gecko-dev/mfbt/RangedArray.h

45 lines
1.2 KiB
C++

/* -*- 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