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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_lstbsearch.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: cacharle <marvin@42.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2020/01/30 09:17:51 by cacharle #+# #+# */
/* Updated: 2020/02/28 12:12:12 by cacharle ### ########.fr */
/* */
/* ************************************************************************** */
#include "libft.h"
#include "libft_lst.h"
static t_ftlst *st_lstmiddle(t_ftlst *lst, t_ftlst *last)
{
t_ftlst *slow;
t_ftlst *fast;
if (lst == NULL)
return (NULL);
slow = lst;
fast = lst;
while (fast != last)
{
fast = fast->next;
if (fast == last)
break ;
slow = slow->next;
fast = fast->next;
}
return (slow);
}
static t_ftlst *st_lstbsearch_rec(t_ftlst *lst, t_ftlst *last,
t_ftcompar_func cmp, const void *ref)
{
int res;
t_ftlst *mid;
if (lst == NULL)
return (NULL);
mid = st_lstmiddle(lst, last);
if (mid == NULL)
return (NULL);
if (mid->next == NULL)
{
if (cmp(ref, mid->content) == 0)
return (mid);
return (NULL);
}
res = cmp(ref, mid->next->content);
if (res < 0)
return (st_lstbsearch_rec(lst, mid, cmp, ref));
else if (res > 0)
return (st_lstbsearch_rec(mid->next->next, NULL, cmp, ref));
return (mid->next);
}
t_ftlst *ft_lstbsearch(t_ftlst *lst, t_ftcompar_func cmp,
const void *ref)
{
return (st_lstbsearch_rec(lst, NULL, cmp, ref));
}
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