--- /dev/null
+/* Ordered set data type implemented by an array.
+ 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. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+/* Specification. */
+#include "gl_array_oset.h"
+
+#include <stdlib.h>
+
+#include "xalloc.h"
+
+/* Checked size_t computations. */
+#include "xsize.h"
+
+/* -------------------------- gl_oset_t Data Type -------------------------- */
+
+/* Concrete gl_oset_impl type, valid for this file only. */
+struct gl_oset_impl
+{
+ struct gl_oset_impl_base base;
+ /* An array of ALLOCATED elements, of which the first COUNT are used.
+ 0 <= COUNT <= ALLOCATED. */
+ const void **elements;
+ size_t count;
+ size_t allocated;
+};
+
+static gl_oset_t
+gl_array_create_empty (gl_oset_implementation_t implementation,
+ gl_setelement_compar_fn compar_fn)
+{
+ struct gl_oset_impl *set =
+ (struct gl_oset_impl *) xmalloc (sizeof (struct gl_oset_impl));
+
+ set->base.vtable = implementation;
+ set->base.compar_fn = compar_fn;
+ set->elements = NULL;
+ set->count = 0;
+ set->allocated = 0;
+
+ return set;
+}
+
+static size_t
+gl_array_size (gl_oset_t set)
+{
+ return set->count;
+}
+
+static size_t
+gl_array_indexof (gl_oset_t set, const void *elt)
+{
+ size_t count = set->count;
+
+ if (count > 0)
+ {
+ gl_setelement_compar_fn compar = set->base.compar_fn;
+ size_t low = 0;
+ size_t high = count;
+
+ /* At each loop iteration, low < high; for indices < low the values
+ are smaller than ELT; for indices >= high the values are greater
+ than ELT. So, if the element occurs in the list, is at
+ low <= position < high. */
+ do
+ {
+ size_t mid = low + (high - low) / 2; /* low <= mid < high */
+ int cmp = (compar != NULL
+ ? compar (set->elements[mid], elt)
+ : (set->elements[mid] > elt ? 1 :
+ set->elements[mid] < elt ? -1 : 0));
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid;
+ else /* cmp == 0 */
+ /* We have an element equal to ELT at index MID. */
+ return mid;
+ }
+ while (low < high);
+ }
+ return (size_t)(-1);
+}
+
+static bool
+gl_array_search (gl_oset_t set, const void *elt)
+{
+ return gl_array_indexof (set, elt) != (size_t)(-1);
+}
+
+/* Ensure that set->allocated > set->count. */
+static void
+grow (gl_oset_t set)
+{
+ size_t new_allocated;
+ size_t memory_size;
+ const void **memory;
+
+ new_allocated = xtimes (set->allocated, 2);
+ new_allocated = xsum (new_allocated, 1);
+ memory_size = xtimes (new_allocated, sizeof (const void *));
+ if (size_overflow_p (memory_size))
+ /* Overflow, would lead to out of memory. */
+ xalloc_die ();
+ memory = (const void **) xrealloc (set->elements, memory_size);
+ if (memory == NULL)
+ /* Out of memory. */
+ xalloc_die ();
+ set->elements = memory;
+ set->allocated = new_allocated;
+}
+
+/* Add the given element ELT at the given position,
+ 0 <= position <= gl_oset_size (set). */
+static inline void
+gl_array_add_at (gl_oset_t set, size_t position, const void *elt)
+{
+ size_t count = set->count;
+ const void **elements;
+ size_t i;
+
+ if (count == set->allocated)
+ grow (set);
+ elements = set->elements;
+ for (i = count; i > position; i--)
+ elements[i] = elements[i - 1];
+ elements[position] = elt;
+ set->count = count + 1;
+}
+
+/* Remove the element at the given position,
+ 0 <= position < gl_oset_size (set). */
+static inline void
+gl_array_remove_at (gl_oset_t set, size_t position)
+{
+ size_t count = set->count;
+ const void **elements;
+ size_t i;
+
+ elements = set->elements;
+ for (i = position + 1; i < count; i++)
+ elements[i - 1] = elements[i];
+ set->count = count - 1;
+}
+
+static bool
+gl_array_add (gl_oset_t set, const void *elt)
+{
+ size_t count = set->count;
+ size_t low = 0;
+
+ if (count > 0)
+ {
+ gl_setelement_compar_fn compar = set->base.compar_fn;
+ size_t high = count;
+
+ /* At each loop iteration, low < high; for indices < low the values
+ are smaller than ELT; for indices >= high the values are greater
+ than ELT. So, if the element occurs in the list, is at
+ low <= position < high. */
+ do
+ {
+ size_t mid = low + (high - low) / 2; /* low <= mid < high */
+ int cmp = (compar != NULL
+ ? compar (set->elements[mid], elt)
+ : (set->elements[mid] > elt ? 1 :
+ set->elements[mid] < elt ? -1 : 0));
+
+ if (cmp < 0)
+ low = mid + 1;
+ else if (cmp > 0)
+ high = mid;
+ else /* cmp == 0 */
+ return false;
+ }
+ while (low < high);
+ }
+ gl_array_add_at (set, low, elt);
+ return true;
+}
+
+static bool
+gl_array_remove (gl_oset_t set, const void *elt)
+{
+ size_t index = gl_array_indexof (set, elt);
+ if (index != (size_t)(-1))
+ {
+ gl_array_remove_at (set, index);
+ return true;
+ }
+ else
+ return false;
+}
+
+static void
+gl_array_free (gl_oset_t set)
+{
+ if (set->elements != NULL)
+ free (set->elements);
+ free (set);
+}
+
+/* --------------------- gl_oset_iterator_t Data Type --------------------- */
+
+static gl_oset_iterator_t
+gl_array_iterator (gl_oset_t set)
+{
+ gl_oset_iterator_t result;
+
+ result.vtable = set->base.vtable;
+ result.set = set;
+ result.count = set->count;
+ result.p = set->elements + 0;
+ result.q = set->elements + set->count;
+
+ return result;
+}
+
+static bool
+gl_array_iterator_next (gl_oset_iterator_t *iterator, const void **eltp)
+{
+ gl_oset_t set = iterator->set;
+ if (iterator->count != set->count)
+ {
+ if (iterator->count != set->count + 1)
+ /* Concurrent modifications were done on the set. */
+ abort ();
+ /* The last returned element was removed. */
+ iterator->count--;
+ iterator->p--;
+ iterator->q--;
+ }
+ if (iterator->p < iterator->q)
+ {
+ const void **p = (const void **) iterator->p;
+ *eltp = *p;
+ iterator->p = p + 1;
+ return true;
+ }
+ else
+ return false;
+}
+
+static void
+gl_array_iterator_free (gl_oset_iterator_t *iterator)
+{
+}
+
+
+const struct gl_oset_implementation gl_array_oset_implementation =
+ {
+ gl_array_create_empty,
+ gl_array_size,
+ gl_array_search,
+ gl_array_add,
+ gl_array_remove,
+ gl_array_free,
+ gl_array_iterator,
+ gl_array_iterator_next,
+ gl_array_iterator_free
+ };
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