hakmem/core/box/smallobject_hotbox_v4_box.h

// smallobject_hotbox_v4_box.h - SmallObject HotHeap v4 (型スケルトン)
//
// 役割:
//   - v4 のページ / クラス / TLS コンテキスト型と API 宣言だけを定義する箱。
//   - 挙動はまだ v3/v1 のまま。alloc/free 本体は後続フェーズで実装する。
#pragma once

#include <stddef.h>
#include <stdbool.h>
#include <stdint.h>

#include "tiny_geometry_box.h"

#ifndef SMALLOBJECT_NUM_CLASSES
#define SMALLOBJECT_NUM_CLASSES TINY_NUM_CLASSES
#endif

// Page metadata for v4 HotBox
typedef struct small_page_v4 {
    void* freelist;
    uint16_t used;
    uint16_t capacity;
    uint8_t class_idx;
    uint8_t flags;
    uint32_t block_size;
    uint8_t* base;
    void* slab_ref;  // Superslab / lease token (box境界で扱う)
    struct small_page_v4* next;
} small_page_v4;

// Per-class heap state (current / partial / full lists)
typedef struct small_class_heap_v4 {
    small_page_v4* current;
    small_page_v4* partial_head;
    small_page_v4* full_head;
    uint32_t partial_count;
} small_class_heap_v4;

// TLS heap context (per-thread)
typedef struct small_heap_ctx_v4 {
    small_class_heap_v4 cls[SMALLOBJECT_NUM_CLASSES];
} small_heap_ctx_v4;

// TLS accessor (実装は後続フェーズで追加)
small_heap_ctx_v4* small_heap_ctx_v4_get(void);

// Hot path API (C7-only stub; later phases will expand)
void* small_heap_alloc_fast_v4(small_heap_ctx_v4* ctx, int class_idx);
void small_heap_free_fast_v4(small_heap_ctx_v4* ctx, int class_idx, void* ptr);
int smallobject_hotbox_v4_can_own(int class_idx, void* ptr);