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Diffstat (limited to 'mfbt/IntegerRange.h')
| -rw-r--r-- | mfbt/IntegerRange.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/mfbt/IntegerRange.h b/mfbt/IntegerRange.h new file mode 100644 index 000000000..8d5d2e4d6 --- /dev/null +++ b/mfbt/IntegerRange.h @@ -0,0 +1,181 @@ +/* -*- 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/. */ + +/* Iterator over ranges of integers */ + +#ifndef mozilla_IntegerRange_h +#define mozilla_IntegerRange_h + +#include "mozilla/Assertions.h" +#include "mozilla/ReverseIterator.h" +#include "mozilla/TypeTraits.h" + +namespace mozilla { + +namespace detail { + +template<typename IntTypeT> +class IntegerIterator +{ +public: + template<typename IntType> + explicit IntegerIterator(IntType aCurrent) + : mCurrent(aCurrent) { } + + template<typename IntType> + explicit IntegerIterator(const IntegerIterator<IntType>& aOther) + : mCurrent(aOther.mCurrent) { } + + IntTypeT operator*() const { return mCurrent; } + + /* Increment and decrement operators */ + + IntegerIterator& operator++() { ++mCurrent; return *this; } + IntegerIterator& operator--() { --mCurrent; return *this; } + IntegerIterator operator++(int) { auto ret = *this; ++mCurrent; return ret; } + IntegerIterator operator--(int) { auto ret = *this; --mCurrent; return ret; } + + /* Comparison operators */ + + template<typename IntType1, typename IntType2> + friend bool operator==(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + template<typename IntType1, typename IntType2> + friend bool operator!=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + template<typename IntType1, typename IntType2> + friend bool operator<(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + template<typename IntType1, typename IntType2> + friend bool operator<=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + template<typename IntType1, typename IntType2> + friend bool operator>(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + template<typename IntType1, typename IntType2> + friend bool operator>=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2); + +private: + IntTypeT mCurrent; +}; + +template<typename IntType1, typename IntType2> +bool operator==(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent == aIter2.mCurrent; +} + +template<typename IntType1, typename IntType2> +bool operator!=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent != aIter2.mCurrent; +} + +template<typename IntType1, typename IntType2> +bool operator<(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent < aIter2.mCurrent; +} + +template<typename IntType1, typename IntType2> +bool operator<=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent <= aIter2.mCurrent; +} + +template<typename IntType1, typename IntType2> +bool operator>(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent > aIter2.mCurrent; +} + +template<typename IntType1, typename IntType2> +bool operator>=(const IntegerIterator<IntType1>& aIter1, + const IntegerIterator<IntType2>& aIter2) +{ + return aIter1.mCurrent >= aIter2.mCurrent; +} + +template<typename IntTypeT> +class IntegerRange +{ +public: + typedef IntegerIterator<IntTypeT> iterator; + typedef IntegerIterator<IntTypeT> const_iterator; + typedef ReverseIterator<IntegerIterator<IntTypeT>> reverse_iterator; + typedef ReverseIterator<IntegerIterator<IntTypeT>> const_reverse_iterator; + + template<typename IntType> + explicit IntegerRange(IntType aEnd) + : mBegin(0), mEnd(aEnd) { } + + template<typename IntType1, typename IntType2> + IntegerRange(IntType1 aBegin, IntType2 aEnd) + : mBegin(aBegin), mEnd(aEnd) { } + + iterator begin() const { return iterator(mBegin); } + const_iterator cbegin() const { return begin(); } + iterator end() const { return iterator(mEnd); } + const_iterator cend() const { return end(); } + reverse_iterator rbegin() const { return reverse_iterator(mEnd); } + const_reverse_iterator crbegin() const { return rbegin(); } + reverse_iterator rend() const { return reverse_iterator(mBegin); } + const_reverse_iterator crend() const { return rend(); } + +private: + IntTypeT mBegin; + IntTypeT mEnd; +}; + +template<typename T, bool = IsUnsigned<T>::value> +struct GeqZero +{ + static bool check(T t) { + return t >= 0; + } +}; + +template<typename T> +struct GeqZero<T, true> +{ + static bool check(T t) { + return true; + } +}; + +} // namespace detail + +template<typename IntType> +detail::IntegerRange<IntType> +MakeRange(IntType aEnd) +{ + static_assert(IsIntegral<IntType>::value, "value must be integral"); + MOZ_ASSERT(detail::GeqZero<IntType>::check(aEnd), + "Should never have negative value here"); + return detail::IntegerRange<IntType>(aEnd); +} + +template<typename IntType1, typename IntType2> +detail::IntegerRange<IntType2> +MakeRange(IntType1 aBegin, IntType2 aEnd) +{ + static_assert(IsIntegral<IntType1>::value && IsIntegral<IntType2>::value, + "values must both be integral"); + static_assert(IsSigned<IntType1>::value == IsSigned<IntType2>::value, + "signed/unsigned mismatch"); + MOZ_ASSERT(aEnd >= aBegin, "End value should be larger than begin value"); + return detail::IntegerRange<IntType2>(aBegin, aEnd); +} + +} // namespace mozilla + +#endif // mozilla_IntegerRange_h |