LXR busybox/libbb/llist.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * linked list helper functions.
   4 *
   5 * Copyright (C) 2003 Glenn McGrath
   6 * Copyright (C) 2005 Vladimir Oleynik
   7 * Copyright (C) 2005 Bernhard Reutner-Fischer
   8 * Copyright (C) 2006 Rob Landley <rob@landley.net>
   9 *
  10 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  11 */
  12
  13#include "libbb.h"
  14
  15/* Add data to the start of the linked list.  */
  16void FAST_FUNC llist_add_to(llist_t **old_head, void *data)
  17{
  18        llist_t *new_head = xmalloc(sizeof(llist_t));
  19
  20        new_head->data = data;
  21        new_head->link = *old_head;
  22        *old_head = new_head;
  23}
  24
  25/* Add data to the end of the linked list.  */
  26void FAST_FUNC llist_add_to_end(llist_t **list_head, void *data)
  27{
  28        llist_t *new_item = xmalloc(sizeof(llist_t));
  29
  30        new_item->data = data;
  31        new_item->link = NULL;
  32
  33        if (!*list_head)
  34                *list_head = new_item;
  35        else {
  36                llist_t *tail = *list_head;
  37
  38                while (tail->link)
  39                        tail = tail->link;
  40                tail->link = new_item;
  41        }
  42}
  43
  44/* Remove first element from the list and return it */
  45void* FAST_FUNC llist_pop(llist_t **head)
  46{
  47        void *data, *next;
  48
  49        if (!*head)
  50                return NULL;
  51
  52        data = (*head)->data;
  53        next = (*head)->link;
  54        free(*head);
  55        *head = next;
  56
  57        return data;
  58}
  59
  60/* Unlink arbitrary given element from the list */
  61void FAST_FUNC llist_unlink(llist_t **head, llist_t *elm)
  62{
  63        llist_t *crt;
  64
  65        if (!(elm && *head))
  66                return;
  67
  68        if (elm == *head) {
  69                *head = (*head)->link;
  70                return;
  71        }
  72
  73        for (crt = *head; crt; crt = crt->link) {
  74                if (crt->link == elm) {
  75                        crt->link = elm->link;
  76                        return;
  77                }
  78        }
  79}
  80
  81/* Recursively free all elements in the linked list.  If freeit != NULL
  82 * call it on each datum in the list */
  83void FAST_FUNC llist_free(llist_t *elm, void (*freeit) (void *data))
  84{
  85        while (elm) {
  86                void *data = llist_pop(&elm);
  87
  88                if (freeit)
  89                        freeit(data);
  90        }
  91}
  92
  93/* Reverse list order. */
  94llist_t* FAST_FUNC llist_rev(llist_t *list)
  95{
  96        llist_t *rev = NULL;
  97
  98        while (list) {
  99                llist_t *next = list->link;
 100
 101                list->link = rev;
 102                rev = list;
 103                list = next;
 104        }
 105        return rev;
 106}
 107