| /* Abstract ordered set data type. |
| Copyright (C) 2006-2007, 2009-2020 Free Software Foundation, Inc. |
| Written by Bruno Haible <bruno@clisp.org>, 2006. |
| |
| 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_OSET_H |
| #define _GL_OSET_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_OSET_INLINE |
| # define GL_OSET_INLINE _GL_INLINE |
| #endif |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| |
| /* gl_oset is an abstract ordered set data type. It can contain any number |
| of objects ('void *' or 'const void *' pointers) in the order of a given |
| comparator function. Duplicates (in the sense of the comparator) are |
| forbidden. |
| |
| There are several implementations of this ordered set datatype, optimized |
| for different operations or for memory. You can start using the simplest |
| ordered set implementation, GL_ARRAY_OSET, 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_oset_create call. |
| |
| The implementations are: |
| GL_ARRAY_OSET a growable array |
| GL_AVLTREE_OSET a binary tree (AVL tree) |
| GL_RBTREE_OSET a binary tree (red-black tree) |
| |
| 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_OSET is the most compact representation, and |
| GL_AVLTREE_OSET, GL_RBTREE_OSET need more memory. |
| |
| The guaranteed average performance of the operations is, for a set of |
| n elements: |
| |
| Operation ARRAY TREE |
| |
| gl_oset_size O(1) O(1) |
| gl_oset_add O(n) O(log n) |
| gl_oset_remove O(n) O(log n) |
| gl_oset_search O(log n) O(log n) |
| gl_oset_search_atleast O(log n) O(log n) |
| gl_oset_iterator O(1) O(log n) |
| gl_oset_iterator_next O(1) O(log n) |
| */ |
| |
| /* -------------------------- gl_oset_t Data Type -------------------------- */ |
| |
| /* Type of function used to compare two elements. Same as for qsort(). |
| NULL denotes pointer comparison. */ |
| typedef int (*gl_setelement_compar_fn) (const void *elt1, const void *elt2); |
| |
| #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 |
| |
| /* Type of function used to compare an element with a threshold. |
| Returns true if the element is greater or equal than the threshold. */ |
| typedef bool (*gl_setelement_threshold_fn) (const void *elt, const void *threshold); |
| |
| struct gl_oset_impl; |
| /* Type representing an entire ordered set. */ |
| typedef struct gl_oset_impl * gl_oset_t; |
| |
| struct gl_oset_implementation; |
| /* Type representing a ordered set datatype implementation. */ |
| typedef const struct gl_oset_implementation * gl_oset_implementation_t; |
| |
| #if 0 /* Unless otherwise specified, these are defined inline below. */ |
| |
| /* Creates an empty set. |
| IMPLEMENTATION is one of GL_ARRAY_OSET, GL_AVLTREE_OSET, GL_RBTREE_OSET. |
| COMPAR_FN is an element comparison function or NULL. |
| DISPOSE_FN is an element disposal function or NULL. */ |
| /* declared in gl_xoset.h */ |
| extern gl_oset_t gl_oset_create_empty (gl_oset_implementation_t implementation, |
| gl_setelement_compar_fn compar_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| /* Likewise. Returns NULL upon out-of-memory. */ |
| extern gl_oset_t gl_oset_nx_create_empty (gl_oset_implementation_t implementation, |
| gl_setelement_compar_fn compar_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| |
| /* Returns the current number of elements in an ordered set. */ |
| extern size_t gl_oset_size (gl_oset_t set); |
| |
| /* Searches whether an element is already in the ordered set. |
| Returns true if found, or false if not present in the set. */ |
| extern bool gl_oset_search (gl_oset_t set, const void *elt); |
| |
| /* Searches the least element in the ordered set that compares greater or equal |
| to the given THRESHOLD. The representation of the THRESHOLD is defined |
| by the THRESHOLD_FN. |
| Returns true and stores the found element in *ELTP if found, otherwise returns |
| false. */ |
| extern bool gl_oset_search_atleast (gl_oset_t set, |
| gl_setelement_threshold_fn threshold_fn, |
| const void *threshold, |
| const void **eltp); |
| |
| /* Adds an element to an ordered set. |
| Returns true if it was not already in the set and added, false otherwise. */ |
| /* declared in gl_xoset.h */ |
| extern bool gl_oset_add (gl_oset_t set, const void *elt); |
| /* Likewise. Returns -1 upon out-of-memory. */ |
| extern int gl_oset_nx_add (gl_oset_t set, const void *elt) |
| #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) |
| __attribute__ ((__warn_unused_result__)) |
| #endif |
| ; |
| |
| /* Removes an element from an ordered set. |
| Returns true if it was found and removed. */ |
| extern bool gl_oset_remove (gl_oset_t set, const void *elt); |
| |
| /* Frees an entire ordered 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_oset_free (gl_oset_t set); |
| |
| #endif /* End of inline and gl_xoset.h-defined functions. */ |
| |
| /* --------------------- gl_oset_iterator_t Data Type --------------------- */ |
| |
| /* Functions for iterating through an ordered set. */ |
| |
| /* Type of an iterator that traverses an ordered 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_oset_iterator_next. */ |
| const struct gl_oset_implementation *vtable; |
| /* For detecting whether the last returned element was removed. */ |
| gl_oset_t set; |
| size_t count; |
| /* Other, implementation-private fields. */ |
| void *p; void *q; |
| size_t i; size_t j; |
| } gl_oset_iterator_t; |
| |
| #if 0 /* These are defined inline below. */ |
| |
| /* Creates an iterator traversing an ordered set. |
| The set's contents must not be modified while the iterator is in use, |
| except for removing the last returned element. */ |
| extern gl_oset_iterator_t gl_oset_iterator (gl_oset_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_oset_iterator_next (gl_oset_iterator_t *iterator, |
| const void **eltp); |
| |
| /* Frees an iterator. */ |
| extern void gl_oset_iterator_free (gl_oset_iterator_t *iterator); |
| |
| #endif /* End of inline functions. */ |
| |
| /* ------------------------ Implementation Details ------------------------ */ |
| |
| struct gl_oset_implementation |
| { |
| /* gl_oset_t functions. */ |
| gl_oset_t (*nx_create_empty) (gl_oset_implementation_t implementation, |
| gl_setelement_compar_fn compar_fn, |
| gl_setelement_dispose_fn dispose_fn); |
| size_t (*size) (gl_oset_t set); |
| bool (*search) (gl_oset_t set, const void *elt); |
| bool (*search_atleast) (gl_oset_t set, |
| gl_setelement_threshold_fn threshold_fn, |
| const void *threshold, const void **eltp); |
| int (*nx_add) (gl_oset_t set, const void *elt); |
| bool (*remove_elt) (gl_oset_t set, const void *elt); |
| void (*oset_free) (gl_oset_t set); |
| /* gl_oset_iterator_t functions. */ |
| gl_oset_iterator_t (*iterator) (gl_oset_t set); |
| bool (*iterator_next) (gl_oset_iterator_t *iterator, const void **eltp); |
| void (*iterator_free) (gl_oset_iterator_t *iterator); |
| }; |
| |
| struct gl_oset_impl_base |
| { |
| const struct gl_oset_implementation *vtable; |
| gl_setelement_compar_fn compar_fn; |
| gl_setelement_dispose_fn dispose_fn; |
| }; |
| |
| /* Define all functions of this file as accesses to the |
| struct gl_oset_implementation. */ |
| |
| GL_OSET_INLINE gl_oset_t |
| gl_oset_nx_create_empty (gl_oset_implementation_t implementation, |
| gl_setelement_compar_fn compar_fn, |
| gl_setelement_dispose_fn dispose_fn) |
| { |
| return implementation->nx_create_empty (implementation, compar_fn, |
| dispose_fn); |
| } |
| |
| GL_OSET_INLINE size_t |
| gl_oset_size (gl_oset_t set) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable->size (set); |
| } |
| |
| GL_OSET_INLINE bool |
| gl_oset_search (gl_oset_t set, const void *elt) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable->search (set, elt); |
| } |
| |
| GL_OSET_INLINE bool |
| gl_oset_search_atleast (gl_oset_t set, |
| gl_setelement_threshold_fn threshold_fn, |
| const void *threshold, const void **eltp) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable |
| ->search_atleast (set, threshold_fn, threshold, eltp); |
| } |
| |
| GL_OSET_INLINE int |
| #if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4) |
| __attribute__ ((__warn_unused_result__)) |
| #endif |
| gl_oset_nx_add (gl_oset_t set, const void *elt) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable->nx_add (set, elt); |
| } |
| |
| GL_OSET_INLINE bool |
| gl_oset_remove (gl_oset_t set, const void *elt) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable |
| ->remove_elt (set, elt); |
| } |
| |
| GL_OSET_INLINE void |
| gl_oset_free (gl_oset_t set) |
| { |
| ((const struct gl_oset_impl_base *) set)->vtable->oset_free (set); |
| } |
| |
| GL_OSET_INLINE gl_oset_iterator_t |
| gl_oset_iterator (gl_oset_t set) |
| { |
| return ((const struct gl_oset_impl_base *) set)->vtable->iterator (set); |
| } |
| |
| GL_OSET_INLINE bool |
| gl_oset_iterator_next (gl_oset_iterator_t *iterator, const void **eltp) |
| { |
| return iterator->vtable->iterator_next (iterator, eltp); |
| } |
| |
| GL_OSET_INLINE void |
| gl_oset_iterator_free (gl_oset_iterator_t *iterator) |
| { |
| iterator->vtable->iterator_free (iterator); |
| } |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| _GL_INLINE_HEADER_END |
| |
| #endif /* _GL_OSET_H */ |