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remove the finger trimming loops from PTree::lower_bound and upper_bound

This commit is contained in:
Russell Sears 2020-04-16 15:25:33 -07:00
parent ea02c5b896
commit c9489d45c5
1 changed files with 15 additions and 8 deletions
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23
fdbclient/VersionedMap.h
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@ -87,6 +87,7 @@ namespace PTreeImpl {
static constexpr size_t N = 64;
PTreeFingerEntry entries_[N];
size_t size_ = 0;
size_t bound_sz_ = 0;
public:
PTreeFinger() {}
@ -97,12 +98,14 @@ namespace PTreeImpl {
PTreeFinger& operator=(PTreeFinger const& f) {
size_ = f.size_;
bound_sz_ = f.bound_sz_;
std::copy(f.entries_, f.entries_ + size_, entries_);
return *this;
}
PTreeFinger& operator=(PTreeFinger&& f) {
size_ = std::exchange(f.size_, 0);
bound_sz_ = f.bound_sz_;
std::copy(f.entries_, f.entries_ + size_, entries_);
return *this;
}
@ -124,6 +127,14 @@ namespace PTreeImpl {
entries_[size_++] = { node, less };
ASSERT(size_ < N);
}
void push_for_bound(PTree<T> const* node, bool less) {
push_back(node, less);
bound_sz_ = less ? size_ : bound_sz_;
}
// remove the end of the finger so that the last entry is less than the probe
void trim_to_bound() { size_ = bound_sz_; }
};
template<class T>
@ -179,14 +190,12 @@ namespace PTreeImpl {
template <class T, class X>
void lower_bound(const Reference<PTree<T>>& p, Version at, const X& x, PTreeFinger<T>& f) {
if (!p) {
while (f.size() && !(f.back_less())) {
f.pop_back();
}
f.trim_to_bound();
return;
}
int cmp = compare(x, p->data);
bool less = cmp < 0;
f.push_back(p.getPtr(), less);
f.push_for_bound(p.getPtr(), less);
if (cmp == 0) return;
lower_bound(p->child(!less, at), at, x, f);
}
@ -194,13 +203,11 @@ namespace PTreeImpl {
template <class T, class X>
void upper_bound(const Reference<PTree<T>>& p, Version at, const X& x, PTreeFinger<T>& f) {
if (!p) {
while (f.size() && !(f.back_less())) {
f.pop_back();
}
f.trim_to_bound();
return;
}
bool less = x < p->data;
f.push_back(p.getPtr(), less);
f.push_for_bound(p.getPtr(), less);
upper_bound(p->child(!less, at), at, x, f);
}