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/* Copyright (c) 2015, 2017 The Linux Foundation. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
* * Neither the name of The Linux Foundation, nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#ifndef __LOC_UNORDERDED_SETMAP_H__
#define __LOC_UNORDERDED_SETMAP_H__
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using std::unordered_set;
using std::unordered_map;
namespace loc_util {
// Trim from *fromSet* any elements that also exist in *rVals*.
// The optional *goneVals*, if not null, will be populated with removed elements.
template <typename T>
inline static void trimSet(unordered_set<T>& fromSet, const unordered_set<T>& rVals,
unordered_set<T>* goneVals) {
for (auto val : rVals) {
if (fromSet.erase(val) > 0 && nullptr != goneVals) {
goneVals->insert(val);
}
}
}
// this method is destructive to the input unordered_sets.
// the return set is the interset extracted out from the two input sets, *s1* and *s2*.
// *s1* and *s2* will be left with the intersect removed from them.
template <typename T>
static unordered_set<T> removeAndReturnInterset(unordered_set<T>& s1, unordered_set<T>& s2) {
unordered_set<T> common(0);
for (auto b = s2.begin(); b != s2.end(); b++) {
auto a = find(s1.begin(), s1.end(), *b);
if (a != s1.end()) {
// this is a common item of both l1 and l2, remove from both
// but after we add to common
common.insert(*a);
s1.erase(a);
s2.erase(b);
}
}
return common;
}
template <typename KEY, typename VAL>
class LocUnorderedSetMap {
unordered_map<KEY, unordered_set<VAL>> mMap;
// Trim the VALs pointed to by *iter*, with everything that also exist in *rVals*.
// If the set becomes empty, remove the map entry. *goneVals*, if not null, records
// the trimmed VALs.
bool trimOrRemove(typename unordered_map<KEY, unordered_set<VAL>>::iterator iter,
const unordered_set<VAL>& rVals, unordered_set<VAL>* goneVals) {
trimSet<VAL>(iter->second, rVals, goneVals);
bool removeEntry = (iter->second.empty());
if (removeEntry) {
mMap.erase(iter);
}
return removeEntry;
}
public:
inline LocUnorderedSetMap() {}
inline LocUnorderedSetMap(size_t size) : mMap(size) {}
inline bool empty() { return mMap.empty(); }
// This gets the raw pointer to the VALs pointed to by *key*
// If the entry is not in the map, nullptr will be returned.
inline unordered_set<VAL>* getValSetPtr(const KEY& key) {
auto entry = mMap.find(key);
return (entry != mMap.end()) ? &(entry->second) : nullptr;
}
// This gets a copy of VALs pointed to by *key*
// If the entry is not in the map, an empty set will be returned.
inline unordered_set<VAL> getValSet(const KEY& key) {
auto entry = mMap.find(key);
return (entry != mMap.end()) ? entry->second : unordered_set<VAL>(0);
}
// This gets all the KEYs from the map
inline unordered_set<KEY> getKeys() {
unordered_set<KEY> keys(0);
for (auto entry : mMap) {
keys.insert(entry.first);
}
return keys;
}
inline bool remove(const KEY& key) {
return mMap.erase(key) > 0;
}
// This looks into all the entries keyed by *keys*. Remove any VALs from the entries
// that also exist in *rVals*. If the entry is left with an empty set, the entry will
// be removed. The optional parameters *goneKeys* and *goneVals* will record the KEYs
// (or entries) and the collapsed VALs removed from the map, respectively.
inline void trimOrRemove(unordered_set<KEY>&& keys, const unordered_set<VAL>& rVals,
unordered_set<KEY>* goneKeys, unordered_set<VAL>* goneVals) {
trimOrRemove(keys, rVals, goneKeys, goneVals);
}
inline void trimOrRemove(unordered_set<KEY>& keys, const unordered_set<VAL>& rVals,
unordered_set<KEY>* goneKeys, unordered_set<VAL>* goneVals) {
for (auto key : keys) {
auto iter = mMap.find(key);
if (iter != mMap.end() && trimOrRemove(iter, rVals, goneVals) && nullptr != goneKeys) {
goneKeys->insert(iter->first);
}
}
}
// This adds all VALs from *newVals* to the map entry keyed by *key*. Or if it
// doesn't exist yet, add the set to the map.
bool add(const KEY& key, const unordered_set<VAL>& newVals) {
bool newEntryAdded = false;
if (!newVals.empty()) {
auto iter = mMap.find(key);
if (iter != mMap.end()) {
iter->second.insert(newVals.begin(), newVals.end());
} else {
mMap[key] = newVals;
newEntryAdded = true;
}
}
return newEntryAdded;
}
// This adds to each of entries in the map keyed by *keys* with the VALs in the
// *enwVals*. If there new entries added (new key in *keys*), *newKeys*, if not
// null, would be populated with those keys.
inline void add(const unordered_set<KEY>& keys, const unordered_set<VAL>&& newVals,
unordered_set<KEY>* newKeys) {
add(keys, newVals, newKeys);
}
inline void add(const unordered_set<KEY>& keys, const unordered_set<VAL>& newVals,
unordered_set<KEY>* newKeys) {
for (auto key : keys) {
if (add(key, newVals) && nullptr != newKeys) {
newKeys->insert(key);
}
}
}
// This puts *newVals* into the map keyed by *key*, and returns the VALs that are
// in effect removed from the keyed VAL set in the map entry.
// This call would also remove those same VALs from *newVals*.
inline unordered_set<VAL> update(const KEY& key, unordered_set<VAL>& newVals) {
unordered_set<VAL> goneVals(0);
if (newVals.empty()) {
mMap.erase(key);
} else {
auto curVals = mMap[key];
mMap[key] = newVals;
goneVals = removeAndReturnInterset(curVals, newVals);
}
return goneVals;
}
};
} // namespace loc_util
#endif // #ifndef __LOC_UNORDERDED_SETMAP_H__
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