diff options
Diffstat (limited to 'mysys/tree.c')
| -rw-r--r-- | mysys/tree.c | 25 |
1 files changed, 16 insertions, 9 deletions
diff --git a/mysys/tree.c b/mysys/tree.c index 489262fcdc7..f72a4961312 100644 --- a/mysys/tree.c +++ b/mysys/tree.c @@ -17,26 +17,33 @@ /* Code for handling red-black (balanced) binary trees. key in tree is allocated accrding to following: - 1) If free_element function is given to init_tree or size < 0 then tree - will not allocate keys and only a pointer to each key is saved in tree. - key_sizes must be 0 to init and search. + + 1) If size < 0 then tree will not allocate keys and only a pointer to + each key is saved in tree. + compare and search functions uses and returns key-pointer + + 2) If size == 0 then there are two options: + - key_size != 0 to tree_insert: The key will be stored in the tree. + - key_size == 0 to tree_insert: A pointer to the key is stored. compare and search functions uses and returns key-pointer. - 2) if key_size is given to init_tree then each node will continue the + + 3) if key_size is given to init_tree then each node will continue the key and calls to insert_key may increase length of key. if key_size > sizeof(pointer) and key_size is a multiple of 8 (double allign) then key will be put on a 8 alligned adress. Else the key will be on adress (element+1). This is transparent for user compare and search functions uses a pointer to given key-argument. - 3) If init_tree - keysize is 0 then key_size must be given to tree_insert - and tree_insert will alloc space for key. - compare and search functions uses a pointer to given key-argument. + + - If you use a free function for tree-elements and you are freeing + the element itself, you should use key_size = 0 to init_tree and + tree_search The actual key in TREE_ELEMENT is saved as a pointer or after the TREE_ELEMENT struct. If one uses only pointers in tree one can use tree_set_pointer() to change address of data. - Copyright Monty Program KB. - By monty. + + Implemented by monty. */ #include "mysys_priv.h" |