From 4d30ce40c7bd681f1719a97a1eae8987dea39955 Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Mon, 9 Jan 2017 01:33:01 +0000
Subject: [PATCH] refs #852 Added reverse iterators to CRange and CSequence.

---
 src/blackmisc/range.h    | 13 +++++++++++++
 src/blackmisc/sequence.h | 20 ++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/blackmisc/range.h b/src/blackmisc/range.h
index 7c0b3c806..2d43d3881 100644
--- a/src/blackmisc/range.h
+++ b/src/blackmisc/range.h
@@ -180,6 +180,8 @@ namespace BlackMisc
         typedef const value_type *const_pointer;
         typedef I const_iterator;
         typedef I iterator;
+        typedef std::reverse_iterator<I> const_reverse_iterator;
+        typedef std::reverse_iterator<I> reverse_iterator;
         typedef typename std::iterator_traits<I>::difference_type difference_type;
         //! @}
 
@@ -194,6 +196,17 @@ namespace BlackMisc
         const_iterator cend() const { return m_end; }
         //! @}
 
+        //! Reverse begin and end iterators.
+        //! @{
+        const_reverse_iterator rbegin() const { return const_reverse_iterator(m_end); }
+        const_reverse_iterator crbegin() const { return const_reverse_iterator(m_end); }
+        const_reverse_iterator rend() const { return const_reverse_iterator(m_begin); }
+        const_reverse_iterator crend() const { return const_reverse_iterator(m_begin); }
+        //! @}
+
+        //! Create a range from reverse iterators.
+        CRange<const_reverse_iterator> reverse() const { return { rbegin(), rend() }; }
+
         //! Implicit conversion to any container of value_type which supports push_back. This will copy elements.
         template <class T, class = std::enable_if_t<std::is_convertible<value_type, typename T::value_type>::value>>
         operator T() const
diff --git a/src/blackmisc/sequence.h b/src/blackmisc/sequence.h
index 8756f13c2..b476fcc75 100644
--- a/src/blackmisc/sequence.h
+++ b/src/blackmisc/sequence.h
@@ -57,6 +57,8 @@ namespace BlackMisc
         typedef const T *const_pointer;
         typedef typename Iterators::ConstRandomAccessIterator<T> const_iterator;
         typedef typename Iterators::RandomAccessIterator<T> iterator;
+        typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
+        typedef std::reverse_iterator<iterator> reverse_iterator;
         typedef ptrdiff_t difference_type;
         typedef int size_type;
         //! @}
@@ -113,6 +115,24 @@ namespace BlackMisc
         //! Returns const iterator one past the end of the sequence.
         const_iterator cend() const { return pimpl() ? pimpl()->cend() : const_iterator(); }
 
+        //! Returns iterator at the beginning of the reversed sequence.
+        reverse_iterator rbegin() { return reverse_iterator(end()); }
+
+        //! Returns const iterator at the beginning of the reversed sequence.
+        const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
+
+        //! Returns const iterator at the beginning of the reversed sequence.
+        const_reverse_iterator crbegin() const { return const_reverse_iterator(cend()); }
+
+        //! Returns iterator at the end of the reversed sequence.
+        reverse_iterator rend() { return reverse_iterator(begin()); }
+
+        //! Returns const iterator at the end of the reversed sequence.
+        const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
+
+        //! Returns const iterator at the end of the reversed sequence.
+        const_reverse_iterator crend() const { return const_reverse_iterator(cbegin()); }
+
         //! Swap this sequence with another.
         void swap(CSequence &other) noexcept { m_pimpl.swap(other.m_pimpl); }