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)
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
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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).
General ones (works with sorted and unsorted lists as well)
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.
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
Determine if the path_list has a given string or not.
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 = …;.
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
Append a new string to the end of the path_list.
Make an unsorted list sorted.
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.
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.