Revision efbaf4de libavutil/tree.h

View differences:

libavutil/tree.h
42 42 
void *av_tree_find(const struct AVTreeNode *root, void *key, int (*cmp)(void *key, const void *b), void *next[2]);
43 43 

  		




  44
  44
  
    
/**


  		




  45
  
  
    
 * Finds a element for which cmp(key, elem)==0, if no such element is found key


  		




  46
  
  
    
 * is inserted into the tree.


  		




  
  45
  
    
 * Inserts or removes an element.


  		




  
  46
  
    
 * If *next is NULL then the element supplied will be removed, if no such


  		




  
  47
  
    
 * element exists behavior is undefined.


  		




  
  48
  
    
 * If *next is not NULL then the element supplied will be inserted, unless


  		




  
  49
  
    
 * it already exists in the tree.


  		




  47
  50
  
    
 * @param rootp A pointer to a pointer to the root node of the tree. Note that


  		




  48
  51
  
    
 *              the root node can change during insertions, this is required


  		




  49
  52
  
    
 *              to keep the tree balanced.


  		




  50
  
  
    
 * @param next AVTreeNode used for the inserted element, must be allocated and


  		




  51
  
  
    
 *             zeroed by the user. And will be set to NULL if used by


  		




  52
  
  
    
 *             av_tree_insert(). This allows the use of flat arrays, which have


  		




  
  53
  
    
 * @param next Used to allocate and free AVTreeNodes. For insertion the user


  		




  
  54
  
    
 *             must set it to an allocated and zeroed object of at least


  		




  
  55
  
    
 *             av_tree_node_size bytes size. av_tree_insert() will set it to


  		




  
  56
  
    
 *             NULL if it has been consumed.


  		




  
  57
  
    
 *             For deleting elements *next is set to NULL by the user and


  		




  
  58
  
    
 *             av_tree_node_size() will set it to the AVTreeNode which was


  		




  
  59
  
    
 *             used for the removed element.


  		




  
  60
  
    
 *             This allows the use of flat arrays, which have


  		




  53
  61
  
    
 *             lower overhead compared to many malloced elements.


  		




  54
  62
  
    
 *             You might want to define a function like:


  		




  55
  63
  
    
 *             void *tree_insert(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b), AVTreeNode **next){


  		




  56
  64
  
    
 *                 if(!*next) *next= av_mallocz(av_tree_node_size);


  		




  57
  65
  
    
 *                 return av_tree_insert(rootp, key, cmp, next);


  		




  58
  66
  
    
 *             }


  		




  
  67
  
    
 *             void *tree_remove(struct AVTreeNode **rootp, void *key, int (*cmp)(void *key, const void *b, AVTreeNode **next)){


  		




  
  68
  
    
 *                 if(*next) av_freep(next);


  		




  
  69
  
    
 *                 return av_tree_insert(rootp, key, cmp, next);


  		




  
  70
  
    
 *             }


  		




  59
  71
  
    
 *


  		




  60
  72
  
    
 * @return If no insertion happened, the found element.


  		




  61
  
  
    
 *         If an insertion happened, then either key or NULL will be returned.


  		




  
  73
  
    
 *         If an insertion or removial happened, then either key or NULL will be returned.


  		




  62
  74
  
    
 *         Which one it is depends on the tree state and the implementation. You


  		




  63
  75
  
    
 *         should make no assumptions that it's one or the other in the code.


  		




  64
  76
  
    
 */


  		












Also available in:  Unified diff