EVOLUTION-NINJA

Edit File: api-string-list.txt

string-list API =============== The string_list API offers a data structure and functions to handle sorted and unsorted string lists. A "sorted" list is one whose entries are sorted by string value in `strcmp()` order. The 'string_list' struct used to be called 'path_list', but was renamed because it is not specific to paths. The caller: . Allocates and clears a `struct string_list` variable. . Initializes the members. You might want to set the flag `strdup_strings` if the strings should be strdup()ed. For example, this is necessary when you add something like git_path("..."), since that function returns a static buffer that will change with the next call to git_path(). + If you need something advanced, you can manually malloc() the `items` member (you need this if you add things later) and you should set the `nr` and `alloc` members in that case, too. . Adds new items to the list, using `string_list_append`, `string_list_append_nodup`, `string_list_insert`, `string_list_split`, and/or `string_list_split_in_place`. . Can check if a string is in the list using `string_list_has_string` or `unsorted_string_list_has_string` and get it from the list using `string_list_lookup` for sorted lists. . Can sort an unsorted list using `sort_string_list`. . Can remove duplicate items from a sorted list using `string_list_remove_duplicates`. . Can remove individual items of an unsorted list using `unsorted_string_list_delete_item`. . Can remove items not matching a criterion from a sorted or unsorted list using `filter_string_list`, or remove empty strings using `string_list_remove_empty_items`. . Finally it should free the list using `string_list_clear`. Example: ---- struct string_list list = STRING_LIST_INIT_NODUP; int i; string_list_append(&list, "foo"); string_list_append(&list, "bar"); for (i = 0; i < list.nr; i++) printf("%s\n", list.items[i].string) ---- NOTE: It is more efficient to build an unsorted list and sort it afterwards, instead of building a sorted list (`O(n log n)` instead of `O(n^2)`). + However, if you use the list to check if a certain string was added already, you should not do that (using unsorted_string_list_has_string()), because the complexity would be quadratic again (but with a worse factor). Functions --------- * General ones (works with sorted and unsorted lists as well) `filter_string_list`:: Apply a function to each item in a list, retaining only the items for which the function returns true. If free_util is true, call free() on the util members of any items that have to be deleted. Preserve the order of the items that are retained. `string_list_remove_empty_items`:: Remove any empty strings from the list. If free_util is true, call free() on the util members of any items that have to be deleted. Preserve the order of the items that are retained. `print_string_list`:: Dump a string_list to stdout, useful mainly for debugging purposes. It can take an optional header argument and it writes out the string-pointer pairs of the string_list, each one in its own line. `string_list_clear`:: Free a string_list. The `string` pointer of the items will be freed in case the `strdup_strings` member of the string_list is set. The second parameter controls if the `util` pointer of the items should be freed or not. * Functions for sorted lists only `string_list_has_string`:: Determine if the string_list has a given string or not. `string_list_insert`:: Insert a new element to the string_list. The returned pointer can be handy if you want to write something to the `util` pointer of the string_list_item containing the just added string. If the given string already exists the insertion will be skipped and the pointer to the existing item returned. + Since this function uses xrealloc() (which die()s if it fails) if the list needs to grow, it is safe not to check the pointer. I.e. you may write `string_list_insert(...)->util = ...;`. `string_list_lookup`:: Look up a given string in the string_list, returning the containing string_list_item. If the string is not found, NULL is returned. `string_list_remove_duplicates`:: Remove all but the first of consecutive entries that have the same string value. If free_util is true, call free() on the util members of any items that have to be deleted. * Functions for unsorted lists only `string_list_append`:: Append a new string to the end of the string_list. If `strdup_string` is set, then the string argument is copied; otherwise the new `string_list_entry` refers to the input string. `string_list_append_nodup`:: Append a new string to the end of the string_list. The new `string_list_entry` always refers to the input string, even if `strdup_string` is set. This function can be used to hand ownership of a malloc()ed string to a `string_list` that has `strdup_string` set. `sort_string_list`:: Sort the list's entries by string value in `strcmp()` order. `unsorted_string_list_has_string`:: It's like `string_list_has_string()` but for unsorted lists. `unsorted_string_list_lookup`:: It's like `string_list_lookup()` but for unsorted lists. + The above two functions need to look through all items, as opposed to their counterpart for sorted lists, which performs a binary search. `unsorted_string_list_delete_item`:: Remove an item from a string_list. The `string` pointer of the items will be freed in case the `strdup_strings` member of the string_list is set. The third parameter controls if the `util` pointer of the items should be freed or not. `string_list_split`:: `string_list_split_in_place`:: Split a string into substrings on a delimiter character and append the substrings to a `string_list`. If `maxsplit` is non-negative, then split at most `maxsplit` times. Return the number of substrings appended to the list. + `string_list_split` requires a `string_list` that has `strdup_strings` set to true; it leaves the input string untouched and makes copies of the substrings in newly-allocated memory. `string_list_split_in_place` requires a `string_list` that has `strdup_strings` set to false; it splits the input string in place, overwriting the delimiter characters with NULs and creating new string_list_items that point into the original string (the original string must therefore not be modified or freed while the `string_list` is in use). Data structures --------------- * `struct string_list_item` Represents an item of the list. The `string` member is a pointer to the string, and you may use the `util` member for any purpose, if you want. * `struct string_list` Represents the list itself. . The array of items are available via the `items` member. . The `nr` member contains the number of items stored in the list. . The `alloc` member is used to avoid reallocating at every insertion. You should not tamper with it. . Setting the `strdup_strings` member to 1 will strdup() the strings before adding them, see above.