[821] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * linked list helper functions.
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| 4 | *
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| 5 | * Copyright (C) 2003 Glenn McGrath
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| 6 | * Copyright (C) 2005 Vladimir Oleynik
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| 7 | * Copyright (C) 2005 Bernhard Fischer
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| 8 | * Copyright (C) 2006 Rob Landley <rob@landley.net>
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| 9 | *
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[1765] | 10 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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[821] | 11 | */
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[1765] | 12 |
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[821] | 13 | #include "libbb.h"
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| 14 |
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| 15 | /* Add data to the start of the linked list. */
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| 16 | void llist_add_to(llist_t **old_head, void *data)
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| 17 | {
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| 18 | llist_t *new_head = xmalloc(sizeof(llist_t));
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[1765] | 19 |
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[821] | 20 | new_head->data = data;
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| 21 | new_head->link = *old_head;
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| 22 | *old_head = new_head;
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| 23 | }
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| 24 |
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| 25 | /* Add data to the end of the linked list. */
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| 26 | void llist_add_to_end(llist_t **list_head, void *data)
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| 27 | {
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| 28 | llist_t *new_item = xmalloc(sizeof(llist_t));
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[1765] | 29 |
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[821] | 30 | new_item->data = data;
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| 31 | new_item->link = NULL;
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| 32 |
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[1765] | 33 | if (!*list_head)
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| 34 | *list_head = new_item;
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[821] | 35 | else {
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| 36 | llist_t *tail = *list_head;
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[1765] | 37 |
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| 38 | while (tail->link)
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| 39 | tail = tail->link;
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[821] | 40 | tail->link = new_item;
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| 41 | }
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| 42 | }
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| 43 |
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| 44 | /* Remove first element from the list and return it */
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| 45 | void *llist_pop(llist_t **head)
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| 46 | {
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[1765] | 47 | void *data, *next;
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[821] | 48 |
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[1765] | 49 | if (!*head)
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| 50 | return NULL;
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[821] | 51 |
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[1765] | 52 | data = (*head)->data;
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| 53 | next = (*head)->link;
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| 54 | free(*head);
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| 55 | *head = next;
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| 56 |
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[821] | 57 | return data;
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| 58 | }
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| 59 |
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[1765] | 60 | /* Unlink arbitrary given element from the list */
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| 61 | void llist_unlink(llist_t **head, llist_t *elm)
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| 62 | {
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| 63 | llist_t *crt;
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| 64 |
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| 65 | if (!(elm && *head))
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| 66 | return;
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| 67 |
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| 68 | if (elm == *head) {
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| 69 | *head = (*head)->link;
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| 70 | return;
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| 71 | }
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| 72 |
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| 73 | for (crt = *head; crt; crt = crt->link) {
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| 74 | if (crt->link == elm) {
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| 75 | crt->link = elm->link;
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| 76 | return;
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| 77 | }
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| 78 | }
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| 79 | }
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| 80 |
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[821] | 81 | /* Recursively free all elements in the linked list. If freeit != NULL
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| 82 | * call it on each datum in the list */
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[1765] | 83 | void llist_free(llist_t *elm, void (*freeit) (void *data))
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[821] | 84 | {
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| 85 | while (elm) {
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| 86 | void *data = llist_pop(&elm);
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[1765] | 87 |
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| 88 | if (freeit)
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| 89 | freeit(data);
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[821] | 90 | }
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| 91 | }
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[1765] | 92 |
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| 93 | #ifdef UNUSED
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| 94 | /* Reverse list order. */
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| 95 | llist_t *llist_rev(llist_t *list)
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| 96 | {
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| 97 | llist_t *rev = NULL;
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| 98 |
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| 99 | while (list) {
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| 100 | llist_t *next = list->link;
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| 101 |
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| 102 | list->link = rev;
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| 103 | rev = list;
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| 104 | list = next;
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| 105 | }
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| 106 | return rev;
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| 107 | }
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[821] | 108 | #endif
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