#include "ufd.h"
#include "stdlib.h"
#include <sys/queue.h>


void ufd__init(struct ufd_t* ufd, struct context_entry_t* thread)
{
    TAILQ_INIT(&ufd->children);
    ufd->thread = thread;
    ufd->repr = ufd,
    ufd->parent = NULL;
}


void ufd__join(struct ufd_t* th1, struct ufd_t* th2)
{
    struct ufd_t* a = ufd__find(th1);
    struct ufd_t* b = ufd__find(th2);

    if (a != b)
    {
        a->parent = th2;
        a->repr = b;
        TAILQ_INSERT_TAIL(&a->repr->children, a, link);
    }
}


struct ufd_t* ufd__find(struct ufd_t* th)
{
    if (th->repr == th)
        return th;

    struct ufd_t* nrepr = ufd__find(th->repr);
    th->repr = nrepr;
    return nrepr;
}


void ufd__delete(struct ufd_t* th)
{
    struct ufd_t* child;

    TAILQ_FOREACH(child, &th->children, link) {
        child->parent = NULL;
        child->repr = child;
    }
}