lib/gl_array_set.c

   1 /* Set data type implemented by an array.
   2    Copyright (C) 2006-2019 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 <stdlib.h>
  24
  25 /* Checked size_t computations.  */
  26 #include "xsize.h"
  27
  28 #ifndef uintptr_t
  29 # define uintptr_t unsigned long
  30 #endif
  31
  32 /* --------------------------- gl_set_t Data Type --------------------------- */
  33
  34 /* Concrete gl_set_impl type, valid for this file only.  */
  35 struct gl_set_impl
  36 {
  37   struct gl_set_impl_base base;
  38   /* An array of ALLOCATED elements, of which the first COUNT are used.
  39      0 <= COUNT <= ALLOCATED.  */
  40   const void **elements;
  41   size_t count;
  42   size_t allocated;
  43 };
  44
  45 static gl_set_t
  46 gl_array_nx_create_empty (gl_set_implementation_t implementation,
  47                           gl_setelement_equals_fn equals_fn,
  48                           gl_setelement_hashcode_fn hashcode_fn,
  49                           gl_setelement_dispose_fn dispose_fn)
  50 {
  51   struct gl_set_impl *set =
  52     (struct gl_set_impl *) malloc (sizeof (struct gl_set_impl));
  53
  54   if (set == NULL)
  55     return NULL;
  56
  57   set->base.vtable = implementation;
  58   set->base.equals_fn = equals_fn;
  59   set->base.dispose_fn = dispose_fn;
  60   set->elements = NULL;
  61   set->count = 0;
  62   set->allocated = 0;
  63
  64   return set;
  65 }
  66
  67 static size_t
  68 gl_array_size (gl_set_t set)
  69 {
  70   return set->count;
  71 }
  72
  73 static bool
  74 gl_array_search (gl_set_t set, const void *elt)
  75 {
  76   size_t count = set->count;
  77
  78   if (count > 0)
  79     {
  80       gl_setelement_equals_fn equals = set->base.equals_fn;
  81       const void **elements = set->elements;
  82       if (equals != NULL)
  83         {
  84           size_t i;
  85
  86           for (i = 0; i < count; i++)
  87             if (equals (elements[i], elt))
  88               return true;
  89         }
  90       else
  91         {
  92           size_t i;
  93
  94           for (i = 0; i < count; i++)
  95             if (elements[i] == elt)
  96               return true;
  97         }
  98     }
  99   return false;
 100 }
 101
 102 /* Ensure that set->allocated > set->count.
 103    Return 0 upon success, -1 upon out-of-memory.  */
 104 static int
 105 grow (gl_set_t set)
 106 {
 107   size_t new_allocated;
 108   size_t memory_size;
 109   const void **memory;
 110
 111   new_allocated = xtimes (set->allocated, 2);
 112   new_allocated = xsum (new_allocated, 1);
 113   memory_size = xtimes (new_allocated, sizeof (const void *));
 114   if (size_overflow_p (memory_size))
 115     /* Overflow, would lead to out of memory.  */
 116     return -1;
 117   memory = (const void **) realloc (set->elements, memory_size);
 118   if (memory == NULL)
 119     /* Out of memory.  */
 120     return -1;
 121   set->elements = memory;
 122   set->allocated = new_allocated;
 123   return 0;
 124 }
 125
 126 static int
 127 gl_array_nx_add (gl_set_t set, const void *elt)
 128 {
 129   if (gl_array_search (set, elt))
 130     return 0;
 131   else
 132     {
 133       size_t count = set->count;
 134
 135       if (count == set->allocated)
 136         if (grow (set) < 0)
 137           return -1;
 138       set->elements[count] = elt;
 139       set->count = count + 1;
 140       return 1;
 141     }
 142 }
 143
 144 /* Remove the element at the given position,
 145    0 <= position < gl_set_size (set).  */
 146 static void
 147 gl_array_remove_at (gl_set_t set, size_t position)
 148 {
 149   size_t count = set->count;
 150   const void **elements = set->elements;
 151   size_t i;
 152
 153   if (set->base.dispose_fn != NULL)
 154     set->base.dispose_fn (elements[position]);
 155   for (i = position + 1; i < count; i++)
 156     elements[i - 1] = elements[i];
 157   set->count = count - 1;
 158 }
 159
 160 static bool
 161 gl_array_remove (gl_set_t set, const void *elt)
 162 {
 163   size_t count = set->count;
 164
 165   if (count > 0)
 166     {
 167       gl_setelement_equals_fn equals = set->base.equals_fn;
 168       const void **elements = set->elements;
 169
 170       if (equals != NULL)
 171         {
 172           size_t i;
 173
 174           for (i = 0; i < count; i++)
 175             if (equals (elements[i], elt))
 176               {
 177                 gl_array_remove_at (set, i);
 178                 return true;
 179               }
 180         }
 181       else
 182         {
 183           size_t i;
 184
 185           for (i = 0; i < count; i++)
 186             if (elements[i] == elt)
 187               {
 188                 gl_array_remove_at (set, i);
 189                 return true;
 190               }
 191         }
 192     }
 193   return false;
 194 }
 195
 196 static void
 197 gl_array_free (gl_set_t set)
 198 {
 199   if (set->elements != NULL)
 200     {
 201       if (set->base.dispose_fn != NULL)
 202         {
 203           size_t count = set->count;
 204
 205           if (count > 0)
 206             {
 207               gl_setelement_dispose_fn dispose = set->base.dispose_fn;
 208               const void **elements = set->elements;
 209
 210               do
 211                 dispose (*elements++);
 212               while (--count > 0);
 213             }
 214         }
 215       free (set->elements);
 216     }
 217   free (set);
 218 }
 219
 220 /* ---------------------- gl_set_iterator_t Data Type ---------------------- */
 221
 222 static gl_set_iterator_t
 223 gl_array_iterator (gl_set_t set)
 224 {
 225   gl_set_iterator_t result;
 226
 227   result.vtable = set->base.vtable;
 228   result.set = set;
 229   result.count = set->count;
 230   result.p = set->elements + 0;
 231   result.q = set->elements + set->count;
 232 #if defined GCC_LINT || defined lint
 233   result.i = 0;
 234   result.j = 0;
 235 #endif
 236
 237   return result;
 238 }
 239
 240 static bool
 241 gl_array_iterator_next (gl_set_iterator_t *iterator, const void **eltp)
 242 {
 243   gl_set_t set = iterator->set;
 244   if (iterator->count != set->count)
 245     {
 246       if (iterator->count != set->count + 1)
 247         /* Concurrent modifications were done on the set.  */
 248         abort ();
 249       /* The last returned element was removed.  */
 250       iterator->count--;
 251       iterator->p = (const void **) iterator->p - 1;
 252       iterator->q = (const void **) iterator->q - 1;
 253     }
 254   if (iterator->p < iterator->q)
 255     {
 256       const void **p = (const void **) iterator->p;
 257       *eltp = *p;
 258       iterator->p = p + 1;
 259       return true;
 260     }
 261   else
 262     return false;
 263 }
 264
 265 static void
 266 gl_array_iterator_free (gl_set_iterator_t *iterator)
 267 {
 268 }
 269
 270
 271 const struct gl_set_implementation gl_array_set_implementation =
 272   {
 273     gl_array_nx_create_empty,
 274     gl_array_size,
 275     gl_array_search,
 276     gl_array_nx_add,
 277     gl_array_remove,
 278     gl_array_free,
 279     gl_array_iterator,
 280     gl_array_iterator_next,
 281     gl_array_iterator_free
 282   };