michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set ts=8 sts=2 et sw=2 tw=80: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_Range_h
michael@0: #define mozilla_Range_h
michael@0: 
michael@0: #include "mozilla/NullPtr.h"
michael@0: #include "mozilla/RangedPtr.h"
michael@0: 
michael@0: #include <stddef.h>
michael@0: 
michael@0: namespace mozilla {
michael@0: 
michael@0: // Range<T> is a tuple containing a pointer and a length.
michael@0: template <typename T>
michael@0: class Range
michael@0: {
michael@0:     RangedPtr<T> mStart;
michael@0:     RangedPtr<T> mEnd;
michael@0: 
michael@0:     typedef void (Range::* ConvertibleToBool)();
michael@0:     void nonNull() {}
michael@0: 
michael@0:   public:
michael@0:     Range() : mStart(nullptr, 0), mEnd(nullptr, 0) {}
michael@0:     Range(T* p, size_t len)
michael@0:       : mStart(p, p, p + len),
michael@0:         mEnd(p + len, p, p + len)
michael@0:     {}
michael@0: 
michael@0:     RangedPtr<T> start() const { return mStart; }
michael@0:     RangedPtr<T> end() const { return mEnd; }
michael@0:     size_t length() const { return mEnd - mStart; }
michael@0: 
michael@0:     T& operator[](size_t offset) {
michael@0:       return mStart[offset];
michael@0:     }
michael@0: 
michael@0:     const T& operator[](size_t offset) const {
michael@0:       return mStart[offset];
michael@0:     }
michael@0: 
michael@0:     operator ConvertibleToBool() const { return mStart ? &Range::nonNull : 0; }
michael@0: };
michael@0: 
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif /* mozilla_Range_h */