C++ pred函数代码示例

 std::pair<I1, I2>
 operator()(I1 begin1, S1 end1, I2 begin2, C pred_ = C{}, P1 proj1_ = P1{},
     P2 proj2_ = P2{}) const
 {
     auto &&pred = as_function(pred_);
     auto &&proj1 = as_function(proj1_);
     auto &&proj2 = as_function(proj2_);
     for(; begin1 != end1; ++begin1, ++begin2)
         if(!pred(proj1(*begin1), proj2(*begin2)))
             break;
     return {begin1, begin2};
 }

static optional<pair<expr, unsigned>> find_hyp_core(expr const & meta, F && pred) {
    expr const * it = &meta;
    unsigned i = 0;
    while (is_app(*it)) {
        expr const & h = app_arg(*it);
        if (pred(h))
            return some(mk_pair(h, i));
        i++;
        it = &app_fn(*it);
    }
    return optional<pair<expr, unsigned>>();
}

void test_adjacent_find_async(ExPolicy&& policy,
    hpx::partitioned_vector<T>& xvalues)
{
    auto result =
        hpx::parallel::adjacent_find(policy, xvalues.begin(), xvalues.end())
            .get();
    HPX_TEST_EQ(std::distance(xvalues.begin(), result), 31);

    result = hpx::parallel::adjacent_find(policy, xvalues.begin(),
        xvalues.end(), pred()).get();
    HPX_TEST_EQ(std::distance(xvalues.begin(), result), 4);
}

 static constexpr auto
 group_helper(Xs&& xs, Pred&& pred, std::index_sequence<0, i...>) {
     using info = detail::group_indices<
         hana::value<decltype(
             pred(hana::at_c<i - 1>(static_cast<Xs&&>(xs)),
                  hana::at_c<i>(static_cast<Xs&&>(xs)))
         )>()...
     >;
     return info::template finish<S>(static_cast<Xs&&>(xs),
         std::make_index_sequence<info::n_groups>{}
     );
 }

 tagged_pair<tag::in1(I1), tag::in2(I2)>
 operator()(I1 begin1, S1 end1, I2 begin2, S2 end2, C pred_ = C{}, P1 proj1_ = P1{},
     P2 proj2_ = P2{}) const
 {
     auto &&pred = as_function(pred_);
     auto &&proj1 = as_function(proj1_);
     auto &&proj2 = as_function(proj2_);
     for(; begin1 != end1 &&  begin2 != end2; ++begin1, ++begin2)
         if(!pred(proj1(*begin1), proj2(*begin2)))
             break;
     return {begin1, begin2};
 }

CGameTask*	CGameTaskManager::GiveGameTaskToActor(CGameTask* t, u32 timeToComplete, bool bCheckExisting)
{
	if(bCheckExisting && HasGameTask(t->m_ID)) return NULL;
	m_flags.set					(eChanged, TRUE);

	GameTasks().push_back				(SGameTaskKey(t->m_ID) );
	GameTasks().back().game_task			= t;
	t->m_ReceiveTime				= Level().GetGameTime();
	t->m_TimeToComplete				= t->m_ReceiveTime + timeToComplete;

	
	std::sort						(GameTasks().begin(), GameTasks().end(), task_prio_pred);

	ARTICLE_VECTOR& article_vector = Actor()->encyclopedia_registry->registry().objects();


	SGameTaskObjective	*obj = NULL;
	for (u32 i = 0; i < t->m_Objectives.size(); ++i){
		obj = &t->m_Objectives[i];
		if(obj->article_id.size()){
		FindArticleByIDPred pred(obj->article_id);
		if( std::find_if(article_vector.begin(), article_vector.end(), pred) == article_vector.end() ){
			CEncyclopediaArticle article;
			article.Load(obj->article_id);
			article_vector.push_back(ARTICLE_DATA(obj->article_id, Level().GetGameTime(), article.data()->articleType));
			}
		}

		if(obj->object_id!=u16(-1) && obj->map_location.size() && obj->def_location_enabled){
			CMapLocation* ml =	Level().MapManager().AddMapLocation(obj->map_location, obj->object_id);
			if(obj->map_hint.size())	ml->SetHint(obj->map_hint);
			ml->DisablePointer			();
			ml->SetSerializable			(true);
		}
	}
	CGameTask* _at = ActiveTask();
	if	( (NULL==_at) || (_at->m_priority > t->m_priority) )
	{
		SetActiveTask(t->m_ID, 1);
	}


	//установить флажок необходимости прочтения тасков в PDA
	if(HUD().GetUI()){
		CUIGameSP* pGameSP = smart_cast<CUIGameSP*>(HUD().GetUI()->UIGame());
		if(pGameSP) 
			pGameSP->PdaMenu->PdaContentsChanged	(pda_section::quests);
	}
	if(true /*t->m_ID!="user_task"*/)
		t->Objective(0).ChangeStateCallback();

	return t;
}

  void trimRightIf(std::string& str, P pred) {
    std::string::iterator i = str.end();

    for (; i != str.begin();) {
      if (!pred(*(--i))) {
	++i;
	break;
      }
    }
        
    str.erase(i, str.end());
  }

//---------------------------------------------------------------------------
void tTVPLayerManager::ReleaseTouchCapture( tjs_uint32 id )
{
	FindTouchID pred( id );
	std::vector<tTVPTouchCaptureLayer>::iterator itr = std::find_if( TouchCapture.begin(), TouchCapture.end(), pred );
	if( itr != TouchCapture.end() )
	{
		tTJSNI_BaseLayer* old = itr->Owner;
		if( old && old->Owner ) old->Owner->Release();
		TouchCapture.erase(itr);
	}
	if( ReleaseTouchCaptureIDMark == (tjs_int64)id ) ReleaseTouchCaptureIDMark = -1;
}

/* slist_find -- Trouve le premier élément de la liste égal à item
 * (d'après le prédicat pred) et positionne le pointeur de liste dessus.
 * Renvoie un pointeur sur son son contenu.
 * Si l'élément n'a pas pu ^etre trouvé, renvoie NULL.
 * Complexité: O(longueur(list)*C(pred))
 */
void *slist_find(SList *list, void *item, int (*pred)(void *, void *))
{
  assert((list != NULL) && (pred != NULL));
  if (slist_empty(list)) return NULL;

  for (slist_reset(list); list->current != NULL; slist_next(list))
    if (pred(slist_current(list), item)) break;
  if (list->current != NULL)
    return list->current->item; /* Trouvé */
  else
    return NULL;                /* Pas trouvé */
}

// Separation
// Keeps boids from getting too close to one another
Pvector Boid::Separation(vector<Boid> boids)
{
	// Distance of field of vision for separation between boids
	float desiredseparation = desSep;
	Pvector steer(0, 0);
	int count = 0;
	// For every boid in the system, check if it's too close
	for (int i = 0; i < boids.size(); i++) {
		// Calculate distance from current boid to boid we're looking at
		float d = location.distance(boids[i].location);
		// If this is a fellow boid and it's too close, move away from it
		if ((d > 0) && (d < desiredseparation)) {
			Pvector diff(0, 0);
			diff = diff.subTwoVector(location, boids[i].location);
			diff.normalize();
			diff.divScalar(d);      // Weight by distance
			steer.addVector(diff);
			count++;
		}
		// If current boid is a predator and the boid we're looking at is also
		// a predator, then separate only slightly
		if ((d > 0) && (d < desSep) && predatorStatus == true
			&& boids[i].predatorStatus == true) {
			Pvector pred2pred(0, 0);
			pred2pred = pred2pred.subTwoVector(location, boids[i].location);
			pred2pred.normalize();
			pred2pred.divScalar(d);
			steer.addVector(pred2pred);
			count++;
		}
		// If current boid is not a predator, but the boid we're looking at is
		// a predator, then create a large separation Pvector
		else if ((d > 0) && (d < desiredseparation + 70) && boids[i].predatorStatus == true) {
			Pvector pred(0, 0);
			pred = pred.subTwoVector(location, boids[i].location);
			pred.mulScalar(900);
			steer.addVector(pred);
			count++;
		}
	}
	// Adds average difference of location to acceleration
	if (count > 0)
		steer.divScalar(static_cast<float>(count));
	if (steer.magnitude() > 0) {
		// Steering = Desired - Velocity
		steer.normalize();
		steer.mulScalar(maxSpeed);
		steer.subVector(velocity);
		steer.limit(maxForce);
	}
	return steer;
}

 I
 operator()(I begin, S end, C pred_ = C{}, P proj_ = P{}) const
 {
     auto &&pred = as_function(pred_);
     auto &&proj = as_function(proj_);
     if(begin == end)
         return begin;
     auto next = begin;
     for(; ++next != end; begin = next)
         if(pred(proj(*begin), proj(*next)))
             return begin;
     return next;
 }

static void FallbackLoad(size_t width, size_t height, size_t depth,
                         const uint8_t *input, size_t inputRowPitch, size_t inputDepthPitch,
                         uint8_t *output, size_t outputRowPitch, size_t outputDepthPitch)
{
    if (pred())
    {
        prefered(width, height, depth, input, inputRowPitch, inputDepthPitch, output, outputRowPitch, outputDepthPitch);
    }
    else
    {
        fallback(width, height, depth, input, inputRowPitch, inputDepthPitch, output, outputRowPitch, outputDepthPitch);
    }
}

    /// INTERNAL ONLY
    match_results<BidiIter> const &operator ()(regex_id_type regex_id, size_type index = 0) const
    {
        // BUGBUG this is linear, make it O(1)
        static match_results<BidiIter> const s_null;

        regex_id_filter_predicate<BidiIter> pred(regex_id);
        typename nested_results_type::const_iterator
            begin = this->nested_results_.begin()
          , end = this->nested_results_.end()
          , cur = detail::find_nth_if(begin, end, index, pred);

        return (cur == end) ? s_null : *cur;
    }

 std::pair<std::size_t, OutputIterator>
 biconnected_components(const Graph & g, ComponentMap comp,
                        OutputIterator out, DiscoverTimeMap discover_time,
                        LowPointMap lowpt, VertexIndexMap index_map)
 {
   typedef typename graph_traits<Graph>::vertex_descriptor vertex_t;
   std::vector<vertex_t> pred(num_vertices(g));
   vertex_t vert = graph_traits<Graph>::null_vertex();
   return biconnected_components
            (g, comp, out, discover_time, lowpt,
             make_iterator_property_map(pred.begin(), index_map, vert),
             index_map);
 }

void condition_test_waits(condition_test_data* data)
{
    boost::mutex::scoped_lock lock(data->mutex);
    BOOST_CHECK(lock ? true : false);

    // Test wait.
    while (data->notified != 1)
        data->condition.wait(lock);
    BOOST_CHECK(lock ? true : false);
    BOOST_CHECK_EQUAL(data->notified, 1);
    data->awoken++;
    data->condition.notify_one();

    // Test predicate wait.
    data->condition.wait(lock, cond_predicate(data->notified, 2));
    BOOST_CHECK(lock ? true : false);
    BOOST_CHECK_EQUAL(data->notified, 2);
    data->awoken++;
    data->condition.notify_one();

    // Test timed_wait.
    boost::xtime xt = delay(10);
    while (data->notified != 3)
        data->condition.timed_wait(lock, xt);
    BOOST_CHECK(lock ? true : false);
    BOOST_CHECK_EQUAL(data->notified, 3);
    data->awoken++;
    data->condition.notify_one();

    // Test predicate timed_wait.
    xt = delay(10);
    cond_predicate pred(data->notified, 4);
    BOOST_CHECK(data->condition.timed_wait(lock, xt, pred));
    BOOST_CHECK(lock ? true : false);
    BOOST_CHECK(pred());
    BOOST_CHECK_EQUAL(data->notified, 4);
    data->awoken++;
    data->condition.notify_one();
}