add constexpr-array-shim to test constexpr on C++14

test/CMakeLists.txt

@@ -7,6 +7,7 @@ foreach(test-source ${test-sources})
     list(APPEND test-targets ${test-target})
 
     add_executable(${test-target} ${test-source})
+    target_include_directories(${test-target} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
     target_link_libraries(${test-target} PRIVATE ring-buffer)
 endforeach()
 
@@ -27,7 +28,7 @@ foreach(test-directory ${test-directories})
     endif()
     add_executable(${test-target} ${test-directory-sources})
     if(IS_DIRECTORY ${test-directory}/include)
-        target_include_directories(${test-target} PRIVATE ${test-directory}/include)
+        target_include_directories(${test-target} PRIVATE ${CMAKE_CURRENT_SOURCE_DIR} ${test-directory}/include)
     endif()
     target_link_libraries(${test-target} PRIVATE ring-buffer)
 endforeach()

test/constexpr-array-shim.h

@@ -0,0 +1,56 @@
+#ifndef _CONSTEXPR_ARRAY_SHIM_H
+#define _CONSTEXPR_ARRAY_SHIM_H
+
+#include <array>
+
+#if defined( __cpp_lib_array_constexpr) && __cpp_lib_array_constexpr >= 201606L
+template <typename T, size_t N>
+using constexpr_array = array;
+#else
+template <typename T, size_t N>
+struct constexpr_array {
+    using size_type = size_t;
+    using value_type = T;
+
+    T data[N];
+
+    constexpr size_t size() const {
+        return N;
+    }
+
+    constexpr T* begin() {
+        return data;
+    }
+
+    constexpr T* end() {
+        return &data[N];
+    }
+
+    constexpr const T* begin() const {
+        return data;
+    }
+
+    constexpr const T* end() const {
+        return &data[N];
+    }
+
+    constexpr const T* cbegin() const {
+        return data;
+    }
+
+    constexpr const T* cend() const {
+        return &data[N];
+    }
+
+    constexpr T& operator[](size_t index) {
+        return data[index];
+    }
+
+    constexpr const T& operator[](size_t index) const {
+        return data[index];
+    }
+};
+
+#endif
+
+#endif

test/push-iterate-const-constexpr.cpp

@@ -2,8 +2,10 @@
 #include <ring-buffer.h>
 
 #ifdef RING_BUFFER_CONSTEXPR
+#include "constexpr-array-shim.h"
+
 template <typename T, size_t N>
-constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b) {
+constexpr bool array_equal(const constexpr_array<T, N>& a, const constexpr_array<T, N>& b) {
     for (size_t i = 0; i < N; i++) {
         if (a[i] != b[i]) return false;
     }
@@ -12,9 +14,9 @@ constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b)
 }
 
 constexpr bool test() {
-    std::array<int, 4> init{0, 0, 0, 0};
-    ring_buffer<int, 4> buf(init);
-    const ring_buffer<int, 4>& const_buf = buf;
+    constexpr_array<int, 4> init{0, 0, 0, 0};
+    basic_ring_buffer<constexpr_array<int, 4>> buf(init);
+    const basic_ring_buffer<constexpr_array<int, 4>>& const_buf = buf;
 
     buf.push_back(1);
     buf.push_back(2);
@@ -24,8 +26,8 @@ constexpr bool test() {
     buf.push_back(6);
 
     {
-        std::array<int, 4> expected{3, 4, 5, 6};
-        std::array<int, 4> actual{0, 0, 0, 0};
+        constexpr_array<int, 4> expected{3, 4, 5, 6};
+        constexpr_array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (const int& i : const_buf) {
             actual[actual_index++] = i;
@@ -36,8 +38,8 @@ constexpr bool test() {
     buf.push_back(7);
 
     {
-        std::array<int, 4> expected{4, 5, 6, 7};
-        std::array<int, 4> actual{0, 0, 0, 0};
+        constexpr_array<int, 4> expected{4, 5, 6, 7};
+        constexpr_array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (const int& i : const_buf) {
             actual[actual_index++] = i;
@@ -48,7 +50,7 @@ constexpr bool test() {
     return true;
 }
 
-static_assert(test());
+static_assert(test(), "");
 #endif
 
 int main() {}

test/push-iterate-constexpr.cpp

@@ -2,8 +2,10 @@
 #include <ring-buffer.h>
 
 #ifdef RING_BUFFER_CONSTEXPR
+#include "constexpr-array-shim.h"
+
 template <typename T, size_t N>
-constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b) {
+constexpr bool array_equal(const constexpr_array<T, N>& a, const constexpr_array<T, N>& b) {
     for (size_t i = 0; i < N; i++) {
         if (a[i] != b[i]) return false;
     }
@@ -12,8 +14,8 @@ constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b)
 }
 
 constexpr bool test() {
-    std::array<int, 4> init{0, 0, 0, 0};
-    ring_buffer<int, 4> buf(init);
+    constexpr_array<int, 4> init{0, 0, 0, 0};
+    basic_ring_buffer<constexpr_array<int, 4>> buf(init);
 
     buf.push_back(1);
     buf.push_back(2);
@@ -23,8 +25,8 @@ constexpr bool test() {
     buf.push_back(6);
 
     {
-        std::array<int, 4> expected{13, 14, 15, 16};
-        std::array<int, 4> actual{0, 0, 0, 0};
+        constexpr_array<int, 4> expected{13, 14, 15, 16};
+        constexpr_array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (int& i : buf) {
             i += 10;
@@ -36,8 +38,8 @@ constexpr bool test() {
     buf.push_back(7);
 
     {
-        std::array<int, 4> expected{24, 25, 26, 17};
-        std::array<int, 4> actual{0, 0, 0, 0};
+        constexpr_array<int, 4> expected{24, 25, 26, 17};
+        constexpr_array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (int& i : buf) {
             i += 10;
@@ -49,7 +51,7 @@ constexpr bool test() {
     return true;
 }
 
-static_assert(test());
+static_assert(test(), "");
 #endif
 
 int main() {}