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 */ 68 struct string_list_item { 69 char *string; 70 void *util; 71 }; 72 73 typedef 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 */ 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() */ 92 }; 93 94 #define STRING_LIST_INIT_NODUP { 0 } 95 #define STRING_LIST_INIT_DUP { .strdup_strings = 1 } 96 97 /* General functions which work with both sorted and unsorted lists. */ 98 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. 103 */ 104 void string_list_init_nodup(struct string_list *list); 105 void string_list_init_dup(struct string_list *list); 106 107 /** Callback function type for for_each_string_list */ 108 typedef int (*string_list_each_func_t)(struct string_list_item *, void *); 109 110 /** 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. 115 */ 116 void filter_string_list(struct string_list *list, int free_util, 117 string_list_each_func_t want, void *cb_data); 118 119 /** 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. 124 */ 125 void string_list_clear(struct string_list *list, int free_util); 126 127 /** 128 * Callback type for `string_list_clear_func`. The string associated 129 * with the util pointer is passed as the second argument 130 */ 131 typedef void (*string_list_clear_func_t)(void *p, const char *str); 132 133 /** 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); 135 136 /** 137 * Apply `func` to each item. If `func` returns nonzero, the 138 * iteration aborts and the return value is propagated. 139 */ 140 int for_each_string_list(struct string_list *list, 141 string_list_each_func_t func, void *cb_data); 142 143 /** 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) 148 149 /** 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. 153 */ 154 void string_list_remove_empty_items(struct string_list *list, int free_util); 155 156 /* Use these functions only on sorted lists: */ 157 158 /** 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); 162 163 /** 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. 169 * 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 = ...;`. 173 */ 174 struct string_list_item *string_list_insert(struct string_list *list, const char *string); 175 176 /** 177 * Remove the given string from the sorted list. If the string 178 * doesn't exist, the list is not altered. 179 */ 180 void string_list_remove(struct string_list *list, const char *string, 181 int free_util); 182 183 /** 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. 186 */ 187 struct string_list_item *string_list_lookup(struct string_list *list, const char *string); 188 189 /* 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. 193 */ 194 void string_list_remove_duplicates(struct string_list *sorted_list, int free_util); 195 196 197 /* Use these functions only on unsorted lists: */ 198 199 /** 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. 203 */ 204 struct string_list_item *string_list_append(struct string_list *list, const char *string); 205 206 /** 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. 211 */ 212 struct string_list_item *string_list_append_nodup(struct string_list *list, char *string); 213 214 /** 215 * Sort the list's entries by string value in order specified by list->cmp 216 * (strcmp() if list->cmp is NULL). 217 */ 218 void string_list_sort(struct string_list *list); 219 220 /** 221 * Like `string_list_has_string()` but for unsorted lists. Linear in 222 * size of the list. 223 */ 224 int unsorted_string_list_has_string(struct string_list *list, const char *string); 225 226 /** 227 * Like `string_list_lookup()` but for unsorted lists. Linear in size 228 * of the list. 229 */ 230 struct string_list_item *unsorted_string_list_lookup(struct string_list *list, 231 const char *string); 232 /** 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. 237 */ 238 void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util); 239 240 /** 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. 247 * 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) -> ["", ""] 255 */ 256 int string_list_split(struct string_list *list, const char *string, 257 int delim, int maxsplit); 258 259 /* 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. 265 */ 266 int string_list_split_in_place(struct string_list *list, char *string, 267 int delim, int maxsplit); 268 #endif /* STRING_LIST_H */ 269