From 47f3737fb4debec248626e1a6001d91a1fde79d5 Mon Sep 17 00:00:00 2001
From: Ferdinand Bachmann <theferdi265@gmail.com>
Date: Sat, 18 Apr 2020 13:46:17 +0200
Subject: [PATCH] fix ring-buffer for simple constexpr usage

---
 include/ring-buffer.h                 | 2 ++
 test/push-iterate-const-constexpr.cpp | 9 ++++++---
 test/push-iterate-constexpr.cpp       | 9 ++++++---
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/ring-buffer.h b/include/ring-buffer.h
index 939681f..6cf6d70 100644
--- a/include/ring-buffer.h
+++ b/include/ring-buffer.h
@@ -2,6 +2,7 @@
 #define _RING_BUFFER_H
 
 #include <array>
+#include <utility>
 #include <ring-buffer-config.h>
 #include <ring-buffer-iterator.h>
 
@@ -20,6 +21,7 @@ private:
 public:
     basic_ring_buffer() = default;
     ~basic_ring_buffer() = default;
+    CONSTEXPR basic_ring_buffer(const Container& other) COND_NOEXCEPT(noexcept(Container(other))) : container(other) {}
     basic_ring_buffer(const basic_ring_buffer& other) = default;
     basic_ring_buffer(basic_ring_buffer&& other) = default;
     basic_ring_buffer& operator=(const basic_ring_buffer& other) = default;
diff --git a/test/push-iterate-const-constexpr.cpp b/test/push-iterate-const-constexpr.cpp
index 2deb805..93080ac 100644
--- a/test/push-iterate-const-constexpr.cpp
+++ b/test/push-iterate-const-constexpr.cpp
@@ -1,6 +1,7 @@
 #include <array>
 #include <ring-buffer.h>
 
+#ifdef RING_BUFFER_CONSTEXPR
 template <typename T, size_t N>
 constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b) {
     for (size_t i = 0; i < N; i++) {
@@ -11,7 +12,8 @@ constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b)
 }
 
 constexpr bool test() {
-    ring_buffer<int, 4> buf;
+    std::array<int, 4> init{0, 0, 0, 0};
+    ring_buffer<int, 4> buf(init);
     const ring_buffer<int, 4>& const_buf = buf;
 
     buf.push_back(1);
@@ -23,7 +25,7 @@ constexpr bool test() {
 
     {
         std::array<int, 4> expected{3, 4, 5, 6};
-        std::array<int, 4> actual;
+        std::array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (const int& i : const_buf) {
             actual[actual_index++] = i;
@@ -35,7 +37,7 @@ constexpr bool test() {
 
     {
         std::array<int, 4> expected{4, 5, 6, 7};
-        std::array<int, 4> actual;
+        std::array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (const int& i : const_buf) {
             actual[actual_index++] = i;
@@ -47,5 +49,6 @@ constexpr bool test() {
 }
 
 static_assert(test());
+#endif
 
 int main() {}
diff --git a/test/push-iterate-constexpr.cpp b/test/push-iterate-constexpr.cpp
index 16e1ccc..226bf5a 100644
--- a/test/push-iterate-constexpr.cpp
+++ b/test/push-iterate-constexpr.cpp
@@ -1,6 +1,7 @@
 #include <array>
 #include <ring-buffer.h>
 
+#ifdef RING_BUFFER_CONSTEXPR
 template <typename T, size_t N>
 constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b) {
     for (size_t i = 0; i < N; i++) {
@@ -11,7 +12,8 @@ constexpr bool array_equal(const std::array<T, N>& a, const std::array<T, N>& b)
 }
 
 constexpr bool test() {
-    ring_buffer<int, 4> buf;
+    std::array<int, 4> init{0, 0, 0, 0};
+    ring_buffer<int, 4> buf(init);
 
     buf.push_back(1);
     buf.push_back(2);
@@ -22,7 +24,7 @@ constexpr bool test() {
 
     {
         std::array<int, 4> expected{13, 14, 15, 16};
-        std::array<int, 4> actual;
+        std::array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (int& i : buf) {
             i += 10;
@@ -35,7 +37,7 @@ constexpr bool test() {
 
     {
         std::array<int, 4> expected{24, 25, 26, 17};
-        std::array<int, 4> actual;
+        std::array<int, 4> actual{0, 0, 0, 0};
         int actual_index = 0;
         for (int& i : buf) {
             i += 10;
@@ -48,5 +50,6 @@ constexpr bool test() {
 }
 
 static_assert(test());
+#endif
 
 int main() {}