/*
 * include/free_list.h
 *
 * Free list management routines for liballoc
 * CISC 301 -- Operating Systems, Project 3
 *
 * Copyright (C) 2025  Douglas B. Rumbaugh <dbrumbaugh@harrisburgu.edu>
 * 
 * Distributed under the Modified BSD License
 *
 */
#ifndef H_LIBALLOC_FREELIST
#define H_LIBALLOC_FREELIST

#include <stdlib.h>

#include "constants.h"
#include "alloc_header.h"

typedef struct free_nd {
  size_t size;
  struct free_nd *next;
} free_nd;

/*
 * Scans the specified free list for the first node with >= the
 * specified size and returns a pointer to it. If no such node can
 * be found, returns NULL.
 */
free_nd *fl_find_first_fit(free_nd *free_list, size_t size);

/*
 * Split the specified free list node based on the required size, while
 * maintaining alignment, and update the free list accordingly. If the
 * specified node cannot be split (e.g., it's an exact match for size
 * within alignment restrictions), simply remove it from the list.
 *
 * If the head of the free list is updated by this operation, the free
 * list pointer passed as an argument will be updated to reflect this
 *
 * Returns a pointer to the region of memory removed from the list.
 */
void *fl_split_node(free_nd **free_list, free_nd *nd, size_t size);

/*
 * Scans the free list for adjacent nodes and merges them together
 */
void fl_coalesce_nodes(free_nd *free_list);

/*
 * Scans the free list for the correct location for the specified
 * pointer, and link it into the list at that point.
 *
 * If the head of the free list is updated by this operation, the free
 * list pointer passed as an argument will be updated to reflect this
 */
void fl_add_node(free_nd **free_list, void *ptr);

#endif