| /* Abstract set data type. |
| Copyright (C) 2006-2007, 2009-2020 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2018. |
| |
| This program is free software: you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| |
| #ifndef _GL_SET_H |
| #define _GL_SET_H |
| |
| #include <stdbool.h> |
| #include <stddef.h> |
| |
| #ifndef _GL_INLINE_HEADER_BEGIN |
| #error "Please include config.h first." |
| #endif |
| _GL_INLINE_HEADER_BEGIN |
| #ifndef GL_SET_INLINE |
| # define GL_SET_INLINE _GL_INLINE |
| #endif |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| /* gl_set is an abstract set data type. It can contain any number of objects |
| ('void *' or 'const void *' pointers); the order does not matter. |
| Duplicates (in the sense of the comparator) are forbidden. |
| |
| There are several implementations of this set datatype, optimized for |
| different operations or for memory. You can start using the simplest set |
| implementation, GL_ARRAY_SET, and switch to a different implementation |
| later, when you realize which operations are performed the most frequently. |
| The API of the different implementations is exactly the same; when switching |
| to a different implementation, you only have to change the gl_set_create |
| call. |
| |
| The implementations are: |
| GL_ARRAY_SET a growable array |
| GL_LINKEDHASH_SET a hash table with a linked list |
| GL_HASH_SET a hash table |
| |
| The memory consumption is asymptotically the same: O(1) for every object |
| in the set. When looking more closely at the average memory consumed |
| for an object, GL_ARRAY_SET is the most compact representation, then comes |
| GL_HASH_SET, and GL_LINKEDHASH_SET needs the most memory. |
| |
| The guaranteed average performance of the operations is, for a set of |
| n elements: |
| |
| Operation ARRAY LINKEDHASH |
| HASH |
| |
| gl_set_size O(1) O(1) |
| gl_set_add O(n) O(1) |
| gl_set_remove O(n) O(1) |
| gl_set_search O(n) O(1) |
| gl_set_iterator O(1) O(1) |
| gl_set_iterator_next O(1) O(1) |
| */ |
| |
| /* --------------------------- gl_set_t Data Type --------------------------- */ |
| |
| /* Type of function used to compare two elements. |
| NULL denotes pointer comparison. */ |
| typedef bool (*gl_setelement_equals_fn) (const void *elt1, const void *elt2); |
| |
| /* Type of function used to compute a hash code. |
| NULL denotes a function that depends only on the pointer itself. */ |
| typedef size_t (*gl_setelement_hashcode_fn) (const void *elt); |
| |
| #ifndef _GL_SETELEMENT_DISPOSE_FN_DEFINED |
| /* Type of function used to dispose an element once it's removed from a set. |
| NULL denotes a no-op. */ |
| typedef void (*gl_setelement_dispose_fn) (const void *elt); |
| # define _GL_SETELEMENT_DISPOSE_FN_DEFINED 1 |
| #endif |
| |
| struct gl_set_impl; |
| /* Type representing an entire set. */ |
| typedef struct gl_set_impl * gl_set_t; |
| |
| struct gl_set_implementation; |
| /* Type representing a set datatype implementation. */ |
| typedef const struct gl_set_implementation * gl_set_implementation_t; |
| |
| #if 0 /* Unless otherwise specified, these are defined inline below. */ |
| |
| /* Creates an empty set. |
| IMPLEMENTATION is one of GL_ARRAY_SET, GL_LINKEDHASH_SET, GL_HASH_SET. |
| EQUALS_FN is an element comparison function or NULL. |
| HASHCODE_FN is an element hash code function or NULL. |
| DISPOSE_FN is an element disposal function or NULL. */ |
| /* declared in gl_xset.h */ |
| extern gl_set_t gl_set_create_empty (gl_set_implementation_t implementation, |
| gl_setelement_equals_fn equals_fn, |
| gl_setelement_hashcode_fn hashcode_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| /* Likewise. Returns NULL upon out-of-memory. */ |
| extern gl_set_t gl_set_nx_create_empty (gl_set_implementation_t implementation, |
| gl_setelement_equals_fn equals_fn, |
| gl_setelement_hashcode_fn hashcode_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| |
| /* Returns the current number of elements in a set. */ |
| extern size_t gl_set_size (gl_set_t set); |
| |
| /* Searches whether an element is already in the set. |
| Returns true if found, or false if not present in the set. */ |
| extern bool gl_set_search (gl_set_t set, const void *elt); |
| |
| /* Adds an element to a set. |
| Returns true if it was not already in the set and added, false otherwise. */ |
| /* declared in gl_xset.h */ |
| extern bool gl_set_add (gl_set_t set, const void *elt); |
| /* Likewise. Returns -1 upon out-of-memory. */ |
| extern int gl_set_nx_add (gl_set_t set, const void *elt) |
| #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) |
| __attribute__ ((__warn_unused_result__)) |
| #endif |
| ; |
| |
| /* Removes an element from a set. |
| Returns true if it was found and removed. */ |
| extern bool gl_set_remove (gl_set_t set, const void *elt); |
| |
| /* Frees an entire set. |
| (But this call does not free the elements of the set. It only invokes |
| the DISPOSE_FN on each of the elements of the set.) */ |
| extern void gl_set_free (gl_set_t set); |
| |
| #endif /* End of inline and gl_xset.h-defined functions. */ |
| |
| /* ---------------------- gl_set_iterator_t Data Type ---------------------- */ |
| |
| /* Functions for iterating through a set. |
| Note: Iterating through a set of type GL_HASH_SET returns the elements in an |
| unpredictable order. If you need a predictable order, use GL_LINKEDHASH_SET |
| instead of GL_HASH_SET. */ |
| |
| /* Type of an iterator that traverses a set. |
| This is a fixed-size struct, so that creation of an iterator doesn't need |
| memory allocation on the heap. */ |
| typedef struct |
| { |
| /* For fast dispatch of gl_set_iterator_next. */ |
| const struct gl_set_implementation *vtable; |
| /* For detecting whether the last returned element was removed. */ |
| gl_set_t set; |
| size_t count; |
| /* Other, implementation-private fields. */ |
| void *p; void *q; |
| size_t i; size_t j; |
| } gl_set_iterator_t; |
| |
| #if 0 /* These are defined inline below. */ |
| |
| /* Creates an iterator traversing a set. |
| The set's contents must not be modified while the iterator is in use, |
| except for removing the last returned element. */ |
| extern gl_set_iterator_t gl_set_iterator (gl_set_t set); |
| |
| /* If there is a next element, stores the next element in *ELTP, advances the |
| iterator and returns true. Otherwise, returns false. */ |
| extern bool gl_set_iterator_next (gl_set_iterator_t *iterator, |
| const void **eltp); |
| |
| /* Frees an iterator. */ |
| extern void gl_set_iterator_free (gl_set_iterator_t *iterator); |
| |
| #endif /* End of inline functions. */ |
| |
| /* ------------------------ Implementation Details ------------------------ */ |
| |
| struct gl_set_implementation |
| { |
| /* gl_set_t functions. */ |
| gl_set_t (*nx_create_empty) (gl_set_implementation_t implementation, |
| gl_setelement_equals_fn equals_fn, |
| gl_setelement_hashcode_fn hashcode_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| size_t (*size) (gl_set_t set); |
| bool (*search) (gl_set_t set, const void *elt); |
| int (*nx_add) (gl_set_t set, const void *elt); |
| bool (*remove_elt) (gl_set_t set, const void *elt); |
| void (*set_free) (gl_set_t set); |
| /* gl_set_iterator_t functions. */ |
| gl_set_iterator_t (*iterator) (gl_set_t set); |
| bool (*iterator_next) (gl_set_iterator_t *iterator, const void **eltp); |
| void (*iterator_free) (gl_set_iterator_t *iterator); |
| }; |
| |
| struct gl_set_impl_base |
| { |
| const struct gl_set_implementation *vtable; |
| gl_setelement_equals_fn equals_fn; |
| gl_setelement_dispose_fn dispose_fn; |
| }; |
| |
| /* Define all functions of this file as accesses to the |
| struct gl_set_implementation. */ |
| |
| GL_SET_INLINE gl_set_t |
| gl_set_nx_create_empty (gl_set_implementation_t implementation, |
| gl_setelement_equals_fn equals_fn, |
| gl_setelement_hashcode_fn hashcode_fn, |
| gl_setelement_dispose_fn dispose_fn) |
| { |
| return implementation->nx_create_empty (implementation, equals_fn, |
| hashcode_fn, dispose_fn); |
| } |
| |
| GL_SET_INLINE size_t |
| gl_set_size (gl_set_t set) |
| { |
| return ((const struct gl_set_impl_base *) set)->vtable->size (set); |
| } |
| |
| GL_SET_INLINE bool |
| gl_set_search (gl_set_t set, const void *elt) |
| { |
| return ((const struct gl_set_impl_base *) set)->vtable->search (set, elt); |
| } |
| |
| GL_SET_INLINE int |
| #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) |
| __attribute__ ((__warn_unused_result__)) |
| #endif |
| gl_set_nx_add (gl_set_t set, const void *elt) |
| { |
| return ((const struct gl_set_impl_base *) set)->vtable->nx_add (set, elt); |
| } |
| |
| GL_SET_INLINE bool |
| gl_set_remove (gl_set_t set, const void *elt) |
| { |
| return ((const struct gl_set_impl_base *) set)->vtable->remove_elt (set, elt); |
| } |
| |
| GL_SET_INLINE void |
| gl_set_free (gl_set_t set) |
| { |
| ((const struct gl_set_impl_base *) set)->vtable->set_free (set); |
| } |
| |
| GL_SET_INLINE gl_set_iterator_t |
| gl_set_iterator (gl_set_t set) |
| { |
| return ((const struct gl_set_impl_base *) set)->vtable->iterator (set); |
| } |
| |
| GL_SET_INLINE bool |
| gl_set_iterator_next (gl_set_iterator_t *iterator, const void **eltp) |
| { |
| return iterator->vtable->iterator_next (iterator, eltp); |
| } |
| |
| GL_SET_INLINE void |
| gl_set_iterator_free (gl_set_iterator_t *iterator) |
| { |
| iterator->vtable->iterator_free (iterator); |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| _GL_INLINE_HEADER_END |
| |
| #endif /* _GL_SET_H */ |