Loss interval sequence length
   */
  struct tfrc_loss_interval {
  	u64		 li_seqno:48,
  			 li_ccval:4,
  			 li_is_closed:1;
  	u32		 li_length;
  };
  
  /**
   *  tfrc_loss_hist  -  Loss record database
   *  @ring:	Circular queue managed in LIFO manner
   *  @counter:	Current count of entries (can be more than %LIH_SIZE)
   *  @i_mean:	Current Average Loss Interval [RFC 3448, 5.4]
   */
  struct tfrc_loss_hist {
  	struct tfrc_loss_interval	*ring[LIH_SIZE];
  	u8				counter;
  	u32				i_mean;
  };
  
  static inline void tfrc_lh_init(struct tfrc_loss_hist *lh)
  {
  	memset(lh, 0, sizeof(struct tfrc_loss_hist));
  }
  
  static inline u8 tfrc_lh_is_initialised(struct tfrc_loss_hist *lh)
  {
  	return lh->counter > 0;
  }
  
  static inline u8 tfrc_lh_length(struct tfrc_loss_hist *lh)
  {
  	return min(lh->counter, (u8)LIH_SIZE);
  }
  
  struct tfrc_rx_hist;
  
  extern int  tfrc_lh_interval_add(struct tfrc_loss_hist *, struct tfrc_rx_hist *,
  				 u32 (*first_li)(struct sock *), struct sock *);
  extern u8   tfrc_lh_update_i_mean(struct tfrc_loss_hist *lh, struct sk_buff *);
  extern void tfrc_lh_cleanup(struct tfrc_loss_hist *lh);
  
  #endif /* _DCCP_LI_HIST_ */
  