1/**************************************************************************
2 *
3 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28/**
29 * @file
30 * Generic handle table implementation.
31 *
32 * @author José Fonseca <jrfonseca@tungstengraphics.com>
33 */
34
35
36#include "pipe/p_compiler.h"
37#include "util/u_debug.h"
38
39#include "util/u_memory.h"
40#include "util/u_handle_table.h"
41
42
43#define HANDLE_TABLE_INITIAL_SIZE 16
44
45
46struct handle_table
47{
48   /** Object array. Empty handles have a null object */
49   void **objects;
50
51   /** Number of objects the handle can currently hold */
52   unsigned size;
53   /** Number of consecutive objects allocated at the start of the table */
54   unsigned filled;
55
56   /** Optional object destructor */
57   void (*destroy)(void *object);
58};
59
60
61struct handle_table *
62handle_table_create(void)
63{
64   struct handle_table *ht;
65
66   ht = MALLOC_STRUCT(handle_table);
67   if(!ht)
68      return NULL;
69
70   ht->objects = (void **)CALLOC(HANDLE_TABLE_INITIAL_SIZE, sizeof(void *));
71   if(!ht->objects) {
72      FREE(ht);
73      return NULL;
74   }
75
76   ht->size = HANDLE_TABLE_INITIAL_SIZE;
77   ht->filled = 0;
78
79   ht->destroy = NULL;
80
81   return ht;
82}
83
84
85void
86handle_table_set_destroy(struct handle_table *ht,
87                         void (*destroy)(void *object))
88{
89   assert(ht);
90   if (!ht)
91      return;
92   ht->destroy = destroy;
93}
94
95
96/**
97 * Resize the table if necessary
98 */
99static INLINE int
100handle_table_resize(struct handle_table *ht,
101                    unsigned minimum_size)
102{
103   unsigned new_size;
104   void **new_objects;
105
106   if(ht->size > minimum_size)
107      return ht->size;
108
109   new_size = ht->size;
110   while(!(new_size > minimum_size))
111      new_size *= 2;
112   assert(new_size);
113
114   new_objects = (void **)REALLOC((void *)ht->objects,
115				  ht->size*sizeof(void *),
116				  new_size*sizeof(void *));
117   if(!new_objects)
118      return 0;
119
120   memset(new_objects + ht->size, 0, (new_size - ht->size)*sizeof(void *));
121
122   ht->size = new_size;
123   ht->objects = new_objects;
124
125   return ht->size;
126}
127
128
129static INLINE void
130handle_table_clear(struct handle_table *ht,
131                   unsigned index)
132{
133   void *object;
134
135   /* The order here is important so that the object being destroyed is not
136    * present in the table when seen by the destroy callback, because the
137    * destroy callback may directly or indirectly call the other functions in
138    * this module.
139    */
140
141   object = ht->objects[index];
142   if(object) {
143      ht->objects[index] = NULL;
144
145      if(ht->destroy)
146         ht->destroy(object);
147   }
148}
149
150
151unsigned
152handle_table_add(struct handle_table *ht,
153                 void *object)
154{
155   unsigned index;
156   unsigned handle;
157
158   assert(ht);
159   assert(object);
160   if(!object || !ht)
161      return 0;
162
163   /* linear search for an empty handle */
164   while(ht->filled < ht->size) {
165      if(!ht->objects[ht->filled])
166	 break;
167      ++ht->filled;
168   }
169
170   index = ht->filled;
171   handle = index + 1;
172
173   /* check integer overflow */
174   if(!handle)
175      return 0;
176
177   /* grow the table if necessary */
178   if(!handle_table_resize(ht, index))
179      return 0;
180
181   assert(!ht->objects[index]);
182   ht->objects[index] = object;
183   ++ht->filled;
184
185   return handle;
186}
187
188
189unsigned
190handle_table_set(struct handle_table *ht,
191                 unsigned handle,
192                 void *object)
193{
194   unsigned index;
195
196   assert(ht);
197   assert(handle);
198   if(!handle || !ht)
199      return 0;
200
201   assert(object);
202   if(!object)
203      return 0;
204
205   index = handle - 1;
206
207   /* grow the table if necessary */
208   if(!handle_table_resize(ht, index))
209      return 0;
210
211   handle_table_clear(ht, index);
212
213   ht->objects[index] = object;
214
215   return handle;
216}
217
218
219void *
220handle_table_get(struct handle_table *ht,
221                 unsigned handle)
222{
223   void *object;
224
225   assert(ht);
226   assert(handle);
227   if(!handle || !ht || handle > ht->size)
228      return NULL;
229
230   object = ht->objects[handle - 1];
231
232   return object;
233}
234
235
236void
237handle_table_remove(struct handle_table *ht,
238                    unsigned handle)
239{
240   void *object;
241   unsigned index;
242
243   assert(ht);
244   assert(handle);
245   if(!handle || !ht || handle > ht->size)
246      return;
247
248   index = handle - 1;
249   object = ht->objects[index];
250   if(!object)
251      return;
252
253   handle_table_clear(ht, index);
254
255   if(index < ht->filled)
256      ht->filled = index;
257}
258
259
260unsigned
261handle_table_get_next_handle(struct handle_table *ht,
262                             unsigned handle)
263{
264   unsigned index;
265
266   for(index = handle; index < ht->size; ++index) {
267      if(ht->objects[index])
268	 return index + 1;
269   }
270
271   return 0;
272}
273
274
275unsigned
276handle_table_get_first_handle(struct handle_table *ht)
277{
278   return handle_table_get_next_handle(ht, 0);
279}
280
281
282void
283handle_table_destroy(struct handle_table *ht)
284{
285   unsigned index;
286   assert(ht);
287
288   if (!ht)
289      return;
290
291   if(ht->destroy)
292      for(index = 0; index < ht->size; ++index)
293         handle_table_clear(ht, index);
294
295   FREE(ht->objects);
296   FREE(ht);
297}
298
299