fuse separated into separate header

BUILD.bazel

@@ -6,7 +6,7 @@ package(default_visibility = ["//visibility:public"])
 
 cc_library(
     name = "magic_enum",
-    hdrs = ["include/magic_enum.hpp"],
+    hdrs = ["include/magic_enum.hpp", "include/magic_enum_fuse.hpp"],
     includes = ["include"],
 )
 

doc/reference.md

@@ -350,6 +350,8 @@ template <typename... Es>
 [[nodiscard]] constexpr optional<enum_fuse_t> enum_fuse(Es... values) noexcept;
 ```
 
+* You should add the required file `<magic_enum_fuse.hpp>`.
+
 * Returns a typesafe bijective mix of several enum values. This can be used to emulate 2D switch/case statements.
 
 * Return type is `optional<enum_fuse_t>` where `enum_fuse_t` is an incomplete enum, it is unique for any given combination of `Es...`.

include/magic_enum.hpp

@@ -1277,54 +1277,6 @@ constexpr auto enum_for_each(Lambda&& lambda) {
   return detail::for_each<D>(std::forward<Lambda>(lambda), std::make_index_sequence<detail::count_v<D>>{});
 }
 
-namespace detail {
-
-template <typename E>
-constexpr optional<std::uintmax_t> fuse_one_enum(optional<std::uintmax_t> hash, E value) noexcept {
-  if (hash) {
-    if (const auto index = enum_index(value)) {
-      return (*hash << log2(enum_count<E>() + 1)) | *index;
-    }
-  }
-  return {};
-}
-
-template <typename E>
-constexpr optional<std::uintmax_t> fuse_enum(E value) noexcept {
-  return fuse_one_enum(0, value);
-}
-
-template <typename E, typename... Es>
-constexpr optional<std::uintmax_t> fuse_enum(E head, Es... tail) noexcept {
-  return fuse_one_enum(fuse_enum(tail...), head);
-}
-
-template <typename... Es>
-constexpr auto typesafe_fuse_enum(Es... values) noexcept {
-  enum class enum_fuse_t : std::uintmax_t;
-  const auto fuse = fuse_enum(values...);
-  if (fuse) {
-    return optional<enum_fuse_t>{static_cast<enum_fuse_t>(*fuse)};
-  }
-  return optional<enum_fuse_t>{};
-}
-
-} // namespace magic_enum::detail
-
-// Returns a bijective mix of several enum values. This can be used to emulate 2D switch/case statements.
-template <typename... Es>
-[[nodiscard]] constexpr auto enum_fuse(Es... values) noexcept {
-  static_assert((std::is_enum_v<std::decay_t<Es>> && ...), "magic_enum::enum_fuse requires enum type.");
-  static_assert(sizeof...(Es) >= 2, "magic_enum::enum_fuse requires at least 2 values.");
-  static_assert((detail::log2(enum_count<Es>() + 1) + ...) <= (sizeof(std::uintmax_t) * 8), "magic_enum::enum_fuse does not work for large enums");
-#if defined(MAGIC_ENUM_NO_TYPESAFE_ENUM_FUSE)
-  const auto fuse = detail::fuse_enum<std::decay_t<Es>...>(values...);
-#else
-  const auto fuse = detail::typesafe_fuse_enum<std::decay_t<Es>...>(values...);
-#endif
-  return assert(fuse), fuse;
-}
-
 namespace ostream_operators {
 
 template <typename Char, typename Traits, typename E, detail::enable_if_t<E, int> = 0>

include/magic_enum_fuse.hpp

@@ -0,0 +1,89 @@
+//  __  __             _        ______                          _____
+// |  \/  |           (_)      |  ____|                        / ____|_     _
+// | \  / | __ _  __ _ _  ___  | |__   _ __  _   _ _ __ ___   | |   _| |_ _| |_
+// | |\/| |/ _` |/ _` | |/ __| |  __| | '_ \| | | | '_ ` _ \  | |  |_   _|_   _|
+// | |  | | (_| | (_| | | (__  | |____| | | | |_| | | | | | | | |____|_|   |_|
+// |_|  |_|\__,_|\__, |_|\___| |______|_| |_|\__,_|_| |_| |_|  \_____|
+//                __/ | https://github.com/Neargye/magic_enum
+//               |___/  version 0.8.0
+//
+// Licensed under the MIT License <http://opensource.org/licenses/MIT>.
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2019 - 2022 Daniil Goncharov <neargye@gmail.com>.
+//
+// Permission is hereby  granted, free of charge, to any  person obtaining a copy
+// of this software and associated  documentation files (the "Software"), to deal
+// in the Software  without restriction, including without  limitation the rights
+// to  use, copy,  modify, merge,  publish, distribute,  sublicense, and/or  sell
+// copies  of  the Software,  and  to  permit persons  to  whom  the Software  is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE  IS PROVIDED "AS  IS", WITHOUT WARRANTY  OF ANY KIND,  EXPRESS OR
+// IMPLIED,  INCLUDING BUT  NOT  LIMITED TO  THE  WARRANTIES OF  MERCHANTABILITY,
+// FITNESS FOR  A PARTICULAR PURPOSE AND  NONINFRINGEMENT. IN NO EVENT  SHALL THE
+// AUTHORS  OR COPYRIGHT  HOLDERS  BE  LIABLE FOR  ANY  CLAIM,  DAMAGES OR  OTHER
+// LIABILITY, WHETHER IN AN ACTION OF  CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE  OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+#ifndef NEARGYE_MAGIC_ENUM_FUSE_HPP
+#define NEARGYE_MAGIC_ENUM_FUSE_HPP
+
+#include "magic_enum.hpp"
+
+namespace magic_enum {
+
+namespace detail {
+
+template <typename E>
+constexpr optional<std::uintmax_t> fuse_one_enum(optional<std::uintmax_t> hash, E value) noexcept {
+  if (hash) {
+    if (const auto index = enum_index(value)) {
+      return (*hash << log2(enum_count<E>() + 1)) | *index;
+    }
+  }
+  return {};
+}
+
+template <typename E>
+constexpr optional<std::uintmax_t> fuse_enum(E value) noexcept {
+  return fuse_one_enum(0, value);
+}
+
+template <typename E, typename... Es>
+constexpr optional<std::uintmax_t> fuse_enum(E head, Es... tail) noexcept {
+  return fuse_one_enum(fuse_enum(tail...), head);
+}
+
+template <typename... Es>
+constexpr auto typesafe_fuse_enum(Es... values) noexcept {
+  enum class enum_fuse_t : std::uintmax_t;
+  const auto fuse = fuse_enum(values...);
+  if (fuse) {
+    return optional<enum_fuse_t>{static_cast<enum_fuse_t>(*fuse)};
+  }
+  return optional<enum_fuse_t>{};
+}
+
+} // namespace magic_enum::detail
+
+// Returns a bijective mix of several enum values. This can be used to emulate 2D switch/case statements.
+template <typename... Es>
+[[nodiscard]] constexpr auto enum_fuse(Es... values) noexcept {
+  static_assert((std::is_enum_v<std::decay_t<Es>> && ...), "magic_enum::enum_fuse requires enum type.");
+  static_assert(sizeof...(Es) >= 2, "magic_enum::enum_fuse requires at least 2 values.");
+  static_assert((detail::log2(enum_count<std::decay_t<Es>>() + 1) + ...) <= (sizeof(std::uintmax_t) * 8), "magic_enum::enum_fuse does not work for large enums");
+#if defined(MAGIC_ENUM_NO_TYPESAFE_ENUM_FUSE)
+  const auto fuse = detail::fuse_enum<std::decay_t<Es>...>(values...);
+#else
+  const auto fuse = detail::typesafe_fuse_enum<std::decay_t<Es>...>(values...);
+#endif
+  return assert(fuse), fuse;
+}
+
+} // namespace magic_enum
+
+#endif // NEARGYE_MAGIC_ENUM_FUSE_HPP

test/test.cpp

@@ -28,6 +28,7 @@
 #undef  MAGIC_ENUM_RANGE_MAX
 #define MAGIC_ENUM_RANGE_MAX 120
 #include <magic_enum.hpp>
+#include <magic_enum_fuse.hpp>
 
 #include <array>
 #include <cctype>

test/test_flags.cpp

@@ -33,6 +33,7 @@
 #include <catch2/catch.hpp>
 
 #include <magic_enum.hpp>
+#include <magic_enum_fuse.hpp>
 
 #include <array>
 #include <cctype>