From c99bf2205cc3f23e5310ea97f18db6eb711e7410 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@pdimov.com>
Date: Fri, 2 Jun 2017 05:41:13 +0300
Subject: [PATCH] Move index() into variant_base to avoid needless ix_ >= 0
 checks when single buffered

---
 include/boost/variant2/variant.hpp | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/boost/variant2/variant.hpp b/include/boost/variant2/variant.hpp
index cf41d4a..9f3a980 100644
--- a/include/boost/variant2/variant.hpp
+++ b/include/boost/variant2/variant.hpp
@@ -413,6 +413,11 @@ template<class... T> struct variant_base_impl<true, true, T...>
     {
     }
 
+    constexpr std::size_t index() const noexcept
+    {
+        return ix_ - 1;
+    }
+
     template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
     {
         size_t const J = I+1;
@@ -486,6 +491,11 @@ template<class... T> struct variant_base_impl<true, false, T...>
     {
     }
 
+    constexpr std::size_t index() const noexcept
+    {
+        return ix_ >= 0? ix_ - 1: -ix_ - 1;
+    }
+
     template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
     {
         size_t const J = I+1;
@@ -555,6 +565,11 @@ template<class... T> struct variant_base_impl<false, true, T...>
         _destroy();
     }
 
+    constexpr std::size_t index() const noexcept
+    {
+        return ix_ - 1;
+    }
+
     template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
     {
         size_t const J = I+1;
@@ -661,6 +676,11 @@ template<class... T> struct variant_base_impl<false, false, T...>
         _destroy();
     }
 
+    constexpr std::size_t index() const noexcept
+    {
+        return ix_ >= 0? ix_ - 1: -ix_ - 1;
+    }
+
     template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
     {
         size_t const J = I+1;
@@ -958,10 +978,7 @@ public:
 
     // value status
 
-    constexpr size_t index() const noexcept
-    {
-        return this->ix_ >= 0? this->ix_ - 1 : -this->ix_ - 1;
-    }
+    using variant_base::index;
 
     // swap