gecko-dev/mfbt/Range.h

59 lines
1.7 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/. */
#ifndef mozilla_Range_h
#define mozilla_Range_h
#include "mozilla/RangedPtr.h"
#include "mozilla/TypeTraits.h"
#include <stddef.h>
namespace mozilla {
// Range<T> is a tuple containing a pointer and a length.
template <typename T>
class Range
{
const RangedPtr<T> mStart;
const RangedPtr<T> mEnd;
public:
Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
Range(T* aPtr, size_t aLength)
: mStart(aPtr, aPtr, aPtr + aLength),
mEnd(aPtr + aLength, aPtr, aPtr + aLength)
{}
Range(const RangedPtr<T>& aStart, const RangedPtr<T>& aEnd)
: mStart(aStart.get(), aStart.get(), aEnd.get()),
mEnd(aEnd.get(), aStart.get(), aEnd.get())
{
// Only accept two RangedPtrs within the same range.
aStart.checkIdenticalRange(aEnd);
MOZ_ASSERT(aStart <= aEnd);
}
template<typename U,
class = typename EnableIf<IsConvertible<U (*)[], T (*)[]>::value,
int>::Type>
MOZ_IMPLICIT Range(const Range<U>& aOther)
: mStart(aOther.mStart),
mEnd(aOther.mEnd)
{}
RangedPtr<T> begin() const { return mStart; }
RangedPtr<T> end() const { return mEnd; }
size_t length() const { return mEnd - mStart; }
T& operator[](size_t aOffset) const { return mStart[aOffset]; }
explicit operator bool() const { return mStart != nullptr; }
};
} // namespace mozilla
#endif /* mozilla_Range_h */