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support for HA_READ_PREFIX_LAST_OR_PREV, HA_READ_PREFIX_LAST and HA_READ_BEFORE_KEY

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ram@mysql.r18.ru 2002-11-28 13:31:35 +04:00
parent d2e5a5ddd2
commit 520fdc9f83
1 changed files with 33 additions and 20 deletions
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53
mysys/tree.c
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@ -335,54 +335,67 @@ void *tree_search_key(TREE *tree, const void *key,
enum ha_rkey_function flag, void *custom_arg)
{
int cmp;
TREE_ELEMENT *element = tree->root;
TREE_ELEMENT **last_left_step_parent = NULL;
TREE_ELEMENT **last_equal_element = NULL;
TREE_ELEMENT *element= tree->root;
TREE_ELEMENT **last_left_step_parent= NULL, **last_right_step_parent= NULL;
TREE_ELEMENT **last_equal_element= NULL;
/*
TODO: handle HA_READ_KEY_OR_PREV, HA_READ_BEFORE_KEY, HA_READ_PREFIX,
HA_READ_PREFIX_LAST flags if needed.
TODO: support for HA_READ_KEY_OR_PREV, HA_READ_PREFIX flags if needed.
*/
*parents = &tree->null_element;
while (element != &tree->null_element)
{
*++parents = element;
if ((cmp = (*tree->compare)(custom_arg, ELEMENT_KEY(tree, element),
key)) == 0)
*++parents= element;
if ((cmp= (*tree->compare)(custom_arg, ELEMENT_KEY(tree, element),
key)) == 0)
{
switch (flag) {
case HA_READ_KEY_EXACT:
case HA_READ_KEY_OR_NEXT:
last_equal_element = parents;
cmp = 1;
break;
case HA_READ_BEFORE_KEY:
last_equal_element= parents;
cmp= 1;
break;
case HA_READ_AFTER_KEY:
cmp = -1;
break;
cmp= -1;
break;
case HA_READ_PREFIX_LAST:
case HA_READ_PREFIX_LAST_OR_PREV:
last_equal_element= parents;
cmp= -1;
break;
default:
return NULL;
return NULL;
}
}
if (cmp < 0) /* element < key */
{
element = element->right;
last_right_step_parent= parents;
element= element->right;
}
else
{
last_left_step_parent = parents;
element = element->left;
last_left_step_parent= parents;
element= element->left;
}
}
switch (flag) {
case HA_READ_KEY_EXACT:
*last_pos = last_equal_element;
case HA_READ_PREFIX_LAST:
*last_pos= last_equal_element;
break;
case HA_READ_KEY_OR_NEXT:
*last_pos = last_equal_element ? last_equal_element : last_left_step_parent;
*last_pos= last_equal_element ? last_equal_element : last_left_step_parent;
break;
case HA_READ_AFTER_KEY:
*last_pos = last_left_step_parent;
*last_pos= last_left_step_parent;
break;
case HA_READ_PREFIX_LAST_OR_PREV:
*last_pos= last_equal_element ? last_equal_element : last_right_step_parent;
break;
case HA_READ_BEFORE_KEY:
*last_pos= last_right_step_parent;
break;
default:
return NULL;