gecko/mfbt/Range.h
Terrence Cole 10fccde0ad Bug 811060 - Implement mozilla::Range; r=Waldo
--HG--
extra : rebase_source : a303294de705fca72eb31f7b5c7db787d0bc7260
2012-11-12 16:37:33 -08:00

50 lines
1.2 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sw=4 et tw=78:
*
* 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/NullPtr.h"
#include "mozilla/RangedPtr.h"
#include <stddef.h>
namespace mozilla {
// Range<T> is a tuple containing a pointer and a length.
template <typename T>
class Range
{
RangedPtr<T> mStart;
RangedPtr<T> mEnd;
typedef void (Range::* ConvertibleToBool)();
void nonNull() {}
public:
Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
Range(T* p, size_t len)
: mStart(p, p, p + len),
mEnd(p + len, p, p + len)
{}
RangedPtr<T> start() const { return mStart; }
RangedPtr<T> end() const { return mEnd; }
size_t length() const { return mEnd - mStart; }
T& operator[](size_t offset) {
return mStart[offset];
}
operator ConvertibleToBool() const { return mStart ? &Range::nonNull : 0; }
};
} // namespace mozilla
#endif // mozilla_Range_h_