#ifndef __LIST_H
#define __LIST_H

/* This file is from Linux Kernel (include/linux/list.h) 
 * and modified by simply removing hardware prefetching of list items. 
 * Here by copyright, credits attributed to wherever they belong.
 * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
 */

/*
 * Simple doubly linked list implementation.
 *
 * Some of the internal functions ("__xxx") are useful when
 * manipulating whole lists rather than single entries, as
 * sometimes we already know the next/prev entries and we can
 * generate better code by using them directly rather than
 * using the generic single-entry routines.
 */

struct list_head {
	struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name) \
	struct list_head name = LIST_HEAD_INIT(name)

#define INIT_LIST_HEAD(ptr) do { \
	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
} while (0)

/*
 * Insert a new entry between two known consecutive entries. 
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_add(struct list_head *new_element,
			      struct list_head *prev,
			      struct list_head *next)
{
	next->prev = new_element;
	new_element->next = next;
	new_element->prev = prev;
	prev->next = new_element;
}

/**
 * list_add - add a new entry
 * @new: new entry to be added
 * @head: list head to add it after
 *
 * Insert a new entry after the specified head.
 * This is good for implementing stacks.
 */
static inline void list_add(struct list_head *new_element, struct list_head *head)
{
	__list_add(new_element, head, head->next);
}

/**
 * list_add_tail - add a new entry
 * @new: new entry to be added
 * @head: list head to add it before
 *
 * Insert a new entry before the specified head.
 * This is useful for implementing queues.
 */
static inline void list_add_tail(struct list_head *new_element, struct list_head *head)
{
	__list_add(new_element, head->prev, head);
}

/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
	next->prev = prev;
	prev->next = next;
}

/**
 * list_del - deletes entry from list.
 * @entry: the element to delete from the list.
 * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
 */
static inline void list_del(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	entry->next = (list_head *) 0;
	entry->prev = (list_head *) 0;
}

/**
 * list_del_init - deletes entry from list and reinitialize it.
 * @entry: the element to delete from the list.
 */
static inline void list_del_init(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	INIT_LIST_HEAD(entry); 
}

/**
 * list_move - delete from one list and add as another's head
 * @list: the entry to move
 * @head: the head that will precede our entry
 */
static inline void list_move(struct list_head *list, struct list_head *head)
{
        __list_del(list->prev, list->next);
        list_add(list, head);
}

/**
 * list_move_tail - delete from one list and add as another's tail
 * @list: the entry to move
 * @head: the head that will follow our entry
 */
static inline void list_move_tail(struct list_head *list,
				  struct list_head *head)
{
        __list_del(list->prev, list->next);
        list_add_tail(list, head);
}

/**
 * list_empty - tests whether a list is empty
 * @head: the list to test.
 */
static inline int list_empty(struct list_head *head)
{
	return head->next == head;
}

static inline void __list_splice(struct list_head *list,
				 struct list_head *head)
{
	struct list_head *first = list->next;
	struct list_head *last = list->prev;
	struct list_head *at = head->next;

	first->prev = head;
	head->next = first;

	last->next = at;
	at->prev = last;
}

/**
 * list_splice - join two lists
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice(struct list_head *list, struct list_head *head)
{
	if (!list_empty(list))
		__list_splice(list, head);
}

/**
 * list_splice_init - join two lists and reinitialise the emptied list.
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * The list at @list is reinitialised
 */
static inline void list_splice_init(struct list_head *list,
				    struct list_head *head)
{
	if (!list_empty(list)) {
		__list_splice(list, head);
		INIT_LIST_HEAD(list);
	}
}

/**
 * list_entry - get the struct for this entry
 * @ptr:	the &struct list_head pointer.
 * @type:	the type of the struct this is embedded in.
 * @member:	the name of the list_struct within the struct.
 */
#define list_entry(ptr, type, member) \
	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))

/**
 * list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop counter.
 * @head:	the head for your list.
 */
#define list_for_each(pos, head) \
	for (pos = (head)->next; pos != (head); \
        	pos = pos->next)
/**
 * list_for_each_prev	-	iterate over a list backwards
 * @pos:	the &struct list_head to use as a loop counter.
 * @head:	the head for your list.
 */
#define list_for_each_prev(pos, head) \
	for (pos = (head)->prev; pos != (head); \
        	pos = pos->prev)
        	
/**
 * list_for_each_safe	-	iterate over a list safe against removal of list entry
 * @pos:	the &struct list_head to use as a loop counter.
 * @n:		another &struct list_head to use as temporary storage
 * @head:	the head for your list.
 */
#define list_for_each_safe(pos, n, head) \
	for (pos = (head)->next, n = pos->next; pos != (head); \
		pos = n, n = pos->next)

/**
 * list_for_each_entry	-	iterate over list of given type
 * @pos:	the type * to use as a loop counter.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry(pos, head, member)				\
	for (pos = list_entry((head)->next, typeid(*pos), member);	\
	     &pos->member != (head); 					\
	     pos = list_entry(pos->member.next, typeid(*pos), member))

/**
 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 * @pos:	the type * to use as a loop counter.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry_safe(pos, n, head, member)			\
	for (pos = list_entry((head)->next, typeid(*pos), member),	\
		n = list_entry(pos->member.next, typeid(*pos), member);	\
	     &pos->member != (head); 					\
	     pos = n, n = list_entry(n->member.next, typeid(*n), member))


#endif

#include <stdio.h>
#include <stdlib.h>

#include "list.h"


struct kool_list{
        int to;
        struct list_head list;
        int from;
        };

int main(int argc, char **argv){

        struct kool_list *tmp;
        struct list_head *pos, *q;
        unsigned int i;

        struct kool_list mylist;
        INIT_LIST_HEAD(&mylist.list);
        
        for(i=5; i!=0; --i){
                tmp= (struct kool_list *)malloc(sizeof(struct kool_list));

                
                printf("enter to and from:");
                scanf("%d %d", &tmp->to, &tmp->from);

                /* add the new item 'tmp' to the list of items in mylist */
                list_add(&(tmp->list), &(mylist.list));
                
        }
        printf("\n");



       
        printf("traversing the list using list_for_each()\n");
        list_for_each(pos, &mylist.list){

                
                 tmp= list_entry(pos, struct kool_list, list);

             

                 printf("to= %d from= %d\n", tmp->to, tmp->from);

        }
        printf("\n");
       
        printf("traversing the list using list_for_each_entry()\n");
		list_for_each_entry(tmp, &mylist.list, list)
                 printf("to= %d from= %d\n", tmp->to, tmp->from);
        printf("\n");


        printf("deleting the list using list_for_each_safe()\n");
        list_for_each_safe(pos, q, &mylist.list){
                 tmp= list_entry(pos, struct kool_list, list);
                 printf("freeing item to= %d from= %d\n", tmp->to, tmp->from);
                 list_del(pos);
                 free(tmp);
        }

        return 0;
}

#include <list>
#include <iostream>

typedef std::pair<int,int> entry_t;
typedef std::list<entry_t > List;
void print_entry(entry_t& i)
{
	std::cout <<"to :" <<i.first <<" from :" <<i.second <<std::endl;
}

int main()
{
	List mylist;
	
	for(int i = 0; i <5; ++i)
	{
		int to,from;
		std::cout <<"please enter to:";
		std::cin >>to;
		std::cout <<"please enter from:";
		std::cin >>from;
		
		mylist.push_back( std::make_pair(to,from) );
	}
	
	std::cout<< "traversing the list" <<std::endl;
	std::for_each(mylist.begin(), mylist.end(), &print_entry);
}

#include <list>
#include <iostream>
#include <algorithm>
#include <boost/foreach.hpp>

using std::list;
using std::cout;
using std::cin;
using std::for_each;

struct kool_list {
	int to;
	int from;
};

inline void print(kool_list &t) {
	cout << "to = " << t.to << " from = " << t.from << "\n";
}

int main(int argc, char *argv[]) {
	list<kool_list> mylist;

	for (int i = 5; i != 0; --i) {
		kool_list tmp;
		cout << "enter to and from: ";
		cin >> tmp.to >> tmp.from;
		mylist.push_back(tmp);
	}

	cout << "Traversing list with iterators\n";
	for (list<kool_list>::iterator i = mylist.begin(); i != mylist.end(); i++)
		cout << "to = " << i->to << " from = " << i->from << "\n";

	cout << "Traversing list with std::for_each\n";
	for_each(mylist.begin(), mylist.end(), print);

	cout << "Traversing list through BOOST_FOREACH\n";
	BOOST_FOREACH(kool_list t, mylist)
		cout << "to = " << t.to << " from = " << t.from << "\n";

	cout << "Deleting the entire list at once using list.clear()\n";
	mylist.clear();
	
	return 0;
}