mirror of https://github.com/aria2/aria2
Simplified PieceStatMan and RarestPieceSelector.
Simplified PieceStatMan and RarestPieceSelector, but computation order to select piece index is still O(N) and unchanged. Updating piece stat is improved to O(N) for bitfield update and O(1) for single index update, while old implementation needs O(NlogN) and O(N) respectively.pull/1/head
Tatsuhiro Tsujikawa
parent
37016c6587
commit
6ee913b0bc
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@ -34,6 +34,7 @@
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/* copyright --> */
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#include "PieceStatMan.h"
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#include <limits>
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#include <algorithm>
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#include "SimpleRandomizer.h"
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@ -41,138 +42,80 @@
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namespace aria2 {
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PieceStat::PieceStat(size_t index):order_(0), index_(index), count_(0) {}
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void PieceStat::addCount()
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{
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if(count_ < SIZE_MAX) {
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++count_;
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}
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}
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void PieceStat::subCount()
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{
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if(count_ > 0) {
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--count_;
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}
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}
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namespace {
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class GenPieceStat {
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private:
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size_t index_;
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public:
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GenPieceStat():index_(0) {}
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SharedHandle<PieceStat> operator()()
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{
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return SharedHandle<PieceStat>(new PieceStat(index_++));
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}
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};
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} // namespace
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PieceStatMan::PieceStatMan(size_t pieceNum, bool randomShuffle):
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pieceStats_(pieceNum),
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sortedPieceStatIndexes_(pieceNum)
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order_(pieceNum),
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counts_(pieceNum)
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{
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std::generate(pieceStats_.begin(), pieceStats_.end(), GenPieceStat());
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std::vector<SharedHandle<PieceStat> > sortedPieceStats(pieceStats_);
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for(size_t i = 0; i < pieceNum; ++i) {
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order_[i] = i;
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}
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// we need some randomness in ordering.
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if(randomShuffle) {
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std::random_shuffle(sortedPieceStats.begin(), sortedPieceStats.end(),
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std::random_shuffle(order_.begin(), order_.end(),
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*(SimpleRandomizer::getInstance().get()));
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}
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{
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size_t order = 0;
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for(std::vector<SharedHandle<PieceStat> >::const_iterator i =
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sortedPieceStats.begin(), eoi = sortedPieceStats.end();
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i != eoi; ++i) {
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sortedPieceStatIndexes_[order] = (*i)->getIndex();
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(*i)->setOrder(order++);
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}
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}
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}
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PieceStatMan::~PieceStatMan() {}
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namespace {
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class PieceStatRarer {
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private:
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const std::vector<SharedHandle<PieceStat> >& pieceStats_;
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public:
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PieceStatRarer(const std::vector<SharedHandle<PieceStat> >& ps):
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pieceStats_(ps) {}
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bool operator()(size_t lhs, size_t rhs) const
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{
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return *pieceStats_[lhs] < *pieceStats_[rhs];
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void inc(int& x)
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{
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if(x < std::numeric_limits<int>::max()) {
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++x;
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}
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};
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}
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} // namespace
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namespace {
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void sub(int& x)
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{
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if(x > 0) {
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--x;
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}
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}
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} // namespace
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void PieceStatMan::addPieceStats(const unsigned char* bitfield,
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size_t bitfieldLength)
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{
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const size_t nbits = pieceStats_.size();
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assert(nbits <= bitfieldLength*8);
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for(size_t i = 0; i < nbits; ++i) {
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for(size_t i = 0, nbits = counts_.size(); i < nbits; ++i) {
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if(bitfield::test(bitfield, nbits, i)) {
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pieceStats_[i]->addCount();
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inc(counts_[i]);
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}
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}
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std::sort(sortedPieceStatIndexes_.begin(), sortedPieceStatIndexes_.end(),
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PieceStatRarer(pieceStats_));
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}
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void PieceStatMan::subtractPieceStats(const unsigned char* bitfield,
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size_t bitfieldLength)
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{
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const size_t nbits = pieceStats_.size();
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assert(nbits <= bitfieldLength*8);
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for(size_t i = 0; i < nbits; ++i) {
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for(size_t i = 0, nbits = counts_.size(); i < nbits; ++i) {
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if(bitfield::test(bitfield, nbits, i)) {
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pieceStats_[i]->subCount();
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sub(counts_[i]);
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}
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}
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std::sort(sortedPieceStatIndexes_.begin(), sortedPieceStatIndexes_.end(),
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PieceStatRarer(pieceStats_));
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}
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void PieceStatMan::updatePieceStats(const unsigned char* newBitfield,
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size_t newBitfieldLength,
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const unsigned char* oldBitfield)
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{
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const size_t nbits = pieceStats_.size();
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assert(nbits <= newBitfieldLength*8);
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for(size_t i = 0; i < nbits; ++i) {
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for(size_t i = 0, nbits = counts_.size(); i < nbits; ++i) {
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bool inNew = bitfield::test(newBitfield, nbits, i);
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bool inOld = bitfield::test(oldBitfield, nbits, i);
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if(inNew) {
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if(!inOld) {
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pieceStats_[i]->addCount();
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inc(counts_[i]);
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}
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} else if(inOld) {
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pieceStats_[i]->subCount();
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sub(counts_[i]);
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}
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}
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std::sort(sortedPieceStatIndexes_.begin(), sortedPieceStatIndexes_.end(),
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PieceStatRarer(pieceStats_));
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}
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void PieceStatMan::addPieceStats(size_t index)
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{
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std::vector<size_t>::iterator cur =
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std::lower_bound(sortedPieceStatIndexes_.begin(),
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sortedPieceStatIndexes_.end(),
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index, PieceStatRarer(pieceStats_));
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pieceStats_[index]->addCount();
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std::vector<size_t>::iterator to =
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std::upper_bound(cur+1, sortedPieceStatIndexes_.end(),
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index, PieceStatRarer(pieceStats_));
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std::rotate(cur, cur+1, to);
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inc(counts_[index]);
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}
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} // namespace aria2
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@ -43,53 +43,10 @@
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namespace aria2 {
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class PieceStat {
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private:
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size_t order_;
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size_t index_;
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size_t count_;
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public:
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PieceStat(size_t index);
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bool operator<(const PieceStat& pieceStat) const
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{
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if(count_ == pieceStat.count_) {
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return order_ < pieceStat.order_;
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} else {
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return count_ < pieceStat.count_;
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}
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}
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void addCount();
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void subCount();
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size_t getOrder() const
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{
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return order_;
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}
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void setOrder(size_t order)
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{
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order_ = order;
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}
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size_t getIndex() const
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{
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return index_;
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}
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size_t getCount() const
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{
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return count_;
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}
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};
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class PieceStatMan {
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private:
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std::vector<SharedHandle<PieceStat> > pieceStats_;
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std::vector<size_t> sortedPieceStatIndexes_;
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std::vector<size_t> order_;
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std::vector<int> counts_;
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public:
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PieceStatMan(size_t pieceNum, bool randomShuffle);
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@ -107,17 +64,15 @@ public:
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size_t newBitfieldLength,
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const unsigned char* oldBitfield);
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// Returns piece index in rarest first order.
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const std::vector<size_t>& getRarerPieceIndexes() const
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const std::vector<size_t>& getOrder() const
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{
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return sortedPieceStatIndexes_;
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return order_;
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}
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const std::vector<SharedHandle<PieceStat> >& getPieceStats() const
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const std::vector<int>& getCounts() const
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{
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return pieceStats_;
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return counts_;
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}
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};
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} // namespace aria2
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@ -34,47 +34,35 @@
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/* copyright --> */
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#include "RarestPieceSelector.h"
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#include <cassert>
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#include <limits>
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#include <algorithm>
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#include "PieceStatMan.h"
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#include "bitfield.h"
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namespace aria2 {
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RarestPieceSelector::RarestPieceSelector
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(const SharedHandle<PieceStatMan>& pieceStatMan):pieceStatMan_(pieceStatMan) {}
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namespace {
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class FindRarestPiece
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{
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private:
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const unsigned char* misbitfield_;
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size_t numbits_;
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public:
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FindRarestPiece(const unsigned char* misbitfield, size_t numbits):
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misbitfield_(misbitfield), numbits_(numbits) {}
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bool operator()(const size_t& index)
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{
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assert(index < numbits_);
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unsigned char mask = (128 >> (index%8));
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return misbitfield_[index/8]&mask;
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}
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};
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} // namespace
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bool RarestPieceSelector::select
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(size_t& index, const unsigned char* bitfield, size_t nbits) const
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{
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const std::vector<size_t>& pieceIndexes =
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pieceStatMan_->getRarerPieceIndexes();
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std::vector<size_t>::const_iterator i =
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std::find_if(pieceIndexes.begin(), pieceIndexes.end(),
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FindRarestPiece(bitfield, nbits));
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if(i == pieceIndexes.end()) {
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const std::vector<size_t>& order = pieceStatMan_->getOrder();
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const std::vector<int>& counts = pieceStatMan_->getCounts();
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int min = std::numeric_limits<int>::max();
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size_t bestIdx = nbits;
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for(size_t i = 0; i < nbits; ++i) {
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size_t idx = order[i];
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if(bitfield::test(bitfield, nbits, idx) && counts[idx] < min) {
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min = counts[idx];
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bestIdx = idx;
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}
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}
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if(bestIdx == nbits) {
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return false;
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} else {
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index = *i;
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index = bestIdx;
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return true;
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}
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}
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@ -31,56 +31,33 @@ void PieceStatManTest::testAddPieceStats_index()
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PieceStatMan pieceStatMan(10, false);
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pieceStatMan.addPieceStats(1);
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{
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size_t indexes[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 1 };
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size_t counts[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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CPPUNIT_ASSERT_EQUAL((size_t)10, stats.size());
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int ans[] = { 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 };
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const std::vector<size_t>& order(pieceStatMan.getOrder());
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(i, order[i]);
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
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}
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}
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pieceStatMan.addPieceStats(1);
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{
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size_t indexes[] = { 0, 2, 3, 4, 5, 6, 7, 8, 9, 1 };
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size_t counts[] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 2 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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int ans[] = { 0, 2, 0, 0, 0, 0, 0, 0, 0, 0 };
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
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}
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}
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pieceStatMan.addPieceStats(3);
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pieceStatMan.addPieceStats(9);
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pieceStatMan.addPieceStats(3);
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pieceStatMan.addPieceStats(0);
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{
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size_t indexes[] = { 2, 4, 5, 6, 7, 8, 0, 9, 1, 3 };
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size_t counts[] = { 0, 0, 0, 0, 0, 0, 1, 1, 2, 2 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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int ans[] = { 1, 2, 0, 2, 0, 0, 0, 0, 0, 1 };
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
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}
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}
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}
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void PieceStatManTest::testAddPieceStats_bitfield()
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@ -89,36 +66,18 @@ void PieceStatManTest::testAddPieceStats_bitfield()
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const unsigned char bitfield[] = { 0xaa, 0x80 };
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pieceStatMan.addPieceStats(bitfield, sizeof(bitfield));
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{
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size_t indexes[] = { 1, 3, 5, 7, 9, 0, 2, 4, 6, 8 };
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size_t counts[] = { 0, 0, 0, 0, 0, 1, 1, 1, 1, 1 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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CPPUNIT_ASSERT_EQUAL((size_t)10, stats.size());
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int ans[] = { 1, 0, 1, 0, 1, 0, 1, 0, 1, 0 };
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
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}
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}
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pieceStatMan.addPieceStats(bitfield, sizeof(bitfield));
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{
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size_t indexes[] = { 1, 3, 5, 7, 9, 0, 2, 4, 6, 8 };
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size_t counts[] = { 0, 0, 0, 0, 0, 2, 2, 2, 2, 2 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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CPPUNIT_ASSERT_EQUAL((size_t)10, stats.size());
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int ans[] = { 2, 0, 2, 0, 2, 0, 2, 0, 2, 0 };
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
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}
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}
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}
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@ -126,13 +85,10 @@ void PieceStatManTest::testAddPieceStats_bitfield()
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void PieceStatManTest::testUpdatePieceStats()
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{
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PieceStatMan pieceStatMan(10, false);
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const unsigned char bitfield[] = { 0xff, 0xc0 };
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pieceStatMan.addPieceStats(bitfield, sizeof(bitfield));
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const unsigned char oldBitfield[] = { 0xf0, 0x00 };
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const unsigned char newBitfield[] = { 0x1f, 0x00 };
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pieceStatMan.updatePieceStats(newBitfield, sizeof(newBitfield), oldBitfield);
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{
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// idx: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
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@ -141,19 +97,10 @@ void PieceStatManTest::testUpdatePieceStats()
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// new: 0, 0, 0, 1, 1, 1, 1, 1, 0, 0
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// ---------------------------------
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// res: 0, 0, 0, 1, 2, 2, 2, 2, 1, 1
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size_t indexes[] = { 0, 1, 2, 3, 8, 9, 4, 5, 6, 7 };
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size_t counts[] = { 0, 0, 0, 1, 1, 1, 2, 2, 2, 2 };
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const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
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const std::vector<SharedHandle<PieceStat> >& stats
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(pieceStatMan.getPieceStats());
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CPPUNIT_ASSERT_EQUAL((size_t)10, stats.size());
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int ans[] = { 0, 0, 0, 1, 2, 2, 2, 2, 1, 1 };
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const std::vector<int>& counts(pieceStatMan.getCounts());
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for(size_t i = 0; i < 10; ++i) {
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CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
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CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
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CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -161,12 +108,9 @@ void PieceStatManTest::testUpdatePieceStats()
|
|||
void PieceStatManTest::testSubtractPieceStats()
|
||||
{
|
||||
PieceStatMan pieceStatMan(10, false);
|
||||
|
||||
const unsigned char bitfield[] = { 0xf0, 0x00 };
|
||||
pieceStatMan.addPieceStats(bitfield, sizeof(bitfield));
|
||||
|
||||
const unsigned char newBitfield[] = { 0x3f, 0x00 };
|
||||
|
||||
pieceStatMan.subtractPieceStats(newBitfield, sizeof(newBitfield));
|
||||
{
|
||||
// idx: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9
|
||||
|
|
@ -174,19 +118,10 @@ void PieceStatManTest::testSubtractPieceStats()
|
|||
// new: 0, 0, 1, 1, 1, 1, 1, 1, 0, 0
|
||||
// ---------------------------------
|
||||
// res: 1, 1, 0, 0, 0, 0, 0, 0, 0, 0
|
||||
|
||||
size_t indexes[] = { 2, 3, 4, 5, 6, 7, 8, 9, 0, 1 };
|
||||
size_t counts[] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1 };
|
||||
|
||||
const std::vector<size_t>& statsidx(pieceStatMan.getRarerPieceIndexes());
|
||||
const std::vector<SharedHandle<PieceStat> >& stats
|
||||
(pieceStatMan.getPieceStats());
|
||||
|
||||
CPPUNIT_ASSERT_EQUAL((size_t)10, stats.size());
|
||||
|
||||
int ans[] = { 1, 1, 0, 0, 0, 0, 0, 0, 0, 0 };
|
||||
const std::vector<int>& counts(pieceStatMan.getCounts());
|
||||
for(size_t i = 0; i < 10; ++i) {
|
||||
CPPUNIT_ASSERT_EQUAL(indexes[i], statsidx[i]);
|
||||
CPPUNIT_ASSERT_EQUAL(counts[i], stats[statsidx[i]]->getCount());
|
||||
CPPUNIT_ASSERT_EQUAL(ans[i], counts[i]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue