source: MondoRescue/branches/stable/mondo/src/lib/mr_list.c @ 1361

/*
 * $Id$
 *
 * List handling functions safe from a memory management point of view 
 *
 */

#include <stdio.h>
#include <string.h>
#include <time.h>

#include "mr_list.h"

/* List allocation and initialization */
void mr_list_alloc(struct mr_list *list) {

    list = mr_malloc(sizeof(struct mr_list));
    list->first = NULL;
    list->last = NULL;
}

/* Elt of list allocation and initialization */
void mr_list_alloc_elt(struct mr_list_elt *elt, void *data) {

    elt = mr_malloc(sizeof(struct mr_list_elt));
    elt->data = (void *)data;
    elt->prev = NULL;
    elt->next = NULL;
}

void mr_list_free_elt(struct mr_list_elt *elt) {
    mr_free(elt->data);
    mr_free(elt);
}

/* List desallocation and removal */
void mr_list_free(struct mr_list *list) {

    struct mr_list_elt *elt = list->first;
    struct mr_list_elt *elt2 = NULL;
    
    while (elt != NULL) {
        /* preserve next elt */
        elt2 = elt->next;
        /* Purge elt */
        mr_list_free_elt(elt);
        /* next elt to consider */
        elt = elt2;
    }

    mr_free(list);
}

/* Count the number of elements in the list */
int mr_list_length(struct mr_list *list) {

    int i = 0;
    struct mr_list_elt *p = list->first;

    while (p != NULL) {
        i++;
        p = p->next;
    }
    return(i);
}

/* Add an element first in the list */
void mr_list_add_elt_first(struct mr_list *list, struct mr_list_elt *elt) {
    
    if (list->first != NULL) {
        /* if there was a first elt shift it */
        list->first->prev = elt;
        elt->next = list->first;
    } else {
        /* if there was no first, there was no last as well, so set it up */
        list->last = elt;
    }
    list->first = elt;
}

/* Add an element last in the list */
void mr_list_add_elt_last(struct mr_list *list, struct mr_list_elt *elt) {
    
    if (list->last != NULL) {
        /* if there was a last elt use it */
        list->last->next = elt;
        elt->prev = list->last;
    } else {
        /* if there was no last, there was no first as well, so set it up */
        list->first = elt;
    }
    list->last = elt;
}

/* Add an element in the list after the ref elt given in parameter */
void mr_list_add_elt_after(struct mr_list *list, struct mr_list_elt *ref, struct mr_list_elt *elt) {

    if (ref->next != NULL) {
        /* if there was a next elt, shit it */
        ref->next->prev = elt;
        elt->next = ref->next;
    } else {
        /* If not, it's the last elt */
        list->last = elt;
    }
    ref->next = elt;
    elt->prev = ref;
}

/* Add an element in the list before the ref elt given in parameter */
void mr_list_add_elt_before(struct mr_list *list, struct mr_list_elt *ref, struct mr_list_elt *elt) {

    if (ref->prev != NULL) {
        /* if there was a prev elt, shit it */
        ref->prev->next = elt;
        elt->prev = ref->prev;
    } else {
        /* If not, it's the first elt */
        list->first = elt;
    }
    ref->prev = elt;
    elt->next = ref;
}

/* Delete the first element in the list */
void mr_list_del_elt_first(struct mr_list *list) {

    struct mr_list_elt *elt = list->first;

    if (elt->next != NULL) {
        /* There are other elts behind */
        list->first = elt->next;
    }
    mr_list_free_elt(elt);
}

/* Delete the last element in the list */
void mr_list_del_elt_last(struct mr_list *list) {

    struct mr_list_elt *elt = list->last;

    if (elt->prev != NULL) {
        /* There are other elts before */
        list->last = elt->prev;
    }
    mr_list_free_elt(elt);
}

/* Delete an element in the list after the ref elt given in parameter */
void mr_list_del_elt_after(struct mr_list *list, struct mr_list_elt *ref) {

    struct mr_list_elt *elt = ref->next;

    if (elt != NULL) {
        /* if there was a next elt, delete it */
        if (elt->next != NULL) {
            /* there is an elt behind, shift it */
            elt->prev->next = elt->next;
            elt->next->prev = elt->prev;
            mr_list_free_elt(elt);
        } else {
            /* that elt is the last one */
            mr_list_del_elt_last(list);
        }
    } else {
        /* If not, ref is the last elt */
        mr_msg(3, "No elt to delete available after the last one");
    }
}

/* Delete an element in the list before the ref elt given in parameter */
void mr_list_del_elt_before(struct mr_list *list, struct mr_list_elt *ref) {

    struct mr_list_elt *elt = ref->prev;

    if (elt != NULL) {
        /* if there was a previous elt, delete it */
        if (elt->prev != NULL) {
            /* there is an elt before, shift it */
            elt->prev->next = elt->next;
            elt->next->prev = elt->prev;
            mr_list_free_elt(elt);
        } else {
            /* that elt is the first one */
            mr_list_del_elt_firt(list);
        }
    } else {
        /* If not, ref is the first elt */
        mr_msg(3, "No elt to delete available before the first one");
    }
}