Add class ArraySelector
The ArraySelector selects the best array implementation based on
template arguments.
Change-Id: I93c6db1a638e924b85292e63bca9525610ec2e2f
diff --git a/include/ceres/internal/array_selector.h b/include/ceres/internal/array_selector.h
new file mode 100644
index 0000000..841797f
--- /dev/null
+++ b/include/ceres/internal/array_selector.h
@@ -0,0 +1,95 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2020 Google Inc. All rights reserved.
+// http://ceres-solver.org/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: darius.rueckert@fau.de (Darius Rueckert)
+//
+
+#ifndef CERES_PUBLIC_INTERNAL_ARRAY_SELECTOR_H_
+#define CERES_PUBLIC_INTERNAL_ARRAY_SELECTOR_H_
+
+#include <array>
+#include <vector>
+
+#include "ceres/internal/fixed_array.h"
+#include "ceres/types.h"
+
+namespace ceres {
+namespace internal {
+
+// StaticFixedArray selects the best array implementation based on template
+// arguments. If the size is not known at compile-time, pass
+// ceres::DYNAMIC as a size-template argument.
+//
+// Three different containers are selected in different scenarios:
+//
+// num_elements == DYNAMIC:
+// -> ceres::internal::FixedArray<T, max_stack_size>(size)
+
+// num_elements != DYNAMIC && num_elements <= max_stack_size
+// -> std::array<T,num_elements>
+
+// num_elements != DYNAMIC && num_elements > max_stack_size
+// -> std::vector<T>(num_elements)
+//
+template <typename T,
+ int num_elements,
+ int max_num_elements_on_stack,
+ bool dynamic = (num_elements == DYNAMIC),
+ bool fits_on_stack = (num_elements <= max_num_elements_on_stack)>
+struct ArraySelector {};
+
+template <typename T,
+ int num_elements,
+ int max_num_elements_on_stack,
+ bool fits_on_stack>
+struct ArraySelector<T,
+ num_elements,
+ max_num_elements_on_stack,
+ true,
+ fits_on_stack>
+ : ceres::internal::FixedArray<T, max_num_elements_on_stack> {
+ ArraySelector(int s)
+ : ceres::internal::FixedArray<T, max_num_elements_on_stack>(s) {}
+};
+
+template <typename T, int num_elements, int max_num_elements_on_stack>
+struct ArraySelector<T, num_elements, max_num_elements_on_stack, false, true>
+ : std::array<T, num_elements> {
+ ArraySelector(int s) { CHECK_EQ(s, num_elements); }
+};
+
+template <typename T, int num_elements, int max_num_elements_on_stack>
+struct ArraySelector<T, num_elements, max_num_elements_on_stack, false, false>
+ : std::vector<T> {
+ ArraySelector(int s) : std::vector<T>(s) { CHECK_EQ(s, num_elements); }
+};
+
+} // namespace internal
+} // namespace ceres
+
+#endif // CERES_PUBLIC_INTERNAL_ARRAY_SELECTOR_H_
diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index 9329162..ea67cf2 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -409,6 +409,7 @@
ceres_test(algorithm)
ceres_test(array_utils)
+ ceres_test(array_selector)
ceres_test(autodiff)
ceres_test(autodiff_first_order_function)
ceres_test(autodiff_cost_function)
diff --git a/internal/ceres/array_selector_test.cc b/internal/ceres/array_selector_test.cc
new file mode 100644
index 0000000..f7fef3c
--- /dev/null
+++ b/internal/ceres/array_selector_test.cc
@@ -0,0 +1,79 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2020 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation
+// and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+// used to endorse or promote products derived from this software without
+// specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: darius.rueckert@fau.de (Darius Rueckert)
+//
+
+#include "ceres/internal/array_selector.h"
+
+#include "gtest/gtest.h"
+
+namespace ceres {
+namespace internal {
+
+// This test only checks, if the correct array implementations are selected. The
+// test for FixedArray is in fixed_array_test.cc. Tests for std::array and
+// std::vector are not included in ceres.
+TEST(ArraySelector, FixedArray) {
+ ArraySelector<int, DYNAMIC, 20> array1(10);
+ static_assert(
+ std::is_base_of<internal::FixedArray<int, 20>, decltype(array1)>::value,
+ "");
+ EXPECT_EQ(array1.size(), 10);
+
+ ArraySelector<int, DYNAMIC, 10> array2(20);
+ static_assert(
+ std::is_base_of<internal::FixedArray<int, 10>, decltype(array2)>::value,
+ "");
+ EXPECT_EQ(array2.size(), 20);
+}
+
+TEST(ArraySelector, Array) {
+ ArraySelector<int, 10, 20> array1(10);
+ static_assert(std::is_base_of<std::array<int, 10>, decltype(array1)>::value,
+ "");
+ EXPECT_EQ(array1.size(), 10);
+
+ ArraySelector<int, 20, 20> array2(20);
+ static_assert(std::is_base_of<std::array<int, 20>, decltype(array2)>::value,
+ "");
+ EXPECT_EQ(array2.size(), 20);
+}
+
+TEST(ArraySelector, Vector) {
+ ArraySelector<int, 20, 10> array1(20);
+ static_assert(std::is_base_of<std::vector<int>, decltype(array1)>::value, "");
+ EXPECT_EQ(array1.size(), 20);
+
+ ArraySelector<int, 1, 0> array2(1);
+ static_assert(std::is_base_of<std::vector<int>, decltype(array2)>::value, "");
+ EXPECT_EQ(array2.size(), 1);
+}
+
+} // namespace internal
+} // namespace ceres
