整理

include/boost/smart_ptr/detail/quick_allocator.hpp

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+#ifndef BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED
+#define BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED
+
+// Copyright 2003 David Abrahams
+// Copyright 2003, 2025 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/header_deprecated.hpp>
+#include <memory>
+#include <cstddef>
+
+BOOST_HEADER_DEPRECATED("std::allocator or std::pmr::synchronized_pool_resource")
+
+namespace boost
+{
+namespace detail
+{
+
+template<class T> struct quick_allocator
+{
+    static void* alloc()
+    {
+        return std::allocator<T>().allocate( 1 );
+    }
+
+    static void* alloc( std::size_t n )
+    {
+        if( n != sizeof(T) ) // class-specific delete called for a derived object
+        {
+            return ::operator new( n );
+        }
+        else
+        {
+            return alloc();
+        }
+    }
+
+    static void dealloc( void* p )
+    {
+        if( p != 0 ) // 18.4.1.1/13
+        {
+            std::allocator<T>().deallocate( static_cast<T*>( p ), 1 );
+        }
+    }
+
+    static void dealloc( void* p, std::size_t n )
+    {
+        if( n != sizeof(T) ) // class-specific delete called for a derived object
+        {
+            ::operator delete( p );
+        }
+        else
+        {
+            dealloc( p );
+        }
+    }
+};
+
+} // namespace detail
+} // namespace boost
+
+#endif  // #ifndef BOOST_SMART_PTR_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED