From 941c631a5ff3deb3fc73f2d0c44738e2c36d885f Mon Sep 17 00:00:00 2001
From: 0xFEEDC0DE64 <daniel@brunner.ninja>
Date: Mon, 11 Jul 2022 16:05:42 +0200
Subject: [PATCH] Downgrade for old compiler

---
 CMakeLists.txt                  |  1 +
 src/espstrutils.cpp             |  1 +
 src/futurecpp.h                 | 30 ++++++++++++++++++++++++++++++
 src/taskutils.cpp               |  3 +++
 src/wrappers/websocket_client.h |  1 +
 5 files changed, 36 insertions(+)
 create mode 100644 src/futurecpp.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 53b3c49..44c3251 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,7 @@ set(headers
     src/espcrc32builder.h
     src/esprandom.h
     src/espstrutils.h
+    src/futurecpp.h
     src/lockhelper.h
     src/lockingqueue.h
     src/recursivelockhelper.h
diff --git a/src/espstrutils.cpp b/src/espstrutils.cpp
index 684689a..a0a0b88 100644
--- a/src/espstrutils.cpp
+++ b/src/espstrutils.cpp
@@ -10,6 +10,7 @@
 #include <esp_log.h>
 
 // 3rdparty lib includes
+#include <futurecpp.h>
 #include <fmt/core.h>
 
 using namespace std::string_literals;
diff --git a/src/futurecpp.h b/src/futurecpp.h
new file mode 100644
index 0000000..b67578c
--- /dev/null
+++ b/src/futurecpp.h
@@ -0,0 +1,30 @@
+#pragma once
+
+// system includes
+#include <cstring>
+#include <limits>
+#include <type_traits>
+
+// C++20 backports (until espressif finally updates their aged compiler suite)
+
+namespace std {
+template <class To, class From>
+typename std::enable_if_t<
+    sizeof(To) == sizeof(From) && std::is_trivially_copyable_v<From> && std::is_trivially_copyable_v<To>,
+    To>
+// constexpr support needs compiler magic
+bit_cast(const From& src) noexcept
+{
+    static_assert(std::is_trivially_constructible_v<To>,
+                  "This implementation additionally requires destination type to be trivially constructible");
+
+    To dst;
+    std::memcpy(&dst, &src, sizeof(To));
+    return dst;
+}
+
+template <typename EnumT, typename = std::enable_if_t<std::is_enum<EnumT>{}>>
+constexpr std::underlying_type_t<EnumT> to_underlying(EnumT e) noexcept {
+    return static_cast<std::underlying_type_t<EnumT>>(e);
+}
+} // namespace std
diff --git a/src/taskutils.cpp b/src/taskutils.cpp
index f4f0ae8..daaf29c 100644
--- a/src/taskutils.cpp
+++ b/src/taskutils.cpp
@@ -9,6 +9,9 @@
 // esp-idf includes
 #include <esp_log.h>
 
+// 3rdparty lib includes
+#include <futurecpp.h>
+
 namespace espcpputils {
 namespace {
 constexpr const char * const TAG = "ESPCPPUTILS";
diff --git a/src/wrappers/websocket_client.h b/src/wrappers/websocket_client.h
index 49582cd..163cb3d 100644
--- a/src/wrappers/websocket_client.h
+++ b/src/wrappers/websocket_client.h
@@ -11,6 +11,7 @@
 
 // 3rdparty lib includes
 #include <fmt/core.h>
+#include <futurecpp.h>
 
 namespace espcpputils {
 class websocket_client