#ifndef SAND_ARENA_ALLOCATOR_H
#define SAND_ARENA_ALLOCATOR_H

// This module defines an arena allocator which implements `SandAllocator`. It
// is useful if one needs to allocate a lot of objects with the same lifetime
// very quickly. When the arena is destroyed, all objects allocated within are
// freed.

#include "allocator.h"

// This should only be used internally by an arena allocator.
// It is only public because of C's stone-age """modules""".
typedef struct _SandRegion {
	struct _SandRegion *prev;
	size_t capacity;
	size_t used;
	unsigned char data[];
} SandRegion;

typedef struct {
	SandAllocator *parent;
	SandRegion *current_region;
} SandArena;

SandArena sand_create_arena(SandAllocator *parent);

// Returns a `SandAllocator` which is valid as long as the arena is.
// The arena must not be moved afterwards, as the allocator retains a pointer to the arena.
SandAllocator sand_get_allocator_for_arena(SandArena *);

void sand_destroy_arena(SandArena *);

#endif