Feature: add as_span method

CHANGELOG.md

@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Tooling and docs: unit tests, mkdocs site, Doxygen docs, and version bumping config.
 - Static analysis: clang-tidy integration with follow-up fixes.
 - CI workflows for build, test on GitHub
+- `as_span()` method for creating full array views (#1)
 
 ### Changed
 

include/nd_array/nd_array.hpp

@@ -825,7 +825,7 @@ namespace cppa
 		/// \brief Creates an owning array by deep-copying an nd_span
 		/// \param t_span Source span to copy
 		/// \return Newly allocated array with the same contents
-		/// 	hrows std::invalid_argument if span rank exceeds MaxRank
+		/// \throws std::invalid_argument if span rank exceeds MaxRank
 		static nd_array from_span( const nd_span<const Ty, MaxRank>& t_span ) { return from_span_impl( t_span ); }
 
 		/// \brief Creates an owning array by deep-copying an nd_span
@@ -1206,6 +1206,20 @@ namespace cppa
 		/// \return Const pointer to the first element
 		[[nodiscard]] const_pointer data( ) const noexcept { return m_data.get( ); }
 
+		/// \brief Creates a span view of the entire array
+		/// \return Non-owning span view of all elements
+		/// \example
+		/// \code
+		/// nd_array<double> arr(3, 4);
+		/// arr.fill(1.0);
+		/// nd_span<double> span = arr.as_span();  // View of entire array
+		/// \endcode
+		[[nodiscard]] nd_span<Ty, MaxRank> as_span( ) noexcept { return nd_span<Ty, MaxRank>( m_data.get( ), m_extents, m_strides, m_rank ); }
+
+		/// \brief Creates a const span view of the entire array
+		/// \return Non-owning const span view of all elements
+		[[nodiscard]] nd_span<const Ty, MaxRank> as_span( ) const noexcept { return nd_span<const Ty, MaxRank>( m_data.get( ), m_extents, m_strides, m_rank ); }
+
 		/// \brief Returns a pointer to the first element for flat iteration
 		[[nodiscard]] pointer begin( ) noexcept { return m_data.get( ); }
 

tests/test_nd_array.cpp

@@ -501,3 +501,54 @@ TEST_CASE( "nd_array - Span to array", "[nd_array][span][copy]" )
 		REQUIRE( assigned( 0, 1 ) == 7 );
 	}
 }
+
+TEST_CASE( "nd_array - Array to span", "[nd_array][span][view]" )
+{
+	SECTION( "Create span from array" )
+	{
+		nd_array<int> arr( 3, 4 );
+		arr.fill( 5 );
+		arr( 1, 2 ) = 42;
+
+		nd_span<int> span = arr.as_span( );
+
+		REQUIRE( span.rank( ) == 2 );
+		REQUIRE( span.extent( 0 ) == 3 );
+		REQUIRE( span.extent( 1 ) == 4 );
+		REQUIRE( span.size( ) == 12 );
+		REQUIRE( span( 1, 2 ) == 42 );
+
+		// Modify through span
+		span( 0, 0 ) = 99;
+		REQUIRE( arr( 0, 0 ) == 99 );
+	}
+
+	SECTION( "Create const span from const array" )
+	{
+		const nd_array<int> arr = []( ) {
+			nd_array<int> temp( 2, 3 );
+			temp.fill( 10 );
+			return temp;
+		}( );
+
+		nd_span<const int> span = arr.as_span( );
+
+		REQUIRE( span.rank( ) == 2 );
+		REQUIRE( span.extent( 0 ) == 2 );
+		REQUIRE( span.extent( 1 ) == 3 );
+		REQUIRE( span( 0, 0 ) == 10 );
+	}
+
+	SECTION( "Span references same data" )
+	{
+		nd_array<double> arr( 5 );
+		arr.fill( 3.14 );
+
+		auto span = arr.as_span( );
+		REQUIRE( span.data( ) == arr.data( ) );
+
+		// Modify array, check span sees changes
+		arr( 3 ) = 2.71;
+		REQUIRE( span( 3 ) == 2.71 );
+	}
+}