lib/gl_array_set.c

   1 /* Set data type implemented by an array.
   2    Copyright (C) 2006-2024 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2018.
   4
   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 3 of the License, or
   8    (at your option) any later version.
   9
  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.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 /* Specification.  */
  21 #include "gl_array_set.h"
  22
  23 #include <stdint.h>
  24 #include <stdlib.h>
  25
  26 /* Checked size_t computations.  */
  27 #include "xsize.h"
  28
  29 /* --------------------------- gl_set_t Data Type --------------------------- */
  30
  31 /* Concrete gl_set_impl type, valid for this file only.  */
  32 struct gl_set_impl
  33 {
  34   struct gl_set_impl_base base;
  35   /* An array of ALLOCATED elements, of which the first COUNT are used.
  36      0 <= COUNT <= ALLOCATED.  */
  37   const void **elements;
  38   size_t count;
  39   size_t allocated;
  40 };
  41
  42 static gl_set_t
  43 gl_array_nx_create_empty (gl_set_implementation_t implementation,
  44                           gl_setelement_equals_fn equals_fn,
  45                           gl_setelement_hashcode_fn hashcode_fn,
  46                           gl_setelement_dispose_fn dispose_fn)
  47 {
  48   struct gl_set_impl *set =
  49     (struct gl_set_impl *) malloc (sizeof (struct gl_set_impl));
  50
  51   if (set == NULL)
  52     return NULL;
  53
  54   set->base.vtable = implementation;
  55   set->base.equals_fn = equals_fn;
  56   set->base.dispose_fn = dispose_fn;
  57   set->elements = NULL;
  58   set->count = 0;
  59   set->allocated = 0;
  60
  61   return set;
  62 }
  63
  64 static size_t
  65 gl_array_size (gl_set_t set)
  66 {
  67   return set->count;
  68 }
  69
  70 static bool
  71 gl_array_search (gl_set_t set, const void *elt)
  72 {
  73   size_t count = set->count;
  74
  75   if (count > 0)
  76     {
  77       gl_setelement_equals_fn equals = set->base.equals_fn;
  78       const void **elements = set->elements;
  79       if (equals != NULL)
  80         {
  81           size_t i;
  82
  83           for (i = 0; i < count; i++)
  84             if (equals (elements[i], elt))
  85               return true;
  86         }
  87       else
  88         {
  89           size_t i;
  90
  91           for (i = 0; i < count; i++)
  92             if (elements[i] == elt)
  93               return true;
  94         }
  95     }
  96   return false;
  97 }
  98
  99 /* Ensure that set->allocated > set->count.
 100    Return 0 upon success, -1 upon out-of-memory.  */
 101 static int
 102 grow (gl_set_t set)
 103 {
 104   size_t new_allocated;
 105   size_t memory_size;
 106   const void **memory;
 107
 108   new_allocated = xtimes (set->allocated, 2);
 109   new_allocated = xsum (new_allocated, 1);
 110   memory_size = xtimes (new_allocated, sizeof (const void *));
 111   if (size_overflow_p (memory_size))
 112     /* Overflow, would lead to out of memory.  */
 113     return -1;
 114   memory = (const void **) realloc (set->elements, memory_size);
 115   if (memory == NULL)
 116     /* Out of memory.  */
 117     return -1;
 118   set->elements = memory;
 119   set->allocated = new_allocated;
 120   return 0;
 121 }
 122
 123 static int
 124 gl_array_nx_add (gl_set_t set, const void *elt)
 125 {
 126   if (gl_array_search (set, elt))
 127     return 0;
 128   else
 129     {
 130       size_t count = set->count;
 131
 132       if (count == set->allocated)
 133         if (grow (set) < 0)
 134           return -1;
 135       set->elements[count] = elt;
 136       set->count = count + 1;
 137       return 1;
 138     }
 139 }
 140
 141 /* Remove the element at the given position,
 142    0 <= position < gl_set_size (set).  */
 143 static void
 144 gl_array_remove_at (gl_set_t set, size_t position)
 145 {
 146   size_t count = set->count;
 147   const void **elements = set->elements;
 148   size_t i;
 149
 150   if (set->base.dispose_fn != NULL)
 151     set->base.dispose_fn (elements[position]);
 152   for (i = position + 1; i < count; i++)
 153     elements[i - 1] = elements[i];
 154   set->count = count - 1;
 155 }
 156
 157 static bool
 158 gl_array_remove (gl_set_t set, const void *elt)
 159 {
 160   size_t count = set->count;
 161
 162   if (count > 0)
 163     {
 164       gl_setelement_equals_fn equals = set->base.equals_fn;
 165       const void **elements = set->elements;
 166
 167       if (equals != NULL)
 168         {
 169           size_t i;
 170
 171           for (i = 0; i < count; i++)
 172             if (equals (elements[i], elt))
 173               {
 174                 gl_array_remove_at (set, i);
 175                 return true;
 176               }
 177         }
 178       else
 179         {
 180           size_t i;
 181
 182           for (i = 0; i < count; i++)
 183             if (elements[i] == elt)
 184               {
 185                 gl_array_remove_at (set, i);
 186                 return true;
 187               }
 188         }
 189     }
 190   return false;
 191 }
 192
 193 static void
 194 gl_array_free (gl_set_t set)
 195 {
 196   if (set->elements != NULL)
 197     {
 198       if (set->base.dispose_fn != NULL)
 199         {
 200           size_t count = set->count;
 201
 202           if (count > 0)
 203             {
 204               gl_setelement_dispose_fn dispose = set->base.dispose_fn;
 205               const void **elements = set->elements;
 206
 207               do
 208                 dispose (*elements++);
 209               while (--count > 0);
 210             }
 211         }
 212       free (set->elements);
 213     }
 214   free (set);
 215 }
 216
 217 /* ---------------------- gl_set_iterator_t Data Type ---------------------- */
 218
 219 static gl_set_iterator_t
 220 gl_array_iterator (gl_set_t set)
 221 {
 222   gl_set_iterator_t result;
 223
 224   result.vtable = set->base.vtable;
 225   result.set = set;
 226   result.count = set->count;
 227   result.p = set->elements + 0;
 228   result.q = set->elements + set->count;
 229 #if defined GCC_LINT || defined lint
 230   result.i = 0;
 231   result.j = 0;
 232 #endif
 233
 234   return result;
 235 }
 236
 237 static bool
 238 gl_array_iterator_next (gl_set_iterator_t *iterator, const void **eltp)
 239 {
 240   gl_set_t set = iterator->set;
 241   if (iterator->count != set->count)
 242     {
 243       if (iterator->count != set->count + 1)
 244         /* Concurrent modifications were done on the set.  */
 245         abort ();
 246       /* The last returned element was removed.  */
 247       iterator->count--;
 248       iterator->p = (const void **) iterator->p - 1;
 249       iterator->q = (const void **) iterator->q - 1;
 250     }
 251   if (iterator->p < iterator->q)
 252     {
 253       const void **p = (const void **) iterator->p;
 254       *eltp = *p;
 255       iterator->p = p + 1;
 256       return true;
 257     }
 258   else
 259     return false;
 260 }
 261
 262 static void
 263 gl_array_iterator_free (gl_set_iterator_t *iterator)
 264 {
 265 }
 266
 267
 268 const struct gl_set_implementation gl_array_set_implementation =
 269   {
 270     gl_array_nx_create_empty,
 271     gl_array_size,
 272     gl_array_search,
 273     gl_array_nx_add,
 274     gl_array_remove,
 275     gl_array_free,
 276     gl_array_iterator,
 277     gl_array_iterator_next,
 278     gl_array_iterator_free
 279   };