/* cfile.c
 * capture_file GUI-independent manipulation
 * Vassilii Khachaturov <vassilii@tarunz.org>
 *
 * $Id$
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <glib.h>

#include <epan/packet.h>

#include "cfile.h"

void
cap_file_init(capture_file *cf)
{
  /* Initialize the capture file struct */
  cf->plist_start    = NULL;
  cf->plist_end      = NULL;
  cf->wth            = NULL;
  cf->filename       = NULL;
  cf->source         = NULL;
  cf->user_saved     = FALSE;
  cf->is_tempfile    = FALSE;
  cf->rfcode         = NULL;
  cf->dfilter        = NULL;
  cf->has_snap       = FALSE;
  cf->snap           = WTAP_MAX_PACKET_SIZE;
  cf->count          = 0;
  cf->last_found_num = 0;
  cf->last_found_fd  = NULL;
  cf->redissecting   = FALSE;
}

void
cap_file_add_fdata(capture_file *cf, frame_data *fdata)
{
  frame_data *plist_end = cf->plist_end;
  fdata->prev = plist_end;
  if (plist_end != NULL)
    plist_end->next = fdata;
  else
    cf->plist_start = fdata;
  cf->plist_end = fdata;
}

/*
 * Find the frame_data for the specified frame number.
 * Do some caching to make this work reasonably fast for
 * forward and backward sequential passes through the packets.
 */
frame_data *
cap_file_find_fdata(capture_file *cf, guint32 num)
{
  frame_data *fdata;

  if (num == 0) {
    /* There is no frame number 0 */
    return NULL;
  }

  /*
   * Did we remember a frame number from a sequential pass through
   * the frames?
   */
  if (cf->last_found_num != 0) {
    /*
     * Yes.  Is this that frame?
     */
    if (num == cf->last_found_num) {
      /* Yes - return it. */
      return cf->last_found_fd;
    }

    /*
     * No.  Is it the frame just after that frame?
     */
    if (num == cf->last_found_num + 1) {
      /*
       * Yes - if there is such a frame, remember it and return it.
       */
      fdata = cf->last_found_fd->next;
      if (fdata != NULL) {
        cf->last_found_num = num;
        cf->last_found_fd = fdata;
      }
      return fdata;	/* could be null, if there is no such frame */
    }

    /*
     * No.  Is it the frame just before that frame?
     */
    if (num == cf->last_found_num - 1) {
      /*
       * Yes - if there is such a frame, remember it and return it.
       */
      fdata = cf->last_found_fd->prev;
      if (fdata != NULL) {
        cf->last_found_num = num;
        cf->last_found_fd = fdata;
      }
      return fdata;	/* could be null, if there is no such frame */
    }
  }

  for (fdata = cf->plist_start; fdata != NULL && fdata->num < num;
       fdata = fdata->next)
    ;
  if (fdata != NULL) {
    cf->last_found_num = num;
    cf->last_found_fd = fdata;
  }
  return fdata;
}