hakmem/core/box/tiny_heap_env_box.h

// tiny_heap_env_box.h - ENV gate for TinyHeap front (A/B 切り替え)
// 役割:
//   - 新しい TinyHeap front を ON/OFF する環境変数の読み出しをホットパス外に分離。
//   - デフォルト OFF（環境変数が未設定または 0 のとき）。
#pragma once

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include "c7_hotpath_env_box.h"  // tiny_c7_hot_enabled()

// TinyHeap profile modes (HAKMEM_TINY_HEAP_PROFILE)
enum {
    TINY_HEAP_PROFILE_LEGACY = 0,         // TinyHeap OFF / 既存 front
    TINY_HEAP_PROFILE_C7_SAFE = 1,        // C7 TinyHeap + SAFE meta
    TINY_HEAP_PROFILE_C7_ULTRA_BENCH = 2, // C7 TinyHeap + ULTRA (bench 専用)
    TINY_HEAP_PROFILE_CUSTOM = 3,         // クラス/メタを ENV で直接指定
};

// ENV: HAKMEM_TINY_HEAP_PROFILE
static inline int tiny_heap_profile_mode(void) {
    static int g_mode = -1;
    if (__builtin_expect(g_mode == -1, 0)) {
        const char* e = getenv("HAKMEM_TINY_HEAP_PROFILE");
        if (!e || !*e) {
            g_mode = TINY_HEAP_PROFILE_LEGACY;
        } else if (strcasecmp(e, "C7_SAFE") == 0) {
            g_mode = TINY_HEAP_PROFILE_C7_SAFE;
        } else if (strcasecmp(e, "C7_ULTRA_BENCH") == 0 || strcasecmp(e, "C7_ULTRA") == 0) {
            g_mode = TINY_HEAP_PROFILE_C7_ULTRA_BENCH;
        } else if (strcasecmp(e, "CUSTOM") == 0) {
            g_mode = TINY_HEAP_PROFILE_CUSTOM;
        } else if (strcasecmp(e, "LEGACY") == 0) {
            g_mode = TINY_HEAP_PROFILE_LEGACY;
        } else {
            int v = atoi(e);
            if (v < 0) v = 0;
            if (v > 3) v = 3;
            g_mode = v;
        }
    }
    return g_mode;
}

static inline unsigned tiny_heap_profile_default_class_mask(int profile_mode) {
    switch (profile_mode) {
    case TINY_HEAP_PROFILE_C7_SAFE:
    case TINY_HEAP_PROFILE_C7_ULTRA_BENCH:
        return 1u << 7; // C7 のみ
    case TINY_HEAP_PROFILE_CUSTOM:
    case TINY_HEAP_PROFILE_LEGACY:
    default:
        return 0u;
    }
}

static inline int tiny_heap_profile_default_c7_meta_mode(int profile_mode) {
    switch (profile_mode) {
    case TINY_HEAP_PROFILE_C7_SAFE:
        return 1;
    case TINY_HEAP_PROFILE_C7_ULTRA_BENCH:
        return 2;
    case TINY_HEAP_PROFILE_CUSTOM:
    case TINY_HEAP_PROFILE_LEGACY:
    default:
        return 0;
    }
}

// ENV: HAKMEM_TINY_HEAP_BOX=1 で TinyHeap front を有効化
static inline int tiny_heap_box_enabled(void) {
    static int g_enable = -1;
    if (__builtin_expect(g_enable == -1, 0)) {
        const char* e = getenv("HAKMEM_TINY_HEAP_BOX");
        if (e && *e) {
            g_enable = (*e != '0') ? 1 : 0;
        } else {
            // profile が LEGACY 以外なら自動で ON
            g_enable = (tiny_heap_profile_mode() != TINY_HEAP_PROFILE_LEGACY) ? 1 : 0;
        }
    }
    return g_enable;
}

// ENV gate: C6 Hot front (直線パス) を有効化するか
static inline int tiny_c6_hot_enabled(void) {
    static int g_enable = -1;
    if (__builtin_expect(g_enable == -1, 0)) {
        const char* e = getenv("HAKMEM_TINY_C6_HOT");
        g_enable = (e && *e && *e != '0') ? 1 : 0;
    }
    return g_enable;
}

// ENV: HAKMEM_TINY_HEAP_CLASSES (bitmask, bit i が 1 のクラスを TinyHeap 経路に載せる)
// 例: 0x80 (デフォルト) → C7 のみ / 0xC0 → C6 + C7 / 0xFF → 全クラス
static inline int tiny_heap_class_enabled(int class_idx) {
    static int g_parsed = 0;
    static unsigned g_mask = 0;

    if (__builtin_expect(!g_parsed, 0)) {
        g_mask = 0;
        const char* e = getenv("HAKMEM_TINY_HEAP_CLASSES");
        if (e && *e) {
            unsigned v = (unsigned)strtoul(e, NULL, 0);
            g_mask = v & 0xFFu;
        } else {
            g_mask = tiny_heap_profile_default_class_mask(tiny_heap_profile_mode());
        }
        g_parsed = 1;
    }

    if (!tiny_heap_box_enabled()) return 0;
    if (class_idx < 0 || class_idx >= TINY_NUM_CLASSES) return 0;
    return (g_mask & (1u << class_idx)) != 0;
}

// TinyHeap front とクラス bitmask の両方が有効なときにだけ TinyHeap 経路を使う
static inline int tiny_heap_class_route_enabled(int class_idx) {
    if (class_idx == 7) {
        return tiny_heap_box_enabled() && tiny_c7_hot_enabled() && tiny_heap_class_enabled(class_idx);
    }
    if (class_idx == 6) {
        return tiny_heap_box_enabled() && tiny_c6_hot_enabled() && tiny_heap_class_enabled(class_idx);
    }
    return tiny_heap_box_enabled() && tiny_heap_class_enabled(class_idx);
}

// Helper: TinyHeap front + C7 Hot path が両方 ON のときに true
static inline int tiny_c7_heap_mode_enabled(void) {
    return tiny_heap_class_route_enabled(7);
}

// ---------------------------------------------------------------------------
// TinyHotHeap v2 (未配線、Phase30: skeleton 用)
// ---------------------------------------------------------------------------

// ENV: HAKMEM_TINY_HOTHEAP_V2=1 で v2 Box を有効化（デフォルト OFF）
static inline int tiny_hotheap_v2_enabled(void) {
    static int g_enable = -1;
    if (__builtin_expect(g_enable == -1, 0)) {
        const char* e = getenv("HAKMEM_TINY_HOTHEAP_V2");
        g_enable = (e && *e && *e != '0') ? 1 : 0;
    }
    return g_enable;
}

// ENV: HAKMEM_TINY_HOTHEAP_CLASSES (bitmask) - v2 用クラスマスク（デフォルト 0 = 全 OFF）
static inline int tiny_hotheap_v2_class_enabled(uint8_t class_idx) {
    static int g_parsed = 0;
    static unsigned g_mask = 0;

    if (__builtin_expect(!g_parsed, 0)) {
        const char* e = getenv("HAKMEM_TINY_HOTHEAP_CLASSES");
        if (e && *e) {
            unsigned v = (unsigned)strtoul(e, NULL, 0);
            g_mask = v & 0xFFu;
        } else {
            g_mask = 0; // デフォルトは全 OFF（v2 は明示的に ON にする）
        }
        g_parsed = 1;
    }

    if (!tiny_hotheap_v2_enabled()) return 0;
    if (class_idx >= TINY_NUM_CLASSES) return 0;
    return (g_mask & (1u << class_idx)) != 0;
}

// C7 用 v2 gate（C7 front からのみ参照）
static inline int tiny_c7_hotheap_v2_enabled(void) {
    return tiny_hotheap_v2_class_enabled(7);
}