345 lines
13 KiB
C
Executable File
345 lines
13 KiB
C
Executable File
/* Abstract ordered set data type.
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Copyright (C) 2006-2007, 2009-2024 Free Software Foundation, Inc.
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Written by Bruno Haible <bruno@clisp.org>, 2006.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#ifndef _GL_OSET_H
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#define _GL_OSET_H
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/* This file uses _GL_INLINE_HEADER_BEGIN, _GL_INLINE,
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_GL_ATTRIBUTE_NODISCARD. */
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#if !_GL_CONFIG_H_INCLUDED
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#error "Please include config.h first."
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#endif
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#include <stddef.h>
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_GL_INLINE_HEADER_BEGIN
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#ifndef GL_OSET_INLINE
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# define GL_OSET_INLINE _GL_INLINE
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* gl_oset is an abstract ordered set data type. It can contain any number
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of objects ('void *' or 'const void *' pointers) in the order of a given
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comparator function. Duplicates (in the sense of the comparator) are
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forbidden.
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There are several implementations of this ordered set datatype, optimized
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for different operations or for memory. You can start using the simplest
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ordered set implementation, GL_ARRAY_OSET, and switch to a different
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implementation later, when you realize which operations are performed
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the most frequently. The API of the different implementations is exactly
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the same; when switching to a different implementation, you only have to
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change the gl_oset_create call.
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The implementations are:
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GL_ARRAY_OSET a growable array
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GL_AVLTREE_OSET a binary tree (AVL tree)
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GL_RBTREE_OSET a binary tree (red-black tree)
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The memory consumption is asymptotically the same: O(1) for every object
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in the set. When looking more closely at the average memory consumed
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for an object, GL_ARRAY_OSET is the most compact representation, and
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GL_AVLTREE_OSET, GL_RBTREE_OSET need more memory.
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The guaranteed average performance of the operations is, for a set of
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n elements:
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Operation ARRAY TREE
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gl_oset_size O(1) O(1)
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gl_oset_add O(n) O(log n)
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gl_oset_remove O(n) O(log n)
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gl_oset_update O(n) O(log n)
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gl_oset_search O(log n) O(log n)
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gl_oset_search_atleast O(log n) O(log n)
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gl_oset_iterator O(1) O(log n)
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gl_oset_iterator_atleast O(log n) O(log n)
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gl_oset_iterator_next O(1) O(log n)
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*/
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/* -------------------------- gl_oset_t Data Type -------------------------- */
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/* Type of function used to compare two elements. Same as for qsort().
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NULL denotes pointer comparison. */
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typedef int (*gl_setelement_compar_fn) (const void *elt1, const void *elt2);
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#ifndef _GL_SETELEMENT_DISPOSE_FN_DEFINED
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/* Type of function used to dispose an element once it's removed from a set.
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NULL denotes a no-op. */
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typedef void (*gl_setelement_dispose_fn) (const void *elt);
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# define _GL_SETELEMENT_DISPOSE_FN_DEFINED 1
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#endif
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/* Type of function used to compare an element with a threshold.
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Returns true if the element is greater or equal than the threshold. */
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typedef bool (*gl_setelement_threshold_fn) (const void *elt, const void *threshold);
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struct gl_oset_impl;
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/* Type representing an entire ordered set. */
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typedef struct gl_oset_impl * gl_oset_t;
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struct gl_oset_implementation;
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/* Type representing a ordered set datatype implementation. */
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typedef const struct gl_oset_implementation * gl_oset_implementation_t;
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#if 0 /* Unless otherwise specified, these are defined inline below. */
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/* Creates an empty set.
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IMPLEMENTATION is one of GL_ARRAY_OSET, GL_AVLTREE_OSET, GL_RBTREE_OSET.
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COMPAR_FN is an element comparison function or NULL.
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DISPOSE_FN is an element disposal function or NULL. */
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/* declared in gl_xoset.h */
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extern gl_oset_t gl_oset_create_empty (gl_oset_implementation_t implementation,
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gl_setelement_compar_fn compar_fn,
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gl_setelement_dispose_fn dispose_fn)
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/*_GL_ATTRIBUTE_DEALLOC (gl_oset_free, 1)*/
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_GL_ATTRIBUTE_RETURNS_NONNULL;
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/* Likewise. Returns NULL upon out-of-memory. */
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extern gl_oset_t gl_oset_nx_create_empty (gl_oset_implementation_t implementation,
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gl_setelement_compar_fn compar_fn,
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gl_setelement_dispose_fn dispose_fn)
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/*_GL_ATTRIBUTE_DEALLOC (gl_oset_free, 1)*/;
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/* Returns the current number of elements in an ordered set. */
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extern size_t gl_oset_size (gl_oset_t set);
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/* Searches whether an element is already in the ordered set.
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Returns true if found, or false if not present in the set. */
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extern bool gl_oset_search (gl_oset_t set, const void *elt);
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/* Searches the least element in the ordered set that compares greater or equal
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to the given THRESHOLD. The representation of the THRESHOLD is defined
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by the THRESHOLD_FN.
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Returns true and stores the found element in *ELTP if found, otherwise returns
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false. */
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extern bool gl_oset_search_atleast (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold,
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const void **eltp);
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/* Adds an element to an ordered set.
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Returns true if it was not already in the set and added, false otherwise. */
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/* declared in gl_xoset.h */
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extern bool gl_oset_add (gl_oset_t set, const void *elt);
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/* Likewise. Returns -1 upon out-of-memory. */
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_GL_ATTRIBUTE_NODISCARD
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extern int gl_oset_nx_add (gl_oset_t set, const void *elt);
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/* Removes an element from an ordered set.
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Returns true if it was found and removed. */
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extern bool gl_oset_remove (gl_oset_t set, const void *elt);
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/* Invokes ACTION (ELT, ACTION_DATA) and updates the given ordered set if,
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during this invocation, the attributes/properties of the element ELT change
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in a way that influences the comparison function.
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Warning: During the invocation of ACTION, the ordered set is inconsistent
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and must not be accessed!
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Returns 1 if the position of the element in the ordered set has changed as
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a consequence, 0 if the element stayed at the same position, or -1 if it
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collided with another element and was therefore removed. */
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extern int gl_oset_update (gl_oset_t set, const void *elt,
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void (*action) (const void *elt, void *action_data),
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void *action_data);
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/* Frees an entire ordered set.
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(But this call does not free the elements of the set. It only invokes
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the DISPOSE_FN on each of the elements of the set.) */
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extern void gl_oset_free (gl_oset_t set);
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#endif /* End of inline and gl_xoset.h-defined functions. */
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/* --------------------- gl_oset_iterator_t Data Type --------------------- */
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/* Functions for iterating through an ordered set. */
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/* Type of an iterator that traverses an ordered set.
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This is a fixed-size struct, so that creation of an iterator doesn't need
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memory allocation on the heap. */
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typedef struct
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{
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/* For fast dispatch of gl_oset_iterator_next. */
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const struct gl_oset_implementation *vtable;
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/* For detecting whether the last returned element was removed. */
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gl_oset_t set;
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size_t count;
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/* Other, implementation-private fields. */
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void *p; void *q;
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size_t i; size_t j;
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} gl_oset_iterator_t;
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#if 0 /* These are defined inline below. */
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/* Creates an iterator traversing an ordered set.
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The set's contents must not be modified while the iterator is in use,
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except for removing the last returned element. */
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extern gl_oset_iterator_t gl_oset_iterator (gl_oset_t set);
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/* Creates an iterator traversing the tail of an ordered set, that comprises
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the elements that compare greater or equal to the given THRESHOLD. The
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representation of the THRESHOLD is defined by the THRESHOLD_FN. */
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extern gl_oset_iterator_t gl_oset_iterator_atleast (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold);
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/* If there is a next element, stores the next element in *ELTP, advances the
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iterator and returns true. Otherwise, returns false. */
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extern bool gl_oset_iterator_next (gl_oset_iterator_t *iterator,
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const void **eltp);
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/* Frees an iterator. */
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extern void gl_oset_iterator_free (gl_oset_iterator_t *iterator);
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#endif /* End of inline functions. */
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/* ------------------------ Implementation Details ------------------------ */
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struct gl_oset_implementation
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{
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/* gl_oset_t functions. */
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gl_oset_t (*nx_create_empty) (gl_oset_implementation_t implementation,
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gl_setelement_compar_fn compar_fn,
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gl_setelement_dispose_fn dispose_fn);
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size_t (*size) (gl_oset_t set);
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bool (*search) (gl_oset_t set, const void *elt);
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bool (*search_atleast) (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold, const void **eltp);
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int (*nx_add) (gl_oset_t set, const void *elt);
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bool (*remove_elt) (gl_oset_t set, const void *elt);
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int (*update) (gl_oset_t set, const void *elt,
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void (*action) (const void * /*elt*/, void * /*action_data*/),
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void *action_data);
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void (*oset_free) (gl_oset_t set);
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/* gl_oset_iterator_t functions. */
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gl_oset_iterator_t (*iterator) (gl_oset_t set);
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gl_oset_iterator_t (*iterator_atleast) (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold);
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bool (*iterator_next) (gl_oset_iterator_t *iterator, const void **eltp);
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void (*iterator_free) (gl_oset_iterator_t *iterator);
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};
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struct gl_oset_impl_base
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{
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const struct gl_oset_implementation *vtable;
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gl_setelement_compar_fn compar_fn;
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gl_setelement_dispose_fn dispose_fn;
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};
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/* Define all functions of this file as accesses to the
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struct gl_oset_implementation. */
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GL_OSET_INLINE
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/*_GL_ATTRIBUTE_DEALLOC (gl_oset_free, 1)*/
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gl_oset_t
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gl_oset_nx_create_empty (gl_oset_implementation_t implementation,
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gl_setelement_compar_fn compar_fn,
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gl_setelement_dispose_fn dispose_fn)
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{
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return implementation->nx_create_empty (implementation, compar_fn,
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dispose_fn);
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}
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GL_OSET_INLINE size_t
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gl_oset_size (gl_oset_t set)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable->size (set);
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}
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GL_OSET_INLINE bool
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gl_oset_search (gl_oset_t set, const void *elt)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable->search (set, elt);
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}
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GL_OSET_INLINE bool
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gl_oset_search_atleast (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold, const void **eltp)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable
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->search_atleast (set, threshold_fn, threshold, eltp);
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}
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_GL_ATTRIBUTE_NODISCARD GL_OSET_INLINE int
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gl_oset_nx_add (gl_oset_t set, const void *elt)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable->nx_add (set, elt);
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}
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GL_OSET_INLINE bool
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gl_oset_remove (gl_oset_t set, const void *elt)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable
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->remove_elt (set, elt);
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}
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GL_OSET_INLINE int
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gl_oset_update (gl_oset_t set, const void *elt,
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void (*action) (const void * /*elt*/, void * /*action_data*/),
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void *action_data)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable
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->update (set, elt, action, action_data);
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}
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GL_OSET_INLINE void
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gl_oset_free (gl_oset_t set)
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{
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((const struct gl_oset_impl_base *) set)->vtable->oset_free (set);
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}
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GL_OSET_INLINE gl_oset_iterator_t
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gl_oset_iterator (gl_oset_t set)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable->iterator (set);
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}
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GL_OSET_INLINE gl_oset_iterator_t
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gl_oset_iterator_atleast (gl_oset_t set,
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gl_setelement_threshold_fn threshold_fn,
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const void *threshold)
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{
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return ((const struct gl_oset_impl_base *) set)->vtable
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->iterator_atleast (set, threshold_fn, threshold);
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}
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GL_OSET_INLINE bool
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gl_oset_iterator_next (gl_oset_iterator_t *iterator, const void **eltp)
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{
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return iterator->vtable->iterator_next (iterator, eltp);
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}
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GL_OSET_INLINE void
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gl_oset_iterator_free (gl_oset_iterator_t *iterator)
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{
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iterator->vtable->iterator_free (iterator);
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}
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#ifdef __cplusplus
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}
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#endif
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_GL_INLINE_HEADER_END
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#endif /* _GL_OSET_H */
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