1string-list API 2=============== 3 4The string_list API offers a data structure and functions to handle sorted 5and unsorted string lists. 6 7The 'string_list' struct used to be called 'path_list', but was renamed 8because it is not specific to paths. 9 10The 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+ 19If you need something advanced, you can manually malloc() the `items` 20member (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 `sort_string_list`. 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`. 41 42. Finally it should free the list using `string_list_clear`. 43 44Example: 45 46---- 47struct string_list list; 48int i; 49 50memset(&list, 0, sizeof(struct string_list)); 51string_list_append(&list, "foo"); 52string_list_append(&list, "bar"); 53for (i = 0; i < list.nr; i++) 54 printf("%s\n", list.items[i].string) 55---- 56 57NOTE: It is more efficient to build an unsorted list and sort it 58afterwards, instead of building a sorted list (`O(n log n)` instead of 59`O(n^2)`). 60+ 61However, if you use the list to check if a certain string was added 62already, you should not do that (using unsorted_string_list_has_string()), 63because the complexity would be quadratic again (but with a worse factor). 64 65Functions 66--------- 67 68* General ones (works with sorted and unsorted lists as well) 69 70`filter_string_list`:: 71 72 Apply a function to each item in a list, retaining only the 73 items for which the function returns true. If free_util is 74 true, call free() on the util members of any items that have 75 to be deleted. Preserve the order of the items that are 76 retained. 77 78`print_string_list`:: 79 80 Dump a string_list to stdout, useful mainly for debugging purposes. It 81 can take an optional header argument and it writes out the 82 string-pointer pairs of the string_list, each one in its own line. 83 84`string_list_clear`:: 85 86 Free a string_list. The `string` pointer of the items will be freed in 87 case the `strdup_strings` member of the string_list is set. The second 88 parameter controls if the `util` pointer of the items should be freed 89 or not. 90 91* Functions for sorted lists only 92 93`string_list_has_string`:: 94 95 Determine if the string_list has a given string or not. 96 97`string_list_insert`:: 98 99 Insert a new element to the string_list. The returned pointer can be 100 handy if you want to write something to the `util` pointer of the 101 string_list_item containing the just added string. If the given 102 string already exists the insertion will be skipped and the 103 pointer to the existing item returned. 104+ 105Since this function uses xrealloc() (which die()s if it fails) if the 106list needs to grow, it is safe not to check the pointer. I.e. you may 107write `string_list_insert(...)->util = ...;`. 108 109`string_list_lookup`:: 110 111 Look up a given string in the string_list, returning the containing 112 string_list_item. If the string is not found, NULL is returned. 113 114`string_list_remove_duplicates`:: 115 116 Remove all but the first of consecutive entries that have the 117 same string value. If free_util is true, call free() on the 118 util members of any items that have to be deleted. 119 120* Functions for unsorted lists only 121 122`string_list_append`:: 123 124 Append a new string to the end of the string_list. If 125 `strdup_string` is set, then the string argument is copied; 126 otherwise the new `string_list_entry` refers to the input 127 string. 128 129`string_list_append_nodup`:: 130 131 Append a new string to the end of the string_list. The new 132 `string_list_entry` always refers to the input string, even if 133 `strdup_string` is set. This function can be used to hand 134 ownership of a malloc()ed string to a `string_list` that has 135 `strdup_string` set. 136 137`sort_string_list`:: 138 139 Make an unsorted list sorted. 140 141`unsorted_string_list_has_string`:: 142 143 It's like `string_list_has_string()` but for unsorted lists. 144 145`unsorted_string_list_lookup`:: 146 147 It's like `string_list_lookup()` but for unsorted lists. 148+ 149The above two functions need to look through all items, as opposed to their 150counterpart for sorted lists, which performs a binary search. 151 152`unsorted_string_list_delete_item`:: 153 154 Remove an item from a string_list. The `string` pointer of the items 155 will be freed in case the `strdup_strings` member of the string_list 156 is set. The third parameter controls if the `util` pointer of the 157 items should be freed or not. 158 159`string_list_split`:: 160`string_list_split_in_place`:: 161 162 Split a string into substrings on a delimiter character and 163 append the substrings to a `string_list`. If `maxsplit` is 164 non-negative, then split at most `maxsplit` times. Return the 165 number of substrings appended to the list. 166+ 167`string_list_split` requires a `string_list` that has `strdup_strings` 168set to true; it leaves the input string untouched and makes copies of 169the substrings in newly-allocated memory. 170`string_list_split_in_place` requires a `string_list` that has 171`strdup_strings` set to false; it splits the input string in place, 172overwriting the delimiter characters with NULs and creating new 173string_list_items that point into the original string (the original 174string must therefore not be modified or freed while the `string_list` 175is in use). 176 177 178Data structures 179--------------- 180 181* `struct string_list_item` 182 183Represents an item of the list. The `string` member is a pointer to the 184string, and you may use the `util` member for any purpose, if you want. 185 186* `struct string_list` 187 188Represents the list itself. 189 190. The array of items are available via the `items` member. 191. The `nr` member contains the number of items stored in the list. 192. The `alloc` member is used to avoid reallocating at every insertion. 193 You should not tamper with it. 194. Setting the `strdup_strings` member to 1 will strdup() the strings 195 before adding them, see above.