////////////////////////////////////////////////////////////
//~ Buddy types

//- Block
Struct(BuddyBlock)
{
    b32 is_used;
    struct BuddyLevel *level;
    BuddyBlock *parent;
    BuddyBlock *sibling;

    /* Links to block in level's unused list or in ctx's free list */
    BuddyBlock *prev;
    BuddyBlock *next;

    u8 *memory;
};

//- Level
Struct(BuddyLevel)
{
    struct BuddyCtx *ctx;
    b32 backed;  /* Signals whether this level is backed by memory in the ctx arena */
    u32 tier;
    u64 size;
    BuddyBlock *first_unused_block;
};

//- Ctx
Struct(BuddyCtx)
{
    Arena *meta_arena;
    Arena *data_arena;
    BuddyLevel *levels;
    BuddyBlock *first_free_block;
};

////////////////////////////////////////////////////////////
//~ Buddy context operations

BuddyCtx *AcquireBuddyCtx(u64 reserve);
void ReleaseBuddyCtx(BuddyCtx *ctx);

////////////////////////////////////////////////////////////
//~ Buddy block operations

//- Acquire / release
BuddyBlock *AcquireBuddyBlock(BuddyCtx *ctx, u64 size);
void ReleaseBuddyBlock(BuddyBlock *block);

//- Push / pop
BuddyBlock *PushBuddyBlock(BuddyCtx *ctx);
void PopBuddyBlock(BuddyCtx *ctx, BuddyLevel *level, BuddyBlock *block);

//- Get unused
BuddyBlock *GetUnusedBuddyBlock(BuddyCtx *ctx, BuddyLevel *level);