include/vlc_arrays.h

   1 /*****************************************************************************
   2  * vlc_arrays.h : Arrays and data structures handling
   3  *****************************************************************************
   4  * Copyright (C) 1999-2004 VLC authors and VideoLAN
   5  * $Id$
   6  *
   7  * Authors: Samuel Hocevar <sam@zoy.org>
   8  *          Clément Stenac <zorglub@videolan.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifndef VLC_ARRAYS_H_
  26 #define VLC_ARRAYS_H_
  27
  28 /**
  29  * \file
  30  * This file defines functions, structures and macros for handling arrays in vlc
  31  */
  32
  33 /* realloc() that never fails *if* downsizing */
  34 static inline void *realloc_down( void *ptr, size_t size )
  35 {
  36     void *ret = realloc( ptr, size );
  37     return ret ? ret : ptr;
  38 }
  39
  40 /**
  41  * This wrapper around realloc() will free the input pointer when
  42  * realloc() returns NULL. The use case ptr = realloc(ptr, newsize) will
  43  * cause a memory leak when ptr pointed to a heap allocation before,
  44  * leaving the buffer allocated but unreferenced. vlc_realloc() is a
  45  * drop-in replacement for that use case (and only that use case).
  46  */
  47 static inline void *realloc_or_free( void *p, size_t sz )
  48 {
  49     void *n = realloc(p,sz);
  50     if( !n )
  51         free(p);
  52     return n;
  53 }
  54
  55 #define TAB_INIT( count, tab )                  \
  56   do {                                          \
  57     (count) = 0;                                \
  58     (tab) = NULL;                               \
  59   } while(0)
  60
  61 #define TAB_CLEAN( count, tab )                 \
  62   do {                                          \
  63     free( tab );                                \
  64     (count)= 0;                                 \
  65     (tab)= NULL;                                \
  66   } while(0)
  67
  68 #define TAB_APPEND_CAST( cast, count, tab, p )             \
  69   do {                                          \
  70     if( (count) > 0 )                           \
  71         (tab) = cast realloc( tab, sizeof( *(tab) ) * ( (count) + 1 ) ); \
  72     else                                        \
  73         (tab) = cast malloc( sizeof( *(tab) ) );    \
  74     if( !(tab) ) abort();                       \
  75     (tab)[count] = (p);                         \
  76     (count)++;                                  \
  77   } while(0)
  78
  79 #define TAB_APPEND( count, tab, p )             \
  80     TAB_APPEND_CAST( , count, tab, p )
  81
  82 #define TAB_FIND( count, tab, p, idx )          \
  83   do {                                          \
  84     for( (idx) = 0; (idx) < (count); (idx)++ )  \
  85         if( (tab)[(idx)] == (p) )               \
  86             break;                              \
  87     if( (idx) >= (count) )                      \
  88         (idx) = -1;                             \
  89   } while(0)
  90
  91
  92 #define TAB_ERASE( count, tab, index )      \
  93   do {                                      \
  94         if( (count) > 1 )                   \
  95             memmove( (tab) + (index),       \
  96                      (tab) + (index) + 1,   \
  97                      ((count) - (index) - 1 ) * sizeof( *(tab) ) );\
  98         (count)--;                          \
  99         if( (count) == 0 )                  \
 100         {                                   \
 101             free( tab );                    \
 102             (tab) = NULL;                   \
 103         }                                   \
 104   } while(0)
 105
 106 #define TAB_REMOVE( count, tab, p )             \
 107   do {                                          \
 108         int i_index;                            \
 109         TAB_FIND( count, tab, p, i_index );     \
 110         if( i_index >= 0 )                      \
 111             TAB_ERASE( count, tab, i_index );   \
 112   } while(0)
 113
 114 #define TAB_INSERT_CAST( cast, count, tab, p, index ) do { \
 115     if( (count) > 0 )                           \
 116         (tab) = cast realloc( tab, sizeof( *(tab) ) * ( (count) + 1 ) ); \
 117     else                                        \
 118         (tab) = cast malloc( sizeof( *(tab) ) );       \
 119     if( !(tab) ) abort();                       \
 120     if( (count) - (index) > 0 )                 \
 121         memmove( (tab) + (index) + 1,           \
 122                  (tab) + (index),               \
 123                  ((count) - (index)) * sizeof( *(tab) ) );\
 124     (tab)[(index)] = (p);                       \
 125     (count)++;                                  \
 126 } while(0)
 127
 128 #define TAB_INSERT( count, tab, p, index )      \
 129     TAB_INSERT_CAST( , count, tab, p, index )
 130
 131 /**
 132  * Binary search in a sorted array. The key must be comparable by < and >
 133  * \param entries array of entries
 134  * \param count number of entries
 135  * \param elem key to check within an entry (like .id, or ->i_id)
 136  * \param zetype type of the key
 137  * \param key value of the key
 138  * \param answer index of answer within the array. -1 if not found
 139  */
 140 #define BSEARCH( entries, count, elem, zetype, key, answer ) \
 141    do {  \
 142     int low = 0, high = count - 1;   \
 143     answer = -1; \
 144     while( low <= high ) {\
 145         int mid = ((unsigned int)low + (unsigned int)high) >> 1;\
 146         zetype mid_val = entries[mid] elem;\
 147         if( mid_val < key ) \
 148             low = mid + 1; \
 149         else if ( mid_val > key ) \
 150             high = mid -1;  \
 151         else    \
 152         {   \
 153             answer = mid;  break;   \
 154         }\
 155     } \
 156  } while(0)
 157
 158
 159 /************************************************************************
 160  * Dynamic arrays with progressive allocation
 161  ************************************************************************/
 162
 163 /* Internal functions */
 164 #define _ARRAY_ALLOC(array, newsize) {                                      \
 165     (array).i_alloc = newsize;                                              \
 166     (array).p_elems = realloc( (array).p_elems, (array).i_alloc *           \
 167                                sizeof(*(array).p_elems) );                  \
 168     if( !(array).p_elems ) abort();                                         \
 169 }
 170
 171 #define _ARRAY_GROW1(array) {                                               \
 172     if( (array).i_alloc < 10 )                                              \
 173         _ARRAY_ALLOC(array, 10 )                                            \
 174     else if( (array).i_alloc == (array).i_size )                            \
 175         _ARRAY_ALLOC(array, (int)((array).i_alloc * 1.5) )                    \
 176 }
 177
 178 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 179
 180 /* API */
 181 #define DECL_ARRAY(type) struct {                                           \
 182     int i_alloc;                                                            \
 183     int i_size;                                                             \
 184     type *p_elems;                                                          \
 185 }
 186
 187 #define TYPEDEF_ARRAY(type, name) typedef DECL_ARRAY(type) name;
 188
 189 #define ARRAY_INIT(array)                                                   \
 190   do {                                                                      \
 191     (array).i_alloc = 0;                                                    \
 192     (array).i_size = 0;                                                     \
 193     (array).p_elems = NULL;                                                 \
 194   } while(0)
 195
 196 #define ARRAY_RESET(array)                                                  \
 197   do {                                                                      \
 198     (array).i_alloc = 0;                                                    \
 199     (array).i_size = 0;                                                     \
 200     free( (array).p_elems ); (array).p_elems = NULL;                        \
 201   } while(0)
 202
 203 #define ARRAY_APPEND(array, elem)                                           \
 204   do {                                                                      \
 205     _ARRAY_GROW1(array);                                                    \
 206     (array).p_elems[(array).i_size] = elem;                                 \
 207     (array).i_size++;                                                       \
 208   } while(0)
 209
 210 #define ARRAY_INSERT(array,elem,pos)                                        \
 211   do {                                                                      \
 212     _ARRAY_GROW1(array);                                                    \
 213     if( (array).i_size - pos ) {                                            \
 214         memmove( (array).p_elems + pos + 1, (array).p_elems + pos,          \
 215                  ((array).i_size-pos) * sizeof(*(array).p_elems) );         \
 216     }                                                                       \
 217     (array).p_elems[pos] = elem;                                            \
 218     (array).i_size++;                                                       \
 219   } while(0)
 220
 221 #define _ARRAY_SHRINK(array) {                                              \
 222     if( (array).i_size > 10 && (array).i_size < (int)((array).i_alloc / 1.5) ) {  \
 223         _ARRAY_ALLOC(array, (array).i_size + 5);                            \
 224     }                                                                       \
 225 }
 226
 227 #define ARRAY_REMOVE(array,pos)                                             \
 228   do {                                                                      \
 229     if( (array).i_size - (pos) - 1 )                                        \
 230     {                                                                       \
 231         memmove( (array).p_elems + pos, (array).p_elems + pos + 1,          \
 232                  ( (array).i_size - pos - 1 ) *sizeof(*(array).p_elems) );  \
 233     }                                                                       \
 234     (array).i_size--;                                                       \
 235     _ARRAY_SHRINK(array);                                                   \
 236   } while(0)
 237
 238 #define ARRAY_VAL(array, pos) array.p_elems[pos]
 239
 240 #define ARRAY_BSEARCH(array, elem, zetype, key, answer) \
 241     BSEARCH( (array).p_elems, (array).i_size, elem, zetype, key, answer)
 242
 243 #define FOREACH_ARRAY( item, array ) { \
 244     int fe_idx; \
 245     for( fe_idx = 0 ; fe_idx < (array).i_size ; fe_idx++ ) \
 246     { \
 247         item = (array).p_elems[fe_idx];
 248
 249 #define FOREACH_END() } }
 250
 251
 252 /************************************************************************
 253  * Dynamic arrays with progressive allocation (Preferred API)
 254  ************************************************************************/
 255 typedef struct vlc_array_t
 256 {
 257     size_t i_count;
 258     void ** pp_elems;
 259 } vlc_array_t;
 260
 261 static inline void vlc_array_init( vlc_array_t * p_array )
 262 {
 263     p_array->i_count = 0;
 264     p_array->pp_elems = NULL;
 265 }
 266
 267 static inline void vlc_array_clear( vlc_array_t * p_array )
 268 {
 269     free( p_array->pp_elems );
 270     vlc_array_init( p_array );
 271 }
 272
 273 /* Read */
 274 static inline size_t vlc_array_count( vlc_array_t * p_array )
 275 {
 276     return p_array->i_count;
 277 }
 278
 279 #ifndef __cplusplus
 280 # define vlc_array_item_at_index(ar, idx) \
 281     _Generic((ar), \
 282         const vlc_array_t *: ((ar)->pp_elems[idx]), \
 283         vlc_array_t *: ((ar)->pp_elems[idx]))
 284 #else
 285 static inline void *vlc_array_item_at_index( vlc_array_t *ar, size_t idx )
 286 {
 287     return ar->pp_elems[idx];
 288 }
 289
 290 static inline const void *vlc_array_item_at_index( const vlc_array_t *ar,
 291                                                    size_t idx )
 292 {
 293     return ar->pp_elems[idx];
 294 }
 295 #endif
 296
 297 static inline ssize_t vlc_array_index_of_item( const vlc_array_t *ar,
 298                                                const void *elem )
 299 {
 300     for( size_t i = 0; i < ar->i_count; i++ )
 301     {
 302         if( ar->pp_elems[i] == elem )
 303             return i;
 304     }
 305     return -1;
 306 }
 307
 308 /* Write */
 309 static inline int vlc_array_insert( vlc_array_t *ar, void *elem, int idx )
 310 {
 311     void **pp = (void **)realloc( ar->pp_elems,
 312                                   sizeof( void * ) * (ar->i_count + 1) );
 313     if( unlikely(pp == NULL) )
 314         return -1;
 315
 316     size_t tail = ar->i_count - idx;
 317     if( tail > 0 )
 318         memmove( pp + idx + 1, pp + idx, sizeof( void * ) * tail );
 319
 320     pp[idx] = elem;
 321     ar->i_count++;
 322     ar->pp_elems = pp;
 323     return 0;
 324 }
 325
 326 static inline void vlc_array_insert_or_abort( vlc_array_t *ar, void *elem, int idx )
 327 {
 328     if( vlc_array_insert( ar, elem, idx ) )
 329         abort();
 330 }
 331
 332 static inline int vlc_array_append( vlc_array_t *ar, void *elem )
 333 {
 334     void **pp = (void **)realloc( ar->pp_elems,
 335                                   sizeof( void * ) * (ar->i_count + 1) );
 336     if( unlikely(pp == NULL) )
 337         return -1;
 338
 339     pp[ar->i_count++] = elem;
 340     ar->pp_elems = pp;
 341     return 0;
 342 }
 343
 344 static inline void vlc_array_append_or_abort( vlc_array_t *ar, void *elem )
 345 {
 346     if( vlc_array_append( ar, elem ) != 0 )
 347         abort();
 348 }
 349
 350 static inline void vlc_array_remove( vlc_array_t *ar, size_t idx )
 351 {
 352     void **pp = ar->pp_elems;
 353     size_t tail = ar->i_count - idx - 1;
 354
 355     if( tail > 0 )
 356         memmove( pp + idx, pp + idx + 1, sizeof( void * ) * tail );
 357
 358     ar->i_count--;
 359
 360     if( ar->i_count > 0 )
 361     {
 362         pp = (void **)realloc( pp, sizeof( void * ) * ar->i_count );
 363         if( likely(pp != NULL) )
 364             ar->pp_elems = pp;
 365     }
 366     else
 367     {
 368         free( pp );
 369         ar->pp_elems = NULL;
 370     }
 371 }
 372
 373
 374 /************************************************************************
 375  * Dictionaries
 376  ************************************************************************/
 377
 378 /* This function is not intended to be crypto-secure, we only want it to be
 379  * fast and not suck too much. This one is pretty fast and did 0 collisions
 380  * in wenglish's dictionary.
 381  */
 382 static inline uint64_t DictHash( const char *psz_string, int hashsize )
 383 {
 384     uint64_t i_hash = 0;
 385     if( psz_string )
 386     {
 387         while( *psz_string )
 388         {
 389             i_hash += *psz_string++;
 390             i_hash += i_hash << 10;
 391             i_hash ^= i_hash >> 8;
 392         }
 393     }
 394     return i_hash % hashsize;
 395 }
 396
 397 typedef struct vlc_dictionary_entry_t
 398 {
 399     char *   psz_key;
 400     void *   p_value;
 401     struct vlc_dictionary_entry_t * p_next;
 402 } vlc_dictionary_entry_t;
 403
 404 typedef struct vlc_dictionary_t
 405 {
 406     int i_size;
 407     vlc_dictionary_entry_t ** p_entries;
 408 } vlc_dictionary_t;
 409
 410 static void * const kVLCDictionaryNotFound = NULL;
 411
 412 static inline void vlc_dictionary_init( vlc_dictionary_t * p_dict, int i_size )
 413 {
 414     p_dict->p_entries = NULL;
 415
 416     if( i_size > 0 )
 417     {
 418         p_dict->p_entries = (vlc_dictionary_entry_t **)calloc( i_size, sizeof(*p_dict->p_entries) );
 419         if( !p_dict->p_entries )
 420             i_size = 0;
 421     }
 422     p_dict->i_size = i_size;
 423 }
 424
 425 static inline void vlc_dictionary_clear( vlc_dictionary_t * p_dict,
 426                                          void ( * pf_free )( void * p_data, void * p_obj ),
 427                                          void * p_obj )
 428 {
 429     if( p_dict->p_entries )
 430     {
 431         for( int i = 0; i < p_dict->i_size; i++ )
 432         {
 433             vlc_dictionary_entry_t * p_current, * p_next;
 434             p_current = p_dict->p_entries[i];
 435             while( p_current )
 436             {
 437                 p_next = p_current->p_next;
 438                 if( pf_free != NULL )
 439                     ( * pf_free )( p_current->p_value, p_obj );
 440                 free( p_current->psz_key );
 441                 free( p_current );
 442                 p_current = p_next;
 443             }
 444         }
 445         free( p_dict->p_entries );
 446         p_dict->p_entries = NULL;
 447     }
 448     p_dict->i_size = 0;
 449 }
 450
 451 static inline int
 452 vlc_dictionary_has_key( const vlc_dictionary_t * p_dict, const char * psz_key )
 453 {
 454     if( !p_dict->p_entries )
 455         return 0;
 456
 457     int i_pos = DictHash( psz_key, p_dict->i_size );
 458     const vlc_dictionary_entry_t * p_entry = p_dict->p_entries[i_pos];
 459     for( ; p_entry != NULL; p_entry = p_entry->p_next )
 460     {
 461         if( !strcmp( psz_key, p_entry->psz_key ) )
 462             break;
 463     }
 464     return p_entry != NULL;
 465 }
 466
 467 static inline void *
 468 vlc_dictionary_value_for_key( const vlc_dictionary_t * p_dict, const char * psz_key )
 469 {
 470     if( !p_dict->p_entries )
 471         return kVLCDictionaryNotFound;
 472
 473     int i_pos = DictHash( psz_key, p_dict->i_size );
 474     vlc_dictionary_entry_t * p_entry = p_dict->p_entries[i_pos];
 475
 476     if( !p_entry )
 477         return kVLCDictionaryNotFound;
 478
 479     /* Make sure we return the right item. (Hash collision) */
 480     do {
 481         if( !strcmp( psz_key, p_entry->psz_key ) )
 482             return p_entry->p_value;
 483         p_entry = p_entry->p_next;
 484     } while( p_entry );
 485
 486     return kVLCDictionaryNotFound;
 487 }
 488
 489 static inline int
 490 vlc_dictionary_keys_count( const vlc_dictionary_t * p_dict )
 491 {
 492     vlc_dictionary_entry_t * p_entry;
 493     int i, count = 0;
 494
 495     if( !p_dict->p_entries )
 496         return 0;
 497
 498     for( i = 0; i < p_dict->i_size; i++ )
 499     {
 500         for( p_entry = p_dict->p_entries[i]; p_entry; p_entry = p_entry->p_next ) count++;
 501     }
 502     return count;
 503 }
 504
 505 static inline bool
 506 vlc_dictionary_is_empty( const vlc_dictionary_t * p_dict )
 507 {
 508     if( p_dict->p_entries )
 509         for( int i = 0; i < p_dict->i_size; i++ )
 510             if( p_dict->p_entries[i] )
 511                 return false;
 512     return true;
 513 }
 514
 515 static inline char **
 516 vlc_dictionary_all_keys( const vlc_dictionary_t * p_dict )
 517 {
 518     vlc_dictionary_entry_t * p_entry;
 519     char ** ppsz_ret;
 520     int i, count = vlc_dictionary_keys_count( p_dict );
 521
 522     ppsz_ret = (char**)malloc(sizeof(char *) * (count + 1));
 523     if( unlikely(!ppsz_ret) )
 524         return NULL;
 525
 526     count = 0;
 527     for( i = 0; i < p_dict->i_size; i++ )
 528     {
 529         for( p_entry = p_dict->p_entries[i]; p_entry; p_entry = p_entry->p_next )
 530             ppsz_ret[count++] = strdup( p_entry->psz_key );
 531     }
 532     ppsz_ret[count] = NULL;
 533     return ppsz_ret;
 534 }
 535
 536 static inline void
 537 vlc_dictionary_insert_impl_( vlc_dictionary_t * p_dict, const char * psz_key,
 538                              void * p_value, bool rebuild )
 539 {
 540     if( !p_dict->p_entries )
 541         vlc_dictionary_init( p_dict, 1 );
 542
 543     int i_pos = DictHash( psz_key, p_dict->i_size );
 544     vlc_dictionary_entry_t * p_entry;
 545
 546     p_entry = (vlc_dictionary_entry_t *)malloc(sizeof(*p_entry));
 547     p_entry->psz_key = strdup( psz_key );
 548     p_entry->p_value = p_value;
 549     p_entry->p_next = p_dict->p_entries[i_pos];
 550     p_dict->p_entries[i_pos] = p_entry;
 551     if( rebuild )
 552     {
 553         /* Count how many items there was */
 554         int count;
 555         for( count = 1; p_entry->p_next; count++ )
 556             p_entry = p_entry->p_next;
 557         if( count > 3 ) /* XXX: this need tuning */
 558         {
 559             /* Here it starts to be not good, rebuild a bigger dictionary */
 560             struct vlc_dictionary_t new_dict;
 561             int i_new_size = ( (p_dict->i_size+2) * 3) / 2; /* XXX: this need tuning */
 562             int i;
 563             vlc_dictionary_init( &new_dict, i_new_size );
 564             for( i = 0; i < p_dict->i_size; i++ )
 565             {
 566                 p_entry = p_dict->p_entries[i];
 567                 while( p_entry )
 568                 {
 569                     vlc_dictionary_insert_impl_( &new_dict, p_entry->psz_key,
 570                                              p_entry->p_value,
 571                                              false /* To avoid multiple rebuild loop */);
 572                     p_entry = p_entry->p_next;
 573                 }
 574             }
 575
 576             vlc_dictionary_clear( p_dict, NULL, NULL );
 577             p_dict->i_size = new_dict.i_size;
 578             p_dict->p_entries = new_dict.p_entries;
 579         }
 580     }
 581 }
 582
 583 static inline void
 584 vlc_dictionary_insert( vlc_dictionary_t * p_dict, const char * psz_key, void * p_value )
 585 {
 586     vlc_dictionary_insert_impl_( p_dict, psz_key, p_value, true );
 587 }
 588
 589 static inline void
 590 vlc_dictionary_remove_value_for_key( const vlc_dictionary_t * p_dict, const char * psz_key,
 591                                      void ( * pf_free )( void * p_data, void * p_obj ),
 592                                      void * p_obj )
 593 {
 594     if( !p_dict->p_entries )
 595         return;
 596
 597     int i_pos = DictHash( psz_key, p_dict->i_size );
 598     vlc_dictionary_entry_t * p_entry = p_dict->p_entries[i_pos];
 599     vlc_dictionary_entry_t * p_prev;
 600
 601     if( !p_entry )
 602         return; /* Not found, nothing to do */
 603
 604     /* Hash collision */
 605     p_prev = NULL;
 606     do {
 607         if( !strcmp( psz_key, p_entry->psz_key ) )
 608         {
 609             if( pf_free != NULL )
 610                 ( * pf_free )( p_entry->p_value, p_obj );
 611             if( !p_prev )
 612                 p_dict->p_entries[i_pos] = p_entry->p_next;
 613             else
 614                 p_prev->p_next = p_entry->p_next;
 615             free( p_entry->psz_key );
 616             free( p_entry );
 617             return;
 618         }
 619         p_prev = p_entry;
 620         p_entry = p_entry->p_next;
 621     } while( p_entry );
 622
 623     /* No key was found */
 624 }
 625
 626 #ifdef __cplusplus
 627 // C++ helpers
 628 template <typename T>
 629 void vlc_delete_all( T &container )
 630 {
 631     typename T::iterator it = container.begin();
 632     while ( it != container.end() )
 633     {
 634         delete *it;
 635         ++it;
 636     }
 637     container.clear();
 638 }
 639
 640 #endif
 641
 642 #endif