Add span length and addition

core/test/base/range.cpp

@@ -60,6 +60,19 @@ TEST(Span, CreatesPoint)
 }
 
 
+TEST(Span, AddsSpan)
+{
+    ASSERT_EQ(gko::span(6, 10), gko::span(2, 3) + gko::span(4, 7));
+}
+
+
+TEST(Span, KnowsItsLength)
+{
+    gko::span s{3, 5};
+    ASSERT_EQ(2, s.length());
+}
+
+
 TEST(Span, LessThanEvaluatesToTrue)
 {
     ASSERT_TRUE(gko::span(2, 3) < gko::span(4, 7));
@@ -645,7 +658,7 @@ TEST(Range, DividesScalarAndRange)
 }
 
 
-TEST(Range, AddsRangeAndSclar)
+TEST(Range, AddsRangeAndScalar)
 {
     dummy_range r{5u, 1, 2};
 
@@ -656,7 +669,7 @@ TEST(Range, AddsRangeAndSclar)
 }
 
 
-TEST(Range, SubtractsRangeAndSclar)
+TEST(Range, SubtractsRangeAndScalar)
 {
     dummy_range r{5u, 1, 2};
 
@@ -667,7 +680,7 @@ TEST(Range, SubtractsRangeAndSclar)
 }
 
 
-TEST(Range, MultipliesRangeAndSclar)
+TEST(Range, MultipliesRangeAndScalar)
 {
     dummy_range r{5u, 1, 2};
 
@@ -678,7 +691,7 @@ TEST(Range, MultipliesRangeAndSclar)
 }
 
 
-TEST(Range, DividesRangeAndSclar)
+TEST(Range, DividesRangeAndScalar)
 {
     dummy_range r{5u, 1, 2};
 

include/ginkgo/core/base/range.hpp

@@ -101,6 +101,17 @@ struct span {
      */
     constexpr bool is_valid() const { return begin < end; }
 
+    /**
+     * Returns the length of a span.
+     *
+     * @return `this->end - this->begin`
+     */
+    constexpr size_type length() const
+    {
+        GKO_ASSERT(is_valid());
+        return end - begin;
+    }
+
     /**
      * Beginning of the span.
      */
@@ -155,6 +166,13 @@ GKO_ATTRIBUTES GKO_INLINE constexpr bool operator!=(const span &first,
 }
 
 
+GKO_ATTRIBUTES GKO_INLINE constexpr span operator+(const span &first,
+                                                   const span &second)
+{
+    return gko::span{first.begin + second.begin, first.end + second.end};
+}
+
+
 namespace detail {