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

plist *create_empty_list()
{
	plist *l = (plist*) calloc(1,sizeof(plist));
	l->first = NULL;
	l->last = NULL;
	return l;
}

int empty(plist *l)
{
	if (l->first == NULL)
		return 1;
	return 0;
}

void print_l(plist *l)
{
	if (empty(l)) {
		printf("empty list\n");
		return;
	}
	printf("--->\n");
	pnode* current = l->first;
	while (current) {
		print_p(current->elem);
		current = current->next;
	}
	printf("<---\n");

}

void add(plist *l, person *p)
{
	pnode *node = (pnode*) calloc(1, sizeof(pnode));
	node->prev = NULL;
	node->next = NULL;
	node->elem = p;
	if (empty(l)) {
		l->first = node;
		l->last = node;
	} else {
		l->last->next = node;
		node->prev = l->last;
		l->last = node;
	}

}

void swap(plist *list, pnode *n1, pnode *n2)
{
#ifdef __SWAP_CONTENT__
         /* person *tmp = n1->elem;
	 n1->elem=n2->elem;
	 n2->elem=tmp;
	 */
#else
	//nothing to do
	if (n1 == n2)
		return;
	//if n2 is the first element, we treat n2 as n1
	if (list->first == n2) {
		pnode *tmp = n1;
		n1 = n2;
		n2 = tmp;
	}
	//if n1 is the last element, we treat n1 as n2
	if (list->last == n1) {
		pnode *tmp = n1;
		n1 = n2;
		n2 = tmp;
	}
	//to assume, that n2 is not the first and n1 is not the last element

	pnode *tmp_n1_next = n1->next;
	pnode *tmp_n1_prev = n1->prev;
	pnode *tmp_n2_prev = n2->prev;
	pnode *tmp_n2_next = n2->next;

	n1->next = n2->next;
	n2->prev = n1->prev;
	if (list->first == n1) {
		list->first = n2;

		if (list->last == n2) {
			n1->prev = n2;
			n2->next = n1;
			list->last = n1;
			return;
		}
	} else {
		tmp_n1_prev->next = n2;
	}

	if (list->last == n2) {
		list->last = n1;
	} else {
		tmp_n2_next->prev = n1;
	}

	//special case
	if (tmp_n1_next == n2) {
		n1->prev = n2;
		n2->next = n1;
	} else {
		n1->prev = tmp_n2_prev;
		n2->next = tmp_n1_next;
	}
#endif
}

void bubblesort(plist *list, int(*cmp)(person*, person*))
{
	if (empty(list))
		return;
	unsigned changed = 1;
	while (changed) {
		changed = 0;
		pnode *current = list->first;
		while (current->next) {
			if (cmp(current->elem, current->next->elem) > 0) {
				swap(list, current, current->next);

				changed = 1;
			}
			if (current->next)
				current = current->next;

		}

	}
	return;
}

person *search_name(plist *list, char* firstname, char*lastname)
{
	pnode *current = list->first;
	while (current) {

		if (strcmp(current->elem->firstname, firstname) == 0 && strcmp(
				current->elem->lastname, lastname) == 0) {
			return current->elem;
		}
		current = current->next;
	}
	return NULL;

}

person *search_date(plist *list, mdate birthday)
{
	pnode *current = list->first;
	while (current) {

		if (datecmp(&(current->elem->birthday), &birthday) == 0) {
			return current->elem;
		}
		current = current->next;
	}
	return NULL;
}

pnode *search_person(plist *list, person *p)
{
	pnode *current = list->first;
	while (current) {

		if (current->elem == p) {
			return current;
		}
		current = current->next;
	}
	return NULL;
}

void remove_node(plist *list, pnode *node)
{
	if (node == NULL || list == NULL)
		return;

	if (list->first == node && list->last == node) {
		//just one element
		list->first = NULL;
		list->last = NULL;
		free(node);
		return;
	}

	if (list->first == node) {
		list->first = node->next;
		list->first->prev = NULL;
		node->next = NULL;
		free(node);
		return;
	}

	if (list->last == node) {
		list->last = node->prev;
		list->last->next = NULL;
		node->prev = NULL;
		free(node);
		return;
	}
	//ordinary case
	node->prev->next = node->next;
	node->next->prev = node->prev;
	node->next = NULL;
	node->prev = NULL;

	//reallocating the memory of node, elem remains
	free(node);
}

void remove_person(plist* l, person* p)
{
	remove_node(l, search_person(l, p));
}

void clear_l(plist *list)
{
	pnode *current = list->first;
	while(current){
		pnode *tmp=current;
		current=current->next;
		//delete also the content
		delete_p(tmp->elem);
		free(tmp);
	}
	list->first=NULL;
	list->last=NULL;
}

#include <list>

Wollte ich auch gerade schreiben.

P.S. was ist denn das für eine monströse swap-Funktion? Bist du sicher, dass das nicht einfacher gegangen wäre?

War damals ne relativ komplexe Uni Aufgabe, dass ich so eine Tauschfunktion gebraucht hab. Zumindestens konnt/ kann ich das heut auch nicht besser. Hat so die ein oder andere Schweissperle gekostet, wie das immer so ist.