82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
#ifndef PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
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#define PERSISTENT_DATA_DATA_STRUCTURES_BTREE_COUNTER_H
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#include "persistent-data/block_counter.h"
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//----------------------------------------------------------------
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namespace persistent_data {
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namespace btree_count_detail {
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template <unsigned Levels, typename ValueTraits, typename ValueCounter>
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class counting_visitor : public btree<Levels, ValueTraits>::visitor {
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public:
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typedef btree<Levels, ValueTraits> tree;
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counting_visitor(block_counter &bc, ValueCounter &vc)
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: bc_(bc),
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vc_(vc) {
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}
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virtual bool visit_internal(node_location const &l,
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typename tree::internal_node const &n) {
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return visit_node(n);
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}
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virtual bool visit_internal_leaf(node_location const &l,
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typename tree::internal_node const &n) {
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return visit_node(n);
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}
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virtual bool visit_leaf(node_location const &l,
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typename tree::leaf_node const &n) {
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if (visit_node(n)) {
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unsigned nr = n.get_nr_entries();
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for (unsigned i = 0; i < nr; i++) {
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// FIXME: confirm l2 is correct
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node_location l2(l);
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l2.push_key(i);
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vc_.visit(l2, n.value_at(i));
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}
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return true;
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}
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return false;
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}
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private:
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template <typename Node>
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bool visit_node(Node const &n) {
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block_address b = n.get_location();
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bool seen = bc_.get_count(b);
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bc_.inc(b);
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return !seen;
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}
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block_counter &bc_;
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ValueCounter &vc_;
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};
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}
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template <typename T>
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struct noop_value_counter {
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void visit(btree_detail::node_location const &loc, T const &v) {
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}
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};
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// Counts how many times each metadata block is referenced in the
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// tree. Blocks already referenced in the block counter are not
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// walked. This walk should only be done once you're sure the tree
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// is not corrupt.
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template <unsigned Levels, typename ValueTraits, typename ValueCounter>
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void count_btree_blocks(btree<Levels, ValueTraits> const &tree, block_counter &bc, ValueCounter &vc) {
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btree_count_detail::counting_visitor<Levels, ValueTraits, ValueCounter> v(bc, vc);
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tree.visit_depth_first(v);
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}
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}
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//----------------------------------------------------------------
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#endif
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