1 /* Ordered set data type implemented by an array.
2 Copyright (C) 2006 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2006.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2, or (at your option)
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
22 #include "gl_array_oset.h"
28 /* Checked size_t computations. */
31 /* -------------------------- gl_oset_t Data Type -------------------------- */
33 /* Concrete gl_oset_impl type, valid for this file only. */
36 struct gl_oset_impl_base base;
37 /* An array of ALLOCATED elements, of which the first COUNT are used.
38 0 <= COUNT <= ALLOCATED. */
39 const void **elements;
45 gl_array_create_empty (gl_oset_implementation_t implementation,
46 gl_setelement_compar_fn compar_fn)
48 struct gl_oset_impl *set = XMALLOC (struct gl_oset_impl);
50 set->base.vtable = implementation;
51 set->base.compar_fn = compar_fn;
60 gl_array_size (gl_oset_t set)
66 gl_array_indexof (gl_oset_t set, const void *elt)
68 size_t count = set->count;
72 gl_setelement_compar_fn compar = set->base.compar_fn;
76 /* At each loop iteration, low < high; for indices < low the values
77 are smaller than ELT; for indices >= high the values are greater
78 than ELT. So, if the element occurs in the list, it is at
79 low <= position < high. */
82 size_t mid = low + (high - low) / 2; /* low <= mid < high */
83 int cmp = (compar != NULL
84 ? compar (set->elements[mid], elt)
85 : (set->elements[mid] > elt ? 1 :
86 set->elements[mid] < elt ? -1 : 0));
93 /* We have an element equal to ELT at index MID. */
102 gl_array_search (gl_oset_t set, const void *elt)
104 return gl_array_indexof (set, elt) != (size_t)(-1);
108 gl_array_search_atleast (gl_oset_t set,
109 gl_setelement_threshold_fn threshold_fn,
110 const void *threshold,
113 size_t count = set->count;
120 /* At each loop iteration, low < high; for indices < low the values are
121 smaller than THRESHOLD; for indices >= high the values are nonexistent.
122 So, if an element >= THRESHOLD occurs in the list, it is at
123 low <= position < high. */
126 size_t mid = low + (high - low) / 2; /* low <= mid < high */
128 if (! threshold_fn (set->elements[mid], threshold))
132 /* We have an element >= THRESHOLD at index MID. But we need the
133 minimal such index. */
135 /* At each loop iteration, low <= high and
136 compar (list->elements[high], value) >= 0,
137 and we know that the first occurrence of the element is at
138 low <= position <= high. */
141 size_t mid2 = low + (high - low) / 2; /* low <= mid2 < high */
143 if (! threshold_fn (set->elements[mid2], threshold))
148 *eltp = set->elements[low];
157 /* Ensure that set->allocated > set->count. */
161 size_t new_allocated;
165 new_allocated = xtimes (set->allocated, 2);
166 new_allocated = xsum (new_allocated, 1);
167 memory_size = xtimes (new_allocated, sizeof (const void *));
168 if (size_overflow_p (memory_size))
169 /* Overflow, would lead to out of memory. */
171 memory = (const void **) xrealloc (set->elements, memory_size);
175 set->elements = memory;
176 set->allocated = new_allocated;
179 /* Add the given element ELT at the given position,
180 0 <= position <= gl_oset_size (set). */
182 gl_array_add_at (gl_oset_t set, size_t position, const void *elt)
184 size_t count = set->count;
185 const void **elements;
188 if (count == set->allocated)
190 elements = set->elements;
191 for (i = count; i > position; i--)
192 elements[i] = elements[i - 1];
193 elements[position] = elt;
194 set->count = count + 1;
197 /* Remove the element at the given position,
198 0 <= position < gl_oset_size (set). */
200 gl_array_remove_at (gl_oset_t set, size_t position)
202 size_t count = set->count;
203 const void **elements;
206 elements = set->elements;
207 for (i = position + 1; i < count; i++)
208 elements[i - 1] = elements[i];
209 set->count = count - 1;
213 gl_array_add (gl_oset_t set, const void *elt)
215 size_t count = set->count;
220 gl_setelement_compar_fn compar = set->base.compar_fn;
223 /* At each loop iteration, low < high; for indices < low the values
224 are smaller than ELT; for indices >= high the values are greater
225 than ELT. So, if the element occurs in the list, it is at
226 low <= position < high. */
229 size_t mid = low + (high - low) / 2; /* low <= mid < high */
230 int cmp = (compar != NULL
231 ? compar (set->elements[mid], elt)
232 : (set->elements[mid] > elt ? 1 :
233 set->elements[mid] < elt ? -1 : 0));
244 gl_array_add_at (set, low, elt);
249 gl_array_remove (gl_oset_t set, const void *elt)
251 size_t index = gl_array_indexof (set, elt);
252 if (index != (size_t)(-1))
254 gl_array_remove_at (set, index);
262 gl_array_free (gl_oset_t set)
264 if (set->elements != NULL)
265 free (set->elements);
269 /* --------------------- gl_oset_iterator_t Data Type --------------------- */
271 static gl_oset_iterator_t
272 gl_array_iterator (gl_oset_t set)
274 gl_oset_iterator_t result;
276 result.vtable = set->base.vtable;
278 result.count = set->count;
279 result.p = set->elements + 0;
280 result.q = set->elements + set->count;
290 gl_array_iterator_next (gl_oset_iterator_t *iterator, const void **eltp)
292 gl_oset_t set = iterator->set;
293 if (iterator->count != set->count)
295 if (iterator->count != set->count + 1)
296 /* Concurrent modifications were done on the set. */
298 /* The last returned element was removed. */
303 if (iterator->p < iterator->q)
305 const void **p = (const void **) iterator->p;
315 gl_array_iterator_free (gl_oset_iterator_t *iterator)
320 const struct gl_oset_implementation gl_array_oset_implementation =
322 gl_array_create_empty,
325 gl_array_search_atleast,
330 gl_array_iterator_next,
331 gl_array_iterator_free