#ifndef HEAP_H
#define HEAP_H
#include <stddef.h>
#include <toxic/config.h>

/*
 * Heap table consists of an array of 1-byte long entries describing
 * each PAGE_SIZE region inside the heap.
 */

/*
 * Each entry in the heap table is 1byte long, where:
 *
 * bit 7: Set when next page in this heap belongs to the same allocation
 * bit 6: Set when the current page in the first in this allocation map
 * bit 5-1: Reserved
 * bit 0: Used flag
 */
#define HEAP_ENTRY_INUSE	0x1
#define HEAP_ENTRY_FREE		0x0

#define HEAP_ENTRY_HAS_NEXT 0x80 /* 0b1000000 */
#define HEAP_ENTRY_IS_FIRST 0x40 /* 0b01000000 */


#define HEAP_ENTRY_USED_MASK		((unsigned char) 0x01)
/*
 * Define a macro for entry size so in future
 * I can turn this into a proper structure
 */
#define HEAP_ENTRY_SIZE		(sizeof(unsigned char))

struct heap_table {
	unsigned char	*entries;
	size_t		count;
};

/* Heap descriptor */
struct heap {
	struct heap_table	*table;
	void			*start_addr;
};

int heap_create(struct heap *heap, void *start, void *end,
		struct heap_table *tbl);

void * heap_malloc(struct heap *heap, size_t size);
void heap_free(struct heap *heap, void *ptr);

#endif /* HEAP_H */