--- /dev/null
+/* Abstract ordered set data type.
+ Copyright (C) 2006 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 2, 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, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#ifndef _GL_OSET_H
+#define _GL_OSET_H
+
+#include <stdbool.h>
+#include <stddef.h>
+
+#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
+ gl_oset_remove
+ gl_oset_search
+ 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);
+
+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;
+
+/* Create 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. */
+extern gl_oset_t gl_oset_create_empty (gl_oset_implementation_t implementation,
+ gl_setelement_compar_fn compar_fn);
+
+/* Return the current number of elements in an ordered set. */
+extern size_t gl_oset_size (gl_oset_t set);
+
+/* Search whether an element is already in the ordered set.
+ Return true if found, or false if not present in the set. */
+extern bool gl_oset_search (gl_oset_t set, const void *elt);
+
+/* Add an element to an ordered set.
+ Return true if it was not already in the set and added. */
+extern bool gl_oset_add (gl_oset_t set, const void *elt);
+
+/* Remove an element from an ordered set.
+ Return true if it was found and removed. */
+extern bool gl_oset_remove (gl_oset_t set, const void *elt);
+
+/* Free an entire ordered set.
+ (But this call does not free the elements of the set.) */
+extern void gl_oset_free (gl_oset_t set);
+
+/* --------------------- 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;
+
+/* Create 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, store the next element in *ELTP, advance the
+ iterator and return true. Otherwise, return false. */
+extern bool gl_oset_iterator_next (gl_oset_iterator_t *iterator,
+ const void **eltp);
+
+/* Free an iterator. */
+extern void gl_oset_iterator_free (gl_oset_iterator_t *iterator);
+
+/* ------------------------ Implementation Details ------------------------ */
+
+struct gl_oset_implementation
+{
+ // gl_oset_t functions.
+ gl_oset_t (*create_empty) (gl_oset_implementation_t implementation,
+ gl_setelement_compar_fn compar_fn);
+ size_t (*size) (gl_oset_t set);
+ bool (*search) (gl_oset_t set, const void *elt);
+ bool (*add) (gl_oset_t set, const void *elt);
+ bool (*remove) (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;
+};
+
+#if HAVE_INLINE
+
+/* Define all functions of this file as inline accesses to the
+ struct gl_oset_implementation.
+ Use #define to avoid a warning because of extern vs. static. */
+
+# define gl_oset_create_empty gl_oset_create_empty_inline
+static inline gl_oset_t
+gl_oset_create_empty (gl_oset_implementation_t implementation,
+ gl_setelement_compar_fn compar_fn)
+{
+ return implementation->create_empty (implementation, compar_fn);
+}
+
+# define gl_oset_size gl_oset_size_inline
+static inline size_t
+gl_oset_size (gl_oset_t set)
+{
+ return ((const struct gl_oset_impl_base *) set)->vtable->size (set);
+}
+
+# define gl_oset_search gl_oset_search_inline
+static inline bool
+gl_oset_search (gl_oset_t set, const void *elt)
+{
+ return ((const struct gl_oset_impl_base *) set)->vtable->search (set, elt);
+}
+
+# define gl_oset_add gl_oset_add_inline
+static inline bool
+gl_oset_add (gl_oset_t set, const void *elt)
+{
+ return ((const struct gl_oset_impl_base *) set)->vtable->add (set, elt);
+}
+
+# define gl_oset_remove gl_oset_remove_inline
+static inline bool
+gl_oset_remove (gl_oset_t set, const void *elt)
+{
+ return ((const struct gl_oset_impl_base *) set)->vtable->remove (set, elt);
+}
+
+# define gl_oset_free gl_oset_free_inline
+static inline void
+gl_oset_free (gl_oset_t set)
+{
+ ((const struct gl_oset_impl_base *) set)->vtable->oset_free (set);
+}
+
+# define gl_oset_iterator gl_oset_iterator_inline
+static inline gl_oset_iterator_t
+gl_oset_iterator (gl_oset_t set)
+{
+ return ((const struct gl_oset_impl_base *) set)->vtable->iterator (set);
+}
+
+# define gl_oset_iterator_next gl_oset_iterator_next_inline
+static inline bool
+gl_oset_iterator_next (gl_oset_iterator_t *iterator, const void **eltp)
+{
+ return iterator->vtable->iterator_next (iterator, eltp);
+}
+
+# define gl_oset_iterator_free gl_oset_iterator_free_inline
+static inline void
+gl_oset_iterator_free (gl_oset_iterator_t *iterator)
+{
+ iterator->vtable->iterator_free (iterator);
+}
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _GL_OSET_H */
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