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/**
* Distributed under the Boost Software License, Version 1.0.
* See accompanying file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt
*/
#include "bplus_iterator.h"
#include "bplus_leaf.h"
#include "bplus_search.h"
static BplusIterator* bplus_iterator_new_full(BplusTree const* tree,
BplusLeaf const* leaf_from, BplusItem const* item_from,
BplusLeaf const* leaf_to, BplusItem const* item_to)
{
BplusIterator* iterator = g_slice_new(BplusIterator);
iterator->leaf_from = leaf_from;
iterator->item_from = item_from;
iterator->leaf_to = leaf_to;
iterator->item_to = item_to;
iterator->item = item_from;
iterator->leaf = leaf_from;
return iterator;
}
static BplusIterator* bplus_iterator_new_to_last(BplusTree const* tree, BplusLeaf const* leaf_from, BplusItem const* item_from)
{
return bplus_iterator_new_full(tree, leaf_from, item_from, tree->last, tree->last->node.items + tree->last->node.length);
}
static BplusIterator* bplus_iterator_new_from_first(BplusTree const* tree, BplusLeaf const* leaf_to, BplusItem const* item_to)
{
return bplus_iterator_new_full(tree, tree->first, tree->first->node.items, leaf_to, item_to);
}
BplusIterator* bplus_iterator_new(BplusTree const* tree)
{
return bplus_iterator_new_to_last(tree, tree->first, tree->first->node.items);
}
void bplus_iterator_destroy(BplusIterator* iterator)
{
g_return_if_fail(iterator != NULL);
g_slice_free(BplusIterator, iterator);
}
gboolean bplus_iterator_next(BplusIterator* iterator)
{
g_return_val_if_fail(iterator != NULL, FALSE);
BplusItem const* const next = iterator->item + 1;
BplusLeaf const* const leaf = iterator->leaf;
if (next == iterator->item_to)
return FALSE;
if (next - leaf->node.items < leaf->node.length)
{
++iterator->item;
}
else
{
if (leaf->right == NULL)
return FALSE;
iterator->leaf = leaf->right;
iterator->item = leaf->right->node.items;
}
return TRUE;
}
gboolean bplus_iterator_previous(BplusIterator* iterator)
{
g_return_val_if_fail(iterator != NULL, FALSE);
BplusItem const* const item = iterator->item;
BplusLeaf const* const leaf = iterator->leaf;
if (item == iterator->item_from)
return FALSE;
if (item - leaf->node.items == 0)
{
if (leaf->left == NULL)
return FALSE;
iterator->leaf = leaf->left;
iterator->item = leaf->left->node.items + leaf->left->node.length;
}
--iterator->item;
return TRUE;
}
BplusItem const* bplus_iterator_get_item(BplusIterator const* iterator)
{
g_return_val_if_fail(iterator != NULL, NULL);
if (iterator->item_from == iterator->item_to)
return NULL;
return iterator->item;
}
BplusIterator* bplus_tree_first(BplusTree const* tree)
{
g_return_val_if_fail(tree != NULL, NULL);
return bplus_iterator_new(tree);
}
BplusIterator* bplus_iterator_from_key(BplusTree const* tree, BplusKey const key)
{
g_return_val_if_fail(tree != NULL, NULL);
BplusPath path_from;
BplusPath path_to;
bplus_tree_get_paths_to_key_range(tree, key, key, &path_from, &path_to);
return bplus_iterator_new_to_last(tree, (BplusLeaf*) path_from.leaf, path_from.leaf->items + path_from.index[0]);
}
BplusIterator* bplus_iterator_to_key(BplusTree const* tree, BplusKey const key)
{
g_return_val_if_fail(tree != NULL, NULL);
BplusPath path_from;
BplusPath path_to;
bplus_tree_get_paths_to_key_range(tree, key, key, &path_from, &path_to);
return bplus_iterator_new_from_first(tree, (BplusLeaf*) path_to.leaf, path_to.leaf->items + path_to.index[0]);
}
BplusIterator* bplus_iterator_for_key(BplusTree const* tree, BplusKey const key)
{
g_return_val_if_fail(tree != NULL, NULL);
BplusPath path_from;
BplusPath path_to;
bplus_tree_get_paths_to_key_range(tree, key, key, &path_from, &path_to);
return bplus_iterator_new_full(tree,
(BplusLeaf*) path_from.leaf, path_from.leaf->items + path_from.index[0],
(BplusLeaf*) path_to.leaf, path_to.leaf->items + path_to.index[0]);
}
BplusIterator* bplus_iterator_for_key_range(BplusTree const* tree, BplusKey const key_from, BplusKey const key_to)
{
g_return_val_if_fail(tree != NULL, NULL);
BplusPath path_from;
BplusPath path_to;
bplus_tree_get_paths_to_key_range(tree, key_from, key_to, &path_from, &path_to);
return bplus_iterator_new_full(tree,
(BplusLeaf*) path_from.leaf, path_from.leaf->items + path_from.index[0],
(BplusLeaf*) path_to.leaf, path_to.leaf->items + path_to.index[0]);
}
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