kfr

commit 0623d0d73c72b57ed50a0499a9646af05b5f1489
parent 17451d4038fda5ad6a720003554db67ee56a9b2e
Author: [email protected] <[email protected]>
Date:   Wed,  7 Sep 2016 15:20:53 +0300

New function: reverse(Expr)

Diffstat:
M
include/kfr/base/basic_expressions.hpp
 | 
22
++++++++++++++++++++++
M
tests/expression_test.cpp
 | 
8
++++++++

2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/include/kfr/base/basic_expressions.hpp b/include/kfr/base/basic_expressions.hpp
@@ -190,6 +190,21 @@ struct expression_slice : expression<E1>
     size_t new_size;
 };
 
+template <typename E1>
+struct expression_reverse : expression<E1>
+{
+    using value_type = value_type_of<E1>;
+    using T          = value_type;
+    expression_reverse(E1&& e1) : expression<E1>(std::forward<E1>(e1)), expr_size(e1.size()) {}
+    template <size_t N>
+    CMT_INLINE vec<T, N> operator()(cinput_t, size_t index, vec_t<T, N> y) const
+    {
+        return reverse(this->argument_first(expr_size - index - N, y));
+    }
+    size_t size() const { return expr_size; }
+    size_t expr_size;
+};
+
 template <typename T, bool precise = false>
 struct expression_linspace;
 
@@ -334,6 +349,13 @@ CMT_INLINE internal::expression_slice<E1> truncate(E1&& e1, size_t size)
     return internal::expression_slice<E1>(std::forward<E1>(e1), 0, size);
 }
 
+template <typename E1, KFR_ENABLE_IF(is_input_expression<E1>::value)>
+CMT_INLINE internal::expression_reverse<E1> reverse(E1&& e1)
+{
+    static_assert(!is_infinite<E1>::value, "e1 must be a sized expression (use slice())");
+    return internal::expression_reverse<E1>(std::forward<E1>(e1));
+}
+
 template <typename T1, typename T2, bool precise = false, typename TF = ftype<common_type<T1, T2>>>
 CMT_INLINE internal::expression_linspace<TF, precise> linspace(T1 start, T2 stop, size_t size,
                                                                bool endpoint = false)
diff --git a/tests/expression_test.cpp b/tests/expression_test.cpp
@@ -91,6 +91,14 @@ TEST(size_calc)
     CHECK(d.size() == 900);
 }
 
+TEST(reverse)
+{
+    univector<int, 21> a = reverse(truncate(counter(), 21));
+    CHECK(a[0] == 20);
+    CHECK(a[1] == 19);
+    CHECK(a[20] == 0);
+}
+
 int main(int argc, char** argv)
 {
     println(library_version());