FT_BASE_DEF( FT_HashLookup )
    ft_hash_lookup( FT_Hash      table,
                    FT_HashNode  keynode );
  
   

************************************************************** @function: ft_hash_add @description: add a new node to a dynamic hash table. the user must call @ft_hash_lookup and allocate a new node before calling this function. @input: table :: hash table handle lookup :: pointer-to-hash-node value returned by @ft_hash_lookup new_node :: handle to new hash node. All its fields must be correctly set, including 'hash'. @return: error code. 0 means success @note: this function should always be used _after_ a call to @ft_hash_lookup that returns a pointer to a NULL handle. Here's an example: { // sets the value corresponding to a given string key // void my_set( FT_Hash table, const char* key, int value ) { MyNode* pnode; MyNodeRec noderec; MyNode node; // set-up key node. It's 'hash' and 'key' fields must // be set correctly.. noderec.hnode.hash = strhash( key ); noderec.key = key; // perform search - return value pnode = (MyNode) ft_hash_lookup( table, &noderec ); if ( *pnode ) { // we found it, simply replace the value in the node (*pnode)->value = value; return; } // allocate a new node - and set it up node = (MyNode) malloc( sizeof(*node) ); if ( node == NULL ) ..... node->hnode.hash = noderec.hnode.hash; node->key = key; node->value = value; // add it to the hash table error = ft_hash_add( table, pnode, node ); if (error) .... }

  
    FT_BASE( FT_Error )
    ft_hash_add( FT_Hash        table,
                 FT_HashLookup  lookup,
                 FT_HashNode    new_node );
  
   

************************************************************** @function: ft_hash_remove @description: try to remove the node corresponding to a given key from a hash table. This must be called after @ft_hash_lookup @input: table :: hash table handle lookup :: pointer-to-hash-node value returned by @ft_hash_lookup @note: this function doesn't free the node itself !! Here's an example: { // sets the value corresponding to a given string key // void my_remove( FT_Hash table, const char* key ) { MyNodeRec noderec; MyNode node; noderec.hnode.hash = strhash(key); noderec.key = key; node = &noderec; pnode = ft_hash_lookup( table, &noderec ); node = *pnode; if ( node != NULL ) { error = ft_hash_remove( table, pnode ); if ( !error ) free( node ); } } }

  
    FT_BASE( FT_Error )
    ft_hash_remove( FT_Hash        table,
                    FT_HashLookup  lookup );
  
   

************************************************************** @function: ft_hash_get_size @description: return the number of elements in a given hash table @input: table :: handle to target hash table structure @return: number of elements. 0 if empty

  
    FT_BASE( FT_UInt )
    ft_hash_get_size( FT_Hash  table );
  
   

************************************************************** @functype: FT_Hash_ForeachFunc @description: a function used to iterate over all elements of a given hash table @input: node :: handle to target @FT_HashNodeRec node structure data :: optional argument to iteration routine @also: @ft_hash_foreach

  
    typedef void  (*FT_Hash_ForeachFunc)( const FT_HashNode  node,
                                          const FT_Pointer   data );
  
   

************************************************************** @function: ft_hash_foreach @description: parse over all elements in a hash table @input: table :: handle to target hash table structure foreach_func :: iteration routine called for each element foreach_data :: optional argument to the iteration routine @note: this function is often used to release all elements from a hash table. See the example given for @ft_hash_done

  
    FT_BASE( void )
    ft_hash_foreach( FT_Hash              table,
                     FT_Hash_ForeachFunc  foreach_func,
                     const FT_Pointer     foreach_data );
  
   

************************************************************** @function: ft_hash_done @description: finalize a given hash table @input: table :: handle to target hash table structure node_func :: optional iteration function pointer. this can be used to destroy all nodes explicitely node_data :: optional argument to the node iterator @note: this function simply frees the hash table's buckets. you probably will need to call @ft_hash_foreach to destroy all its elements before @ft_hash_done, as in the following example: { static void my_node_clear( const MyNode node ) { free( node ); } static void my_done( FT_Hash table ) { ft_hash_done( table, (FT_Hash_ForeachFunc) my_node_clear, NULL ); } }

  
    FT_BASE( void )
    ft_hash_done( FT_Hash              table,
                  FT_Hash_ForeachFunc  item_func,
                  const FT_Pointer     item_data );
  
   /* */
  
   /* compute bucket index from hash value in a dynamic hash table */
   /* this is only used to break encapsulation to speed lookups in */
   /* the FreeType cache manager !!                                */
   /*                                                              */
  
  define  FT_HASH_COMPUTE_INDEX(_table,_hash,_index)                  \
               {                                                       \
                 FT_UInt  _mask  = (_table)->mask;                     \
                 FT_UInt  _hash0 = (_hash);                            \
                                                                       \
                 (_index) = (FT_UInt)( (_hash0) & _mask ) );           \
                 if ( (_index) < (_table)->p )                         \
                   (_index) = (FT_uInt)( (_hash0) & ( 2*_mask+1 ) );   \
               }
  
  FT_END_HEADER
  
  endif /* __FT_HASH_H__ */
  

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[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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(C) Æliens 04/09/2009

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