From dfa8ea714df17d04ed1f2034562d7f5304b5f296 Mon Sep 17 00:00:00 2001
From: Marc Emmers <m.emmers@syrinx.nl>
Date: Wed, 8 Jul 2020 17:14:39 +0200
Subject: [PATCH] Add begin, end, rbegin and rend iterator functions to Span

---
 platform/Span.h | 100 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

diff --git a/platform/Span.h b/platform/Span.h
index c5bac9d682..8f542466f1 100644
--- a/platform/Span.h
+++ b/platform/Span.h
@@ -233,6 +233,16 @@ struct Span {
      */
     typedef element_type &reference;
 
+    /**
+     * Iterator to an ElementType
+     */
+    typedef pointer iterator;
+
+    /**
+     * Reverse iterator to an ElementType
+     */
+    typedef std::reverse_iterator<iterator> reverse_iterator;
+
     /**
      * Size of the Extent; -1 if dynamic.
      */
@@ -349,6 +359,46 @@ struct Span {
         return size() == 0;
     }
 
+    /**
+     * Return an iterator to the first element of the sequence.
+     *
+     * @return An iterator to the first element of the sequence.
+     */
+    iterator begin() const
+    {
+        return _data;
+    }
+
+    /**
+     * Return an iterator to the element following the last element of the sequence.
+     *
+     * @return An iterator to the element following the last element of the sequence.
+     */
+    iterator end() const
+    {
+        return _data + Extent;
+    }
+
+    /**
+     * Return a reverse_iterator to the first element of the reversed sequence.
+     *
+     * @return A reverse_iterator to the first element of the reversed sequence.
+     */
+    reverse_iterator rbegin() const
+    {
+        return reverse_iterator(end());
+    }
+
+    /**
+     * Return a reverse_iterator to the element following the last element of the reversed sequence.
+     *
+     * @return A reverse_iterator to the element following the last element of the reversed sequence.
+     */
+    reverse_iterator rend() const
+    {
+        return reverse_iterator(begin());
+    }
+
     /**
      * Returns a reference to the element at position @p index.
      *
@@ -534,6 +584,16 @@ struct Span<ElementType, SPAN_DYNAMIC_EXTENT> {
      */
     typedef element_type &reference;
 
+    /**
+     * Iterator to an ElementType
+     */
+    typedef pointer iterator;
+
+    /**
+     * Reverse iterator to an ElementType
+     */
+    typedef std::reverse_iterator<iterator> reverse_iterator;
+
     /**
      * Size of the Extent; -1 if dynamic.
      */
@@ -644,6 +704,46 @@ struct Span<ElementType, SPAN_DYNAMIC_EXTENT> {
         return size() == 0;
     }
 
+    /**
+     * Return an iterator to the first element of the sequence.
+     *
+     * @return An iterator to the first element of the sequence.
+     */
+    iterator begin() const
+    {
+        return _data;
+    }
+
+    /**
+     * Return an iterator to the element following the last element of the sequence.
+     *
+     * @return An iterator to the element following the last element of the sequence.
+     */
+    iterator end() const
+    {
+        return _data + _size;
+    }
+
+    /**
+     * Return a reverse_iterator to the first element of the reversed sequence.
+     *
+     * @return A reverse_iterator to the first element of the reversed sequence.
+     */
+    reverse_iterator rbegin() const
+    {
+        return reverse_iterator(end());
+    }
+
+    /**
+     * Return a reverse_iterator to the element following the last element of the reversed sequence.
+     *
+     * @return A reverse_iterator to the element following the last element of the reversed sequence.
+     */
+    reverse_iterator rend() const
+    {
+        return reverse_iterator(begin());
+    }
+
     /**
      * Access to an element of the sequence.
      *