5 * The string_list API offers a data structure and functions to handle
6 * sorted and unsorted arrays of strings. A "sorted" list is one whose
7 * entries are sorted by string value in the order specified by the `cmp`
8 * member (`strcmp()` by default).
12 * . Allocates and clears a `struct string_list` variable.
14 * . Initializes the members. You might want to set the flag `strdup_strings`
15 * if the strings should be strdup()ed. For example, this is necessary
16 * when you add something like git_path("..."), since that function returns
17 * a static buffer that will change with the next call to git_path().
19 * If you need something advanced, you can manually malloc() the `items`
20 * member (you need this if you add things later) and you should set the
21 * `nr` and `alloc` members in that case, too.
23 * . Adds new items to the list, using `string_list_append`,
24 * `string_list_append_nodup`, `string_list_insert`,
25 * `string_list_split`, and/or `string_list_split_in_place`.
27 * . Can check if a string is in the list using `string_list_has_string` or
28 * `unsorted_string_list_has_string` and get it from the list using
29 * `string_list_lookup` for sorted lists.
31 * . Can sort an unsorted list using `string_list_sort`.
33 * . Can remove duplicate items from a sorted list using
34 * `string_list_remove_duplicates`.
36 * . Can remove individual items of an unsorted list using
37 * `unsorted_string_list_delete_item`.
39 * . Can remove items not matching a criterion from a sorted or unsorted
40 * list using `filter_string_list`, or remove empty strings using
41 * `string_list_remove_empty_items`.
43 * . Finally it should free the list using `string_list_clear`.
47 * struct string_list list = STRING_LIST_INIT_NODUP;
50 * string_list_append(&list, "foo");
51 * string_list_append(&list, "bar");
52 * for (i = 0; i < list.nr; i++)
53 * printf("%s\n", list.items[i].string)
55 * NOTE: It is more efficient to build an unsorted list and sort it
56 * afterwards, instead of building a sorted list (`O(n log n)` instead of
59 * However, if you use the list to check if a certain string was added
60 * already, you should not do that (using unsorted_string_list_has_string()),
61 * because the complexity would be quadratic again (but with a worse factor).
65 * Represents an item of the list. The `string` member is a pointer to the
66 * string, and you may use the `util` member for any purpose, if you want.
68 struct string_list_item {
73 typedef int (*compare_strings_fn)(const char *, const char *);
76 * Represents the list itself.
78 * . The array of items are available via the `items` member.
79 * . The `nr` member contains the number of items stored in the list.
80 * . The `alloc` member is used to avoid reallocating at every insertion.
81 * You should not tamper with it.
82 * . Setting the `strdup_strings` member to 1 will strdup() the strings
83 * before adding them, see above.
84 * . The `compare_strings_fn` member is used to specify a custom compare
85 * function, otherwise `strcmp()` is used as the default function.
88 struct string_list_item *items;
89 unsigned int nr, alloc;
90 unsigned int strdup_strings:1;
91 compare_strings_fn cmp; /* NULL uses strcmp() */
94 #define STRING_LIST_INIT_NODUP { NULL, 0, 0, 0, NULL }
95 #define STRING_LIST_INIT_DUP { NULL, 0, 0, 1, NULL }
97 /* General functions which work with both sorted and unsorted lists. */
100 * Initialize the members of the string_list, set `strdup_strings`
101 * member according to the value of the second parameter.
103 void string_list_init(struct string_list *list, int strdup_strings);
105 /** Callback function type for for_each_string_list */
106 typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
109 * Apply `want` to each item in `list`, retaining only the ones for which
110 * the function returns true. If `free_util` is true, call free() on
111 * the util members of any items that have to be deleted. Preserve
112 * the order of the items that are retained.
114 void filter_string_list(struct string_list *list, int free_util,
115 string_list_each_func_t want, void *cb_data);
118 * Free a string_list. The `string` pointer of the items will be freed
119 * in case the `strdup_strings` member of the string_list is set. The
120 * second parameter controls if the `util` pointer of the items should
123 void string_list_clear(struct string_list *list, int free_util);
126 * Callback type for `string_list_clear_func`. The string associated
127 * with the util pointer is passed as the second argument
129 typedef void (*string_list_clear_func_t)(void *p, const char *str);
131 /** Call a custom clear function on each util pointer */
132 void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
135 * Apply `func` to each item. If `func` returns nonzero, the
136 * iteration aborts and the return value is propagated.
138 int for_each_string_list(struct string_list *list,
139 string_list_each_func_t func, void *cb_data);
141 /** Iterate over each item, as a macro. */
142 #define for_each_string_list_item(item,list) \
143 for (item = (list)->items; \
144 item && item < (list)->items + (list)->nr; \
148 * Remove any empty strings from the list. If free_util is true, call
149 * free() on the util members of any items that have to be deleted.
150 * Preserve the order of the items that are retained.
152 void string_list_remove_empty_items(struct string_list *list, int free_util);
154 /* Use these functions only on sorted lists: */
156 /** Determine if the string_list has a given string or not. */
157 int string_list_has_string(const struct string_list *list, const char *string);
158 int string_list_find_insert_index(const struct string_list *list, const char *string,
159 int negative_existing_index);
162 * Insert a new element to the string_list. The returned pointer can
163 * be handy if you want to write something to the `util` pointer of
164 * the string_list_item containing the just added string. If the given
165 * string already exists the insertion will be skipped and the pointer
166 * to the existing item returned.
168 * Since this function uses xrealloc() (which die()s if it fails) if the
169 * list needs to grow, it is safe not to check the pointer. I.e. you may
170 * write `string_list_insert(...)->util = ...;`.
172 struct string_list_item *string_list_insert(struct string_list *list, const char *string);
175 * Remove the given string from the sorted list. If the string
176 * doesn't exist, the list is not altered.
178 void string_list_remove(struct string_list *list, const char *string,
182 * Check if the given string is part of a sorted list. If it is part of the list,
183 * return the corresponding string_list_item, NULL otherwise.
185 struct string_list_item *string_list_lookup(struct string_list *list, const char *string);
188 * Remove all but the first of consecutive entries with the same
189 * string value. If free_util is true, call free() on the util
190 * members of any items that have to be deleted.
192 void string_list_remove_duplicates(struct string_list *sorted_list, int free_util);
195 /* Use these functions only on unsorted lists: */
198 * Add string to the end of list. If list->strdup_string is set, then
199 * string is copied; otherwise the new string_list_entry refers to the
202 struct string_list_item *string_list_append(struct string_list *list, const char *string);
205 * Like string_list_append(), except string is never copied. When
206 * list->strdup_strings is set, this function can be used to hand
207 * ownership of a malloc()ed string to list without making an extra
210 struct string_list_item *string_list_append_nodup(struct string_list *list, char *string);
213 * Sort the list's entries by string value in order specified by list->cmp
214 * (strcmp() if list->cmp is NULL).
216 void string_list_sort(struct string_list *list);
219 * Like `string_list_has_string()` but for unsorted lists. Linear in
222 int unsorted_string_list_has_string(struct string_list *list, const char *string);
225 * Like `string_list_lookup()` but for unsorted lists. Linear in size
228 struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
231 * Remove an item from a string_list. The `string` pointer of the
232 * items will be freed in case the `strdup_strings` member of the
233 * string_list is set. The third parameter controls if the `util`
234 * pointer of the items should be freed or not.
236 void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util);
239 * Split string into substrings on character `delim` and append the
240 * substrings to `list`. The input string is not modified.
241 * list->strdup_strings must be set, as new memory needs to be
242 * allocated to hold the substrings. If maxsplit is non-negative,
243 * then split at most maxsplit times. Return the number of substrings
247 * string_list_split(l, "foo:bar:baz", ':', -1) -> ["foo", "bar", "baz"]
248 * string_list_split(l, "foo:bar:baz", ':', 0) -> ["foo:bar:baz"]
249 * string_list_split(l, "foo:bar:baz", ':', 1) -> ["foo", "bar:baz"]
250 * string_list_split(l, "foo:bar:", ':', -1) -> ["foo", "bar", ""]
251 * string_list_split(l, "", ':', -1) -> [""]
252 * string_list_split(l, ":", ':', -1) -> ["", ""]
254 int string_list_split(struct string_list *list, const char *string,
255 int delim, int maxsplit);
258 * Like string_list_split(), except that string is split in-place: the
259 * delimiter characters in string are overwritten with NULs, and the
260 * new string_list_items point into string (which therefore must not
261 * be modified or freed while the string_list is in use).
262 * list->strdup_strings must *not* be set.
264 int string_list_split_in_place(struct string_list *list, char *string,
265 int delim, int maxsplit);
266 #endif /* STRING_LIST_H */