// Inline helpers for Background Refill Bin (lock-free SLL)
// This header is textually included from hakmem_tiny.c after the following
// symbols are defined:
//   - g_bg_bin_enable, g_bg_bin_target, g_bg_bin_head[]
//   - tiny_bg_refill_main() declaration/definition if needed

static inline void* bgbin_pop(int class_idx) {
    if (!g_bg_bin_enable) return NULL;
    uintptr_t h = atomic_load_explicit(&g_bg_bin_head[class_idx], memory_order_acquire);
    while (h != 0) {
        void* p = (void*)h;
        uintptr_t next = (uintptr_t)(*(void**)p);
        if (atomic_compare_exchange_weak_explicit(&g_bg_bin_head[class_idx], &h, next,
                                                  memory_order_acq_rel, memory_order_acquire)) {
#if HAKMEM_DEBUG_COUNTERS
            g_bgbin_pops[class_idx]++;
#endif
            return p;
        }
    }
    return NULL;
}

static inline void bgbin_push_chain(int class_idx, void* chain_head, void* chain_tail) {
    if (!chain_head) return;
    uintptr_t h = atomic_load_explicit(&g_bg_bin_head[class_idx], memory_order_acquire);
    do { *(void**)chain_tail = (void*)h; }
    while (!atomic_compare_exchange_weak_explicit(&g_bg_bin_head[class_idx], &h,
                                                  (uintptr_t)chain_head,
                                                  memory_order_acq_rel, memory_order_acquire));
}

static inline int bgbin_length_approx(int class_idx, int cap) {
    uintptr_t h = atomic_load_explicit(&g_bg_bin_head[class_idx], memory_order_acquire);
    int n = 0; while (h && n < cap) { void* p = (void*)h; h = (uintptr_t)(*(void**)p); n++; }
    return n;
}