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 individual items of an unsorted list using 34 `unsorted_string_list_delete_item`. 35 36. Finally it should free the list using `string_list_clear`. 37 38Example: 39 40---- 41struct string_list list; 42int i; 43 44memset(&list, 0, sizeof(struct string_list)); 45string_list_append(&list, "foo"); 46string_list_append(&list, "bar"); 47for (i = 0; i < list.nr; i++) 48 printf("%s\n", list.items[i].string) 49---- 50 51NOTE: It is more efficient to build an unsorted list and sort it 52afterwards, instead of building a sorted list (`O(n log n)` instead of 53`O(n^2)`). 54+ 55However, if you use the list to check if a certain string was added 56already, you should not do that (using unsorted_string_list_has_string()), 57because the complexity would be quadratic again (but with a worse factor). 58 59Functions 60--------- 61 62* General ones (works with sorted and unsorted lists as well) 63 64`print_string_list`:: 65 66 Dump a string_list to stdout, useful mainly for debugging purposes. It 67 can take an optional header argument and it writes out the 68 string-pointer pairs of the string_list, each one in its own line. 69 70`string_list_clear`:: 71 72 Free a string_list. The `string` pointer of the items will be freed in 73 case the `strdup_strings` member of the string_list is set. The second 74 parameter controls if the `util` pointer of the items should be freed 75 or not. 76 77* Functions for sorted lists only 78 79`string_list_has_string`:: 80 81 Determine if the string_list has a given string or not. 82 83`string_list_insert`:: 84 85 Insert a new element to the string_list. The returned pointer can be 86 handy if you want to write something to the `util` pointer of the 87 string_list_item containing the just added string. If the given 88 string already exists the insertion will be skipped and the 89 pointer to the existing item returned. 90+ 91Since this function uses xrealloc() (which die()s if it fails) if the 92list needs to grow, it is safe not to check the pointer. I.e. you may 93write `string_list_insert(...)->util = ...;`. 94 95`string_list_lookup`:: 96 97 Look up a given string in the string_list, returning the containing 98 string_list_item. If the string is not found, NULL is returned. 99 100* Functions for unsorted lists only 101 102`string_list_append`:: 103 104 Append a new string to the end of the string_list. If 105 `strdup_string` is set, then the string argument is copied; 106 otherwise the new `string_list_entry` refers to the input 107 string. 108 109`string_list_append_nodup`:: 110 111 Append a new string to the end of the string_list. The new 112 `string_list_entry` always refers to the input string, even if 113 `strdup_string` is set. This function can be used to hand 114 ownership of a malloc()ed string to a `string_list` that has 115 `strdup_string` set. 116 117`sort_string_list`:: 118 119 Make an unsorted list sorted. 120 121`unsorted_string_list_has_string`:: 122 123 It's like `string_list_has_string()` but for unsorted lists. 124 125`unsorted_string_list_lookup`:: 126 127 It's like `string_list_lookup()` but for unsorted lists. 128+ 129The above two functions need to look through all items, as opposed to their 130counterpart for sorted lists, which performs a binary search. 131 132`unsorted_string_list_delete_item`:: 133 134 Remove an item from a string_list. The `string` pointer of the items 135 will be freed in case the `strdup_strings` member of the string_list 136 is set. The third parameter controls if the `util` pointer of the 137 items should be freed or not. 138 139`string_list_split`:: 140`string_list_split_in_place`:: 141 142 Split a string into substrings on a delimiter character and 143 append the substrings to a `string_list`. If `maxsplit` is 144 non-negative, then split at most `maxsplit` times. Return the 145 number of substrings appended to the list. 146+ 147`string_list_split` requires a `string_list` that has `strdup_strings` 148set to true; it leaves the input string untouched and makes copies of 149the substrings in newly-allocated memory. 150`string_list_split_in_place` requires a `string_list` that has 151`strdup_strings` set to false; it splits the input string in place, 152overwriting the delimiter characters with NULs and creating new 153string_list_items that point into the original string (the original 154string must therefore not be modified or freed while the `string_list` 155is in use). 156 157 158Data structures 159--------------- 160 161* `struct string_list_item` 162 163Represents an item of the list. The `string` member is a pointer to the 164string, and you may use the `util` member for any purpose, if you want. 165 166* `struct string_list` 167 168Represents the list itself. 169 170. The array of items are available via the `items` member. 171. The `nr` member contains the number of items stored in the list. 172. The `alloc` member is used to avoid reallocating at every insertion. 173 You should not tamper with it. 174. Setting the `strdup_strings` member to 1 will strdup() the strings 175 before adding them, see above.