memory Directory Reference

Directories
	include
	src

Detailed Description

`memory` — PMR Allocators & Reference Counting

Custom std::pmr::memory_resource allocators for frame-scoped, arena, pool, and general-purpose allocation, plus Rc/Arc smart pointers.

Namespace: helios::mem.

Public API

Allocators

Allocator	Strategy	Thread safety
ArenaAllocator	Growable lock-free bump allocator.	Lock-free allocate
FixedArenaAllocator	Fixed-capacity bump allocator.	Lock-free allocate
StackAllocator	Growable LIFO-aware allocator with marker/rewind.	Lock-free allocate + LIFO deallocate on head
FixedStackAllocator	Fixed-capacity stack allocator.	Lock-free allocate + LIFO deallocate
PoolAllocator	Growable fixed-size-block pool.	Lock-free
FixedPoolAllocator	Fixed-capacity block pool.	Lock-free
FreeListAllocator	Growable best-fit allocator with coalescing.	Mutex-protected
FixedFreeListAllocator	Fixed-capacity best-fit allocator.	Mutex-protected
FrameAllocator<N = 2>	N growable arenas; Advance() rotates and resets.	Delegates to arena

Reference Counting

Type	Purpose
Rc<T>	Non-atomic reference-counted handle (RefCounted alias).
Arc<T>	Atomic reference-counted handle (AtomicRefCounted alias).
PmrRc<T> / PmrArc<T>	PMR allocator variants.
RcFromThis<T> / ArcFromThis<T>	CRTP bases embedding ref counters.
MakeRc<T>(args...)	Factory for Rc<T>.
MakeArc<T>(args...)	Factory for Arc<T>.
MakeRcWith<T>(alloc, args...)	Factory with custom allocator.
MakeArcWith<T>(alloc, args...)	Factory with custom allocator.

Utilities

Type / Function	Purpose
GrowthPolicy	Growable allocator policy (Linear or Geometric).
AllocatorStats	Snapshot of allocation counters and capacity.
AlignedAlloc / AlignedFree	Cross-platform aligned allocation.

mimalloc and global allocation

CMake option	Default	Effect
HELIOS_MEMORY_USE_MIMALLOC	ON	Routes backing AlignedAlloc / growable Create* through mimalloc
HELIOS_MEMORY_ENABLE_PROFILE	ON	Enables memory-module profile macros when profile module is linked
HELIOS_MEMORY_OVERRIDE_GLOBAL_ALLOC	ON	Inherits global operator new/delete hooks when linking memory

Global operator new/delete hooks are inherited automatically when you link helios::module::memory. The hook implementation lives in the memory module and reports allocations to the profiler when the profile module is linked and HELIOS_MEMORY_ENABLE_PROFILE=ON. Disable with -DHELIOS_MEMORY_OVERRIDE_GLOBAL_ALLOC=OFF.

Arena Allocator

#include <helios/memory/arena_allocator.hpp>
 
helios::mem::ArenaAllocator arena(64 * 1024);
std::pmr::polymorphic_allocator<std::byte> alloc(&arena);
 
auto* block = alloc.allocate(256);
// no individual deallocate — memory reclaimed on Reset() or destruction
arena.Reset();

Frame Allocator

#include <helios/memory/frame_allocator.hpp>
 
helios::mem::FrameAllocator frames(64 * 1024);
std::pmr::polymorphic_allocator<std::byte> alloc(&frames);
 
auto* data = alloc.allocate(128);  // current frame
 
frames.Advance();  // next frame; previous arena reset

Pool Allocator

#include <helios/memory/pool_allocator.hpp>
 
helios::mem::PoolAllocator pool(/*block_size=*/64, /*block_count=*/1024);
std::pmr::polymorphic_allocator<MyStruct> alloc(&pool);
 
auto* obj = alloc.new_object<MyStruct>(args...);
alloc.delete_object(obj);

Reference Counting

#include <helios/memory/ref_counted.hpp>
 
class Mesh final : public helios::mem::RcFromThis<Mesh> {
public:
  explicit Mesh(int id) : id_(id) {}
  int Id() const { return id_; }
private:
  int id_ = 0;
};
 
auto mesh = helios::mem::MakeRc<Mesh>(42);
auto copy = mesh;  // shared ownership (single-threaded ref count)
 
class Texture final : public helios::mem::ArcFromThis<Texture> {};
auto tex = helios::mem::MakeArc<Texture>();  // thread-safe ref count

Dependencies

• core — asserts
• mimalloc (default ON) — backing heap via helios::lib::mimalloc::static
• profile (optional) — Tracy scope/zone/lock and backing ALLOC/FREE macros