1 /****************************************************************************** 2 * 3 * Copyright 2016 Google, Inc. 4 * 5 * Licensed under the Apache License, Version 2.0 (the "License"); 6 * you may not use this file except in compliance with the License. 7 * You may obtain a copy of the License at: 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 ******************************************************************************/ 18 19 #pragma once 20 21 #include <stdbool.h> 22 #include <stdlib.h> 23 24 struct list_node_t; 25 typedef struct list_node_t list_node_t; 26 27 struct list_t; 28 typedef struct list_t list_t; 29 30 typedef void (*list_free_cb)(void* data); 31 32 // Iterator callback prototype used for |list_foreach|. 33 // |data| represents the list item currently being iterated, |context| is a 34 // user defined value passed into |list_foreach|. 35 // Callback must return true to continue iterating or false to stop iterating. 36 typedef bool (*list_iter_cb)(void* data, void* context); 37 38 // Returns a new, empty list. Returns NULL if not enough memory could be 39 // allocated for the list structure. The returned list must be freed with 40 // |list_free|. The |callback| specifies a function to be called whenever a 41 // list element is removed from the list. It can be used to release resources 42 // held by the list element, e.g. memory or file descriptor. |callback| may 43 // be NULL if no cleanup is necessary on element removal. 44 list_t* list_new(list_free_cb callback); 45 46 // Frees the list. This function accepts NULL as an argument, in which case it 47 // behaves like a no-op. 48 void list_free(list_t* list); 49 50 // Returns true if |list| is empty (has no elements), false otherwise. 51 // |list| may not be NULL. 52 bool list_is_empty(const list_t* list); 53 54 // Returns true if the list contains |data|, false otherwise. 55 // |list| may not be NULL. 56 bool list_contains(const list_t* list, const void* data); 57 58 // Returns the length of the |list|. |list| may not be NULL. 59 size_t list_length(const list_t* list); 60 61 // Returns the first element in the list without removing it. |list| may not 62 // be NULL or empty. 63 void* list_front(const list_t* list); 64 65 // Returns the last element in the list without removing it. |list| may not 66 // be NULL or empty. 67 void* list_back(const list_t* list); 68 69 // Returns the last node in the list without removing it. |list| may not 70 // be NULL or empty. 71 list_node_t* list_back_node(const list_t* list); 72 73 // Inserts |data| after |prev_node| in |list|. |data|, |list|, and |prev_node| 74 // may not be NULL. This function does not make a copy of |data| so the pointer 75 // must remain valid at least until the element is removed from the list or the 76 // list is freed. Returns true if |data| could be inserted, false otherwise 77 // (e.g. out of memory). 78 bool list_insert_after(list_t* list, list_node_t* prev_node, void* data); 79 80 // Inserts |data| at the beginning of |list|. Neither |data| nor |list| may be 81 // NULL. 82 // This function does not make a copy of |data| so the pointer must remain valid 83 // at least until the element is removed from the list or the list is freed. 84 // Returns true if |data| could be inserted, false otherwise (e.g. out of 85 // memory). 86 bool list_prepend(list_t* list, void* data); 87 88 // Inserts |data| at the end of |list|. Neither |data| nor |list| may be NULL. 89 // This function does not make a copy of |data| so the pointer must remain valid 90 // at least until the element is removed from the list or the list is freed. 91 // Returns true if |data| could be inserted, false otherwise (e.g. out of 92 // memory). 93 bool list_append(list_t* list, void* data); 94 95 // Removes |data| from the list. Neither |list| nor |data| may be NULL. If 96 // |data| 97 // is inserted multiple times in the list, this function will only remove the 98 // first instance. If a free function was specified in |list_new|, it will be 99 // called back with |data|. This function returns true if |data| was found in 100 // the list and removed, false otherwise. 101 bool list_remove(list_t* list, void* data); 102 103 // Removes all elements in the list. Calling this function will return the list 104 // to the 105 // same state it was in after |list_new|. |list| may not be NULL. 106 void list_clear(list_t* list); 107 108 // Iterates through the |list| and calls |callback| for each data element. 109 // Iteration continues until |callback| returns false. The function returns the 110 // pointer to last processed element, or NULL if the list is empty, or all calls 111 // to |callback| returned true. |context| is passed to |callback| on each 112 // iteration. 113 // If the list is empty, |callback| will never be called. It is safe to mutate 114 // the list inside the callback. If an element is added before the node being 115 // visited, there will be no callback for the newly-inserted node. Neither 116 // |list| nor |callback| may be NULL. 117 list_node_t* list_foreach(const list_t* list, list_iter_cb callback, 118 void* context); 119 120 // Returns an iterator to the first element in |list|. |list| may not be NULL. 121 // The returned iterator is valid as long as it does not equal the value 122 // returned by |list_end|. 123 list_node_t* list_begin(const list_t* list); 124 125 // Returns an iterator that points past the end of the list. In other words, 126 // this function returns the value of an invalid iterator for the given list. 127 // When an iterator has the same value as what's returned by this function, you 128 // may no longer call |list_next| with the iterator. |list| may not be NULL. 129 list_node_t* list_end(const list_t* list); 130 131 // Given a valid iterator |node|, this function returns the next value for the 132 // iterator. If the returned value equals the value returned by |list_end|, the 133 // iterator has reached the end of the list and may no longer be used for any 134 // purpose. 135 list_node_t* list_next(const list_node_t* node); 136 137 // Returns the value stored at the location pointed to by the iterator |node|. 138 // |node| must not equal the value returned by |list_end|. 139 void* list_node(const list_node_t* node); 140