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       1             : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set ts=8 sts=2 et sw=2 tw=80: */
       3             : /* This Source Code Form is subject to the terms of the Mozilla Public
       4             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : /* Iterator over ranges of integers */
       8             : 
       9             : #ifndef mozilla_IntegerRange_h
      10             : #define mozilla_IntegerRange_h
      11             : 
      12             : #include "mozilla/Assertions.h"
      13             : #include "mozilla/ReverseIterator.h"
      14             : #include "mozilla/TypeTraits.h"
      15             : 
      16             : namespace mozilla {
      17             : 
      18             : namespace detail {
      19             : 
      20             : template<typename IntTypeT>
      21             : class IntegerIterator
      22             : {
      23             : public:
      24             :   template<typename IntType>
      25       15472 :   explicit IntegerIterator(IntType aCurrent)
      26       15472 :     : mCurrent(aCurrent) { }
      27             : 
      28             :   template<typename IntType>
      29             :   explicit IntegerIterator(const IntegerIterator<IntType>& aOther)
      30             :     : mCurrent(aOther.mCurrent) { }
      31             : 
      32       15601 :   IntTypeT operator*() const { return mCurrent; }
      33             : 
      34             :   /* Increment and decrement operators */
      35             : 
      36       15601 :   IntegerIterator& operator++() { ++mCurrent; return *this; }
      37           0 :   IntegerIterator& operator--() { --mCurrent; return *this; }
      38             :   IntegerIterator operator++(int) { auto ret = *this; ++mCurrent; return ret; }
      39             :   IntegerIterator operator--(int) { auto ret = *this; --mCurrent; return ret; }
      40             : 
      41             :   /* Comparison operators */
      42             : 
      43             :   template<typename IntType1, typename IntType2>
      44             :   friend bool operator==(const IntegerIterator<IntType1>& aIter1,
      45             :                          const IntegerIterator<IntType2>& aIter2);
      46             :   template<typename IntType1, typename IntType2>
      47             :   friend bool operator!=(const IntegerIterator<IntType1>& aIter1,
      48             :                          const IntegerIterator<IntType2>& aIter2);
      49             :   template<typename IntType1, typename IntType2>
      50             :   friend bool operator<(const IntegerIterator<IntType1>& aIter1,
      51             :                         const IntegerIterator<IntType2>& aIter2);
      52             :   template<typename IntType1, typename IntType2>
      53             :   friend bool operator<=(const IntegerIterator<IntType1>& aIter1,
      54             :                          const IntegerIterator<IntType2>& aIter2);
      55             :   template<typename IntType1, typename IntType2>
      56             :   friend bool operator>(const IntegerIterator<IntType1>& aIter1,
      57             :                         const IntegerIterator<IntType2>& aIter2);
      58             :   template<typename IntType1, typename IntType2>
      59             :   friend bool operator>=(const IntegerIterator<IntType1>& aIter1,
      60             :                          const IntegerIterator<IntType2>& aIter2);
      61             : 
      62             : private:
      63             :   IntTypeT mCurrent;
      64             : };
      65             : 
      66             : template<typename IntType1, typename IntType2>
      67             : bool operator==(const IntegerIterator<IntType1>& aIter1,
      68             :                 const IntegerIterator<IntType2>& aIter2)
      69             : {
      70             :   return aIter1.mCurrent == aIter2.mCurrent;
      71             : }
      72             : 
      73             : template<typename IntType1, typename IntType2>
      74       23337 : bool operator!=(const IntegerIterator<IntType1>& aIter1,
      75             :                 const IntegerIterator<IntType2>& aIter2)
      76             : {
      77       23337 :   return aIter1.mCurrent != aIter2.mCurrent;
      78             : }
      79             : 
      80             : template<typename IntType1, typename IntType2>
      81             : bool operator<(const IntegerIterator<IntType1>& aIter1,
      82             :                const IntegerIterator<IntType2>& aIter2)
      83             : {
      84             :   return aIter1.mCurrent < aIter2.mCurrent;
      85             : }
      86             : 
      87             : template<typename IntType1, typename IntType2>
      88             : bool operator<=(const IntegerIterator<IntType1>& aIter1,
      89             :                 const IntegerIterator<IntType2>& aIter2)
      90             : {
      91             :   return aIter1.mCurrent <= aIter2.mCurrent;
      92             : }
      93             : 
      94             : template<typename IntType1, typename IntType2>
      95             : bool operator>(const IntegerIterator<IntType1>& aIter1,
      96             :                const IntegerIterator<IntType2>& aIter2)
      97             : {
      98             :   return aIter1.mCurrent > aIter2.mCurrent;
      99             : }
     100             : 
     101             : template<typename IntType1, typename IntType2>
     102             : bool operator>=(const IntegerIterator<IntType1>& aIter1,
     103             :                 const IntegerIterator<IntType2>& aIter2)
     104             : {
     105             :   return aIter1.mCurrent >= aIter2.mCurrent;
     106             : }
     107             : 
     108             : template<typename IntTypeT>
     109             : class IntegerRange
     110             : {
     111             : public:
     112             :   typedef IntegerIterator<IntTypeT> iterator;
     113             :   typedef IntegerIterator<IntTypeT> const_iterator;
     114             :   typedef ReverseIterator<IntegerIterator<IntTypeT>> reverse_iterator;
     115             :   typedef ReverseIterator<IntegerIterator<IntTypeT>> const_reverse_iterator;
     116             : 
     117             :   template<typename IntType>
     118        7736 :   explicit IntegerRange(IntType aEnd)
     119        7736 :     : mBegin(0), mEnd(aEnd) { }
     120             : 
     121             :   template<typename IntType1, typename IntType2>
     122             :   IntegerRange(IntType1 aBegin, IntType2 aEnd)
     123             :     : mBegin(aBegin), mEnd(aEnd) { }
     124             : 
     125        7732 :   iterator begin() const { return iterator(mBegin); }
     126             :   const_iterator cbegin() const { return begin(); }
     127        7732 :   iterator end() const { return iterator(mEnd); }
     128             :   const_iterator cend() const { return end(); }
     129           4 :   reverse_iterator rbegin() const { return reverse_iterator(mEnd); }
     130             :   const_reverse_iterator crbegin() const { return rbegin(); }
     131           4 :   reverse_iterator rend() const { return reverse_iterator(mBegin); }
     132             :   const_reverse_iterator crend() const { return rend(); }
     133             : 
     134             : private:
     135             :   IntTypeT mBegin;
     136             :   IntTypeT mEnd;
     137             : };
     138             : 
     139             : template<typename T, bool = IsUnsigned<T>::value>
     140             : struct GeqZero
     141             : {
     142           0 :   static bool check(T t) {
     143           0 :     return t >= 0;
     144             :   }
     145             : };
     146             : 
     147             : template<typename T>
     148             : struct GeqZero<T, true>
     149             : {
     150        7736 :   static bool check(T t) {
     151        7736 :     return true;
     152             :   }
     153             : };
     154             : 
     155             : } // namespace detail
     156             : 
     157             : template<typename IntType>
     158             : detail::IntegerRange<IntType>
     159        7736 : IntegerRange(IntType aEnd)
     160             : {
     161             :   static_assert(IsIntegral<IntType>::value, "value must be integral");
     162        7736 :   MOZ_ASSERT(detail::GeqZero<IntType>::check(aEnd),
     163             :              "Should never have negative value here");
     164        7736 :   return detail::IntegerRange<IntType>(aEnd);
     165             : }
     166             : 
     167             : template<typename IntType1, typename IntType2>
     168             : detail::IntegerRange<IntType2>
     169             : IntegerRange(IntType1 aBegin, IntType2 aEnd)
     170             : {
     171             :   static_assert(IsIntegral<IntType1>::value && IsIntegral<IntType2>::value,
     172             :                 "values must both be integral");
     173             :   static_assert(IsSigned<IntType1>::value == IsSigned<IntType2>::value,
     174             :                 "signed/unsigned mismatch");
     175             :   MOZ_ASSERT(aEnd >= aBegin, "End value should be larger than begin value");
     176             :   return detail::IntegerRange<IntType2>(aBegin, aEnd);
     177             : }
     178             : 
     179             : } // namespace mozilla
     180             : 
     181             : #endif // mozilla_IntegerRange_h