xo-alloc/include/xo/ordinaltree/bplustree/LeafNode.hpp

684 lines
29 KiB
C++

/* @file LeafNode.hpp */
#pragma once
#include "GenericNode.hpp"
#include "xo/indentlog/scope.hpp"
#include <cassert>
namespace xo {
namespace tree {
// ----- LeafNodeItem -----
template <typename Key, typename Value, typename Properties>
using LeafNodeItem = NodeItem<NodeType::leaf, Key, Value, Properties>;
/* - define for symmetry with NodeItem<Key, Properties>
* - LeafNodeItem doesn't contain a child pointer;
* it belongs inside a leaf mode, which by definition doesn't have children
*/
template <typename Key, typename Value, typename Properties>
struct NodeItem<NodeType::leaf, Key, Value, Properties> {
public:
using ContentsType = std::pair<Key, Value>;
public:
NodeItem() = default;
NodeItem(std::pair<Key, Value> kv) : kv_pair_{std::move(kv)} {}
std::pair<Key, Value> const & kv_pair() const { return kv_pair_; }
Key const & key () const { return kv_pair_.first; }
Value const & value() const { return kv_pair_.second; }
void assign_value(Value x) { kv_pair_.second = std::move(x); }
private:
/* key+value pair */
std::pair<Key, Value> kv_pair_;
}; /*NodeItem*/
/* struct with same size as LeafNodeItem<Key, Value, Properties>, but POD + with no ctor/dtor */
template <typename Key, typename Value, typename Properties>
using LeafNodeItemPlaceholder = NodeItemPlaceholder<NodeType::leaf, Key, Value, Properties>;
template <typename Key, typename Value, typename Properties, tags::ordinal_tag OrdinalTag = Properties::ordinal_tag_value()>
struct LeafNodeShim : public GenericNode<Key, Value, Properties>
{
LeafNodeShim(NodeType ntype, std::size_t branching_factor) : GenericNode<Key, Value, Properties>(ntype, branching_factor) {}
/* ordinal_enabled: LeafNode will provide .size(): inherits+overrides GenericNodeBase.size() */
};
template <typename Key, typename Value, typename Properties>
struct LeafNodeShim<Key, Value, Properties, tags::ordinal_disabled> : public GenericNode<Key, Value, Properties>
{
LeafNodeShim(NodeType ntype, std::size_t branching_factor) : GenericNode<Key, Value, Properties>(ntype, branching_factor) {}
/* ordinal_disabled: LeafNode provides LeafNode::size(), but not used */
virtual std::size_t size() const = 0;
};
// ----- LeafNode -----
/* require:
* - Properties.branching_factor()
*/
template <typename Key, typename Value, typename Properties>
struct LeafNode : public LeafNodeShim<Key, Value, Properties> {
public:
using GenericNodeType = GenericNode<Key, Value, Properties>;
using LeafNodeType = LeafNode<Key, Value, Properties>;
using LeafNodeItemType = LeafNodeItem<Key, Value, Properties>;
using LeafNodeItemPlaceholderType = LeafNodeItemPlaceholder<Key, Value, Properties>;
using InternalNodeType = InternalNode<Key, Value, Properties>;
using ContentsType = typename LeafNodeItemType::ContentsType;
public:
virtual ~LeafNode();
/* node size in bytes (increases with branching factor) */
static std::size_t node_sizeof(std::size_t branching_factor);
/* named ctor idiom. enforce heap allocation + unique_ptr wrapper */
static std::unique_ptr<LeafNode> make(std::pair<Key const, Value> kv_pair,
Properties const & properties);
/* create+return new leaf node that contains all the items in *src from position [lo_ix, hi_ix),
* after this operation size of *src is reduced by (hi_ix - lo_ix)
*/
static std::unique_ptr<LeafNode> annex(std::size_t lo_ix,
std::size_t hi_ix,
LeafNode * src);
LeafNode * prev_leafnode() const { return prev_leafnode_; }
LeafNode * next_leafnode() const { return next_leafnode_; }
/* .first: true if key in tree already
* .second: index position of (strict) least upper bound in .elt_v[]
* if .n_elt, key has no upper bound in this node
*/
std::pair<bool, std::size_t> find_lub_ix(Key const & key) const;
LeafNodeItemType & lookup_elt(std::size_t i) { return *(reinterpret_cast<LeafNodeItemType *>(&(this->elt_v_[i]))); }
LeafNodeItemType const & lookup_elt(std::size_t i) const { return *(reinterpret_cast<LeafNodeItemType const *>(&(this->elt_v_[i]))); }
void assign_leaf_value(std::size_t elt_ix, Value value) {
assert(elt_ix < this->n_elt_);
this->lookup_elt(elt_ix).assign_value(std::move(value));
} /*assign_leaf_value*/
/* assign precdeing leaf node (= LH sibling if share same parent) */
void assign_prev_leafnode(LeafNode * x) { prev_leafnode_ = x; }
void assign_next_leafnode(LeafNode * x) { next_leafnode_ = x; }
/* insert new leaf at position ix, associating key -> value
* (shuffle existing elements at ix, ix+1.. 1 position to the right)
*/
void insert_leaf_item(std::size_t ix,
std::pair<Key const, Value> const & kv_pair,
bool debug_flag);
/* remove key,value pair at position ix */
void remove_leaf(std::size_t ix, bool debug_flag);
/* append n items from left-hand sibling, as new left-most elements
* require: combined #of items must be at most b = branching factor
*/
void prepend_from_lh_sibling(LeafNode * lh, std::size_t n, bool debug_flag);
/* apepnd n items from right-hand sibling, as new right-most elements
* require: combined #of items must be at most b = branching factor
*/
void append_from_rh_sibling(std::size_t n, LeafNode * rh);
void append_rh_sibling(LeafNode * rh) { this->append_from_rh_sibling(rh->n_elt(), rh); }
/* returns new leaf with lower half of original element vector;
* original updated to retain upper half
*/
std::unique_ptr<LeafNode> split_leaf_lower();
/* returns new leaf with upper half of original element vector;
* original updated to retain lower half
*/
std::unique_ptr<LeafNode> split_leaf_upper();
/* memory for LeafNode instances is always created using new[],
* so required to use delete[] to deallocate
*/
void operator delete (void * mem) noexcept { ::operator delete[](mem); }
// ----- Inherited from GenericNode -----
virtual std::size_t size() const override { return this->n_elt(); }
virtual Key const & glb_key() const override { return this->lookup_elt(0).key(); }
virtual std::size_t verify_helper(InternalNodeType const * parent,
bool with_lub_flag,
Key const & lub_key,
LeafNodeType const * lh_leaf,
LeafNodeType const * rh_leaf) const override;
virtual void verify_glb_key(Key const & key) const override;
virtual FindNodeResult<LeafNodeType> find_min_leaf_node() override;
virtual FindNodeResult<LeafNodeType> find_max_leaf_node() override;
virtual void notify_remove() override;
private:
explicit LeafNode(std::size_t branching_factor);
LeafNode(std::pair<Key const, Value> const & kv_pair,
std::size_t branching_factor);
void assign_siblings(LeafNode * prev, LeafNode * next);
private:
/* previous LeafNode in key order, immediately before (all the keys in) this node.
* use to streamline inorder traversal.
*/
LeafNode * prev_leafnode_ = nullptr;
/* next LeafNode in key order, immediately after (all the keys in) this node.
* streamline inorder traversal.
*/
LeafNode * next_leafnode_ = nullptr;
/* flexible array; actual capacity will be Properties.branching_factor();
* but only members [0 .. n_elt-1] are defined.
*
* actual type of .elt_v[i] is LeafNodeItem<Key, Value, Properties>;
* need to use POD LeafNodeItemPlaceholder<Key, Value, Properties> to satisfy flexible-array rules
*/
LeafNodeItemPlaceholderType elt_v_[];
}; /*LeafNode*/
template <typename Key, typename Value, typename Properties>
LeafNode<Key, Value, Properties>::~LeafNode() {
/* since we're using flexible array for .elt_v[], need to manually run destructors */
for (std::size_t i=0, n=this->branching_factor_; i<n; ++i) {
this->lookup_elt(i).~LeafNodeItemType();
}
/* hygiene */
this->n_elt_ = 0;
this->branching_factor_ = 0;
} /*dtor*/
template <typename Key, typename Value, typename Properties>
std::size_t
LeafNode<Key, Value, Properties>::node_sizeof(std::size_t branching_factor) {
/* since we're using flexible array for .elt_v[], need to manually account for it's allocated size */
return (sizeof(LeafNode)
+ (branching_factor
* sizeof(LeafNodeItem<Key, Value, Properties>)));
} /*node_sizeof*/
template <typename Key, typename Value, typename Properties>
std::unique_ptr<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::make(std::pair<Key const, Value> kv_pair,
Properties const & properties)
{
using xo::scope;
using xo::xtag;
std::size_t mem_z = node_sizeof(properties.branching_factor());
/* storage for LeafNode, including storage cost for flexible array LeafNode.elt_v[] */
std::uint8_t * mem = new std::uint8_t[mem_z];
#ifdef NOT_IN_USE
scope x("LeafNode.make");
x.log(xtag("sizeof(LeafNode)", sizeof(LeafNode)),
xtag("bf", properties.branching_factor()),
xtag("mem_z", mem_z),
xtag("mem", (void *)mem));
#endif
return std::unique_ptr<LeafNode>(new (mem) LeafNode(std::move(kv_pair),
properties.branching_factor()));
} /*make*/
template <typename Key, typename Value, typename Properties>
std::unique_ptr<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::annex(std::size_t lo_ix,
std::size_t hi_ix,
LeafNode * src)
{
using xo::scope;
using xo::xtag;
std::size_t branching_factor = src->branching_factor();
assert(hi_ix >= lo_ix);
assert(hi_ix - lo_ix <= branching_factor);
std::size_t mem_z = node_sizeof(branching_factor);
std::uint8_t * mem = new std::uint8_t[mem_z];
#ifdef NOT_IN_USE
scope x("LeafNode.annex");
x.log(xtag("sizeof(LeafNode)", sizeof(LeafNode)),
xtag("bf", branching_factor),
xtag("mem_z", mem_z),
xtag("mem", (void *)mem));
#endif
std::unique_ptr<LeafNode> new_node(new (mem) LeafNode(branching_factor));
std::size_t old_n = src->n_elt();
new_node->n_elt_ = hi_ix - lo_ix;
std::size_t n_annex = hi_ix - lo_ix;
/* annexing from *src into new_node */
for (std::size_t i = 0; i < n_annex; ++i) {
LeafNodeItemType & new_slot = new_node->lookup_elt(i);
new_slot = std::move(src->lookup_elt(lo_ix + i));
}
/* shuffle over any remaining items in *src starting from hi_ix */
for (std::size_t i = lo_ix; i + n_annex < old_n; ++i) {
LeafNodeItemType & slot = src->lookup_elt(i);
slot = std::move(src->lookup_elt(i + n_annex));
}
src->n_elt_ = old_n - n_annex;
if (lo_ix == 0) {
/* new node builds by taking leftmost elements from src
* -> new node becomes src's predecessor
*/
new_node->assign_siblings(src->prev_leafnode(), src);
} else {
/* new node builds by taking rightmost elements from src
* -> new node becomes src's successor
*/
new_node->assign_siblings(src, src->next_leafnode());
}
return new_node;
} /*annex*/
template <typename Key, typename Value, typename Properties>
std::pair<bool, std::size_t>
LeafNode<Key, Value, Properties>::find_lub_ix(Key const & key) const {
if (key < this->lookup_elt(0).key())
return std::make_pair(false, 0);
/* promise: return value >= 0 */
/* .elt_v[0 .. n_elt-1] are maintained in sorted key order */
std::size_t lo = 0;
std::size_t hi = this->n_elt_;
while (lo + 1 < hi) {
/* desired child item will be in range [lo, hi) */
std::size_t mid = lo + (hi - lo) / 2;
if (key < this->lookup_elt(mid).key())
hi = mid;
else
lo = mid;
}
/* invariant:
* - lo is a valid index: elt_v[lo].kv_pair reflects outcome of most recent call to BplusTree.insert()
* - .elt_v[lo].key <= key
* - if hi<.n_elt, then key < .elt_v[hi].key
*/
bool presence_flag = (key == this->lookup_elt(lo).key());
return std::make_pair(presence_flag, hi);
} /*find_lub_ix*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::insert_leaf_item(std::size_t ix,
std::pair<Key const, Value> const & kv_pair,
bool debug_flag) {
using xo::scope;
using xo::xtag;
scope log(XO_DEBUG(debug_flag),
xtag("self", this),
xtag("n_elt", this->n_elt()),
xtag("bf", this->branching_factor()),
xtag("ix", ix),
xtag("key", kv_pair.first),
xtag("value", kv_pair.second));
if (this->n_elt_ >= this->branching_factor()) {
assert(false);
throw std::runtime_error(tostr("LeafNode::insert_leaf: leaf already full",
xtag("leaf.n_elt", this->n_elt()),
xtag("branching_factor", this->branching_factor())));
}
std::size_t pos_ix = this->n_elt_;
while (pos_ix > ix) {
//scope x1("loop");
//x1.log(xtag("pos_ix", pos_ix));
this->lookup_elt(pos_ix) = std::move(this->lookup_elt(pos_ix - 1));
--pos_ix;
}
++(this->n_elt_);
this->lookup_elt(ix) = LeafNodeItemType(kv_pair);
log.end_scope();
} /*insert_leaf*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::remove_leaf(std::size_t ix, bool debug_flag) {
using xo::scope;
using xo::xtag;
scope log(XO_DEBUG(debug_flag),
xtag("self", this),
xtag("n_elt", this->n_elt()),
xtag("bf", this->branching_factor()),
xtag("ix", ix));
if (this->n_elt_ == 0) {
throw std::runtime_error(tostr("LeafNode::remove_leaf: leaf already empty",
xtag("leaf.n_elt", this->n_elt()),
xtag("branching_factor", this->branching_factor())));
}
/* TODO: removal action for position pos_ix (maintain reductions) */
std::size_t pos_ix = ix;
std::size_t end_ix = this->n_elt_ - 1;
while (pos_ix < end_ix) {
//scope x1("loop");
//x1.log(xtag("pos_ix", pos_ix));
this->lookup_elt(pos_ix) = std::move(this->lookup_elt(pos_ix + 1));
++pos_ix;
}
--(this->n_elt_);
} /*remove_leaf*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::prepend_from_lh_sibling(LeafNode<Key, Value, Properties> * lh, std::size_t n, bool debug_flag) {
using xo::scope;
using xo::xtag;
scope log(XO_DEBUG(debug_flag),
xtag("n", n));
if (this->n_elt() + n > this->branching_factor()) {
assert(false);
throw std::runtime_error(tostr("LeafNode.prepend_from_lh_sibling: expected combined #elt <= bf",
xtag("self.n_elt", this->n_elt()),
xtag("n", n),
xtag("bf", this->branching_factor())));
}
std::size_t n_lh = lh->n_elt();
std::size_t n_rh = this->n_elt();
/* move elts in *this to the right n steps */
for (std::size_t ixp1 = this->n_elt(); ixp1 > 0; --ixp1) {
std::size_t ix = ixp1 - 1;
this->lookup_elt(ix + n) = std::move(this->lookup_elt(ix));
}
/* xfer n elts from upper end of lh, to lower end of *this */
for (std::size_t ix = 0; ix < n; ++ix) {
this->lookup_elt(ix) = lh->lookup_elt(n_lh - n + ix);
}
this->n_elt_ += n;
lh->n_elt_ -= n;
/* note: since we didn't create/destroy any LeafNodes,
* .prev_leafnode / .next_leafnode pointers are unchanged
*/
log.end_scope();
} /*prepend_from_lh_sibling*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::append_from_rh_sibling(std::size_t n, LeafNode<Key, Value, Properties> * rh) {
using xo::xtag;
if (this->n_elt() + n > this->branching_factor()) {
assert(false);
throw std::runtime_error(tostr("LeafNode.append_from_rh_sibling: expected combined #elt <= bf",
xtag("self.n_elt", this->n_elt()),
xtag("n", n),
xtag("bf", this->branching_factor())));
}
std::size_t n_lh = this->n_elt();
for (std::size_t ix = 0; ix < n; ++ix) {
this->lookup_elt(n_lh + ix) = std::move(rh->lookup_elt(ix));
/* note: leaf items are key,value pairs;
* no parent pointers to fixup (cf InternalNode.append_from_rh_sibling)
*/
}
this->n_elt_ += n;
/* shuffle remaining members of rh sibling n items to the left */
for (std::size_t ix = 0; ix < rh->n_elt() - n; ++ix) {
rh->lookup_elt(ix) = std::move(rh->lookup_elt(ix + n));
}
rh->n_elt_ -= n;
/* note: since we didn't create/destroy any LeafNodes,
* .prev_leafnode / .next_leafnode pointers are unchanged
*/
} /*append_from_rh_sibling*/
template <typename Key, typename Value, typename Properties>
std::unique_ptr<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::split_leaf_lower() {
std::size_t n_elt = this->n_elt_;
std::size_t mid_ix = n_elt / 2;
return LeafNode::annex(0, mid_ix, this);
} /*split_leaf_lower*/
template <typename Key, typename Value, typename Properties>
std::unique_ptr<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::split_leaf_upper() {
std::size_t n_elt = this->n_elt_;
std::size_t mid_ix = n_elt / 2;
return LeafNode<Key, Value, Properties>::annex(mid_ix, n_elt, this);
} /*split_leaf_upper*/
template <typename Key, typename Value, typename Properties>
std::size_t
LeafNode<Key, Value, Properties>::verify_helper(InternalNodeType const * parent,
bool with_lub_flag,
Key const & lub_key,
LeafNodeType const * lh_leaf,
LeafNodeType const * rh_leaf) const {
using xo::xtag;
/* verify immediate parent pointer is correct */
if (this->parent() != parent) {
throw std::runtime_error(tostr("LeafNode::verify_helper"
": expected parent pointer to refer to actual parent",
xtag("stored_parent", this->parent()),
xtag("actual_parent", parent)));
}
/* verify locally stored keys appear in sorted order */
std::size_t n = this->n_elt_;
for (std::size_t i=1; i < n; ++i) {
LeafNodeItemType const & prev = this->lookup_elt(i-1);
LeafNodeItemType const & elt = this->lookup_elt(i);
if (prev.key() < elt.key()) {
;
} else {
throw std::runtime_error(tostr("LeafNode::verify_helper"
": expected local keys in strictly increasing order",
xtag("i", i),
xtag("key(i-1)", prev.key()),
xtag("key(i)", elt.key())));
}
}
if (with_lub_flag) {
if (this->lookup_elt(n-1).key() < lub_key) {
;
} else {
throw std::runtime_error(tostr("LeafNode::verify_helper"
": expected last local key before parent-supplied lub key",
xtag("n", n),
xtag("key(n-1)", this->lookup_elt(n-1).key()),
xtag("lub_key", lub_key)));
}
}
/* verify next/prev leafnode pointers are consistent */
if ((lh_leaf && (lh_leaf->next_leafnode() != this))
|| (this->prev_leafnode() != lh_leaf))
{
throw std::runtime_error(tostr("LeafNode::verify_helper"
": inconsistent prev/next leaf pointers",
xtag("parent", parent),
xtag("lh_leaf", lh_leaf),
xtag("lh_leaf.next", lh_leaf ? lh_leaf->next_leafnode() : nullptr),
xtag("self", this),
xtag("self.prev", this->prev_leafnode())));
}
if ((this->next_leafnode() != rh_leaf)
|| (rh_leaf && (rh_leaf->prev_leafnode() != this)))
{
throw std::runtime_error(tostr("LeafNode::verify_helper"
": inconsistent prev/next leaf pointers",
xtag("parent", parent),
xtag("self", this),
xtag("self.next", this->next_leafnode()),
xtag("rh_leaf", rh_leaf),
xtag("rh_leaf.prev", rh_leaf ? rh_leaf->prev_leafnode() : nullptr)));
}
return this->n_elt();
} /*verify_helper*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::verify_glb_key(Key const & key) const {
using xo::xtag;
LeafNodeItemType const & elt = this->lookup_elt(0);
if (elt.key() != key) {
throw std::runtime_error(tostr("LeafNode::verify_glb_key"
": expected stored greatest-lower-bound key to match leftmost leaf's key",
xtag("@", this),
xtag("reported_key", key),
xtag("actual_key", elt.key())));
}
} /*verify_glb_key*/
template <typename Key, typename Value, typename Properties>
FindNodeResult<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::find_min_leaf_node() {
return FindNodeResult<LeafNode<Key, Value, Properties>>(0, this);
} /*find_min_leaf_node*/
template <typename Key, typename Value, typename Properties>
FindNodeResult<LeafNode<Key, Value, Properties>>
LeafNode<Key, Value, Properties>::find_max_leaf_node() {
return FindNodeResult<LeafNode<Key, Value, Properties>>(0, this);
} /*c_find_max_leaf_node*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::notify_remove() {
if (this->prev_leafnode_)
this->prev_leafnode_->assign_next_leafnode(this->next_leafnode_);
if (this->next_leafnode_)
this->next_leafnode_->assign_prev_leafnode(this->prev_leafnode_);
} /*notify_remove*/
template <typename Key, typename Value, typename Properties>
LeafNode<Key, Value, Properties>::LeafNode(std::size_t branching_factor)
: LeafNodeShim<Key, Value, Properties>(NodeType::leaf, branching_factor)
{
/* must call ctor explicitly for each element.
* compiler can't do this for us, b/c it doesn't know size of flexible array
*/
for (std::size_t i = 0, n = branching_factor; i < n; ++i) {
new (&(this->lookup_elt(i))) LeafNodeItemType();
}
}
template <typename Key, typename Value, typename Properties>
LeafNode<Key, Value, Properties>::LeafNode(std::pair<Key const, Value> const & kv_pair,
std::size_t branching_factor)
: LeafNodeShim<Key, Value, Properties>(NodeType::leaf, branching_factor)
{
using xo::scope;
using xo::xtag;
#ifdef NOT_USING_DEBUG
scope x("LeafNode.ctor");
#endif
this->n_elt_ = 1;
/* since .elt_v[] is a flexible array, need to invoke constructors explicitly
* (compiler doesn't know how many elements there are -> can't do it for us
*/
#ifdef NOT_USING_DEBUG
x.log(xtag("elt[0]", &(this->lookup_elt(0))));
#endif
new (&(this->lookup_elt(0))) LeafNodeItemType(kv_pair);
for (std::size_t i = 1, n = branching_factor; i < n; ++i) {
#ifdef NOT_USING_DEBUG
x.log(xtag("i", i),
xtag("elt[i]", &(this->lookup_elt(i))));
#endif
/* using placement-new to invoke ctor explicitly */
new (&(this->lookup_elt(i))) LeafNodeItemType();
}
} /*ctor*/
template <typename Key, typename Value, typename Properties>
void
LeafNode<Key, Value, Properties>::assign_siblings(LeafNode * p, LeafNode * n) {
if (p)
p->assign_next_leafnode(this);
this->prev_leafnode_ = p;
this->next_leafnode_ = n;
if (n)
n->assign_prev_leafnode(this);
} /*assign_siblings*/
} /*namespace tree*/
} /*namespace xo*/
/* end LeafNode.hpp */