/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   malloc.c                                           :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: jhalford <jack@crans.org>                  +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2017/02/17 12:28:02 by jhalford          #+#    #+#             */
/*   Updated: 2017/02/17 13:18:34 by jhalford         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "malloc.h"

t_node	*tiny_zone = NULL;
t_node	*small_zone = NULL;
t_node	*large_zone = NULL;
t_node	*tiny_alloc = NULL;
t_node	*small_alloc = NULL;
t_node	*large_alloc = NULL;

t_node	**find_node(t_node **node, size_t size)
{
	while (*node && (size_t)(*node)->size < size + HEADER_SIZE)
		node = &(*node)->next;
	return (node);
}

void	add_chunk(t_node **node_ref, size_t size)
{
	size_t	chunk_size;

	while (*node_ref)
		node_ref = &(*node_ref)->next;
	if (LARGE(size))
		chunk_size = size + HEADER_SIZE;
	else
		chunk_size = TINY(size) ? malloc_N : malloc_M;
	*node_ref = mmap(NULL, chunk_size, PROT_READ|PROT_WRITE,
				MAP_ANON|MAP_PRIVATE, -1, 0);
	(*node_ref)->size = chunk_size;
	(*node_ref)->next = NULL;
}

void	*split_node(t_node **free, t_node **alloc, size_t size)
{
	t_node		*new_alloc;
	int			free_size;

	free_size = (*free)->size;
	new_alloc = *free;
	*(void**)free += (size + HEADER_SIZE);
	(*free)->size = free_size - (size + HEADER_SIZE);
	new_alloc->size = size;
	insert_node(alloc, new_alloc);
	return ((void*)new_alloc + HEADER_SIZE);
}

void	*malloc(size_t size)
{
	t_node		**zone_ref;
	t_node		**alloc_ref;
	t_node		**node_ref;
	void		*ptr;

	printf("malloc(%zu) was called\n", size);
	if (LARGE(size))
	{
		zone_ref = &large_zone;
		alloc_ref = &large_alloc;
	}
	else
	{
		zone_ref = TINY(size) ? &tiny_zone : &small_zone;
		alloc_ref = TINY(size) ? &tiny_alloc : &small_alloc;
	}
	while (!*(node_ref = find_node(zone_ref, size)))
		add_chunk(node_ref, size);
	ptr = split_node(node_ref, alloc_ref, size);
	return (ptr);
}