git.sesse.net Git - vlc/blob - include/vlc_arrays.h

   1 /*****************************************************************************
   2  * vlc_arrays.h : Arrays and data structures handling
   3  *****************************************************************************
   4  * Copyright (C) 1999-2004 the VideoLAN team
   5  * $Id: vlc_playlist.h 17108 2006-10-15 15:28:34Z zorglub $
   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
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 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 General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/
  23
  24 #if !defined( __LIBVLC__ )
  25   #error You are not libvlc or one of its plugins. You cannot include this file
  26 #endif
  27
  28 #ifndef _VLC_ARRAYS_H_
  29 #define _VLC_ARRAYS_H_
  30
  31 #include <assert.h>
  32
  33 /**
  34  * Simple dynamic array handling. Array is realloced at each insert/removal
  35  */
  36 #if defined( _MSC_VER ) && _MSC_VER < 1300 && !defined( UNDER_CE )
  37 #   define VLCCVP (void**) /* Work-around for broken compiler */
  38 #else
  39 #   define VLCCVP
  40 #endif
  41 #define INSERT_ELEM( p_ar, i_oldsize, i_pos, elem )                           \
  42     do                                                                        \
  43     {                                                                         \
  44         if( !i_oldsize ) (p_ar) = NULL;                                       \
  45         (p_ar) = VLCCVP realloc( p_ar, ((i_oldsize) + 1) * sizeof(*(p_ar)) ); \
  46         if( (i_oldsize) - (i_pos) )                                           \
  47         {                                                                     \
  48             memmove( (p_ar) + (i_pos) + 1, (p_ar) + (i_pos),                  \
  49                      ((i_oldsize) - (i_pos)) * sizeof( *(p_ar) ) );           \
  50         }                                                                     \
  51         (p_ar)[i_pos] = elem;                                                 \
  52         (i_oldsize)++;                                                        \
  53     }                                                                         \
  54     while( 0 )
  55
  56 #define REMOVE_ELEM( p_ar, i_oldsize, i_pos )                                 \
  57     do                                                                        \
  58     {                                                                         \
  59         if( (i_oldsize) - (i_pos) - 1 )                                       \
  60         {                                                                     \
  61             memmove( (p_ar) + (i_pos),                                        \
  62                      (p_ar) + (i_pos) + 1,                                    \
  63                      ((i_oldsize) - (i_pos) - 1) * sizeof( *(p_ar) ) );       \
  64         }                                                                     \
  65         if( i_oldsize > 1 )                                                   \
  66         {                                                                     \
  67             (p_ar) = realloc( p_ar, ((i_oldsize) - 1) * sizeof( *(p_ar) ) );  \
  68         }                                                                     \
  69         else                                                                  \
  70         {                                                                     \
  71             free( p_ar );                                                     \
  72             (p_ar) = NULL;                                                    \
  73         }                                                                     \
  74         (i_oldsize)--;                                                        \
  75     }                                                                         \
  76     while( 0 )
  77
  78 #define TAB_INIT( count, tab )                  \
  79   do {                                          \
  80     (count) = 0;                                \
  81     (tab) = NULL;                               \
  82   } while(0)
  83
  84 #define TAB_CLEAN( count, tab )                 \
  85   do {                                          \
  86     if( tab ) free( tab );                      \
  87     (count)= 0;                                 \
  88     (tab)= NULL;                                \
  89   } while(0)
  90
  91 #define TAB_APPEND_CAST( cast, count, tab, p )             \
  92   do {                                          \
  93     if( (count) > 0 )                           \
  94         (tab) = cast realloc( tab, sizeof( void ** ) * ( (count) + 1 ) ); \
  95     else                                        \
  96         (tab) = cast malloc( sizeof( void ** ) );    \
  97     (tab)[count] = (p);                         \
  98     (count)++;                                  \
  99   } while(0)
 100
 101 #define TAB_APPEND( count, tab, p )             \
 102     TAB_APPEND_CAST( , count, tab, p )
 103 #define TAB_APPEND_CPP( type, count, tab, p )   \
 104     TAB_APPEND_CAST( (type**), count, tab, p )
 105
 106 #define TAB_FIND( count, tab, p, index )        \
 107   do {                                          \
 108         int _i_;                                \
 109         (index) = -1;                           \
 110         for( _i_ = 0; _i_ < (count); _i_++ )    \
 111         {                                       \
 112             if( (tab)[_i_] == (p) )             \
 113             {                                   \
 114                 (index) = _i_;                  \
 115                 break;                          \
 116             }                                   \
 117         }                                       \
 118   } while(0)
 119
 120 #define TAB_REMOVE( count, tab, p )             \
 121   do {                                          \
 122         int _i_index_;                          \
 123         TAB_FIND( count, tab, p, _i_index_ );   \
 124         if( _i_index_ >= 0 )                    \
 125         {                                       \
 126             if( (count) > 1 )                   \
 127             {                                   \
 128                 memmove( ((void**)(tab) + _i_index_),    \
 129                          ((void**)(tab) + _i_index_+1),  \
 130                          ( (count) - _i_index_ - 1 ) * sizeof( void* ) );\
 131             }                                   \
 132             (count)--;                          \
 133             if( (count) == 0 )                  \
 134             {                                   \
 135                 free( tab );                    \
 136                 (tab) = NULL;                   \
 137             }                                   \
 138         }                                       \
 139   } while(0)
 140
 141 #define TAB_INSERT_CAST( cast, count, tab, p, index ) do { \
 142     if( (count) > 0 )                           \
 143         (tab) = cast realloc( tab, sizeof( void ** ) * ( (count) + 1 ) ); \
 144     else                                        \
 145         (tab) = cast malloc( sizeof( void ** ) );       \
 146     if( (count) - (index) > 0 )                 \
 147         memmove( (void**)(tab) + (index) + 1,   \
 148                  (void**)(tab) + (index),       \
 149                  ((count) - (index)) * sizeof(*(tab)) );\
 150     (tab)[(index)] = (p);                       \
 151     (count)++;                                  \
 152 } while(0)
 153
 154 #define TAB_INSERT( count, tab, p, index )      \
 155     TAB_INSERT_CAST( , count, tab, p, index )
 156
 157 /**
 158  * Binary search in a sorted array. The key must be comparable by < and >
 159  * \param entries array of entries
 160  * \param count number of entries
 161  * \param elem key to check within an entry (like .id, or ->i_id)
 162  * \param zetype type of the key
 163  * \param key value of the key
 164  * \param answer index of answer within the array. -1 if not found
 165  */
 166 #define BSEARCH( entries, count, elem, zetype, key, answer ) \
 167    do {  \
 168     int low = 0, high = count - 1;   \
 169     answer = -1; \
 170     while( low <= high ) {\
 171         int mid = (low + high ) / 2; /* Just don't care about 2^30 tables */ \
 172         zetype mid_val = entries[mid] elem;\
 173         if( mid_val < key ) \
 174             low = mid + 1; \
 175         else if ( mid_val > key ) \
 176             high = mid -1;  \
 177         else    \
 178         {   \
 179             answer = mid;  break;   \
 180         }\
 181     } \
 182  } while(0)
 183
 184 /************************************************************************
 185  * Dictionaries
 186  ************************************************************************/
 187
 188 /* This function is not intended to be crypto-secure, we only want it to be
 189  * fast and not suck too much. This one is pretty fast and did 0 collisions
 190  * in wenglish's dictionary.
 191  */
 192 static inline uint64_t DictHash( const char *psz_string )
 193 {
 194     uint64_t i_hash = 0;
 195     if( psz_string )
 196     {
 197         while( *psz_string )
 198         {
 199             i_hash += *psz_string++;
 200             i_hash += i_hash << 10;
 201             i_hash ^= i_hash >> 8;
 202         }
 203     }
 204     return i_hash;
 205 }
 206
 207 typedef struct vlc_dictionary_t
 208 {
 209     struct vlc_dictionary_entries_t
 210     {
 211         char *   psz_key;
 212         uint64_t i_hash;
 213         void *   p_value;
 214     } * p_entries;
 215     int i_entries;
 216 } vlc_dictionary_t;
 217
 218 static void * const kVLCDictionaryNotFound = (void *)-1;
 219
 220 static inline void vlc_dictionary_init( vlc_dictionary_t * p_dict )
 221 {
 222     p_dict->i_entries = 0;
 223     p_dict->p_entries = NULL;
 224 }
 225
 226 static inline void vlc_dictionary_clear( vlc_dictionary_t * p_dict )
 227 {
 228     int i;
 229     for ( i = 0; i < p_dict->i_entries; i++ )
 230     {
 231         free( p_dict->p_entries[i].psz_key );
 232     }
 233     free( p_dict->p_entries );
 234     p_dict->i_entries = 0;
 235     p_dict->p_entries = NULL;
 236 }
 237
 238
 239 static inline void *
 240 vlc_dictionary_value_for_key( vlc_dictionary_t * p_dict, const char * psz_key )
 241 {
 242     uint64_t i_hash;
 243     int i, i_pos;
 244
 245     if( p_dict->i_entries == 0 )
 246         return kVLCDictionaryNotFound;
 247
 248     i_hash = DictHash( psz_key );
 249     BSEARCH( p_dict->p_entries, p_dict->i_entries, .i_hash, uint64_t,
 250              i_hash, i_pos );
 251     if( i_pos == -1 )
 252         return kVLCDictionaryNotFound;
 253
 254     /* Hash found, let's check it looks like the entry */
 255     if( !strcmp( psz_key, p_dict->p_entries[i_pos].psz_key ) )
 256         return p_dict->p_entries[i_pos].p_value;
 257
 258     /* Hash collision! This should be very rare, but we cannot guarantee
 259      * it will never happen. Just do an exhaustive search amongst all
 260      * entries with the same hash. */
 261     for( i = i_pos - 1 ; i > 0 && i_hash == p_dict->p_entries[i].i_hash ; i-- )
 262     {
 263         if( !strcmp( psz_key, p_dict->p_entries[i].psz_key ) )
 264             return p_dict->p_entries[i_pos].p_value;
 265     }
 266     for( i = i_pos + 1 ; i < p_dict->i_entries &&
 267                          i_hash == p_dict->p_entries[i].i_hash ; i++ )
 268     {
 269          if( !strcmp( psz_key, p_dict->p_entries[i].psz_key ))
 270             return p_dict->p_entries[i_pos].p_value;
 271     }
 272     /* Hash found, but entry not found (shouldn't happen!) */
 273     return kVLCDictionaryNotFound;
 274 }
 275
 276 static inline void
 277 vlc_dictionary_insert( vlc_dictionary_t * p_dict, const char * psz_key, void * p_value )
 278 {
 279     uint64_t i_hash = DictHash( psz_key );
 280     int i_new;
 281
 282     /* First, caller should take care not to insert twice the same key */
 283     /* This could be removed for optimization */
 284     assert( vlc_dictionary_value_for_key( p_dict, psz_key ) == kVLCDictionaryNotFound );
 285
 286     /* Find a free slot */
 287     if( p_dict->i_entries == 0 || i_hash <= p_dict->p_entries[0].i_hash )
 288         i_new = 0;
 289     else if( i_hash >= p_dict->p_entries[p_dict->i_entries-1].i_hash )
 290         i_new = p_dict->i_entries;
 291     else
 292     {
 293         int i_low = 0, i_high = p_dict->i_entries - 1;
 294         while( i_high - i_low > 1 )
 295         {
 296             int i_mid = (i_low + i_high)/2;
 297             if( p_dict->p_entries[i_mid].i_hash < i_hash ) {
 298                 i_low = i_mid;
 299             } else if( p_dict->p_entries[i_mid].i_hash > i_hash ) {
 300                 i_high = i_mid;
 301             }
 302         }
 303         if( p_dict->p_entries[i_low].i_hash < i_hash )
 304             i_new = i_high;
 305         else
 306             i_new = i_low;
 307     }
 308     p_dict->p_entries = realloc( p_dict->p_entries, (p_dict->i_entries + 1) *
 309         sizeof( struct vlc_dictionary_entries_t ) );
 310     p_dict->i_entries++;
 311     if( i_new != p_dict->i_entries -1 )
 312     {
 313         memmove( &p_dict->p_entries[i_new+1], &p_dict->p_entries[i_new],
 314          ( p_dict->i_entries - i_new - 1 ) *
 315          sizeof(struct vlc_dictionary_entries_t) );
 316     }
 317
 318     p_dict->p_entries[i_new].i_hash  = i_hash;
 319     p_dict->p_entries[i_new].psz_key = strdup( psz_key );
 320     p_dict->p_entries[i_new].p_value = p_value;
 321 }
 322
 323
 324 /************************************************************************
 325  * Dynamic arrays with progressive allocation
 326  ************************************************************************/
 327
 328 /* Internal functions */
 329 #define _ARRAY_ALLOC(array, newsize) {                                      \
 330     array.i_alloc = newsize;                                                \
 331     array.p_elems = VLCCVP realloc( array.p_elems, array.i_alloc *          \
 332                                     sizeof(*array.p_elems) );               \
 333     assert(array.p_elems);                                                  \
 334 }
 335
 336 #define _ARRAY_GROW1(array) {                                               \
 337     if( array.i_alloc < 10 )                                                \
 338         _ARRAY_ALLOC(array, 10 )                                            \
 339     else if( array.i_alloc == array.i_size )                                \
 340         _ARRAY_ALLOC(array, (int)(array.i_alloc * 1.5) )                    \
 341 }
 342
 343 #define _ARRAY_GROW(array,additional) {                                     \
 344      int i_first = array.i_alloc;                                           \
 345      while( array.i_alloc - i_first < additional )                          \
 346      {                                                                      \
 347          if( array.i_alloc < 10 )                                           \
 348             _ARRAY_ALLOC(array, 10 )                                        \
 349         else if( array.i_alloc == array.i_size )                            \
 350             _ARRAY_ALLOC(array, (int)(array.i_alloc * 1.5) )                \
 351         else break;                                                         \
 352      }                                                                      \
 353 }
 354
 355 #define _ARRAY_SHRINK(array) {                                              \
 356     if( array.i_size > 10 && array.i_size < (int)(array.i_alloc / 1.5) ) {  \
 357         _ARRAY_ALLOC(array, array.i_size + 5);                              \
 358     }                                                                       \
 359 }
 360
 361
 362 /* API */
 363 #define DECL_ARRAY(type) struct {                                           \
 364     int i_alloc;                                                            \
 365     int i_size;                                                             \
 366     type *p_elems;                                                          \
 367 }
 368
 369 #define TYPEDEF_ARRAY(type, name) typedef DECL_ARRAY(type) name;
 370
 371 #define ARRAY_INIT(array)                                                   \
 372     array.i_alloc = 0;                                                      \
 373     array.i_size = 0;                                                       \
 374     array.p_elems = NULL;
 375
 376 #define ARRAY_RESET(array)                                                  \
 377     array.i_alloc = 0;                                                      \
 378     array.i_size = 0;                                                       \
 379     free( array.p_elems ); array.p_elems = NULL;
 380
 381 #define ARRAY_APPEND(array, elem) {                                         \
 382     _ARRAY_GROW1(array);                                                    \
 383     array.p_elems[array.i_size] = elem;                                     \
 384     array.i_size++;                                                         \
 385 }
 386
 387 #define ARRAY_INSERT(array,elem,pos) {                                      \
 388     _ARRAY_GROW1(array);                                                    \
 389     if( array.i_size - pos ) {                                              \
 390         memmove( array.p_elems + pos + 1, array.p_elems + pos,              \
 391                  (array.i_size-pos) * sizeof(*array.p_elems) );             \
 392     }                                                                       \
 393     array.p_elems[pos] = elem;                                              \
 394     array.i_size++;                                                         \
 395 }
 396
 397 #define ARRAY_REMOVE(array,pos) {                                           \
 398     if( array.i_size - (pos) - 1 )                                          \
 399     {                                                                       \
 400         memmove( array.p_elems + pos, array.p_elems + pos + 1,              \
 401                  ( array.i_size - pos - 1 ) *sizeof(*array.p_elems) );      \
 402     }                                                                       \
 403     array.i_size--;                                                         \
 404     _ARRAY_SHRINK(array);                                                   \
 405 }
 406
 407 #define ARRAY_VAL(array, pos) array.p_elems[pos]
 408
 409 #define ARRAY_BSEARCH(array, elem, zetype, key, answer) \
 410     BSEARCH( array.p_elems, array.i_size, elem, zetype, key, answer)
 411
 412 #define FOREACH_ARRAY( item, array ) { \
 413     int fe_idx; \
 414     for( fe_idx = 0 ; fe_idx < array.i_size ; fe_idx++ ) \
 415     { \
 416         item = array.p_elems[fe_idx];
 417
 418 #define FOREACH_END() } }
 419
 420 #endif