foundationdb/fdbrpc/RangeMap.h

278 lines
8.9 KiB
C++

/*
* RangeMap.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FLOW_RANGEMAP_H
#define FLOW_RANGEMAP_H
#pragma once
#include "flow/flow.h"
#include <boost/range.hpp>
#include "flow/IndexedSet.h"
using boost::iterator_range;
template <class Key>
class RangeMapRange {
public:
Key begin, end;
RangeMapRange( Key const& begin, Key const& end ) : begin(begin), end(end) {}
};
template <class Key>
RangeMapRange<Key> rangeMapRange( Key const& begin, Key const& end ) { return RangeMapRange<Key>(begin,end); }
template <class Metric>
struct ConstantMetric {
template<typename pair_type>
Metric operator()(pair_type const& p) const { return Metric(1); }
};
template <class Metric>
struct KeyBytesMetric {
template<typename pair_type>
Metric operator()(pair_type const& p) const { return Metric(p.key.size() + sizeof(pair_type)); }
};
template <class Metric>
struct ValueBytesMetric {
template<typename pair_type>
Metric operator()(pair_type const& p) const { return Metric(p.value.size() + sizeof(pair_type)); }
};
template <class Metric>
struct KeyValueBytesMetric {
template<typename pair_type>
Metric operator()(pair_type const& p) const { return Metric(p.key.size() + p.value.size() + sizeof(pair_type)); }
};
template <class Key, class Val, class Range = RangeMapRange<Key>, class Metric = int, class MetricFunc = ConstantMetric<Metric>>
class RangeMap {
private:
typedef MapPair<Key,Val> pair_type;
//Applications may decrement an iterator before ranges begin, or increment after ranges end, but once in this state cannot do further incrementing or decrementing
template <bool isConst>
class IteratorImpl {
using self_t = IteratorImpl<isConst>;
public:
using value_type = std::conditional_t<isConst, typename Map<Key, Val, pair_type, Metric>::const_iterator,
typename Map<Key, Val, pair_type, Metric>::iterator>;
typedef std::forward_iterator_tag iterator_category;
using difference_type = int;
using pointer = self_t*;
using reference = self_t&;
IteratorImpl() {} // singular
explicit IteratorImpl<isConst>(const value_type it) : it(it) {}
Key const& begin() { return it->key; }
Key const& end() { auto j = it; ++j; return j->key; }
Range range() { return Range(begin(),end()); }
std::conditional_t<isConst, const Val&, Val&> value() {
//ASSERT( it->key != allKeys.end );
return it->value;
}
const Val& cvalue() const { return it->value; }
void operator ++() { ++it; }
void operator --() { it.decrementNonEnd(); }
bool operator==(self_t const& r) const { return it == r.it; }
bool operator!=(self_t const& r) const { return it != r.it; }
// operator* and -> return this
self_t& operator*() { return *this; }
self_t* operator->() { return this; }
private:
value_type it;
};
public:
using iterator = IteratorImpl<false>;
using const_iterator = IteratorImpl<true>;
using Ranges = iterator_range<iterator>;
using ConstRanges = iterator_range<const_iterator>;
explicit RangeMap(Key endKey, Val v=Val(), MetricFunc m = MetricFunc()) : mf(m) {
Key beginKey = Key();
pair_type beginPair(beginKey, v);
map.insert(beginPair, true, mf(beginPair));
pair_type endPair(endKey, Val());
map.insert(endPair, true, mf(endPair));
}
Val const& operator[]( const Key& k ) { return rangeContaining(k).value(); }
Ranges ranges() { return Ranges(iterator(map.begin()), iterator(map.lastItem())); }
ConstRanges ranges() const { return ConstRanges(const_iterator(map.begin()), const_iterator(map.lastItem())); }
// intersectingRanges returns [begin, end] where begin <= r.begin and end >= r.end
Ranges intersectingRanges(const Range& r) {
return Ranges(rangeContaining(r.begin), iterator(map.lower_bound(r.end)));
}
ConstRanges intersectingRanges(const Range& r) const {
return ConstRanges(rangeContaining(r.begin), const_iterator(map.lower_bound(r.end)));
}
// containedRanges() will return all ranges that are fully contained by the passed range (note that a range fully contains itself)
Ranges containedRanges(const Range& r) {
iterator s(map.lower_bound(r.begin));
if (s.begin() >= r.end) return Ranges(s, s);
return Ranges(s, rangeContaining(r.end));
}
template <class ComparableToKey>
iterator rangeContaining(const ComparableToKey& k) {
return iterator(map.lastLessOrEqual(k));
}
template <class ComparableToKey>
const_iterator rangeContaining(const ComparableToKey& k) const {
return const_iterator(map.lastLessOrEqual(k));
}
// Returns the range containing a key infinitesimally before k, or the first range if k==Key()
template <class ComparableToKey>
iterator rangeContainingKeyBefore(const ComparableToKey& k) {
iterator i(map.lower_bound(k));
if (!i->begin().size()) return i;
--i;
return i;
}
template <class ComparableToKey>
const_iterator rangeContainingKeyBefore(const ComparableToKey& k) const {
const_iterator i(map.lower_bound(k));
if ( !i->begin().size() ) return i;
--i;
return i;
}
iterator lastItem() {
auto i(map.lastItem());
i.decrementNonEnd();
return iterator(i);
}
int size() const { return map.size() - 1; } // We always have one range bounded by two entries
iterator randomRange() { return iterator(map.index(deterministicRandom()->randomInt(0, map.size() - 1))); }
const_iterator randomRange() const {
return const_iterator(map.index(deterministicRandom()->randomInt(0, map.size() - 1)));
}
iterator nthRange(int n) { return iterator(map.index(n)); }
const_iterator nthRange(int n) const { return const_iterator(map.index(n)); }
bool allEqual( const Range& r, const Val& v );
template <class ComparableToKey>
void coalesce( const ComparableToKey& k );
void coalesce( const Range& k );
void validateCoalesced();
void operator=(RangeMap&& r) noexcept { map = std::move(r.map); }
//void clear( const Val& value ) { ranges.clear(); ranges.insert(std::make_pair(Key(),value)); }
void insert( const Range& keys, const Val& value );
protected:
Map<Key,Val,pair_type,Metric> map;
const MetricFunc mf;
};
template <class Key, class Val, class Range, class Metric, class MetricFunc>
template <class ComparableToKey>
void RangeMap<Key,Val,Range,Metric,MetricFunc>::coalesce( const ComparableToKey& k ) {
auto begin = map.lastLessOrEqual(k);
auto end = begin;
const Val& compareVal = begin->value;
ASSERT( begin != map.end() );
while( begin != map.begin() && begin->value == compareVal )
begin.decrementNonEnd();
while( end != map.lastItem() && end->value == compareVal )
++end;
if( begin->value != compareVal ) {
++begin;
if( begin == end ) return;
}
++begin;
map.erase(begin, end);
}
template <class Key, class Val, class Range, class Metric, class MetricFunc>
void RangeMap<Key,Val,Range,Metric,MetricFunc>::coalesce( const Range& k ) {
coalesce(k.begin);
auto it = map.lastLessOrEqual(k.begin);
Val* lastVal = &it->value;
++it;
if( it == map.end() )
return;
bool doCheck = true;
while( it != map.lastItem() && doCheck ) {
doCheck = it->key < k.end;
if( it->value == *lastVal ) {
doCheck = true;
auto begin = it;
++it;
map.erase(begin, it);
}
else {
lastVal = &it->value;
++it;
}
}
if( EXPENSIVE_VALIDATION )
validateCoalesced();
}
template <class Key, class Val, class Range, class Metric, class MetricFunc>
void RangeMap<Key,Val,Range,Metric,MetricFunc>::validateCoalesced() {
auto it = map.begin();
Val* lastVal = &it->value;
++it;
auto end = map.lastItem();
for( ; it != end; ++it ) {
ASSERT( it->value != *lastVal );
lastVal = &it->value;
}
}
template <class Key, class Val, class Range, class Metric, class MetricFunc>
bool RangeMap<Key,Val,Range,Metric,MetricFunc>::allEqual( const Range& keys, const Val& val ) {
auto r = intersectingRanges(keys);
for(auto i=r.begin(); i!=r.end(); ++i)
if (i.value() != val)
return false;
return true;
}
template <class Key, class Val, class Range, class Metric, class MetricFunc>
void RangeMap<Key,Val,Range,Metric,MetricFunc>::insert( const Range& keys, const Val& value ) {
if(keys.begin == keys.end)
return;
auto end = map.lower_bound( keys.end );
if( end->key != keys.end ) {
end.decrementNonEnd();
const Val& valueAfterRange = end->value;
pair_type endPair(keys.end, valueAfterRange);
end = map.insert(endPair, true, mf(endPair));
}
auto begin = map.lower_bound( keys.begin );
map.erase(begin, end);
pair_type beginPair(keys.begin, value);
map.insert(beginPair, true, mf(beginPair));
}
#endif