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1#ifndef STRING_LIST_H
2#define STRING_LIST_H
3
4/**
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).
9 *
10 * The caller:
11 *
12 * . Allocates and clears a `struct string_list` variable.
13 *
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().
18 *
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.
22 *
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`.
26 *
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.
30 *
31 * . Can sort an unsorted list using `string_list_sort`.
32 *
33 * . Can remove duplicate items from a sorted list using
34 * `string_list_remove_duplicates`.
35 *
36 * . Can remove individual items of an unsorted list using
37 * `unsorted_string_list_delete_item`.
38 *
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`.
42 *
43 * . Finally it should free the list using `string_list_clear`.
44 *
45 * Example:
46 *
47 * struct string_list list = STRING_LIST_INIT_NODUP;
48 * int i;
49 *
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)
54 *
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
57 * `O(n^2)`).
58 *
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).
62 */
63
64/**
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.
67 */
68struct string_list_item {
69 char *string;
70 void *util;
71};
72
73typedef int (*compare_strings_fn)(const char *, const char *);
74
75/**
76 * Represents the list itself.
77 *
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.
86 */
87struct string_list {
88 struct string_list_item *items;
89 size_t nr;
90 size_t alloc;
91 unsigned int strdup_strings:1;
92 compare_strings_fn cmp; /* NULL uses strcmp() */
93};
94
95#define STRING_LIST_INIT_NODUP { 0 }
96#define STRING_LIST_INIT_DUP { .strdup_strings = 1 }
97
98/* General functions which work with both sorted and unsorted lists. */
99
100/**
101 * Initialize the members of a string_list pointer in the same way as
102 * the corresponding `STRING_LIST_INIT_NODUP` and
103 * `STRING_LIST_INIT_DUP` macros.
104 */
105void string_list_init_nodup(struct string_list *list);
106void string_list_init_dup(struct string_list *list);
107
108/** Callback function type for for_each_string_list */
109typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
110
111/**
112 * Apply `want` to each item in `list`, retaining only the ones for which
113 * the function returns true. If `free_util` is true, call free() on
114 * the util members of any items that have to be deleted. Preserve
115 * the order of the items that are retained.
116 */
117void filter_string_list(struct string_list *list, int free_util,
118 string_list_each_func_t want, void *cb_data);
119
120/**
121 * Free a string_list. The `string` pointer of the items will be freed
122 * in case the `strdup_strings` member of the string_list is set. The
123 * second parameter controls if the `util` pointer of the items should
124 * be freed or not.
125 */
126void string_list_clear(struct string_list *list, int free_util);
127
128/**
129 * Callback type for `string_list_clear_func`. The string associated
130 * with the util pointer is passed as the second argument
131 */
132typedef void (*string_list_clear_func_t)(void *p, const char *str);
133
134/** Call a custom clear function on each util pointer */
135void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
136
137/*
138 * Set the length of a string_list to `nr`, provided that (a) `list`
139 * does not own its own storage, and (b) that `nr` is no larger than
140 * `list->nr`.
141 *
142 * Useful when "shrinking" `list` to write over existing entries that
143 * are no longer used without reallocating.
144 */
145void string_list_setlen(struct string_list *list, size_t nr);
146
147/**
148 * Apply `func` to each item. If `func` returns nonzero, the
149 * iteration aborts and the return value is propagated.
150 */
151int for_each_string_list(struct string_list *list,
152 string_list_each_func_t func, void *cb_data);
153
154/**
155 * Iterate over each item, as a macro.
156 *
157 * Be sure that 'list' is non-NULL. The macro cannot perform NULL
158 * checks due to -Werror=address errors.
159 */
160#define for_each_string_list_item(item,list) \
161 for (item = (list)->items; \
162 item && item < (list)->items + (list)->nr; \
163 ++item)
164
165/**
166 * Remove any empty strings from the list. If free_util is true, call
167 * free() on the util members of any items that have to be deleted.
168 * Preserve the order of the items that are retained.
169 */
170void string_list_remove_empty_items(struct string_list *list, int free_util);
171
172/* Use these functions only on sorted lists: */
173
174/** Determine if the string_list has a given string or not. */
175bool string_list_has_string(const struct string_list *list, const char *string);
176
177/**
178 * Find the index at which a new element should be inserted into the
179 * string_list to maintain sorted order. If exact_match is not NULL,
180 * it will be set to true if the string already exists in the list.
181 */
182size_t string_list_find_insert_index(const struct string_list *list, const char *string,
183 bool *exact_match);
184
185/**
186 * Insert a new element to the string_list. The returned pointer can
187 * be handy if you want to write something to the `util` pointer of
188 * the string_list_item containing the just added string. If the given
189 * string already exists the insertion will be skipped and the pointer
190 * to the existing item returned.
191 *
192 * Since this function uses xrealloc() (which die()s if it fails) if the
193 * list needs to grow, it is safe not to check the pointer. I.e. you may
194 * write `string_list_insert(...)->util = ...;`.
195 */
196struct string_list_item *string_list_insert(struct string_list *list, const char *string);
197
198/**
199 * Remove the given string from the sorted list. If the string
200 * doesn't exist, the list is not altered.
201 */
202void string_list_remove(struct string_list *list, const char *string,
203 int free_util);
204
205/**
206 * Check if the given string is part of a sorted list. If it is part of the list,
207 * return the corresponding string_list_item, NULL otherwise.
208 */
209struct string_list_item *string_list_lookup(struct string_list *list, const char *string);
210
211/*
212 * Remove all but the first of consecutive entries with the same
213 * string value. If free_util is true, call free() on the util
214 * members of any items that have to be deleted.
215 */
216void string_list_remove_duplicates(struct string_list *sorted_list, int free_util);
217
218
219/* Use these functions only on unsorted lists: */
220
221/**
222 * Add string to the end of list. If list->strdup_string is set, then
223 * string is copied; otherwise the new string_list_entry refers to the
224 * input string.
225 */
226struct string_list_item *string_list_append(struct string_list *list, const char *string);
227
228/**
229 * Like string_list_append(), except string is never copied. When
230 * list->strdup_strings is set, this function can be used to hand
231 * ownership of a malloc()ed string to list without making an extra
232 * copy.
233 */
234struct string_list_item *string_list_append_nodup(struct string_list *list, char *string);
235
236/**
237 * Sort the list's entries by string value in order specified by list->cmp
238 * (strcmp() if list->cmp is NULL).
239 */
240void string_list_sort(struct string_list *list);
241
242/**
243 * Like `string_list_has_string()` but for unsorted lists. Linear in
244 * size of the list.
245 */
246int unsorted_string_list_has_string(struct string_list *list, const char *string);
247
248/**
249 * Like `string_list_lookup()` but for unsorted lists. Linear in size
250 * of the list.
251 */
252struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
253 const char *string);
254/**
255 * Remove an item from a string_list. The `string` pointer of the
256 * items will be freed in case the `strdup_strings` member of the
257 * string_list is set. The third parameter controls if the `util`
258 * pointer of the items should be freed or not.
259 */
260void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util);
261
262/**
263 * Split string into substrings on characters in `delim` and append the
264 * substrings to `list`. The input string is not modified.
265 * list->strdup_strings must be set, as new memory needs to be
266 * allocated to hold the substrings. If maxsplit is non-negative,
267 * then split at most maxsplit times. Return the number of substrings
268 * appended to list.
269 *
270 * Examples:
271 * string_list_split(l, "foo:bar:baz", ":", -1) -> ["foo", "bar", "baz"]
272 * string_list_split(l, "foo:bar:baz", ":", 0) -> ["foo:bar:baz"]
273 * string_list_split(l, "foo:bar:baz", ":", 1) -> ["foo", "bar:baz"]
274 * string_list_split(l, "foo:bar:", ":", -1) -> ["foo", "bar", ""]
275 * string_list_split(l, "", ":", -1) -> [""]
276 * string_list_split(l, ":", ":", -1) -> ["", ""]
277 */
278int string_list_split(struct string_list *list, const char *string,
279 const char *delim, int maxsplit);
280
281/*
282 * Like string_list_split(), except that string is split in-place: the
283 * delimiter characters in string are overwritten with NULs, and the
284 * new string_list_items point into string (which therefore must not
285 * be modified or freed while the string_list is in use).
286 * list->strdup_strings must *not* be set.
287 */
288int string_list_split_in_place(struct string_list *list, char *string,
289 const char *delim, int maxsplit);
290
291/* Flag bits for split_f and split_in_place_f functions */
292enum {
293 /*
294 * trim whitespaces around resulting string piece before adding
295 * it to the list
296 */
297 STRING_LIST_SPLIT_TRIM = (1 << 0),
298 /* omit adding empty string piece to the resulting list */
299 STRING_LIST_SPLIT_NONEMPTY = (1 << 1),
300};
301
302int string_list_split_f(struct string_list *, const char *string,
303 const char *delim, int maxsplit, unsigned flags);
304
305int string_list_split_in_place_f(struct string_list *, char *string,
306 const char *delim, int maxsplit, unsigned flags);
307#endif /* STRING_LIST_H */