From f381e80fa50bf5f3e94e90ded2fc25c98ff45817 Mon Sep 17 00:00:00 2001 From: Xidorn Quan Date: Wed, 4 Feb 2015 19:07:32 +1100 Subject: [PATCH] Bug 1126701 - Add IntegerRange for iterating integers. r=waldo --HG-- extra : source : 2977cf3c5b545826a4ec0cdf245e804574cf7ff9 --- mfbt/IntegerRange.h | 202 ++++++++++++++++++++++++++++++++++++++++++++ mfbt/moz.build | 1 + 2 files changed, 203 insertions(+) create mode 100644 mfbt/IntegerRange.h diff --git a/mfbt/IntegerRange.h b/mfbt/IntegerRange.h new file mode 100644 index 000000000000..44d1d6c80c85 --- /dev/null +++ b/mfbt/IntegerRange.h @@ -0,0 +1,202 @@ +/* -*- 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/TypeTraits.h" +#include "mozilla/ReverseIterator.h" + +namespace mozilla { + +namespace detail { + +template +class IntegerIterator +{ +public: + typedef const IntTypeT ValueType; + typedef typename MakeSigned::Type DifferenceType; + + template + explicit IntegerIterator(IntType aCurrent) + : mCurrent(aCurrent) { } + + template + IntegerIterator(const IntegerIterator& aOther) + : mCurrent(aOther.mCurrent) { } + + // Since operator* is required to return a reference, we return + // the reference of our member here. + const IntTypeT& operator*() const { return mCurrent; } + + /* Increments and descrements 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; } + + IntegerIterator operator+(DifferenceType aN) const + { + return IntegerIterator(mCurrent + aN); + } + IntegerIterator operator-(DifferenceType aN) const + { + return IntegerIterator(mCurrent - aN); + } + IntegerIterator& operator+=(DifferenceType aN) + { + mCurrent += aN; + return *this; + } + IntegerIterator& operator-=(DifferenceType aN) + { + mCurrent -= aN; + return *this; + } + + /* Comparison operators */ + + template + friend bool operator==(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + template + friend bool operator!=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + template + friend bool operator<(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + template + friend bool operator<=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + template + friend bool operator>(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + template + friend bool operator>=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2); + +private: + IntTypeT mCurrent; +}; + +template +bool operator==(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent == aIter2.mCurrent; +} + +template +bool operator!=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent != aIter2.mCurrent; +} + +template +bool operator<(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent < aIter2.mCurrent; +} + +template +bool operator<=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent <= aIter2.mCurrent; +} + +template +bool operator>(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent > aIter2.mCurrent; +} + +template +bool operator>=(const IntegerIterator& aIter1, + const IntegerIterator& aIter2) +{ + return aIter1.mCurrent >= aIter2.mCurrent; +} + +template +class IntegerRange +{ +public: + typedef IntegerIterator iterator; + typedef IntegerIterator const_iterator; + typedef ReverseIterator> reverse_iterator; + typedef ReverseIterator> const_reverse_iterator; + + template + explicit IntegerRange(IntType aEnd) + : mBegin(0), mEnd(aEnd) { } + + template + 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::value> +struct GeqZero +{ + static bool check(T t) { + return t >= 0; + } +}; + +template +struct GeqZero +{ + static bool check(T t) { + return true; + } +}; + +} // namespace detail + +template +detail::IntegerRange +MakeRange(IntType aEnd) +{ + MOZ_ASSERT(detail::GeqZero::check(aEnd), + "Should never have negative value here"); + return detail::IntegerRange(aEnd); +} + +template +detail::IntegerRange +MakeRange(IntType1 aBegin, IntType2 aEnd) +{ + static_assert(IsSigned::value == IsSigned::value, + "signed/unsigned mismatch"); + MOZ_ASSERT(aEnd >= aBegin, "End value should be larger than begin value"); + return detail::IntegerRange(aBegin, aEnd); +} + +} // namespace mozilla + +#endif // mozilla_IntegerRange_h diff --git a/mfbt/moz.build b/mfbt/moz.build index 921bc8d0c1d2..82b7e7e7fbea 100644 --- a/mfbt/moz.build +++ b/mfbt/moz.build @@ -37,6 +37,7 @@ EXPORTS.mozilla = [ 'GuardObjects.h', 'HashFunctions.h', 'IntegerPrintfMacros.h', + 'IntegerRange.h', 'IntegerTypeTraits.h', 'IteratorTraits.h', 'JSONWriter.h',