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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10 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
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11 | */
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12 |
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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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19 |
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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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29 |
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30 | new_item->data = data;
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31 | new_item->link = NULL;
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32 |
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33 | if (!*list_head)
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34 | *list_head = new_item;
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35 | else {
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36 | llist_t *tail = *list_head;
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37 |
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38 | while (tail->link)
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39 | tail = tail->link;
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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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47 | void *data, *next;
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48 |
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49 | if (!*head)
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50 | return NULL;
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51 |
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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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57 | return data;
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58 | }
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59 |
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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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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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83 | void llist_free(llist_t *elm, void (*freeit) (void *data))
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84 | {
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85 | while (elm) {
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86 | void *data = llist_pop(&elm);
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87 |
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88 | if (freeit)
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89 | freeit(data);
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90 | }
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91 | }
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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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108 | #endif
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