text: /*
   * This file is part of the Nice GLib ICE library.
   *
   * (C) 2006-2009 Collabora Ltd.
   *  Contact: Youness Alaoui
   * (C) 2006-2009 Nokia Corporation. All rights reserved.
   *  Contact: Kai Vehmanen
   *
   * The contents of this file are subject to the Mozilla Public License Version
   * 1.1 (the "License"); you may not use this file except in compliance with
   * the License. You may obtain a copy of the License at
   * http://www.mozilla.org/MPL/
   *
   * Software distributed under the License is distributed on an "AS IS" basis,
   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
   * for the specific language governing rights and limitations under the
   * License.
   *
   * The Original Code is the Nice GLib ICE library.
   *
   * The Initial Developers of the Original Code are Collabora Ltd and Nokia
   * Corporation. All Rights Reserved.
   *
   * Contributors:
   *   Dafydd Harries, Collabora Ltd.
   *   Youness Alaoui, Collabora Ltd.
   *   Kai Vehmanen, Nokia
   *
   * Alternatively, the contents of this file may be used under the terms of the
   * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
   * case the provisions of LGPL are applicable instead of those above. If you
   * wish to allow use of your version of this file only under the terms of the
   * LGPL and not to allow others to use your version of this file under the
   * MPL, indicate your decision by deleting the provisions above and replace
   * them with the notice and other provisions required by the LGPL. If you do
   * not delete the provisions above, a recipient may use your version of this
   * file under either the MPL or the LGPL.
   */
  
  /*
   * @file candidate.c
   * @brief ICE candidate functions
   */
  
  #ifdef HAVE_CONFIG_H
  # include <config.h>
  #else
  #define NICEAPI_EXPORT
  #endif
  
  #include <string.h>
  
  #include "agent.h"
  #include "component.h"
  
  /* (ICE 4.1.1 "Gathering Candidates") ""Every candidate is a transport
   * address. It also has a type and a base. Three types are defined and 
   * gathered by this specification - host candidates, server reflexive 
   * candidates, and relayed candidates."" (ID-19) */
  
  NICEAPI_EXPORT NiceCandidate *
  nice_candidate_new (NiceCandidateType type)
  {
    NiceCandidate *candidate;
  
    candidate = g_slice_new0 (NiceCandidate);
    candidate->type = type;
    return candidate;
  }
  
  
  NICEAPI_EXPORT void
  nice_candidate_free (NiceCandidate *candidate)
  {
    /* better way of checking if socket is allocated? */
  
    if (candidate->username)
      g_free (candidate->username);
  
    if (candidate->password)
      g_free (candidate->password);
  
    g_slice_free (NiceCandidate, candidate);
  }
  
  
  guint32
  nice_candidate_jingle_priority (NiceCandidate *candidate)
  {
    switch (candidate->type)
      {
      case NICE_CANDIDATE_TYPE_HOST:             return 1000;
      case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 900;
      case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 900;
      case NICE_CANDIDATE_TYPE_RELAYED:          return 500;
      }
  
    /* appease GCC */
    return 0;
  }
  
  guint32
  nice_candidate_msn_priority (NiceCandidate *candidate)
  {
    switch (candidate->type)
      {
      case NICE_CANDIDATE_TYPE_HOST:             return 830;
      case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE: return 550;
      case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:   return 550;
      case NICE_CANDIDATE_TYPE_RELAYED:          return 450;
      }
  
    /* appease GCC */
    return 0;
  }
  
  
  /*
   * ICE 4.1.2.1. "Recommended Formula" (ID-19):
   * returns number between 1 and 0x7effffff 
   */
  guint32
  nice_candidate_ice_priority_full (
    // must be ∈ (0, 126) (max 2^7 - 2)
    guint type_preference,
    // must be ∈ (0, 65535) (max 2^16 - 1)
    guint local_preference,
    // must be ∈ (0, 255) (max 2 ^ 8 - 1)
    guint component_id)
  {
    return (
        0x1000000 * type_preference +
        0x100 * local_preference +
        (0x100 - component_id));
  }
  
  
  guint32
  nice_candidate_ice_priority (const NiceCandidate *candidate)
  {
    guint8 type_preference = 0;
  
    switch (candidate->type)
      {
      case NICE_CANDIDATE_TYPE_HOST:
        type_preference = NICE_CANDIDATE_TYPE_PREF_HOST; break;
      case NICE_CANDIDATE_TYPE_PEER_REFLEXIVE:
        type_preference = NICE_CANDIDATE_TYPE_PREF_PEER_REFLEXIVE; break;
      case NICE_CANDIDATE_TYPE_SERVER_REFLEXIVE:
        type_preference = NICE_CANDIDATE_TYPE_PREF_SERVER_REFLEXIVE; break;
      case NICE_CANDIDATE_TYPE_RELAYED:
        type_preference = NICE_CANDIDATE_TYPE_PREF_RELAYED; break;
      }
  
    /* return _candidate_ice_priority (type_preference, 1, candidate->component_id); */
    return nice_candidate_ice_priority_full (type_preference, 1, candidate->component_id);
  }
  
  /*
   * Calculates the pair priority as specified in ICE
   * sect 5.7.2. "Computing Pair Priority and Ordering Pairs" (ID-19).
   */
  guint64
  nice_candidate_pair_priority (guint32 o_prio, guint32 a_prio)
  {
    guint32 max = o_prio > a_prio ? o_prio : a_prio;
    guint32 min = o_prio < a_prio ? o_prio : a_prio;
  
    return ((guint64)1 << 32) * min + 2 * max + (o_prio > a_prio ? 1 : 0);
  }
  
  /*
   * Copies a candidate
   */
  NICEAPI_EXPORT NiceCandidate *
  nice_candidate_copy (const NiceCandidate *candidate)
  {
    NiceCandidate *copy = nice_candidate_new (candidate->type);
  
    memcpy (copy, candidate, sizeof(NiceCandidate));
  
    copy->username = g_strdup (copy->username);
    copy->password = g_strdup (copy->password);
  
    return copy;
  }
  