layout/generic/nsIntervalSet.cpp
author Boris Zbarsky <bzbarsky@mit.edu>
Sat, 11 May 2019 08:28:29 +0000
changeset 532359 6103006e3172f0ef258a30256b8cc7a6553e7f14
parent 530873 e1993a1f09ac53cd1a04fdf6a87f8cad8e44f73e
permissions -rw-r--r--
Bug 1550937. Stop using [array] in nsIEventListenerService. r=smaug Differential Revision: https://phabricator.services.mozilla.com/D30773

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=8:et:sw=4:
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* a set of ranges on a number-line */

#include "nsIntervalSet.h"
#include <new>
#include <algorithm>
#include "mozilla/PresShell.h"  // for allocation

using namespace mozilla;

nsIntervalSet::nsIntervalSet(PresShell* aPresShell)
    : mList(nullptr), mPresShell(aPresShell) {}

nsIntervalSet::~nsIntervalSet() {
  Interval* current = mList;
  while (current) {
    Interval* trash = current;
    current = current->mNext;
    FreeInterval(trash);
  }
}

void* nsIntervalSet::AllocateInterval() {
  return mPresShell->AllocateByObjectID(eArenaObjectID_nsIntervalSet_Interval,
                                        sizeof(Interval));
}

void nsIntervalSet::FreeInterval(nsIntervalSet::Interval* aInterval) {
  NS_ASSERTION(aInterval, "null interval");

  aInterval->Interval::~Interval();
  mPresShell->FreeByObjectID(eArenaObjectID_nsIntervalSet_Interval, aInterval);
}

void nsIntervalSet::IncludeInterval(coord_type aBegin, coord_type aEnd) {
  auto newInterval = static_cast<Interval*>(AllocateInterval());
  new (newInterval) Interval(aBegin, aEnd);

  Interval** current = &mList;
  while (*current && (*current)->mEnd < aBegin) current = &(*current)->mNext;

  newInterval->mNext = *current;
  *current = newInterval;

  Interval* subsumed = newInterval->mNext;
  while (subsumed && subsumed->mBegin <= aEnd) {
    newInterval->mBegin = std::min(newInterval->mBegin, subsumed->mBegin);
    newInterval->mEnd = std::max(newInterval->mEnd, subsumed->mEnd);
    newInterval->mNext = subsumed->mNext;
    FreeInterval(subsumed);
    subsumed = newInterval->mNext;
  }
}

bool nsIntervalSet::Intersects(coord_type aBegin, coord_type aEnd) const {
  Interval* current = mList;
  while (current && current->mBegin <= aEnd) {
    if (current->mEnd >= aBegin) return true;
    current = current->mNext;
  }
  return false;
}

bool nsIntervalSet::Contains(coord_type aBegin, coord_type aEnd) const {
  Interval* current = mList;
  while (current && current->mBegin <= aBegin) {
    if (current->mEnd >= aEnd) return true;
    current = current->mNext;
  }
  return false;
}