From d1073bb181f8aee7d9acf08fd459ad3446cc1a39 Mon Sep 17 00:00:00 2001
From: Michele Caini <michele.caini@gmail.com>
Date: Wed, 3 Jul 2024 10:28:31 +0200
Subject: [PATCH] view: ::size/::size_hint in_place support for single type
 views

---
 src/entt/entity/view.hpp | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/entt/entity/view.hpp b/src/entt/entity/view.hpp
index 7dc19b0b6..833910b6b 100644
--- a/src/entt/entity/view.hpp
+++ b/src/entt/entity/view.hpp
@@ -660,9 +660,11 @@ public:
 
     /**
      * @brief Returns the number of entities that have the given element.
+     * @tparam Pol Dummy template parameter used for sfinae purposes only.
      * @return Number of entities that have the given element.
      */
-    [[nodiscard]] size_type size() const noexcept {
+    template<typename..., deletion_policy Pol = Policy>
+    [[nodiscard]] std::enable_if_t<Pol != deletion_policy::in_place, size_type> size() const noexcept {
         if constexpr(Policy == deletion_policy::swap_and_pop) {
             return leading ? leading->size() : size_type{};
         } else {
@@ -671,6 +673,16 @@ public:
         }
     }
 
+    /**
+     * @brief Estimates the number of entities iterated by the view.
+     * @tparam Pol Dummy template parameter used for sfinae purposes only.
+     * @return Estimated number of entities iterated by the view.
+     */
+    template<typename..., deletion_policy Pol = Policy>
+    [[nodiscard]] std::enable_if_t<Pol == deletion_policy::in_place, size_type> size_hint() const noexcept {
+        return leading ? leading->size() : size_type{};
+    }
+
     /**
      * @brief Checks whether a view is empty.
      * @return True if the view is empty, false otherwise.