Merge branch 'master' of github.com:nafmo/git-l10n-sv
[alt-git.git] / string-list.h
blob267d6e5769d9bcea057d68bb46e685d59339d05d
1 #ifndef STRING_LIST_H
2 #define STRING_LIST_H
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).
10 * The caller:
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`.
45 * Example:
47 * struct string_list list = STRING_LIST_INIT_NODUP;
48 * int i;
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
57 * `O(n^2)`).
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).
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.
68 struct string_list_item {
69 char *string;
70 void *util;
73 typedef int (*compare_strings_fn)(const char *, const char *);
75 /**
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.
87 struct string_list {
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 { 0 }
95 #define STRING_LIST_INIT_DUP { .strdup_strings = 1 }
97 /* General functions which work with both sorted and unsorted lists. */
99 /**
100 * Initialize the members of a string_list pointer in the same way as
101 * the corresponding `STRING_LIST_INIT_NODUP` and
102 * `STRING_LIST_INIT_DUP` macros.
104 void string_list_init_nodup(struct string_list *list);
105 void string_list_init_dup(struct string_list *list);
107 /** Callback function type for for_each_string_list */
108 typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
111 * Apply `want` to each item in `list`, retaining only the ones for which
112 * the function returns true. If `free_util` is true, call free() on
113 * the util members of any items that have to be deleted. Preserve
114 * the order of the items that are retained.
116 void filter_string_list(struct string_list *list, int free_util,
117 string_list_each_func_t want, void *cb_data);
120 * Free a string_list. The `string` pointer of the items will be freed
121 * in case the `strdup_strings` member of the string_list is set. The
122 * second parameter controls if the `util` pointer of the items should
123 * be freed or not.
125 void string_list_clear(struct string_list *list, int free_util);
128 * Callback type for `string_list_clear_func`. The string associated
129 * with the util pointer is passed as the second argument
131 typedef void (*string_list_clear_func_t)(void *p, const char *str);
133 /** Call a custom clear function on each util pointer */
134 void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
137 * Apply `func` to each item. If `func` returns nonzero, the
138 * iteration aborts and the return value is propagated.
140 int for_each_string_list(struct string_list *list,
141 string_list_each_func_t func, void *cb_data);
143 /** Iterate over each item, as a macro. */
144 #define for_each_string_list_item(item,list) \
145 for (item = (list)->items; \
146 item && item < (list)->items + (list)->nr; \
147 ++item)
150 * Remove any empty strings from the list. If free_util is true, call
151 * free() on the util members of any items that have to be deleted.
152 * Preserve the order of the items that are retained.
154 void string_list_remove_empty_items(struct string_list *list, int free_util);
156 /* Use these functions only on sorted lists: */
158 /** Determine if the string_list has a given string or not. */
159 int string_list_has_string(const struct string_list *list, const char *string);
160 int string_list_find_insert_index(const struct string_list *list, const char *string,
161 int negative_existing_index);
164 * Insert a new element to the string_list. The returned pointer can
165 * be handy if you want to write something to the `util` pointer of
166 * the string_list_item containing the just added string. If the given
167 * string already exists the insertion will be skipped and the pointer
168 * to the existing item returned.
170 * Since this function uses xrealloc() (which die()s if it fails) if the
171 * list needs to grow, it is safe not to check the pointer. I.e. you may
172 * write `string_list_insert(...)->util = ...;`.
174 struct string_list_item *string_list_insert(struct string_list *list, const char *string);
177 * Remove the given string from the sorted list. If the string
178 * doesn't exist, the list is not altered.
180 void string_list_remove(struct string_list *list, const char *string,
181 int free_util);
184 * Check if the given string is part of a sorted list. If it is part of the list,
185 * return the corresponding string_list_item, NULL otherwise.
187 struct string_list_item *string_list_lookup(struct string_list *list, const char *string);
190 * Remove all but the first of consecutive entries with the same
191 * string value. If free_util is true, call free() on the util
192 * members of any items that have to be deleted.
194 void string_list_remove_duplicates(struct string_list *sorted_list, int free_util);
197 /* Use these functions only on unsorted lists: */
200 * Add string to the end of list. If list->strdup_string is set, then
201 * string is copied; otherwise the new string_list_entry refers to the
202 * input string.
204 struct string_list_item *string_list_append(struct string_list *list, const char *string);
207 * Like string_list_append(), except string is never copied. When
208 * list->strdup_strings is set, this function can be used to hand
209 * ownership of a malloc()ed string to list without making an extra
210 * copy.
212 struct string_list_item *string_list_append_nodup(struct string_list *list, char *string);
215 * Sort the list's entries by string value in order specified by list->cmp
216 * (strcmp() if list->cmp is NULL).
218 void string_list_sort(struct string_list *list);
221 * Like `string_list_has_string()` but for unsorted lists. Linear in
222 * size of the list.
224 int unsorted_string_list_has_string(struct string_list *list, const char *string);
227 * Like `string_list_lookup()` but for unsorted lists. Linear in size
228 * of the list.
230 struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
231 const char *string);
233 * Remove an item from a string_list. The `string` pointer of the
234 * items will be freed in case the `strdup_strings` member of the
235 * string_list is set. The third parameter controls if the `util`
236 * pointer of the items should be freed or not.
238 void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util);
241 * Split string into substrings on character `delim` and append the
242 * substrings to `list`. The input string is not modified.
243 * list->strdup_strings must be set, as new memory needs to be
244 * allocated to hold the substrings. If maxsplit is non-negative,
245 * then split at most maxsplit times. Return the number of substrings
246 * appended to list.
248 * Examples:
249 * string_list_split(l, "foo:bar:baz", ':', -1) -> ["foo", "bar", "baz"]
250 * string_list_split(l, "foo:bar:baz", ':', 0) -> ["foo:bar:baz"]
251 * string_list_split(l, "foo:bar:baz", ':', 1) -> ["foo", "bar:baz"]
252 * string_list_split(l, "foo:bar:", ':', -1) -> ["foo", "bar", ""]
253 * string_list_split(l, "", ':', -1) -> [""]
254 * string_list_split(l, ":", ':', -1) -> ["", ""]
256 int string_list_split(struct string_list *list, const char *string,
257 int delim, int maxsplit);
260 * Like string_list_split(), except that string is split in-place: the
261 * delimiter characters in string are overwritten with NULs, and the
262 * new string_list_items point into string (which therefore must not
263 * be modified or freed while the string_list is in use).
264 * list->strdup_strings must *not* be set.
266 int string_list_split_in_place(struct string_list *list, char *string,
267 int delim, int maxsplit);
268 #endif /* STRING_LIST_H */