From 2dc50176b766730efa3a49fda2bfca00aead27ac Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Fri, 30 Sep 2016 15:41:29 +0200
Subject: [PATCH] Support for make_shared

---
 tstl/include/shared_ptr.hpp | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

diff --git a/tstl/include/shared_ptr.hpp b/tstl/include/shared_ptr.hpp
index 14cf6347..00e23b28 100644
--- a/tstl/include/shared_ptr.hpp
+++ b/tstl/include/shared_ptr.hpp
@@ -19,12 +19,14 @@ namespace std {
  *
  * TODO
  */
-template <typename T, typename D = default_delete<T>>
+template <typename T>
 struct shared_ptr {
     using pointer_type = T*; ///< The pointer type
     using reference_type = T&; ///< The reference type
     using element_type = T;  ///< The element type
 
+    struct control_block_t;
+
     constexpr shared_ptr() : ptr(), control_block() {}
 
     constexpr explicit shared_ptr(decltype(nullptr)) : ptr(), control_block() {}
@@ -41,6 +43,10 @@ struct shared_ptr {
         control_block->counter = 1;
     }
 
+    shared_ptr(T* ptr, control_block_t* control_block, int) : ptr(ptr), control_block(control_block) {
+        control_block->counter = 1;
+    }
+
     shared_ptr(const shared_ptr& rhs) : ptr(rhs.ptr), control_block(rhs.control_block) {
         __sync_fetch_and_add(&control_block->counter, 1);
     }
@@ -99,7 +105,6 @@ struct shared_ptr {
         return get();
     }
 
-private:
     struct control_block_t {
         volatile size_t counter;
 
@@ -122,10 +127,30 @@ private:
         }
     };
 
+    template <typename U>
+    struct inplace_control_block_impl : control_block_t {
+        U ptr;
+
+        template<typename... Args>
+        inplace_control_block_impl(Args&&... args) : ptr(std::forward<Args>(args)...){}
+
+        virtual void destroy(){
+            // Nothing to do
+        }
+    };
+
+private:
     pointer_type ptr;
     control_block_t* control_block;
 };
 
+template <typename T, typename... Args>
+std::shared_ptr<T> make_shared(Args&&... args){
+    auto cb = new typename std::shared_ptr<T>::template inplace_control_block_impl<T>(std::forward<Args>(args)...);
+
+    return std::shared_ptr<T>{&cb->ptr, cb, 0};
+}
+
 } //end of namespace std
 
 #endif