From bfacde30f23c7ca3d813d2db42cc4de88bb11549 Mon Sep 17 00:00:00 2001
From: Neargye <neargye@gmail.com>
Date: Sat, 1 Sep 2018 22:08:09 +0500
Subject: [PATCH] fix nameof enum

---
 include/nameof.hpp | 35 +++++++++++++++++++++--------------
 test/test.cpp      | 18 +++++++++++-------
 2 files changed, 32 insertions(+), 21 deletions(-)

diff --git a/include/nameof.hpp b/include/nameof.hpp
index 81e66dd..bde5e31 100644
--- a/include/nameof.hpp
+++ b/include/nameof.hpp
@@ -42,10 +42,10 @@
 #endif
 
 #if (defined(__clang__) || defined(_MSC_VER)) || (defined(__GNUC__) && __GNUC__ >= 5)
-#  define NAMEOF_TYPE_HAS_CONSTEXPR 1
-#  define NAMEOF_TYPE_CONSTEXPR constexpr
+#  define NAMEOF_HAS_CONSTEXPR 1
+#  define NAMEOF_CONSTEXPR constexpr
 #else
-#  define NAMEOF_TYPE_CONSTEXPR inline
+#  define NAMEOF_CONSTEXPR inline
 #endif
 
 namespace nameof {
@@ -347,7 +347,7 @@ constexpr cstring NameofTypePretty(const char* str, std::size_t size, std::size_
 #endif
 
 template <typename T>
-constexpr int NameofEnumImpl1() {
+NAMEOF_CONSTEXPR int NameofEnumImpl1() {
 #if defined(__clang__)
   return sizeof(__PRETTY_FUNCTION__) - sizeof("int nameof::detail::NameofEnumImpl1() [T = ") - sizeof("]") + 1;
 #elif defined(__GNUC__)
@@ -360,7 +360,7 @@ constexpr int NameofEnumImpl1() {
 }
 
 template <typename T, T V>
-constexpr nameof::cstring NameofEnumImpl2() {
+NAMEOF_CONSTEXPR nameof::cstring NameofEnumImpl2() {
 #if defined(__clang__)
   return {__PRETTY_FUNCTION__,
           sizeof(__PRETTY_FUNCTION__) - 1,
@@ -383,20 +383,27 @@ constexpr nameof::cstring NameofEnumImpl2() {
 
 template <typename T, int I = 0>
 struct NameofEnumImpl {
-  constexpr nameof::cstring operator()(T value) const noexcept {
+  NAMEOF_CONSTEXPR nameof::cstring operator()(T value) const {
     return (static_cast<int>(value) - I == 0)
-               ? NameofEnumImpl2<T, T(0 + I)>()
-               : NameofEnumImpl<T, I + 1>{}(value);
+               ? NameofEnumImpl2<T, T(I)>()
+               : (static_cast<int>(value) >= 0)
+                     ? NameofEnumImpl<T, I + 1>{}(value)
+                     : NameofEnumImpl<T, I - 1>{}(value);
   }
 };
 
 template <typename T>
 struct NameofEnumImpl<T, 128> {
-  constexpr nameof::cstring operator()(T) const noexcept { return {}; }
+  NAMEOF_CONSTEXPR nameof::cstring operator()(T) const { return {}; }
 };
 
 template <typename T>
-NAMEOF_TYPE_CONSTEXPR cstring NameofType() {
+struct NameofEnumImpl<T, -128> {
+  NAMEOF_CONSTEXPR nameof::cstring operator()(T) const { return {}; }
+};
+
+template <typename T>
+NAMEOF_CONSTEXPR cstring NameofType() {
 #if defined(__clang__)
   return NameofTypePretty(
       __PRETTY_FUNCTION__,
@@ -407,7 +414,7 @@ NAMEOF_TYPE_CONSTEXPR cstring NameofType() {
   return NameofTypePretty(
       __PRETTY_FUNCTION__,
       sizeof(__PRETTY_FUNCTION__) - 1,
-#  if defined(NAMEOF_TYPE_HAS_CONSTEXPR)
+#  if defined(NAMEOF_HAS_CONSTEXPR)
       sizeof("constexpr nameof::cstring nameof::detail::NameofType() [with T = nameof::detail::nstd::identity<") - 1,
 #  else
       sizeof("nameof::cstring nameof::detail::NameofType() [with T = nameof::detail::nstd::identity<") - 1,
@@ -434,7 +441,7 @@ constexpr cstring Nameof(const char* name, std::size_t size, bool with_suffix =
 
 template <typename T,
           typename = typename std::enable_if<!std::is_reference<T>::value && std::is_enum<T>::value>::type>
-constexpr cstring NameofEnum(T value) {
+NAMEOF_CONSTEXPR cstring NameofEnum(T value) {
 #if defined(__clang__) || defined(_MSC_VER)
   return detail::NameofPretty(detail::NameofEnumImpl<T>{}(value), false);
 #elif defined(__GNUC__)
@@ -445,8 +452,8 @@ return {};
 }
 
 template <typename T>
-NAMEOF_TYPE_CONSTEXPR cstring NameofType() {
-  return detail::NameofType<detail::nstd::identity<T>>();
+NAMEOF_CONSTEXPR cstring NameofType() {
+  return true ? detail::NameofType<detail::nstd::identity<T>>() : detail::NameofType<detail::nstd::identity<T>>();
 }
 
 template <typename T>
diff --git a/test/test.cpp b/test/test.cpp
index b059762..5e7f53e 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -68,7 +68,7 @@ struct Long {
   LL ll;
 };
 
-enum class Color { RED, GREEN, BLUE };
+enum class Color { RED = -1, GREEN, BLUE };
 
 enum Directions { Up, Down, Right, Left};
 
@@ -151,7 +151,7 @@ TEST_CASE("constexpr") {
     static_assert(cx == "RED", "");
     REQUIRE(cx == "RED");
 #elif defined(__GNUC__)
-    REQUIRE(cx == "(const Color)0");
+    REQUIRE(cx == "(const Color)-1");
 #endif
   }
 
@@ -308,13 +308,17 @@ TEST_CASE("NAMEOF_RAW") {
 TEST_CASE("NAMEOF_ENUM") {
 #  if defined(__clang__) || defined(_MSC_VER)
   REQUIRE(NAMEOF_ENUM(Color::RED) == "RED");
-  REQUIRE(NAMEOF_ENUM(color) == "RED");
+  REQUIRE(NAMEOF_ENUM(::color) == "RED");
+
+  auto color_ = Color::BLUE;
+  REQUIRE(NAMEOF_ENUM(Color::BLUE) == "BLUE");
+  REQUIRE(NAMEOF_ENUM(color_) == "BLUE");
 
   REQUIRE(NAMEOF_ENUM(Directions::Right) == "Right");
   REQUIRE(NAMEOF_ENUM(directions) == "Right");
 #  elif defined(__GNUC__)
-  REQUIRE(NAMEOF_ENUM(Color::RED) == "(Color)0");
-  REQUIRE(NAMEOF_ENUM(color) == "(const Color)0");
+  REQUIRE(NAMEOF_ENUM(Color::RED) == "(Color)-1");
+  REQUIRE(NAMEOF_ENUM(color) == "(const Color)-1");
 
   REQUIRE(NAMEOF_ENUM(Directions::Right) == "(Directions)2");
   REQUIRE(NAMEOF_ENUM(directions) == "(const Directions)2");
@@ -430,7 +434,7 @@ TEST_CASE("Spaces and Tabs ignored") {
 #if defined(__clang__) || defined(_MSC_VER)
     REQUIRE(NAMEOF_ENUM(   color   ) == "RED");
 #elif defined(__GNUC__)
-    REQUIRE(NAMEOF_ENUM(   color   ) == "(const Color)0");
+    REQUIRE(NAMEOF_ENUM(   color   ) == "(const Color)-1");
 #endif
     REQUIRE(NAMEOF_TYPE(   struct_var   ) == "SomeStruct");
     REQUIRE(NAMEOF_TYPE_T(   decltype(struct_var)   ) == "SomeStruct");
@@ -443,7 +447,7 @@ TEST_CASE("Spaces and Tabs ignored") {
 #if defined(__clang__) || defined(_MSC_VER)
     REQUIRE(NAMEOF_ENUM(	color	) == "RED");
 #elif defined(__GNUC__)
-    REQUIRE(NAMEOF_ENUM(	color	) == "(const Color)0");
+    REQUIRE(NAMEOF_ENUM(	color	) == "(const Color)-1");
 #endif
     REQUIRE(NAMEOF_TYPE(	struct_var	) == "SomeStruct");
     REQUIRE(NAMEOF_TYPE_T(	decltype(struct_var)	) == "SomeStruct");