mirror of
https://github.com/classilla/tenfourfox.git
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216 lines
7.4 KiB
C
216 lines
7.4 KiB
C
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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* Iterator over contiguous enum values */
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/*
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* Implements generator functions that create a range to iterate over the values
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* of a scoped or unscoped enum. Unlike IntegerRange, which can only function on
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* the underlying integral type, the elements of the generated sequence will
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* have the type of the enum in question.
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*
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* Note that the enum values should be contiguous in the iterated range;
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* unfortunately there exists no way for EnumeratedRange to enforce this
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* either dynamically or at compile time.
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*/
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#ifndef mozilla_EnumeratedRange_h
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#define mozilla_EnumeratedRange_h
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#include "mozilla/IntegerTypeTraits.h"
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#include "mozilla/ReverseIterator.h"
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namespace mozilla {
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namespace detail {
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template<typename IntTypeT, typename EnumTypeT>
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class EnumeratedIterator
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{
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public:
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template<typename EnumType>
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explicit EnumeratedIterator(EnumType aCurrent)
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: mCurrent(aCurrent) { }
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template<typename IntType, typename EnumType>
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explicit EnumeratedIterator(const EnumeratedIterator<IntType, EnumType>& aOther)
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: mCurrent(aOther.mCurrent) { }
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EnumTypeT operator*() const { return mCurrent; }
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/* Increment and decrement operators */
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EnumeratedIterator& operator++()
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{
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mCurrent = EnumTypeT(IntTypeT(mCurrent) + IntTypeT(1));
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return *this;
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}
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EnumeratedIterator& operator--()
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{
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mCurrent = EnumTypeT(IntTypeT(mCurrent) - IntTypeT(1));
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return *this;
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}
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EnumeratedIterator operator++(int)
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{
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auto ret = *this;
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mCurrent = EnumTypeT(IntTypeT(mCurrent) + IntTypeT(1));
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return ret;
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}
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EnumeratedIterator operator--(int)
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{
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auto ret = *this;
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mCurrent = EnumTypeT(IntTypeT(mCurrent) - IntTypeT(1));
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return ret;
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}
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/* Comparison operators */
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template<typename IntType, typename EnumType>
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friend bool operator==(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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template<typename IntType, typename EnumType>
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friend bool operator!=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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template<typename IntType, typename EnumType>
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friend bool operator<(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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template<typename IntType, typename EnumType>
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friend bool operator<=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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template<typename IntType, typename EnumType>
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friend bool operator>(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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template<typename IntType, typename EnumType>
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friend bool operator>=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2);
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private:
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EnumTypeT mCurrent;
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};
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template<typename IntType, typename EnumType>
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bool operator==(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent == aIter2.mCurrent;
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}
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template<typename IntType, typename EnumType>
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bool operator!=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent != aIter2.mCurrent;
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}
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template<typename IntType, typename EnumType>
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bool operator<(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent < aIter2.mCurrent;
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}
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template<typename IntType, typename EnumType>
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bool operator<=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent <= aIter2.mCurrent;
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}
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template<typename IntType, typename EnumType>
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bool operator>(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent > aIter2.mCurrent;
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}
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template<typename IntType, typename EnumType>
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bool operator>=(const EnumeratedIterator<IntType, EnumType>& aIter1,
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const EnumeratedIterator<IntType, EnumType>& aIter2)
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{
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return aIter1.mCurrent >= aIter2.mCurrent;
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}
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template<typename IntTypeT, typename EnumTypeT>
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class EnumeratedRange
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{
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public:
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typedef EnumeratedIterator<IntTypeT, EnumTypeT> iterator;
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typedef EnumeratedIterator<IntTypeT, EnumTypeT> const_iterator;
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typedef ReverseIterator<iterator> reverse_iterator;
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typedef ReverseIterator<const_iterator> const_reverse_iterator;
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template<typename EnumType>
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EnumeratedRange(EnumType aBegin, EnumType aEnd)
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: mBegin(aBegin), mEnd(aEnd) { }
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iterator begin() const { return iterator(mBegin); }
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const_iterator cbegin() const { return begin(); }
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iterator end() const { return iterator(mEnd); }
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const_iterator cend() const { return end(); }
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reverse_iterator rbegin() const { return reverse_iterator(mEnd); }
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const_reverse_iterator crbegin() const { return rbegin(); }
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reverse_iterator rend() const { return reverse_iterator(mBegin); }
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const_reverse_iterator crend() const { return rend(); }
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private:
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EnumTypeT mBegin;
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EnumTypeT mEnd;
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};
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} // namespace detail
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#ifdef __GNUC__
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// Enums can have an unsigned underlying type, which makes some of the
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// comparisons below always true or always false. Temporarily disable
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// -Wtype-limits to avoid breaking -Werror builds.
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# pragma GCC diagnostic push
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# pragma GCC diagnostic ignored "-Wtype-limits"
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#endif
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// Create a range to iterate from aBegin to aEnd, exclusive.
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//
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// (Once we can rely on std::underlying_type, we can remove the IntType
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// template parameter.)
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template<typename IntType, typename EnumType>
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inline detail::EnumeratedRange<IntType, EnumType>
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MakeEnumeratedRange(EnumType aBegin, EnumType aEnd)
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{
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#ifdef DEBUG
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typedef typename MakeUnsigned<IntType>::Type UnsignedType;
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#endif
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static_assert(sizeof(IntType) >= sizeof(EnumType),
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"IntType should be at least as big as EnumType!");
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MOZ_ASSERT(aBegin <= aEnd, "Cannot generate invalid, unbounded range!");
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MOZ_ASSERT_IF(aBegin < EnumType(0), IsSigned<IntType>::value);
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MOZ_ASSERT_IF(aBegin >= EnumType(0) && IsSigned<IntType>::value,
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UnsignedType(aEnd) <= UnsignedType(MaxValue<IntType>::value));
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return detail::EnumeratedRange<IntType, EnumType>(aBegin, aEnd);
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}
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// Create a range to iterate from EnumType(0) to aEnd, exclusive. EnumType(0)
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// should exist, but note that there is no way for us to ensure that it does!
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// Since the enumeration starts at EnumType(0), we know for sure that the values
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// will be in range of our deduced IntType.
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template<typename EnumType>
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inline detail::EnumeratedRange<
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typename UnsignedStdintTypeForSize<sizeof(EnumType)>::Type,
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EnumType>
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MakeEnumeratedRange(EnumType aEnd)
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{
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return MakeEnumeratedRange<
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typename UnsignedStdintTypeForSize<sizeof(EnumType)>::Type>(EnumType(0),
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aEnd);
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}
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#ifdef __GNUC__
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# pragma GCC diagnostic pop
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#endif
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} // namespace mozilla
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#endif // mozilla_EnumeratedRange_h
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