osb/source/core/StarBTree.hpp
Kai Blaschke 431a9c00a5
Fixed a huge amount of Clang warnings
On Linux and macOS, using Clang to compile OpenStarbound produces about 400 MB worth of warnings during the build, making the compiler output unreadable and slowing the build down considerably.

99% of the warnings were unqualified uses of std::move and std::forward, which are now all properly qualified.

Fixed a few other minor warnings about non-virtual destructors and some uses of std::move preventing copy elision on temporary objects.

Most remaining warnings are now unused parameters.
2024-02-19 16:55:19 +01:00

938 lines
28 KiB
C++

#ifndef STAR_B_TREE_HPP
#define STAR_B_TREE_HPP
#include "StarList.hpp"
#include "StarMaybe.hpp"
namespace Star {
// Mixin class for implementing a simple B+ Tree style database. LOTS of
// possibilities for improvement, especially in batch deletes / inserts.
//
// The Base class itself must have the following interface:
//
// struct Base {
// typedef KeyT Key;
// typedef DataT Data;
// typedef PointerT Pointer;
//
// // Index and Leaf types may either be a literal struct, or a pointer, or a
// // handle or whatever. They are meant to be opaque.
// typedef IndexT Index;
// typedef LeafT Leaf;
//
// Pointer rootPointer();
// bool rootIsLeaf();
// void setNewRoot(Pointer pointer, bool isLeaf);
//
// Index createIndex(Pointer beginPointer);
//
// // Load an existing index.
// Index loadIndex(Pointer pointer);
//
// size_t indexPointerCount(Index const& index);
// Pointer indexPointer(Index const& index, size_t i);
// void indexUpdatePointer(Index& index, size_t i, Pointer p);
//
// Key indexKeyBefore(Index const& index, size_t i);
// void indexUpdateKeyBefore(Index& index, size_t i, Key k);
//
// void indexRemoveBefore(Index& index, size_t i);
// void indexInsertAfter(Index& index, size_t i, Key k, Pointer p);
//
// size_t indexLevel(Index const& index);
// void setIndexLevel(Index& index, size_t indexLevel);
//
// // Should return true if index should try to shift elements into this index
// // from sibling index.
// bool indexNeedsShift(Index const& index);
//
// // Should return false if no shift done. If merging, always merge to the
// // left.
// bool indexShift(Index& left, Key const& mid, Index& right);
//
// // If a split has occurred, split right and return the mid-key and new
// // right node.
// Maybe<pair<Key, Index>> indexSplit(Index& index);
//
// // Index updated, needs storing. Return pointer to stored index (may
// // change). Index will not be used after store.
// Pointer storeIndex(Index index);
//
// // Index no longer part of BTree. Index will not be used after delete.
// void deleteIndex(Index index);
//
// // Should create new empty leaf.
// Leaf createLeaf();
//
// Leaf loadLeaf(Pointer pointer);
//
// size_t leafElementCount(Leaf const& leaf);
// Key leafKey(Leaf const& leaf, size_t i);
// Data leafData(Leaf const& leaf, size_t i);
//
// void leafInsert(Leaf& leaf, size_t i, Key k, Data d);
// void leafRemove(Leaf& leaf, size_t i);
//
// // Set and get next-leaf pointers. It is not required that next-leaf
// // pointers be kept or that they be valid, so nextLeaf may return nothing.
// void setNextLeaf(Leaf& leaf, Maybe<Pointer> n);
// Maybe<Pointer> nextLeaf(Leaf const& leaf);
//
// // Should return true if leaf should try to shift elements into this leaf
// // from sibling leaf.
// bool leafNeedsShift(Leaf const& l);
//
// // Should return false if no change necessary. If merging, always merge to
// // the left.
// bool leafShift(Leaf& left, Leaf& right);
//
// // Always split right and return new right node if split occurs.
// Maybe<Leaf> leafSplit(Leaf& leaf);
//
// // Leaf has been updated, and needs to be written to storage. Return new
// // pointer (may be different). Leaf will not be used after store.
// Pointer storeLeaf(Leaf leaf);
//
// // Leaf is no longer part of this BTree. Leaf will not be used after
// // delete.
// void deleteLeaf(Leaf leaf);
// };
template <typename Base>
class BTreeMixin : public Base {
public:
typedef typename Base::Key Key;
typedef typename Base::Data Data;
typedef typename Base::Pointer Pointer;
typedef typename Base::Index Index;
typedef typename Base::Leaf Leaf;
bool contains(Key const& k);
Maybe<Data> find(Key const& k);
// Range is inclusve on lower bound and exclusive on upper bound.
List<pair<Key, Data>> find(Key const& lower, Key const& upper);
// Visitor is called as visitor(key, data).
template <typename Visitor>
void forEach(Key const& lower, Key const& upper, Visitor&& visitor);
// Visitor is called as visitor(key, data).
template <typename Visitor>
void forAll(Visitor&& visitor);
// Recover all key value pairs possible, catching exceptions during scan and
// reading as much data as possible. Visitor is called as visitor(key, data),
// ErrorHandler is called as error(char const*, std::exception const&)
template <typename Visitor, typename ErrorHandler>
void recoverAll(Visitor&& visitor, ErrorHandler&& error);
// Visitor is called either as visitor(Index const&) or visitor(Leaf const&).
// Return false to halt traversal, true to continue.
template <typename Visitor>
void forAllNodes(Visitor&& visitor);
// returns true if old value overwritten.
bool insert(Key k, Data data);
// returns true if key was found.
bool remove(Key k);
// Removes list of keys in the given range, returns count removed.
// TODO: SLOW, right now does lots of different removes separately. Need to
// implement batch inserts and deletes.
List<pair<Key, Data>> remove(Key const& lower, Key const& upper);
uint64_t indexCount();
uint64_t leafCount();
uint64_t recordCount();
uint32_t indexLevels();
void createNewRoot();
private:
struct DataElement {
Key key;
Data data;
};
typedef List<DataElement> DataList;
struct DataCollector {
void operator()(Key const& k, Data const& d);
List<pair<Key, Data>> list;
};
struct RecordCounter {
bool operator()(Index const& index);
bool operator()(Leaf const& leaf);
BTreeMixin* parent;
uint64_t count;
};
struct IndexCounter {
bool operator()(Index const& index);
bool operator()(Leaf const&);
BTreeMixin* parent;
uint64_t count;
};
struct LeafCounter {
bool operator()(Index const& index);
bool operator()(Leaf const&);
BTreeMixin* parent;
uint64_t count;
};
enum ModifyAction {
InsertAction,
RemoveAction
};
enum ModifyState {
LeafNeedsJoin,
IndexNeedsJoin,
LeafSplit,
IndexSplit,
LeafNeedsUpdate,
IndexNeedsUpdate,
Done
};
struct ModifyInfo {
ModifyInfo(ModifyAction a, DataElement e);
DataElement targetElement;
ModifyAction action;
bool found;
ModifyState state;
Key newKey;
Pointer newPointer;
};
bool contains(Index const& index, Key const& k);
bool contains(Leaf const& leaf, Key const& k);
Maybe<Data> find(Index const& index, Key const& k);
Maybe<Data> find(Leaf const& leaf, Key const& k);
// Returns the highest key for the last leaf we have searched
template <typename Visitor>
Key forEach(Index const& index, Key const& lower, Key const& upper, Visitor&& o);
template <typename Visitor>
Key forEach(Leaf const& leaf, Key const& lower, Key const& upper, Visitor&& o);
// Returns the highest key for the last leaf we have searched
template <typename Visitor>
Key forAll(Index const& index, Visitor&& o);
template <typename Visitor>
Key forAll(Leaf const& leaf, Visitor&& o);
template <typename Visitor, typename ErrorHandler>
void recoverAll(Index const& index, Visitor&& o, ErrorHandler&& error);
template <typename Visitor, typename ErrorHandler>
void recoverAll(Leaf const& leaf, Visitor&& o, ErrorHandler&& error);
// Variable size values mean that merges can happen on inserts, so can't
// split up into insert / remove methods
void modify(Leaf& leafNode, ModifyInfo& info);
void modify(Index& indexNode, ModifyInfo& info);
bool modify(DataElement e, ModifyAction action);
// Traverses Indexes down the tree on the left side to get the least valued
// key that is pointed to by any leaf under this index. Needed when joining.
Key getLeftKey(Index const& index);
template <typename Visitor>
void forAllNodes(Index const& index, Visitor&& visitor);
pair<size_t, bool> leafFind(Leaf const& leaf, Key const& key);
size_t indexFind(Index const& index, Key const& key);
};
template <typename Base>
bool BTreeMixin<Base>::contains(Key const& k) {
if (Base::rootIsLeaf())
return contains(Base::loadLeaf(Base::rootPointer()), k);
else
return contains(Base::loadIndex(Base::rootPointer()), k);
}
template <typename Base>
auto BTreeMixin<Base>::find(Key const& k) -> Maybe<Data> {
if (Base::rootIsLeaf())
return find(Base::loadLeaf(Base::rootPointer()), k);
else
return find(Base::loadIndex(Base::rootPointer()), k);
}
template <typename Base>
auto BTreeMixin<Base>::find(Key const& lower, Key const& upper) -> List<pair<Key, Data>> {
DataCollector collector;
forEach(lower, upper, collector);
return collector.list;
}
template <typename Base>
template <typename Visitor>
void BTreeMixin<Base>::forEach(Key const& lower, Key const& upper, Visitor&& visitor) {
if (Base::rootIsLeaf())
forEach(Base::loadLeaf(Base::rootPointer()), lower, upper, std::forward<Visitor>(visitor));
else
forEach(Base::loadIndex(Base::rootPointer()), lower, upper, std::forward<Visitor>(visitor));
}
template <typename Base>
template <typename Visitor>
void BTreeMixin<Base>::forAll(Visitor&& visitor) {
if (Base::rootIsLeaf())
forAll(Base::loadLeaf(Base::rootPointer()), std::forward<Visitor>(visitor));
else
forAll(Base::loadIndex(Base::rootPointer()), std::forward<Visitor>(visitor));
}
template <typename Base>
template <typename Visitor, typename ErrorHandler>
void BTreeMixin<Base>::recoverAll(Visitor&& visitor, ErrorHandler&& error) {
try {
if (Base::rootIsLeaf())
recoverAll(Base::loadLeaf(Base::rootPointer()), std::forward<Visitor>(visitor), std::forward<ErrorHandler>(error));
else
recoverAll(Base::loadIndex(Base::rootPointer()), std::forward<Visitor>(visitor), std::forward<ErrorHandler>(error));
} catch (std::exception const& e) {
error("Error loading root index or leaf node", e);
}
}
template <typename Base>
template <typename Visitor>
void BTreeMixin<Base>::forAllNodes(Visitor&& visitor) {
if (Base::rootIsLeaf())
visitor(Base::loadLeaf(Base::rootPointer()));
else
forAllNodes(Base::loadIndex(Base::rootPointer()), std::forward<Visitor>(visitor));
}
template <typename Base>
bool BTreeMixin<Base>::insert(Key k, Data data) {
return modify(DataElement{std::move(k), std::move(data)}, InsertAction);
}
template <typename Base>
bool BTreeMixin<Base>::remove(Key k) {
return modify(DataElement{std::move(k), Data()}, RemoveAction);
}
template <typename Base>
auto BTreeMixin<Base>::remove(Key const& lower, Key const& upper) -> List<pair<Key, Data>> {
DataCollector collector;
forEach(lower, upper, collector);
for (auto const& elem : collector.list)
remove(elem.first);
return collector.list;
}
template <typename Base>
uint64_t BTreeMixin<Base>::indexCount() {
IndexCounter counter = {this, 0};
forAllNodes(counter);
return counter.count;
}
template <typename Base>
uint64_t BTreeMixin<Base>::leafCount() {
LeafCounter counter = {this, 0};
forAllNodes(counter);
return counter.count;
}
template <typename Base>
uint64_t BTreeMixin<Base>::recordCount() {
RecordCounter counter = {this, 0};
forAllNodes(counter);
return counter.count;
}
template <typename Base>
uint32_t BTreeMixin<Base>::indexLevels() {
if (Base::rootIsLeaf())
return 0;
else
return Base::indexLevel(Base::loadIndex(Base::rootPointer())) + 1;
}
template <typename Base>
void BTreeMixin<Base>::createNewRoot() {
Base::setNewRoot(Base::storeLeaf(Base::createLeaf()), true);
}
template <typename Base>
void BTreeMixin<Base>::DataCollector::operator()(Key const& k, Data const& d) {
list.push_back({k, d});
}
template <typename Base>
bool BTreeMixin<Base>::RecordCounter::operator()(Index const&) {
return true;
}
template <typename Base>
bool BTreeMixin<Base>::RecordCounter::operator()(Leaf const& leaf) {
count += parent->leafElementCount(leaf);
return true;
}
template <typename Base>
bool BTreeMixin<Base>::IndexCounter::operator()(Index const& index) {
++count;
if (parent->indexLevel(index) == 0)
return false;
else
return true;
}
template <typename Base>
bool BTreeMixin<Base>::IndexCounter::operator()(Leaf const&) {
return false;
}
template <typename Base>
bool BTreeMixin<Base>::LeafCounter::operator()(Index const& index) {
if (parent->indexLevel(index) == 0) {
count += parent->indexPointerCount(index);
return false;
} else {
return true;
}
}
template <typename Base>
bool BTreeMixin<Base>::LeafCounter::operator()(Leaf const&) {
return false;
}
template <typename Base>
BTreeMixin<Base>::ModifyInfo::ModifyInfo(ModifyAction a, DataElement e)
: targetElement(std::move(e)), action(a) {
found = false;
state = Done;
}
template <typename Base>
bool BTreeMixin<Base>::contains(Index const& index, Key const& k) {
size_t i = indexFind(index, k);
if (Base::indexLevel(index) == 0)
return contains(Base::loadLeaf(Base::indexPointer(index, i)), k);
else
return contains(Base::loadIndex(Base::indexPointer(index, i)), k);
}
template <typename Base>
bool BTreeMixin<Base>::contains(Leaf const& leaf, Key const& k) {
return leafFind(leaf, k).second;
}
template <typename Base>
auto BTreeMixin<Base>::find(Index const& index, Key const& k) -> Maybe<Data> {
size_t i = indexFind(index, k);
if (Base::indexLevel(index) == 0)
return find(Base::loadLeaf(Base::indexPointer(index, i)), k);
else
return find(Base::loadIndex(Base::indexPointer(index, i)), k);
}
template <typename Base>
auto BTreeMixin<Base>::find(Leaf const& leaf, Key const& k) -> Maybe<Data> {
pair<size_t, bool> res = leafFind(leaf, k);
if (res.second)
return Base::leafData(leaf, res.first);
else
return {};
}
template <typename Base>
template <typename Visitor>
auto BTreeMixin<Base>::forEach(Index const& index, Key const& lower, Key const& upper, Visitor&& o) -> Key {
size_t i = indexFind(index, lower);
Key lastKey;
if (Base::indexLevel(index) == 0)
lastKey = forEach(Base::loadLeaf(Base::indexPointer(index, i)), lower, upper, std::forward<Visitor>(o));
else
lastKey = forEach(Base::loadIndex(Base::indexPointer(index, i)), lower, upper, std::forward<Visitor>(o));
if (!(lastKey < upper))
return lastKey;
while (i < Base::indexPointerCount(index) - 1) {
++i;
// We're visiting the right side of the key, so if lastKey >=
// indexKeyBefore(index, i), we have already visited this node via nextLeaf
// pointers, so skip it.
if (!(lastKey < Base::indexKeyBefore(index, i)))
continue;
if (Base::indexLevel(index) == 0)
lastKey = forEach(Base::loadLeaf(Base::indexPointer(index, i)), lower, upper, std::forward<Visitor>(o));
else
lastKey = forEach(Base::loadIndex(Base::indexPointer(index, i)), lower, upper, std::forward<Visitor>(o));
if (!(lastKey < upper))
break;
}
return lastKey;
}
template <typename Base>
template <typename Visitor>
auto BTreeMixin<Base>::forEach(Leaf const& leaf, Key const& lower, Key const& upper, Visitor&& o) -> Key {
if (Base::leafElementCount(leaf) == 0)
return Key();
size_t lowerIndex = leafFind(leaf, lower).first;
for (size_t i = lowerIndex; i != Base::leafElementCount(leaf); ++i) {
Key currentKey = Base::leafKey(leaf, i);
if (!(currentKey < lower)) {
if (currentKey < upper)
o(currentKey, Base::leafData(leaf, i));
else
return currentKey;
}
}
if (auto nextLeafPointer = Base::nextLeaf(leaf))
return forEach(Base::loadLeaf(*nextLeafPointer), lower, upper, o);
else
return Base::leafKey(leaf, Base::leafElementCount(leaf) - 1);
}
template <typename Base>
template <typename Visitor>
auto BTreeMixin<Base>::forAll(Index const& index, Visitor&& o) -> Key {
Key lastKey;
for (size_t i = 0; i < Base::indexPointerCount(index); ++i) {
// If we're to the right of a given key, but lastKey >= this key, then we
// must have already visited this node via nextLeaf pointers, so we can
// skip it.
if (i > 0 && !(lastKey < Base::indexKeyBefore(index, i)))
continue;
if (Base::indexLevel(index) == 0)
lastKey = forAll(Base::loadLeaf(Base::indexPointer(index, i)), std::forward<Visitor>(o));
else
lastKey = forAll(Base::loadIndex(Base::indexPointer(index, i)), std::forward<Visitor>(o));
}
return lastKey;
}
template <typename Base>
template <typename Visitor>
auto BTreeMixin<Base>::forAll(Leaf const& leaf, Visitor&& o) -> Key {
if (Base::leafElementCount(leaf) == 0)
return Key();
for (size_t i = 0; i != Base::leafElementCount(leaf); ++i) {
Key currentKey = Base::leafKey(leaf, i);
o(Base::leafKey(leaf, i), Base::leafData(leaf, i));
}
if (auto nextLeafPointer = Base::nextLeaf(leaf))
return forAll(Base::loadLeaf(*nextLeafPointer), std::forward<Visitor>(o));
else
return Base::leafKey(leaf, Base::leafElementCount(leaf) - 1);
}
template <typename Base>
template <typename Visitor, typename ErrorHandler>
void BTreeMixin<Base>::recoverAll(Index const& index, Visitor&& visitor, ErrorHandler&& error) {
try {
for (size_t i = 0; i < Base::indexPointerCount(index); ++i) {
if (Base::indexLevel(index) == 0) {
try {
recoverAll(Base::loadLeaf(Base::indexPointer(index, i)), std::forward<Visitor>(visitor), std::forward<ErrorHandler>(error));
} catch (std::exception const& e) {
error("Error loading leaf node", e);
}
} else {
try {
recoverAll(Base::loadIndex(Base::indexPointer(index, i)), std::forward<Visitor>(visitor), std::forward<ErrorHandler>(error));
} catch (std::exception const& e) {
error("Error loading index node", e);
}
}
}
} catch (std::exception const& e) {
error("Error reading index node", e);
}
}
template <typename Base>
template <typename Visitor, typename ErrorHandler>
void BTreeMixin<Base>::recoverAll(Leaf const& leaf, Visitor&& visitor, ErrorHandler&& error) {
try {
for (size_t i = 0; i != Base::leafElementCount(leaf); ++i) {
Key currentKey = Base::leafKey(leaf, i);
visitor(Base::leafKey(leaf, i), Base::leafData(leaf, i));
}
} catch (std::exception const& e) {
error("Error reading leaf node", e);
}
}
template <typename Base>
void BTreeMixin<Base>::modify(Leaf& leafNode, ModifyInfo& info) {
info.state = Done;
pair<size_t, bool> res = leafFind(leafNode, info.targetElement.key);
size_t i = res.first;
if (res.second) {
info.found = true;
Base::leafRemove(leafNode, i);
}
// No change necessary.
if (info.action == RemoveAction && !info.found)
return;
if (info.action == InsertAction)
Base::leafInsert(leafNode, i, info.targetElement.key, std::move(info.targetElement.data));
auto splitResult = Base::leafSplit(leafNode);
if (splitResult) {
Base::setNextLeaf(*splitResult, Base::nextLeaf(leafNode));
info.newKey = Base::leafKey(*splitResult, 0);
info.newPointer = Base::storeLeaf(splitResult.take());
Base::setNextLeaf(leafNode, info.newPointer);
info.state = LeafSplit;
} else if (Base::leafNeedsShift(leafNode)) {
info.state = LeafNeedsJoin;
} else {
info.state = LeafNeedsUpdate;
}
}
template <typename Base>
void BTreeMixin<Base>::modify(Index& indexNode, ModifyInfo& info) {
size_t i = indexFind(indexNode, info.targetElement.key);
Pointer nextPointer = Base::indexPointer(indexNode, i);
Leaf lowerLeaf;
Index lowerIndex;
if (Base::indexLevel(indexNode) == 0) {
lowerLeaf = Base::loadLeaf(nextPointer);
modify(lowerLeaf, info);
} else {
lowerIndex = Base::loadIndex(nextPointer);
modify(lowerIndex, info);
}
if (info.state == Done)
return;
bool selfUpdated = false;
size_t left = 0;
size_t right = 0;
if (i != 0 && i == Base::indexPointerCount(indexNode) - 1) {
left = i - 1;
right = i;
} else {
left = i;
right = i + 1;
}
if (info.state == LeafNeedsJoin) {
if (Base::indexPointerCount(indexNode) < 2) {
// Don't have enough leaves to join, just do the pending update.
info.state = LeafNeedsUpdate;
} else {
Leaf leftLeaf;
Leaf rightLeaf;
if (left == i) {
leftLeaf = lowerLeaf;
rightLeaf = Base::loadLeaf(Base::indexPointer(indexNode, right));
} else {
leftLeaf = Base::loadLeaf(Base::indexPointer(indexNode, left));
rightLeaf = lowerLeaf;
}
if (!Base::leafShift(leftLeaf, rightLeaf)) {
// Leaves not modified, just do the pending update.
info.state = LeafNeedsUpdate;
} else if (Base::leafElementCount(rightLeaf) == 0) {
// Leaves merged.
Base::setNextLeaf(leftLeaf, Base::nextLeaf(rightLeaf));
Base::deleteLeaf(std::move(rightLeaf));
// Replace two sibling pointer elements with one pointing to merged
// leaf.
if (left != 0)
Base::indexUpdateKeyBefore(indexNode, left, Base::leafKey(leftLeaf, 0));
Base::indexUpdatePointer(indexNode, left, Base::storeLeaf(std::move(leftLeaf)));
Base::indexRemoveBefore(indexNode, right);
selfUpdated = true;
} else {
// Leaves shifted.
Base::indexUpdatePointer(indexNode, left, Base::storeLeaf(std::move(leftLeaf)));
// Right leaf first key changes on shift, so always need to update
// left index node.
Base::indexUpdateKeyBefore(indexNode, right, Base::leafKey(rightLeaf, 0));
Base::indexUpdatePointer(indexNode, right, Base::storeLeaf(std::move(rightLeaf)));
selfUpdated = true;
}
}
}
if (info.state == IndexNeedsJoin) {
if (Base::indexPointerCount(indexNode) < 2) {
// Don't have enough indexes to join, just do the pending update.
info.state = IndexNeedsUpdate;
} else {
Index leftIndex;
Index rightIndex;
if (left == i) {
leftIndex = lowerIndex;
rightIndex = Base::loadIndex(Base::indexPointer(indexNode, right));
} else {
leftIndex = Base::loadIndex(Base::indexPointer(indexNode, left));
rightIndex = lowerIndex;
}
if (!Base::indexShift(leftIndex, getLeftKey(rightIndex), rightIndex)) {
// Indexes not modified, just do the pending update.
info.state = IndexNeedsUpdate;
} else if (Base::indexPointerCount(rightIndex) == 0) {
// Indexes merged.
Base::deleteIndex(std::move(rightIndex));
// Replace two sibling pointer elements with one pointing to merged
// index.
if (left != 0)
Base::indexUpdateKeyBefore(indexNode, left, getLeftKey(leftIndex));
Base::indexUpdatePointer(indexNode, left, Base::storeIndex(std::move(leftIndex)));
Base::indexRemoveBefore(indexNode, right);
selfUpdated = true;
} else {
// Indexes shifted.
Base::indexUpdatePointer(indexNode, left, Base::storeIndex(std::move(leftIndex)));
// Right index first key changes on shift, so always need to update
// right index node.
Key keyForRight = getLeftKey(rightIndex);
Base::indexUpdatePointer(indexNode, right, Base::storeIndex(std::move(rightIndex)));
Base::indexUpdateKeyBefore(indexNode, right, keyForRight);
selfUpdated = true;
}
}
}
if (info.state == LeafSplit) {
Base::indexUpdatePointer(indexNode, i, Base::storeLeaf(std::move(lowerLeaf)));
Base::indexInsertAfter(indexNode, i, info.newKey, info.newPointer);
selfUpdated = true;
}
if (info.state == IndexSplit) {
Base::indexUpdatePointer(indexNode, i, Base::storeIndex(std::move(lowerIndex)));
Base::indexInsertAfter(indexNode, i, info.newKey, info.newPointer);
selfUpdated = true;
}
if (info.state == LeafNeedsUpdate) {
Pointer lowerLeafPointer = Base::storeLeaf(std::move(lowerLeaf));
if (lowerLeafPointer != Base::indexPointer(indexNode, i)) {
Base::indexUpdatePointer(indexNode, i, lowerLeafPointer);
selfUpdated = true;
}
}
if (info.state == IndexNeedsUpdate) {
Pointer lowerIndexPointer = Base::storeIndex(std::move(lowerIndex));
if (lowerIndexPointer != Base::indexPointer(indexNode, i)) {
Base::indexUpdatePointer(indexNode, i, lowerIndexPointer);
selfUpdated = true;
}
}
auto splitResult = Base::indexSplit(indexNode);
if (splitResult) {
info.newKey = splitResult->first;
info.newPointer = Base::storeIndex(splitResult.take().second);
info.state = IndexSplit;
selfUpdated = true;
} else if (Base::indexNeedsShift(indexNode)) {
info.state = IndexNeedsJoin;
} else if (selfUpdated) {
info.state = IndexNeedsUpdate;
} else {
info.state = Done;
}
}
template <typename Base>
bool BTreeMixin<Base>::modify(DataElement e, ModifyAction action) {
ModifyInfo info(action, std::move(e));
Leaf lowerLeaf;
Index lowerIndex;
if (Base::rootIsLeaf()) {
lowerLeaf = Base::loadLeaf(Base::rootPointer());
modify(lowerLeaf, info);
} else {
lowerIndex = Base::loadIndex(Base::rootPointer());
modify(lowerIndex, info);
}
if (info.state == IndexNeedsJoin) {
if (Base::indexPointerCount(lowerIndex) == 1) {
// If root index has single pointer, then make that the new root.
// release index first (to support the common use case of delaying
// removes until setNewRoot)
Pointer pointer = Base::indexPointer(lowerIndex, 0);
size_t level = Base::indexLevel(lowerIndex);
Base::deleteIndex(std::move(lowerIndex));
Base::setNewRoot(pointer, level == 0);
} else {
// Else just update.
info.state = IndexNeedsUpdate;
}
}
if (info.state == LeafNeedsJoin) {
// Ignore NeedsJoin on LeafNode root, just update.
info.state = LeafNeedsUpdate;
}
if (info.state == LeafSplit || info.state == IndexSplit) {
Index newRoot;
if (info.state == IndexSplit) {
auto rootIndexLevel = Base::indexLevel(lowerIndex) + 1;
newRoot = Base::createIndex(Base::storeIndex(std::move(lowerIndex)));
Base::setIndexLevel(newRoot, rootIndexLevel);
} else {
newRoot = Base::createIndex(Base::storeLeaf(std::move(lowerLeaf)));
Base::setIndexLevel(newRoot, 0);
}
Base::indexInsertAfter(newRoot, 0, info.newKey, info.newPointer);
Base::setNewRoot(Base::storeIndex(std::move(newRoot)), false);
}
if (info.state == IndexNeedsUpdate) {
Pointer newRootPointer = Base::storeIndex(std::move(lowerIndex));
if (newRootPointer != Base::rootPointer())
Base::setNewRoot(newRootPointer, false);
}
if (info.state == LeafNeedsUpdate) {
Pointer newRootPointer = Base::storeLeaf(std::move(lowerLeaf));
if (newRootPointer != Base::rootPointer())
Base::setNewRoot(newRootPointer, true);
}
return info.found;
}
template <typename Base>
auto BTreeMixin<Base>::getLeftKey(Index const& index) -> Key {
if (Base::indexLevel(index) == 0) {
Leaf leaf = Base::loadLeaf(Base::indexPointer(index, 0));
return Base::leafKey(leaf, 0);
} else {
return getLeftKey(Base::loadIndex(Base::indexPointer(index, 0)));
}
}
template <typename Base>
template <typename Visitor>
void BTreeMixin<Base>::forAllNodes(Index const& index, Visitor&& visitor) {
if (!visitor(index))
return;
for (size_t i = 0; i < Base::indexPointerCount(index); ++i) {
if (Base::indexLevel(index) != 0) {
forAllNodes(Base::loadIndex(Base::indexPointer(index, i)), std::forward<Visitor>(visitor));
} else {
if (!visitor(Base::loadLeaf(Base::indexPointer(index, i))))
return;
}
}
}
template <typename Base>
pair<size_t, bool> BTreeMixin<Base>::leafFind(Leaf const& leaf, Key const& key) {
// Return lower bound binary search result.
size_t size = Base::leafElementCount(leaf);
if (size == 0)
return {0, false};
size_t len = size;
size_t first = 0;
size_t middle = 0;
size_t half;
while (len > 0) {
half = len / 2;
middle = first + half;
if (Base::leafKey(leaf, middle) < key) {
first = middle + 1;
len = len - half - 1;
} else {
len = half;
}
}
return make_pair(first, first < size && !(key < Base::leafKey(leaf, first)));
}
template <typename Base>
size_t BTreeMixin<Base>::indexFind(Index const& index, Key const& key) {
// Return upper bound binary search result of range [1, size];
size_t size = Base::indexPointerCount(index);
if (size == 0)
return 0;
size_t len = size - 1;
size_t first = 1;
size_t middle = 1;
size_t half;
while (len > 0) {
half = len / 2;
middle = first + half;
if (key < Base::indexKeyBefore(index, middle)) {
len = half;
} else {
first = middle + 1;
len = len - half - 1;
}
}
return first - 1;
}
}
#endif