summaryrefslogtreecommitdiff
path: root/legacy/evas/src/lib/data/evas_hash.c
blob: 234a93c49336ce3c1daca68200d8b5bf26885f9f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
#include "evas_common.h"
#include "evas_private.h"

static inline int _evas_hash_gen(const char *key);

static int _evas_hash_alloc_error = 0;

static inline int
_evas_hash_gen(const char *key)
{
   unsigned int hash_num = 5381;
   const unsigned char *ptr;
   
   if (!key) return 0;
   for (ptr = (unsigned char *)key; *ptr; ptr++)
     hash_num = (hash_num * 33) ^ *ptr;
   
   hash_num &= 0xff;
   return (int)hash_num;
}

/**
 * @defgroup Evas_Hash_Data Hash Data Functions
 *
 * Functions that add, access or remove data from hashes.
 *
 * The following example shows how to add and then access data in a
 * hash table:
 * @code
 * Evas_Hash *hash = NULL;
 * extern void *my_data;
 *
 * hash = evas_hash_add(hash, "My Data", my_data);
 * if (evas_hash_alloc_error())
 *   {
 *     fprintf(stderr, "ERROR: Memory is low. Hash allocation failed.\n");
 *     exit(-1);
 *   }
 * if (evas_hash_find(hash, "My Data") == my_data)
 *   {
 *     printf("My Data inserted and successfully found.\n");
 *   }
 * @endcode
 *
 * What follows is another example, showing how the @ref evas_hash_del
 * function is used:
 * @code
 * extern Evas_Hash *hash;
 * extern void *data;
 *
 * printf("Insert some data...\n");
 * hash = evas_hash_add(hash, "My Data", my_data);
 * printf("Removing by key...\n");
 * hash = evas_hash_del(hash, "My Data", NULL);
 * printf("Insert some more data as a NULL key...\n");
 * hash = evas_hash_add(hash, NULL, my_data);
 * printf("Removing by data as a NULL key...\n");
 * hash = evas_hash_del(hash, NULL, my_data);
 * @endcode
 */

/**
 * Adds an entry to the given hash table.
 *
 * @p key is expected to be a unique string within the hash table.
 * Otherwise, you cannot be sure which inserted data pointer will be
 * accessed with @ref evas_hash_find , and removed with
 * @ref evas_hash_del .
 *
 * Key strings are case sensitive.
 *
 * @ref evas_hash_alloc_error should be used to determine if an
 * allocation error occurred during this function.
 *
 * @param   hash The given hash table.  Can be @c NULL, in which case a
 *               new hash table is allocated and returned.
 * @param   key  A unique string.  Can be @c NULL.
 * @param   data Data to associate with the string given by @p key.
 * @return  Either the given hash table, or if the given value for @p
 *          hash is @c NULL, then a new one.  @c NULL will be returned
 *          if memory could not be allocated for a new table.
 * @ingroup Evas_Hash_Data
 */
Evas_Hash *
evas_hash_add(Evas_Hash *hash, const char *key, const void *data)
{
   int hash_num;
   Evas_Hash_El *el;

   if ((!key) || (!data)) return hash;
   _evas_hash_alloc_error = 0;
   if (!hash)
     {
	hash = calloc(1, sizeof(struct _Evas_Hash));
	if (!hash)
	  {
	     _evas_hash_alloc_error = 1;
	     return NULL;
	  }
     }
   if (!(el = malloc(sizeof(struct _Evas_Hash_El) + strlen(key) + 1)))
     {
        if (hash->population <= 0)
	  {
	     free(hash);
	     hash = NULL;
	  }
	_evas_hash_alloc_error = 1;
	return hash;
     };
   el->key = ((char *)el) + sizeof(struct _Evas_Hash_El);
   strcpy(el->key, key);
   el->data = (void *)data;
   hash_num = _evas_hash_gen(key);
   hash->buckets[hash_num] = evas_object_list_prepend(hash->buckets[hash_num], el);
   if (evas_list_alloc_error())
     {
	_evas_hash_alloc_error = 1;
	free(el);
	return hash;
     }
   hash->population++;
   return hash;
}

/**
 * Adds an entry to the given hash table and does not duplicate the string key.
 *
 * @p key is expected to be a unique string within the hash table.
 * Otherwise, you cannot be sure which inserted data pointer will be
 * accessed with @ref evas_hash_find , and removed with
 * @ref evas_hash_del . This call does nto make a copy of the key so it must
 * be a string constant or stored elsewhere (in the object being added) etc.
 *
 * Key strings are case sensitive.
 *
 * @ref evas_hash_alloc_error should be used to determine if an
 * allocation error occurred during this function.
 *
 * @param   hash The given hash table.  Can be @c NULL, in which case a
 *               new hash table is allocated and returned.
 * @param   key  A unique string.  Can be @c NULL.
 * @param   data Data to associate with the string given by @p key.
 * @return  Either the given hash table, or if the given value for @p
 *          hash is @c NULL, then a new one.  @c NULL will be returned
 *          if memory could not be allocated for a new table.
 * @ingroup Evas_Hash_Data
 */
Evas_Hash *
evas_hash_direct_add(Evas_Hash *hash, const char *key, const void *data)
{
   int hash_num;
   Evas_Hash_El *el;

   if ((!key) || (!data)) return hash;
   _evas_hash_alloc_error = 0;
   if (!hash)
     {
	hash = calloc(1, sizeof(struct _Evas_Hash));
	if (!hash)
	  {
	     _evas_hash_alloc_error = 1;
	     return NULL;
	  }
     }
   if (!(el = malloc(sizeof(struct _Evas_Hash_El))))
     {
        if (hash->population <= 0)
	  {
	     free(hash);
	     hash = NULL;
	  }
	_evas_hash_alloc_error = 1;
	return hash;
     };
   el->key = key;
   el->data = (void *)data;
   hash_num = _evas_hash_gen(key);
   hash->buckets[hash_num] = evas_object_list_prepend(hash->buckets[hash_num], el);
   if (evas_list_alloc_error())
     {
	_evas_hash_alloc_error = 1;
	free(el);
	return hash;
     }
   hash->population++;
   return hash;
}

/**
 * Removes the entry identified by @p key or @p data from the given
 * hash table.
 *
 * If @p key is @c NULL, then @p data is used to find a match to
 * remove.
 *
 * @param   hash The given hash table.
 * @param   key  The key string.  Can be @c NULL.
 * @param   data The data pointer to remove if @p key is @c NULL.
 *               Otherwise, not required and can be @c NULL.
 * @return  The modified hash table.  If there are no entries left, the
 *          hash table will be freed and @c NULL will be returned.
 * @ingroup Evas_Hash_Data
 */
Evas_Hash *
evas_hash_del(Evas_Hash *hash, const char *key, const void *data)
{
   int hash_num;
   Evas_Hash_El *el;
   Evas_Object_List *l;

   if (!hash) return NULL;
   hash_num = _evas_hash_gen(key);
   for (l = hash->buckets[hash_num]; l; l = l->next)
     {
	el = (Evas_Hash_El *)l;
	if (((key) && (!strcmp(el->key, key))) ||
	    ((!key) && (el->data == data)))
	  {
	     hash->buckets[hash_num] = evas_object_list_remove(hash->buckets[hash_num], el);
	     free(el);
	     hash->population--;
	     if (hash->population <= 0)
	       {
		  free(hash);
		  hash = NULL;
	       }
	     return hash;
	  }
     }
   return hash;
}

/**
 * Retrieves a specific entry in the given hash table.
 * @param   hash The given hash table.
 * @param   key  The key string of the entry to find.
 * @return  The data pointer for the stored entry, or @c NULL if not
 *          found.
 * @ingroup Evas_Hash_Data
 */
void *
evas_hash_find(Evas_Hash *hash, const char *key)
{
   int hash_num;
   Evas_Hash_El *el;
   Evas_Object_List *l;

   _evas_hash_alloc_error = 0;
   if ((!hash) || (!key)) return NULL;
   hash_num = _evas_hash_gen(key);
   for (l = hash->buckets[hash_num]; l; l = l->next)
     {
	el = (Evas_Hash_El *)l;
	if (!strcmp(el->key, key))
	  {
	     if (l != hash->buckets[hash_num])
	       {
		  hash->buckets[hash_num] = evas_object_list_remove(hash->buckets[hash_num], el);
		  hash->buckets[hash_num] = evas_object_list_prepend(hash->buckets[hash_num], el);
	       }
	     return el->data;
	  }
     }
   return NULL;
}

/**
 * Modifies the entry pointer at the specified key and returns the old entry
 * @param   hash The given hash table.
 * @param   key  The key string of the entry to modify.
 * @param   data The data to replace the old entry, if it exists.
 * @return  The data pointer for the old stored entry, or @c NULL if not
 *          found. If an existing entry is not found, nothing is added to the
 *          hash.
 * @ingroup Evas_Hash_Data
 */
void *
evas_hash_modify(Evas_Hash *hash, const char *key, const void *data)
{
   int hash_num;
   Evas_Hash_El *el;
   Evas_Object_List *l;

   _evas_hash_alloc_error = 0;
   if (!hash) return NULL;
   hash_num = _evas_hash_gen(key);
   for (l = hash->buckets[hash_num]; l; l = l->next)
     {
	el = (Evas_Hash_El *)l;
	if ((key) && (!strcmp(el->key, key)))
	  {
	     void *old_data;
	     
	     if (l != hash->buckets[hash_num])
	       {
		  hash->buckets[hash_num] = evas_object_list_remove(hash->buckets[hash_num], el);
		  hash->buckets[hash_num] = evas_object_list_prepend(hash->buckets[hash_num], el);
	       }
	     old_data = el->data;
	     el->data = (void *) data;
	     return old_data;
	  }
     }
   return NULL;
}

/**
 * @defgroup Evas_Hash_General_Group Hash General Functions
 *
 * Miscellaneous functions that operate on hash objects.
 */

/**
 * Retrieves the number of buckets available in the given hash table.
 * @param hash The given hash table.
 * @return @c 256 if @p hash is not @c NULL.  @c 0 otherwise.
 * @ingroup Evas_Hash_General_Group
 */
int
evas_hash_size(Evas_Hash *hash)
{
   if (!hash) return 0;
   return 256;
}

/**
 * @todo Complete polishing documentation for evas_hash.c. The
 * functions' docs may be grouped, but they need some simplification.
 */

/**
 * Free an entire hash table
 * @param hash The hash table to be freed
 *
 * This function frees up all the memory allocated to storing the specified
 * hash tale pointed to by @p hash. Any entries in the table that the program
 * has no more pointers for elsewhere may now be lost, so this should only be
 * called if the program has lready freed any allocated data in the hash table
 * or has the pointers for data in teh table stored elswehere as well.
 *
 * Example:
 * @code
 * extern Evas_Hash *hash;
 *
 * evas_hash_free(hash);
 * hash = NULL;
 * @endcode
 * @ingroup Evas_Hash_General_Group
 */
void
evas_hash_free(Evas_Hash *hash)
{
   int i, size;

   if (!hash) return;
   size = evas_hash_size(hash);
   for (i = 0; i < size; i++)
     {
	while (hash->buckets[i])
	  {
	     Evas_Hash_El *el;

	     el = (Evas_Hash_El *)hash->buckets[i];
	     hash->buckets[i] = evas_object_list_remove(hash->buckets[i], el);
	     free(el);
	  }
     }
   free(hash);
}

/**
 * Call a function on every member stored in the hash table
 * @param hash The hash table whose members will be walked
 * @param func The function to call on each parameter
 * @param fdata The data pointer to pass to the function being called
 *
 * This function goes through every entry in the hash table @p hash and calls
 * the function @p func on each member. The function should NOT modify the
 * hash table contents if it reeturns 1. IF the hash table contents are
 * modified by this function or the function wishes to stop processing it must
 * return 0, otherwise return 1 to keep processing.
 *
 * Example:
 * @code
 * extern Evas_Hash *hash;
 *
 * Evas_Bool hash_fn(Evas_Hash *hash, const char *key, void *data, void *fdata)
 * {
 *   printf("Func data: %s, Hash entry: %s / %p\n", fdata, key, data);
 *   return 1;
 * }
 *
 * int main(int argc, char **argv)
 * {
 *   char *hash_fn_data;
 *
 *   hash_fn_data = strdup("Hello World");
 *   evas_hash_foreach(hash, hash_fn, hash_fn_data);
 *   free(hash_fn_data);
 * }
 * @endcode
 * @ingroup Evas_Hash_General_Group
 */
void
evas_hash_foreach(Evas_Hash *hash, Evas_Bool (*func) (Evas_Hash *hash, const char *key, void *data, void *fdata), const void *fdata)
{
   int i, size;

   if (!hash) return;
   size = evas_hash_size(hash);
   for (i = 0; i < size; i++)
     {
	Evas_Object_List *l, *next_l;

	for (l = hash->buckets[i]; l;)
	  {
	     Evas_Hash_El *el;

	     next_l = l->next;
	     el = (Evas_Hash_El *)l;
	     if (!func(hash, el->key, el->data, (void *)fdata)) return;
	     l = next_l;
	  }
     }
}

/**
 * Return memory allocation failure flag after an function requiring allocation
 * @return The state of the allocation flag
 *
 * This function returns the state of the memory allocation flag. This flag is
 * set if memory allocations fail during evas_hash_add() calls. If they do, 1
 * will be returned, otherwise 0 will be returned. The flag will remain in its
 * current state until the next call that requires allocation is called, and
 * is then reset.
 *
 * Example:
 * @code
 * Evas_Hash *hash = NULL;
 * extern void *my_data;
 *
 * hash = evas_hash_add(hash, "My Data", my_data);
 * if (evas_hash_alloc_error())
 *   {
 *     fprintf(stderr, "ERROR: Memory is low. Hash allocation failed.\n");
 *     exit(-1);
 *   }
 * if (evas_hash_find(hash, "My Data") == my_data)
 *   {
 *     printf("My Data inserted and successfully found.\n");
 *   }
 * @endcode
 * @ingroup Evas_Hash_General_Group
 */
int
evas_hash_alloc_error(void)
{
   return _evas_hash_alloc_error;
}