Added const chunk iterators

Author: JohanMabille

include/xtensor/xchunked_array.hpp

@@ -75,7 +75,8 @@ namespace xt
         using bool_load_type = xt::bool_load_type<value_type>;
         static constexpr layout_type static_layout = layout_type::dynamic;
         static constexpr bool contiguous_layout = false;
-        using chunk_iterator_type = xchunk_iterator<self_type>;
+        using chunk_iterator = xchunk_iterator<self_type>;
+        using const_chunk_iterator = xchunk_iterator<const self_type>;
 
         template <class S>
         xchunked_array(chunk_storage_type&& chunks, S&& shape, S&& chunk_shape, layout_type chunk_memory_layout = XTENSOR_DEFAULT_LAYOUT);
@@ -136,8 +137,13 @@ namespace xt
         chunk_storage_type& chunks();
         const chunk_storage_type& chunks() const;
 
-        chunk_iterator_type chunk_begin();
-        chunk_iterator_type chunk_end();
+        chunk_iterator chunk_begin();
+        chunk_iterator chunk_end();
+
+        const_chunk_iterator chunk_begin() const;
+        const_chunk_iterator chunk_end() const;
+        const_chunk_iterator chunk_cbegin() const;
+        const_chunk_iterator chunk_cend() const;
 
     private:
 
@@ -489,17 +495,44 @@ namespace xt
     }
 
     template <class CS>
-    inline auto xchunked_array<CS>::chunk_begin() -> chunk_iterator_type
+    inline auto xchunked_array<CS>::chunk_begin() -> chunk_iterator
+    {
+        shape_type chunk_index(m_shape.size(), size_type(0));
+        return chunk_iterator(*this, std::move(chunk_index), 0u);
+    }
+
+    template <class CS>
+    inline auto xchunked_array<CS>::chunk_end() -> chunk_iterator
+    {
+        shape_type sh = xtl::forward_sequence<shape_type, const grid_shape_type>(grid_shape());
+        return chunk_iterator(*this, std::move(sh), grid_size());
+    }
+
+    template <class CS>
+    inline auto xchunked_array<CS>::chunk_begin() const -> const_chunk_iterator
     {
         shape_type chunk_index(m_shape.size(), size_type(0));
-        return chunk_iterator_type(*this, std::move(chunk_index), 0u);
+        return const_chunk_iterator(*this, std::move(chunk_index), 0u);
     }
 
     template <class CS>
-    inline auto xchunked_array<CS>::chunk_end() -> chunk_iterator_type
+    inline auto xchunked_array<CS>::chunk_end() const -> const_chunk_iterator
     {
         shape_type sh = xtl::forward_sequence<shape_type, const grid_shape_type>(grid_shape());
-        return chunk_iterator_type(*this, std::move(sh), grid_size());
+        return const_chunk_iterator(*this, std::move(sh), grid_size());
+    }
+
+    template <class CS>
+    inline auto xchunked_array<CS>::chunk_cbegin() const -> const_chunk_iterator
+    {
+        return chunk_begin();
+    }
+
+    template <class CS>
+    inline auto xchunked_array<CS>::chunk_cend() const -> const_chunk_iterator
+    {
+        return chunk_end();
+
     }
 
     template <class CS>

include/xtensor/xchunked_view.hpp

@@ -35,7 +35,8 @@ namespace xt
         using expression_type = std::decay_t<E>;
         using size_type = size_t;
         using shape_type = svector<size_type>;
-        using chunk_iterator_type = xchunk_iterator<self_type>;
+        using chunk_iterator = xchunk_iterator<self_type>;
+        using const_chunk_iterator = xchunk_iterator<const self_type>;
 
         template <class OE, class S>
         xchunked_view(OE&& e, S&& chunk_shape);
@@ -52,8 +53,13 @@ namespace xt
         expression_type& expression() noexcept;
         const expression_type& expression() const noexcept;
 
-        chunk_iterator_type chunk_begin();
-        chunk_iterator_type chunk_end();
+        chunk_iterator chunk_begin();
+        chunk_iterator chunk_end();
+
+        const_chunk_iterator chunk_begin() const;
+        const_chunk_iterator chunk_end() const;
+        const_chunk_iterator chunk_cbegin() const;
+        const_chunk_iterator chunk_cend() const;
 
     private:
 
@@ -155,16 +161,41 @@ namespace xt
     }
 
     template <class E>
-    inline auto xchunked_view<E>::chunk_begin() -> chunk_iterator_type
+    inline auto xchunked_view<E>::chunk_begin() -> chunk_iterator
+    {
+        shape_type chunk_index(m_shape.size(), size_type(0));
+        return chunk_iterator(*this, std::move(chunk_index), 0u);
+    }
+
+    template <class E>
+    inline auto xchunked_view<E>::chunk_end() -> chunk_iterator
+    {
+        return chunk_iterator(*this, shape_type(grid_shape()), grid_size());
+    }
+
+    template <class E>
+    inline auto xchunked_view<E>::chunk_begin() const -> const_chunk_iterator
     {
         shape_type chunk_index(m_shape.size(), size_type(0));
-        return chunk_iterator_type(*this, std::move(chunk_index), 0u);
+        return const_chunk_iterator(*this, std::move(chunk_index), 0u);
+    }
+
+    template <class E>
+    inline auto xchunked_view<E>::chunk_end() const -> const_chunk_iterator
+    {
+        return const_chunk_iterator(*this, shape_type(grid_shape()), grid_size());
+    }
+
+    template <class E>
+    inline auto xchunked_view<E>::chunk_cbegin() const -> const_chunk_iterator
+    {
+        return chunk_begin();
     }
 
     template <class E>
-    inline auto xchunked_view<E>::chunk_end() -> chunk_iterator_type
+    inline auto xchunked_view<E>::chunk_cend() const -> const_chunk_iterator
     {
-        return chunk_iterator_type(*this, shape_type(grid_shape()), grid_size());
+        return chunk_end();
     }
 
     template <class E, class S>

test/test_xchunked_array.cpp

@@ -123,4 +123,30 @@ namespace xt
 
         EXPECT_EQ(a, b);
     }
+
+    TEST(xchunked_array, chunk_iterator)
+    {
+        std::vector<std::size_t> shape = {10, 10, 10};
+        std::vector<std::size_t> chunk_shape = {2, 2, 2};
+        auto a = chunked_array<double>(shape, chunk_shape);
+        xt::xarray<double> b = arange(1000).reshape({10, 10, 10});
+        noalias(a) = b;
+
+        auto it = a.chunk_begin();
+        auto cit = a.chunk_cbegin();
+
+        for (size_t i = 0; i < 5; ++i)
+        {
+            for (size_t j = 0; j < 5; ++j)
+            {
+                for (size_t k = 0; k < 5; ++k)
+                {
+                    EXPECT_EQ(*((*it).begin()), a(2*i, 2*j, 2*k));
+                    EXPECT_EQ(*((*cit).cbegin()), a(2*i, 2*j, 2*k));
+                    ++it;
+                    ++cit;
+                }
+            }
+        }
+    }
 }