Adding the make_transform_view functions

cmake/unit_testing.cmake

@@ -31,3 +31,4 @@ add_subdirectory( src/tools/Log/test )
 add_subdirectory( src/tools/ranges/IteratorView/test )
 add_subdirectory( src/tools/ranges/TransformIterator/test )
 add_subdirectory( src/tools/ranges/make_view/test )
+add_subdirectory( src/tools/ranges/make_transform_view/test )

src/tools/ranges.hpp

@@ -2,3 +2,4 @@
 #include "tools/ranges/TransformIterator.hpp"
 
 #include "tools/ranges/make_view.hpp"
+#include "tools/ranges/make_transform_view.hpp"

src/tools/ranges/make_transform_view.hpp

@@ -0,0 +1,48 @@
+#ifndef NJOY_TOOLS_RANGES_MAKE_TRANSFORM_VIEW
+#define NJOY_TOOLS_RANGES_MAKE_TRANSFORM_VIEW
+
+// system includes
+
+// other includes
+#include "tools/ranges/IteratorView.hpp"
+#include "tools/ranges/TransformIterator.hpp"
+
+namespace njoy {
+namespace tools {
+namespace ranges {
+
+/**
+ *  @brief Make an IteratorView based on two iterators and a transformation
+ *
+ *  @param[in] begin             the iterator to the beginning of the view
+ *  @param[in] end               the iterator to the end of the view
+ *  @param[in] transformation    the transformation to be applied
+ */
+template < typename Iterator, typename Transformation >
+constexpr auto make_transform_view( Iterator begin, Iterator end,
+                                    Transformation transformation ) {
+
+  using Iter = TransformIterator< Iterator, Transformation >;
+  return IteratorView< Iter >{ Iter( std::move( begin ), transformation ),
+                               Iter( std::move( end ), transformation ) };
+}
+
+/**
+ *  @brief Make an IteratorView based on a container and a transformation
+ *
+ *  @param[in] container         the container
+ *  @param[in] transformation    the transformation to be applied
+ */
+template < typename Container, typename Transformation >
+constexpr auto make_transform_view( Container&& container,
+                                    Transformation transformation ) {
+
+  return make_transform_view( container.begin(), container.end(),
+                              std::move( transformation ) );
+}
+
+} // ranges namespace
+} // tools namespace
+} // njoy namespace
+
+#endif

src/tools/ranges/make_transform_view/test/CMakeLists.txt

@@ -0,0 +1 @@
+add_cpp_test( ranges.make_transform_view make_transform_view.test.cpp )

src/tools/ranges/make_transform_view/test/make_transform_view.test.cpp

@@ -0,0 +1,71 @@
+// include Catch2
+#include <catch2/catch_test_macros.hpp>
+
+// what we are testing
+#include "tools/ranges/make_transform_view.hpp"
+
+// other includes
+
+// convenience typedefs
+using namespace njoy::tools::ranges;
+
+SCENARIO( "make_view" ) {
+
+  GIVEN( "a container with values and a transformation" ) {
+
+    std::vector< int > values = { -2, -1, 0, 1, 2 };
+    auto transform = [] ( auto&& value ) { return 2 * value; };
+
+    WHEN( "when using iterators and the transformation" ) {
+
+      auto chunk = make_transform_view( values.begin(), values.end(), transform );
+
+      THEN( "an IteratorView can be constructed and members can be tested" ) {
+
+        CHECK( 5 == chunk.size() );
+        CHECK( false == chunk.empty() );
+
+        CHECK( -4 == chunk[0] );
+        CHECK( -2 == chunk[1] );
+        CHECK(  0 == chunk[2] );
+        CHECK(  2 == chunk[3] );
+        CHECK(  4 == chunk[4] );
+
+        CHECK( -4 == chunk.at( 0 ) );
+        CHECK( -2 == chunk.at( 1 ) );
+        CHECK(  0 == chunk.at( 2 ) );
+        CHECK(  2 == chunk.at( 3 ) );
+        CHECK(  4 == chunk.at( 4 ) );
+
+        CHECK( -4 == chunk.front() );
+        CHECK(  4 == chunk.back() );
+      } // THEN
+    } // WHEN
+
+    WHEN( "when using the container and the transformation" ) {
+
+      auto chunk = make_transform_view( values, transform );
+
+      THEN( "an IteratorView can be constructed and members can be tested" ) {
+
+        CHECK( 5 == chunk.size() );
+        CHECK( false == chunk.empty() );
+
+        CHECK( -4 == chunk[0] );
+        CHECK( -2 == chunk[1] );
+        CHECK(  0 == chunk[2] );
+        CHECK(  2 == chunk[3] );
+        CHECK(  4 == chunk[4] );
+
+        CHECK( -4 == chunk.at( 0 ) );
+        CHECK( -2 == chunk.at( 1 ) );
+        CHECK(  0 == chunk.at( 2 ) );
+        CHECK(  2 == chunk.at( 3 ) );
+        CHECK(  4 == chunk.at( 4 ) );
+
+        CHECK( -4 == chunk.front() );
+        CHECK(  4 == chunk.back() );
+      } // THEN
+    } // WHEN
+  } // GIVEN
+} // SCENARIO