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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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
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