Foundation

Typhon's lowest-level building blocks — lock-free synchronization primitives, epoch-based memory safety, monotonic deadline/timeout propagation, pinned-memory allocators, and high-performance collections — that every other engine layer (storage, ECS, durability, query) is built on. Nearly the entire surface is internal engine plumbing (a few types, like EpochManager and IMemoryResource, are C# public but namespaced under Typhon.Engine.Internals); the only types meant for direct application use are Deadline, WaitContext, and UnitOfWorkContext — the timeout/cancellation values threaded into every Commit().

🔬 Recommended: read in-depth-overview/01-foundation.md (Chapter 01: Foundation) first to understand the overall design and concepts behind this category, before diving into the specific features below.

Public Features

Feature	Summary	Status	Level
Deadline & Timeout Propagation	Monotonic absolute-deadline timeouts bundled with cooperative cancellation, threaded through every Unit-of-Work via the 24-byte UnitOfWorkContext to eliminate timeout accumulation across nested calls.	✅ Implemented	🔵 Core

Internal Features

Feature	Summary	Status
Reader-Writer & Resource Lifecycle Locks	CAS-only, allocation-free spin-locks every concurrent engine structure embeds for shared/exclusive or lifecycle access.	✅ Implemented
↳ AccessControl (full-featured RW lock)	64-bit reader-writer lock with waiter fairness, in-place promotion, and contention tracking.	✅ Implemented
↳ AccessControlSmall (compact RW lock)	32-bit reader-writer lock for thousands of embedded per-node/per-page latches with short critical sections.	✅ Implemented
↳ ResourceAccessControl (3-mode lifecycle lock)	32-bit Accessing/Modify/Destroy lock where structural growth doesn't block concurrent readers.	✅ Implemented
Epoch-Based Resource Protection	Lock-free epoch/grace-period scheme that protects in-flight page-cache pages from eviction with 2 obligations per transaction instead of per-page ref-counting.	✅ Implemented
High-Resolution Timers	Self-calibrating sub-millisecond periodic timer services (three-phase Sleep→Yield→Spin wait, drift-free metronome scheduling) used for the deadline watchdog, telemetry flush, and epoch advancement, exposing per-tick jitter metrics.	✅ Implemented
↳ Dedicated Timer (HighResolutionTimerService)	A single periodic callback on its own thread, isolated from every other timer in the engine.	✅ Implemented
↳ Shared Timer (HighResolutionSharedTimerService)	One thread multiplexing many periodic callbacks, each at its own rate, waking only when the soonest one is due.	✅ Implemented
In-Memory Hash Maps	Open-addressing, pinned-memory hash set/map types with backward-shift deletion and JIT-specialized hashing that replace .NET HashSet/Dictionary/ConcurrentDictionary on hot paths.	✅ Implemented
↳ Non-Concurrent HashMap<TKey[, TValue]>	Single-threaded open-addressing hash set/map replacing HashSet/Dictionary on a hot path, zero per-entry GC pressure.	✅ Implemented
↳ ConcurrentHashMap<TKey[, TValue]>	Striped, lock-free-read hash set/map replacing ConcurrentDictionary on a shared hot path, per-stripe CAS writes.	✅ Implemented
Page-Backed Linear Hash Map	O(1) exact-match key/value index, persisted in fixed-size chunks, with crash-safe rebuild instead of WAL logging.	✅ Implemented
Memory Allocators	Pinned/unmanaged memory primitives that give every page cache, segment, and hash-map structure stable, GC-immune addresses with parent-owned leak tracking.	✅ Implemented
Concurrent Bitmaps & Collections	Lock-free/CAS-guarded occupancy bitmaps (flat and 3-level) plus a pick/putback slot array for high-contention tracking.	✅ Implemented
Hardware-Accelerated CRC32C Checksums	SSE4.2/ARM-intrinsic CRC32C (Castagnoli polynomial) computation with software-table fallback (~1.3µs per 8KB page) — the checksum primitive backing every page-integrity check in storage and durability.	✅ Implemented