/*
 * Small id to pointer translation service avoiding fixed sized
 * tables.
 */

#define ID_BITS 5

#define ID_MASK ((1 << ID_BITS)-1)
#define ID_FULL ((1 << (1 << ID_BITS))-1)

struct id_layer {
	unsigned int	bitmap: (1<<ID_BITS);
	struct id_layer	*ary[1<<ID_BITS];
};

struct id {
	int		layers;
	int		last;
	int		count;
	int		min_wrap;
	struct id_layer *top;
};

void *id_lookup(struct id *idp, int id);
int id_new(struct id *idp, void *ptr);
void id_remove(struct id *idp, int id);
void id_init(struct id *idp, int min_wrap);

static inline update_bitmap(struct id_layer *p, int bit)
{
	if (p->ary[bit] && p->ary[bit]->bitmap == (typeof(p->bitmap))-1)
		p->bitmap |= 1<<bit;
	else
		p->bitmap &= ~(1<<bit);
}

#ifndef __KERNEL__

#ifndef NULL
#define NULL 0
#endif

static inline struct id_layer *alloc_layer()
{
	struct id_layer *new;

	new = (struct id_layer *)malloc(sizeof(struct id_layer));
	bzero((void *)new, sizeof(struct id_layer));
	return(new);
	
}

static inline void free_layer(struct id_layer *p)
{
	free((void *)p);
}

#else

extern kmem_cache_t *id_layer_cache;

static inline struct id_layer *alloc_layer()
{
	return(kmem_cache_alloc(id_layer_cache, GFP_KERNEL));
}

static inline void free_layer(struct id_layer *p)
{
	kmem_cache_free(id_layer_cache, p);
}

#endif