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![Ævar Arnfjörð Bjarmason](/assets/img/avatar_default.png)
In order to use the new "memcpy() a 'blank' struct on the stack" pattern for string_list_init(), and to make the macro initialization consistent with the function initialization introduce two new string_list_init_{nodup,dup}() functions. These are like the old string_list_init() when called with a false and true second argument, respectively. I think this not only makes things more consistent, but also easier to read. I often had to lookup what the ", 0)" or ", 1)" in these invocations meant, now it's right there in the function name, and corresponds to the macros. A subsequent commit will convert existing API users to this pattern, but as this is a very common API let's leave a compatibility function in place for later removal. This intermediate state also proves that the compatibility function works. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
274 lines
10 KiB
C
274 lines
10 KiB
C
#ifndef STRING_LIST_H
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#define STRING_LIST_H
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/**
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* The string_list API offers a data structure and functions to handle
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* sorted and unsorted arrays of strings. A "sorted" list is one whose
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* entries are sorted by string value in the order specified by the `cmp`
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* member (`strcmp()` by default).
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*
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* The caller:
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*
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* . Allocates and clears a `struct string_list` variable.
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*
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* . Initializes the members. You might want to set the flag `strdup_strings`
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* if the strings should be strdup()ed. For example, this is necessary
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* when you add something like git_path("..."), since that function returns
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* a static buffer that will change with the next call to git_path().
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*
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* If you need something advanced, you can manually malloc() the `items`
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* member (you need this if you add things later) and you should set the
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* `nr` and `alloc` members in that case, too.
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*
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* . Adds new items to the list, using `string_list_append`,
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* `string_list_append_nodup`, `string_list_insert`,
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* `string_list_split`, and/or `string_list_split_in_place`.
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*
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* . Can check if a string is in the list using `string_list_has_string` or
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* `unsorted_string_list_has_string` and get it from the list using
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* `string_list_lookup` for sorted lists.
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*
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* . Can sort an unsorted list using `string_list_sort`.
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*
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* . Can remove duplicate items from a sorted list using
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* `string_list_remove_duplicates`.
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*
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* . Can remove individual items of an unsorted list using
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* `unsorted_string_list_delete_item`.
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*
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* . Can remove items not matching a criterion from a sorted or unsorted
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* list using `filter_string_list`, or remove empty strings using
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* `string_list_remove_empty_items`.
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*
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* . Finally it should free the list using `string_list_clear`.
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*
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* Example:
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*
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* struct string_list list = STRING_LIST_INIT_NODUP;
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* int i;
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*
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* string_list_append(&list, "foo");
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* string_list_append(&list, "bar");
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* for (i = 0; i < list.nr; i++)
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* printf("%s\n", list.items[i].string)
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*
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* NOTE: It is more efficient to build an unsorted list and sort it
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* afterwards, instead of building a sorted list (`O(n log n)` instead of
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* `O(n^2)`).
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*
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* However, if you use the list to check if a certain string was added
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* already, you should not do that (using unsorted_string_list_has_string()),
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* because the complexity would be quadratic again (but with a worse factor).
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*/
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/**
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* Represents an item of the list. The `string` member is a pointer to the
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* string, and you may use the `util` member for any purpose, if you want.
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*/
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struct string_list_item {
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char *string;
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void *util;
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};
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typedef int (*compare_strings_fn)(const char *, const char *);
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/**
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* Represents the list itself.
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*
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* . The array of items are available via the `items` member.
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* . The `nr` member contains the number of items stored in the list.
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* . The `alloc` member is used to avoid reallocating at every insertion.
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* You should not tamper with it.
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* . Setting the `strdup_strings` member to 1 will strdup() the strings
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* before adding them, see above.
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* . The `compare_strings_fn` member is used to specify a custom compare
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* function, otherwise `strcmp()` is used as the default function.
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*/
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struct string_list {
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struct string_list_item *items;
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unsigned int nr, alloc;
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unsigned int strdup_strings:1;
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compare_strings_fn cmp; /* NULL uses strcmp() */
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};
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#define STRING_LIST_INIT_NODUP { 0 }
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#define STRING_LIST_INIT_DUP { .strdup_strings = 1 }
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/* General functions which work with both sorted and unsorted lists. */
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/**
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* Initialize the members of a string_list pointer in the same way as
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* the corresponding `STRING_LIST_INIT_NODUP` and
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* `STRING_LIST_INIT_DUP` macros.
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*/
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void string_list_init_nodup(struct string_list *list);
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void string_list_init_dup(struct string_list *list);
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/**
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* TODO remove: For compatibility with any in-flight older API users
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*/
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void string_list_init(struct string_list *list, int strdup_strings);
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/** Callback function type for for_each_string_list */
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typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
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/**
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* Apply `want` to each item in `list`, retaining only the ones for which
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* the function returns true. If `free_util` is true, call free() on
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* the util members of any items that have to be deleted. Preserve
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* the order of the items that are retained.
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*/
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void filter_string_list(struct string_list *list, int free_util,
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string_list_each_func_t want, void *cb_data);
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/**
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* Free a string_list. The `string` pointer of the items will be freed
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* in case the `strdup_strings` member of the string_list is set. The
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* second parameter controls if the `util` pointer of the items should
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* be freed or not.
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*/
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void string_list_clear(struct string_list *list, int free_util);
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/**
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* Callback type for `string_list_clear_func`. The string associated
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* with the util pointer is passed as the second argument
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*/
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typedef void (*string_list_clear_func_t)(void *p, const char *str);
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/** Call a custom clear function on each util pointer */
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void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
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/**
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* Apply `func` to each item. If `func` returns nonzero, the
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* iteration aborts and the return value is propagated.
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*/
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int for_each_string_list(struct string_list *list,
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string_list_each_func_t func, void *cb_data);
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/** Iterate over each item, as a macro. */
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#define for_each_string_list_item(item,list) \
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for (item = (list)->items; \
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item && item < (list)->items + (list)->nr; \
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++item)
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/**
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* Remove any empty strings from the list. If free_util is true, call
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* free() on the util members of any items that have to be deleted.
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* Preserve the order of the items that are retained.
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*/
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void string_list_remove_empty_items(struct string_list *list, int free_util);
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/* Use these functions only on sorted lists: */
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/** Determine if the string_list has a given string or not. */
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int string_list_has_string(const struct string_list *list, const char *string);
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int string_list_find_insert_index(const struct string_list *list, const char *string,
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int negative_existing_index);
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/**
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* Insert a new element to the string_list. The returned pointer can
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* be handy if you want to write something to the `util` pointer of
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* the string_list_item containing the just added string. If the given
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* string already exists the insertion will be skipped and the pointer
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* to the existing item returned.
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*
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* Since this function uses xrealloc() (which die()s if it fails) if the
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* list needs to grow, it is safe not to check the pointer. I.e. you may
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* write `string_list_insert(...)->util = ...;`.
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*/
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struct string_list_item *string_list_insert(struct string_list *list, const char *string);
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/**
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* Remove the given string from the sorted list. If the string
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* doesn't exist, the list is not altered.
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*/
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void string_list_remove(struct string_list *list, const char *string,
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int free_util);
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/**
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* Check if the given string is part of a sorted list. If it is part of the list,
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* return the corresponding string_list_item, NULL otherwise.
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*/
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struct string_list_item *string_list_lookup(struct string_list *list, const char *string);
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/*
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* Remove all but the first of consecutive entries with the same
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* string value. If free_util is true, call free() on the util
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* members of any items that have to be deleted.
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*/
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void string_list_remove_duplicates(struct string_list *sorted_list, int free_util);
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/* Use these functions only on unsorted lists: */
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/**
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* Add string to the end of list. If list->strdup_string is set, then
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* string is copied; otherwise the new string_list_entry refers to the
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* input string.
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*/
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struct string_list_item *string_list_append(struct string_list *list, const char *string);
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/**
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* Like string_list_append(), except string is never copied. When
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* list->strdup_strings is set, this function can be used to hand
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* ownership of a malloc()ed string to list without making an extra
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* copy.
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*/
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struct string_list_item *string_list_append_nodup(struct string_list *list, char *string);
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/**
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* Sort the list's entries by string value in order specified by list->cmp
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* (strcmp() if list->cmp is NULL).
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*/
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void string_list_sort(struct string_list *list);
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/**
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* Like `string_list_has_string()` but for unsorted lists. Linear in
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* size of the list.
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*/
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int unsorted_string_list_has_string(struct string_list *list, const char *string);
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/**
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* Like `string_list_lookup()` but for unsorted lists. Linear in size
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* of the list.
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*/
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struct string_list_item *unsorted_string_list_lookup(struct string_list *list,
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const char *string);
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/**
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* Remove an item from a string_list. The `string` pointer of the
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* items will be freed in case the `strdup_strings` member of the
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* string_list is set. The third parameter controls if the `util`
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* pointer of the items should be freed or not.
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*/
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void unsorted_string_list_delete_item(struct string_list *list, int i, int free_util);
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/**
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* Split string into substrings on character `delim` and append the
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* substrings to `list`. The input string is not modified.
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* list->strdup_strings must be set, as new memory needs to be
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* allocated to hold the substrings. If maxsplit is non-negative,
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* then split at most maxsplit times. Return the number of substrings
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* appended to list.
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*
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* Examples:
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* string_list_split(l, "foo:bar:baz", ':', -1) -> ["foo", "bar", "baz"]
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* string_list_split(l, "foo:bar:baz", ':', 0) -> ["foo:bar:baz"]
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* string_list_split(l, "foo:bar:baz", ':', 1) -> ["foo", "bar:baz"]
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* string_list_split(l, "foo:bar:", ':', -1) -> ["foo", "bar", ""]
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* string_list_split(l, "", ':', -1) -> [""]
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* string_list_split(l, ":", ':', -1) -> ["", ""]
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*/
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int string_list_split(struct string_list *list, const char *string,
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int delim, int maxsplit);
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/*
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* Like string_list_split(), except that string is split in-place: the
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* delimiter characters in string are overwritten with NULs, and the
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* new string_list_items point into string (which therefore must not
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* be modified or freed while the string_list is in use).
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* list->strdup_strings must *not* be set.
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*/
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int string_list_split_in_place(struct string_list *list, char *string,
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int delim, int maxsplit);
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#endif /* STRING_LIST_H */
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