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Diffstat (limited to 'string-list.h')
| -rw-r--r-- | string-list.h | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/string-list.h b/string-list.h new file mode 100644 index 0000000..6c5d274 --- /dev/null +++ b/string-list.h @@ -0,0 +1,266 @@ +#ifndef STRING_LIST_H +#define STRING_LIST_H + +/** + * The string_list API offers a data structure and functions to handle + * sorted and unsorted arrays of strings. A "sorted" list is one whose + * entries are sorted by string value in the order specified by the `cmp` + * member (`strcmp()` by default). + * + * 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 `string_list_sort`. + * + * . 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). + */ + +/** + * 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_item { + char *string; + void *util; +}; + +typedef int (*compare_strings_fn)(const char *, const char *); + +/** + * 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. + * . The `compare_strings_fn` member is used to specify a custom compare + * function, otherwise `strcmp()` is used as the default function. + */ +struct string_list { + struct string_list_item *items; + unsigned int nr, alloc; + unsigned int strdup_strings:1; + compare_strings_fn cmp; /* NULL uses strcmp() */ +}; + +#define STRING_LIST_INIT_NODUP { NULL, 0, 0, 0, NULL } +#define STRING_LIST_INIT_DUP { NULL, 0, 0, 1, NULL } + +/* General functions which work with both sorted and unsorted lists. */ + +/** + * Initialize the members of the string_list, set `strdup_strings` + * member according to the value of the second parameter. + */ +void string_list_init(struct string_list *list, int strdup_strings); + +/** Callback function type for for_each_string_list */ +typedef int (*string_list_each_func_t)(struct string_list_item *, void *); + +/** + * Apply `want` to each item in `list`, retaining only the ones 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. + */ +void filter_string_list(struct string_list *list, int free_util, + string_list_each_func_t want, void *cb_data); + +/** + * 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. + */ +void string_list_clear(struct string_list *list, int free_util); + +/** + * Callback type for `string_list_clear_func`. The string associated + * with the util pointer is passed as the second argument + */ +typedef void (*string_list_clear_func_t)(void *p, const char *str); + +/** Call a custom clear function on each util pointer */ +void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc); + +/** + * Apply `func` to each item. If `func` returns nonzero, the + * iteration aborts and the return value is propagated. + */ +int for_each_string_list(struct string_list *list, + string_list_each_func_t func, void *cb_data); + +/** Iterate over each item, as a macro. */ +#define for_each_string_list_item(item,list) \ + for (item = (list)->items; \ + item && item < (list)->items + (list)->nr; \ + ++item) + +/** + * 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. + */ +void string_list_remove_empty_items(struct string_list *list, int free_util); + +/* Use these functions only on sorted lists: */ + +/** Determine if the string_list has a given string or not. */ +int string_list_has_string(const struct string_list *list, const char *string); +int string_list_find_insert_index(const struct string_list *list, const char *string, + int negative_existing_index); + +/** + * 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 = ...;`. + */ +struct string_list_item *string_list_insert(struct string_list *list, const char *string); + +/** + * Remove the given string from the sorted list. If the string + * doesn't exist, the list is not altered. + */ +void string_list_remove(struct string_list *list, const char *string, + int free_util); + +/** + * Check if the given string is part of a sorted list. If it is part of the list, + * return the corresponding string_list_item, NULL otherwise. + */ +struct string_list_item *string_list_lookup(struct string_list *list, const char *string); + +/* + * Remove all but the first of consecutive entries with the same + * string value. If free_util is true, call free() on the util + * members of any items that have to be deleted. + */ +void string_list_remove_duplicates(struct string_list *sorted_list, int free_util); + + +/* Use these functions only on unsorted lists: */ + +/** + * Add string to the end of list. If list->strdup_string is set, then + * string is copied; otherwise the new string_list_entry refers to the + * input string. + */ +struct string_list_item *string_list_append(struct string_list *list, const char *string); + +/** + * Like string_list_append(), except string is never copied. When + * list->strdup_strings is set, this function can be used to hand + * ownership of a malloc()ed string to list without making an extra + * copy. + */ +struct string_list_item *string_list_append_nodup(struct string_list *list, char *string); + +/** + * Sort the list's entries by string value in order specified by list->cmp + * (strcmp() if list->cmp is NULL). + */ +void string_list_sort(struct string_list *list); + +/** + * Like `string_list_has_string()` but for unsorted lists. Linear in + * size of the list. + */ +int unsorted_string_list_has_string(struct string_list *list, const char *string); + +/** + * Like `string_list_lookup()` but for unsorted lists. Linear in size + * of the list. + */ +struct string_list_item *unsorted_string_list_lookup(struct string_list *list, + const char *string); +/** + * 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. + */ +void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util); + +/** + * Split string into substrings on character `delim` and append the + * substrings to `list`. The input string is not modified. + * list->strdup_strings must be set, as new memory needs to be + * allocated to hold the substrings. If maxsplit is non-negative, + * then split at most maxsplit times. Return the number of substrings + * appended to list. + * + * Examples: + * string_list_split(l, "foo:bar:baz", ':', -1) -> ["foo", "bar", "baz"] + * string_list_split(l, "foo:bar:baz", ':', 0) -> ["foo:bar:baz"] + * string_list_split(l, "foo:bar:baz", ':', 1) -> ["foo", "bar:baz"] + * string_list_split(l, "foo:bar:", ':', -1) -> ["foo", "bar", ""] + * string_list_split(l, "", ':', -1) -> [""] + * string_list_split(l, ":", ':', -1) -> ["", ""] + */ +int string_list_split(struct string_list *list, const char *string, + int delim, int maxsplit); + +/* + * Like string_list_split(), except that string is split in-place: the + * delimiter characters in string are overwritten with NULs, and the + * new string_list_items point into string (which therefore must not + * be modified or freed while the string_list is in use). + * list->strdup_strings must *not* be set. + */ +int string_list_split_in_place(struct string_list *list, char *string, + int delim, int maxsplit); +#endif /* STRING_LIST_H */ |