| path-list API |
| ============= |
| |
| The path_list API offers a data structure and functions to handle sorted |
| and unsorted string lists. |
| |
| The name is a bit misleading, a path_list may store not only paths but |
| strings in general. |
| |
| The caller: |
| |
| . Allocates and clears a `struct path_list` variable. |
| |
| . Initializes the members. You might want to set the flag `strdup_paths` |
| 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 `path_list_append` or `path_list_insert`. |
| |
| . Can check if a string is in the list using `path_list_has_path` or |
| `unsorted_path_list_has_path` and get it from the list using |
| `path_list_lookup` for sorted lists. |
| |
| . Can sort an unsorted list using `sort_path_list`. |
| |
| . Finally it should free the list using `path_list_clear`. |
| |
| Example: |
| |
| ---- |
| struct path_list list; |
| int i; |
| |
| memset(&list, 0, sizeof(struct path_list)); |
| path_list_append("foo", &list); |
| path_list_append("bar", &list); |
| for (i = 0; i < list.nr; i++) |
| printf("%s\n", list.items[i].path) |
| ---- |
| |
| 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_path_list_has_path()), |
| because the complexity would be quadratic again (but with a worse factor). |
| |
| Functions |
| --------- |
| |
| * General ones (works with sorted and unsorted lists as well) |
| |
| `print_path_list`:: |
| |
| Dump a path_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 path_list, each one in its own line. |
| |
| `path_list_clear`:: |
| |
| Free a path_list. The `path` pointer of the items will be freed in case |
| the `strdup_paths` member of the path_list is set. The second parameter |
| controls if the `util` pointer of the items should be freed or not. |
| |
| * Functions for sorted lists only |
| |
| `path_list_has_path`:: |
| |
| Determine if the path_list has a given string or not. |
| |
| `path_list_insert`:: |
| |
| Insert a new element to the path_list. The returned pointer can be handy |
| if you want to write something to the `util` pointer of the |
| path_list_item containing the just added string. |
| + |
| 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 `path_list_insert(...)->util = ...;`. |
| |
| `path_list_lookup`:: |
| |
| Look up a given string in the path_list, returning the containing |
| path_list_item. If the string is not found, NULL is returned. |
| |
| * Functions for unsorted lists only |
| |
| `path_list_append`:: |
| |
| Append a new string to the end of the path_list. |
| |
| `sort_path_list`:: |
| |
| Make an unsorted list sorted. |
| |
| `unsorted_path_list_has_path`:: |
| |
| It's like `path_list_has_path()` but for unsorted lists. |
| + |
| This function needs to look through all items, as opposed to its |
| counterpart for sorted lists, which performs a binary search. |
| |
| Data structures |
| --------------- |
| |
| * `struct path_list_item` |
| |
| Represents an item of the list. The `path` member is a pointer to the |
| string, and you may use the `util` member for any purpose, if you want. |
| |
| * `struct path_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_paths` member to 1 will strdup() the strings |
| before adding them, see above. |