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git/string-list.h

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#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;
size_t nr;
size_t alloc;
unsigned int strdup_strings:1;
compare_strings_fn cmp; /* NULL uses strcmp() */
};
#define STRING_LIST_INIT_NODUP { 0 }
#define STRING_LIST_INIT_DUP { .strdup_strings = 1 }
/* General functions which work with both sorted and unsorted lists. */
/**
* Initialize the members of a string_list pointer in the same way as
* the corresponding `STRING_LIST_INIT_NODUP` and
* `STRING_LIST_INIT_DUP` macros.
*/
void string_list_init_nodup(struct string_list *list);
void string_list_init_dup(struct string_list *list);
/** 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 */