auto_typemap.hpp: reduce indirection

Implement is_init() method.
Implement optional Size template arg for further optimization.
This commit is contained in:
Nekotekina 2021-02-03 17:51:52 +03:00
parent 5cc9bd7702
commit 8a9320c4ef

View File

@ -1,5 +1,6 @@
#pragma once
#include "util/types.hpp"
#include "util/typeindices.hpp"
#include <utility>
@ -8,41 +9,41 @@
namespace stx
{
// Simplified typemap with exactly one object of each used type, non-moveable.
template <typename Tag /*Tag should be unique*/>
class auto_typemap
template <typename Tag /*Tag should be unique*/, u32 Size = 0, u32 Align = (Size ? 64 : __STDCPP_DEFAULT_NEW_ALIGNMENT__)>
class alignas(Align) auto_typemap
{
// Save default constructor and destructor
struct typeinfo
{
void(*create)(void*& ptr, auto_typemap&) noexcept;
bool(*create)(uchar* ptr, auto_typemap&) noexcept;
void(*destroy)(void* ptr) noexcept;
template <typename T>
static void call_ctor(void*& ptr, auto_typemap& _this) noexcept
static bool call_ctor(uchar* ptr, auto_typemap& _this) noexcept
{
// Don't overwrite if already exists
if (!ptr)
{
// Allow passing reference to "this"
if constexpr (std::is_constructible_v<T, auto_typemap&>)
{
ptr = new T(_this);
return;
new (ptr) T(_this);
return true;
}
// Call default constructor only if available
if constexpr (std::is_default_constructible_v<T>)
{
ptr = new T();
return;
new (ptr) T();
return true;
}
}
return false;
}
template <typename T>
static void call_dtor(void* ptr) noexcept
{
delete static_cast<T*>(ptr);
std::launder(static_cast<T*>(ptr))->~T();
}
template <typename T>
@ -55,8 +56,12 @@ namespace stx
}
};
// Raw pointers to existing objects (may be nullptr)
void** m_list;
// Objects
union
{
uchar* m_list;
mutable uchar m_data[Size ? Size : 1];
};
// Creation order for each object (used to reverse destruction order)
void** m_order;
@ -64,23 +69,44 @@ namespace stx
// Helper for destroying in reverse order
const typeinfo** m_info;
// Indicates whether object is created at given index
bool* m_init;
public:
auto_typemap() noexcept
: m_list(new void*[stx::typelist<typeinfo>().count()]{})
, m_order(new void*[stx::typelist<typeinfo>().count()])
: m_order(new void*[stx::typelist<typeinfo>().count()])
, m_info(new const typeinfo*[stx::typelist<typeinfo>().count()])
, m_init(new bool[stx::typelist<typeinfo>().count()]{})
{
if constexpr (Size == 0)
{
if (stx::typelist<typeinfo>().align() > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
m_list = static_cast<uchar*>(::operator new(usz{stx::typelist<typeinfo>().size()}, std::align_val_t{stx::typelist<typeinfo>().align()}));
}
else
{
m_list = new uchar[stx::typelist<typeinfo>().size()];
}
}
else
{
ensure(Size >= stx::typelist<typeinfo>().size());
ensure(Align >= stx::typelist<typeinfo>().align());
m_data[0] = 0;
}
for (const auto& type : stx::typelist<typeinfo>())
{
const unsigned id = type.index();
type.create(m_list[id], *this);
const u32 id = type.index();
uchar* data = (Size ? +m_data : m_list) + type.pos();
// Allocate initialization order id
if (m_list[id])
if (type.create(data, *this))
{
*m_order++ = m_list[id];
*m_order++ = data;
*m_info++ = &type;
m_init[id] = true;
}
}
}
@ -92,11 +118,11 @@ namespace stx
~auto_typemap()
{
// Get actual number of created objects
unsigned _max = 0;
u32 _max = 0;
for (const auto& type : stx::typelist<typeinfo>())
{
if (m_list[type.index()])
if (m_init[type.index()])
{
// Skip object if not created
_max++;
@ -110,16 +136,28 @@ namespace stx
}
// Pointers should be restored to their positions
delete[] m_init;
delete[] m_info;
delete[] m_order;
delete[] m_list;
if constexpr (Size == 0)
{
if (stx::typelist<typeinfo>().align() > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
{
::operator delete[](m_list, std::align_val_t{stx::typelist<typeinfo>().align()});
}
else
{
delete[] m_list;
}
}
}
// Check if object is not initialized but shall be initialized first (to use in initializing other objects)
template <typename T>
void need() noexcept
{
if (!m_list[stx::typeindex<typeinfo, std::decay_t<T>>()])
if (!m_init[stx::typeindex<typeinfo, std::decay_t<T>>()])
{
if constexpr (std::is_constructible_v<T, auto_typemap&>)
{
@ -139,18 +177,25 @@ namespace stx
template <typename T, typename As = T, typename... Args>
As* init(Args&&... args) noexcept
{
auto& ptr = m_list[stx::typeindex<typeinfo, std::decay_t<T>>()];
if (ptr)
if (std::exchange(m_init[stx::typeindex<typeinfo, std::decay_t<T>, std::decay_t<As>>()], true))
{
// Already exists, recreation is not supported (may be added later)
return nullptr;
}
As* obj = new std::decay_t<As>(std::forward<Args>(args)...);
As* obj = nullptr;
if constexpr (Size != 0)
{
obj = new (m_data + stx::typeoffset<typeinfo, std::decay_t<T>>()) std::decay_t<As>(std::forward<Args>(args)...);
}
else
{
obj = new (m_list + stx::typeoffset<typeinfo, std::decay_t<T>>()) std::decay_t<As>(std::forward<Args>(args)...);
}
*m_order++ = obj;
*m_info++ = &stx::typedata<typeinfo, std::decay_t<T>>();
ptr = static_cast<T*>(obj);
*m_info++ = &stx::typedata<typeinfo, std::decay_t<T>, std::decay_t<As>>();
return obj;
}
@ -163,11 +208,36 @@ namespace stx
return init<T>(std::forward<Args>(args)...);
}
template <typename T>
bool is_init() const noexcept
{
return m_init[stx::typeindex<typeinfo, std::decay_t<T>>()];
}
// Obtain object reference
template <typename T>
T& get() const noexcept
{
return *static_cast<T*>(m_list[stx::typeindex<typeinfo, std::decay_t<T>>()]);
if constexpr (Size != 0)
{
return *std::launder(reinterpret_cast<T*>(m_data + stx::typeoffset<typeinfo, std::decay_t<T>>()));
}
else
{
return *std::launder(reinterpret_cast<T*>(m_list + stx::typeoffset<typeinfo, std::decay_t<T>>()));
}
}
// Obtain object pointer if initialized
template <typename T>
T* try_get() const noexcept
{
if (is_init<T>())
{
[[likely]] return &get<T>();
}
[[unlikely]] return nullptr;
}
};
}