mfbt/RangedArray.h
author James Graham <james@hoppipolla.co.uk>
Thu, 24 Sep 2015 14:51:19 +0100
changeset 264851 84c62ba95e198b4ff851b07499209e9a57687273
parent 245380 3cb74142cd09fdb9b12d2a8bfb02be2ae0346f27
child 268439 c3e202bf0f25772c0eb34078db586449e51ccd00
permissions -rw-r--r--
Bug 1209297 - Update web-platform-tests expected data to revision 2869a58fd81da41f9f904441ff39f9398fba53bc, a=testonly

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 compile-time constant-length array, with bounds-checking assertions -- but
 * unlike mozilla::Array, with indexes biased by a constant.
 *
 * Thus where mozilla::Array<int, 3> is a three-element array indexed by [0, 3),
 * mozilla::RangedArray<int, 8, 3> is a three-element array indexed by [8, 11).
 */

#ifndef mozilla_RangedArray_h
#define mozilla_RangedArray_h

#include "mozilla/Array.h"

namespace mozilla {

template<typename T, size_t MinIndex, size_t Length>
class RangedArray
{
public:
  T& operator[](size_t aIndex)
  {
    MOZ_ASSERT(aIndex == MinIndex || aIndex > MinIndex);
    return mArr[aIndex - MinIndex];
  }

  const T& operator[](size_t aIndex) const
  {
    MOZ_ASSERT(aIndex == MinIndex || aIndex > MinIndex);
    return mArr[aIndex - MinIndex];
  }

private:
  Array<T, Length> mArr;
};

} // namespace mozilla

#endif // mozilla_RangedArray_h