Subversion Repositories eco32

#include "c.h"

static char rcsid[] = "$Id: list.c,v 1.1 2002/08/28 23:12:44 drh Exp $";

static List freenodes;          /* free list nodes */

/* append - append x to list, return new list */

List append(void *x, List list) {

        List new;

        if ((new = freenodes) != NULL)

                freenodes = freenodes->link;

        else

                NEW(new, PERM);

        if (list) {

                new->link = list->link;

                list->link = new;

        } else

                new->link = new;

        new->x = x;

        return new;

}

/* length - # elements in list */

int length(List list) {

        int n = 0;

        if (list) {

                List lp = list;

                do

                        n++;

                while ((lp = lp->link) != list);

        }

        return n;

}

/* ltov - convert list to an NULL-terminated vector allocated in arena */

void *ltov(List *list, unsigned arena) {

        int i = 0;

        void **array = newarray(length(*list) + 1, sizeof array[0], arena);

        if (*list) {

                List lp = *list;

                do {

                        lp = lp->link;

                        array[i++] = lp->x;

                } while (lp != *list);

#ifndef PURIFY

                lp = (*list)->link;

                (*list)->link = freenodes;

                freenodes = lp;

#endif

        }

        *list = NULL;

        array[i] = NULL;

        return array;

}