hakmem/core/box/tiny_static_route_box.h

// tiny_static_route_box.h - Static routing table for policy_snapshot bypass (Phase 3 C3)
// Eliminates per-malloc policy_snapshot + learner evaluation overhead
// ENV gate: HAKMEM_TINY_STATIC_ROUTE=0/1 (default 0)

#pragma once

#include <stdatomic.h>
#include "smallobject_policy_v7_box.h"

typedef struct {
    // 0: uninit/disabled, -1: initializing, 1: ready
    atomic_int inited;
    SmallRouteKind route_kind[8];  // C0-C7 static route (determined at init, no learner update)
} TinyStaticRoute;

extern TinyStaticRoute g_tiny_static_route;

// Hot-path helper: true when static route table is ready (enabled + initialized).
static inline int tiny_static_route_ready_fast(void) {
    return atomic_load_explicit(&g_tiny_static_route.inited, memory_order_acquire) == 1;
}

// Hot-path helper: fetch route kind when tiny_static_route_ready_fast()==true.
static inline SmallRouteKind tiny_static_route_get_kind_fast(int class_idx) {
    return g_tiny_static_route.route_kind[(unsigned)class_idx & 7u];
}

// Initialize static route table (called once, at library load time)
// Returns 1 if static routing is enabled and initialized, 0 otherwise
int tiny_static_route_init_once(void);

// Get static route for class_idx.
// Returns SMALL_ROUTE_LEGACY when disabled/uninitialized/invalid (safe fallback).
SmallRouteKind tiny_static_route_get_kind(int class_idx);

// Refresh from ENV (for bench_apply_profile() sync)
void tiny_static_route_refresh_from_env(void);

// Check if static routing is enabled (cached ENV value)
int tiny_static_route_enabled(void);