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| author | Remko Tronçon <git@el-tramo.be> | 2012-04-23 16:11:21 (GMT) |
|---|---|---|
| committer | Remko Tronçon <git@el-tramo.be> | 2012-04-23 16:11:21 (GMT) |
| commit | 7bd058600b682781abb3fd93bfaf516e7d8d7b23 (patch) | |
| tree | 56ee7619b3785ff09a15ffdb54ac6427cd052dbf /Swiften/Network | |
| parent | 00981790bc39e9a0674feec19ffa792329bb077c (diff) | |
| download | swift-contrib-7bd058600b682781abb3fd93bfaf516e7d8d7b23.zip swift-contrib-7bd058600b682781abb3fd93bfaf516e7d8d7b23.tar.bz2 | |
Another fix for SRV selection.
Diffstat (limited to 'Swiften/Network')
| -rw-r--r-- | Swiften/Network/DomainNameServiceQuery.cpp | 33 | ||||
| -rw-r--r-- | Swiften/Network/UnitTest/DomainNameServiceQueryTest.cpp | 12 |
2 files changed, 20 insertions, 25 deletions
diff --git a/Swiften/Network/DomainNameServiceQuery.cpp b/Swiften/Network/DomainNameServiceQuery.cpp index f7ffecc..da1e1ab 100644 --- a/Swiften/Network/DomainNameServiceQuery.cpp +++ b/Swiften/Network/DomainNameServiceQuery.cpp @@ -8,6 +8,8 @@ #include <numeric> #include <cassert> +#include <functional> +#include <iterator> #include <Swiften/Base/RandomGenerator.h> #include <boost/numeric/conversion/cast.hpp> @@ -21,19 +23,12 @@ namespace { } }; - struct WeightAccumulator { - int operator()(int accumulator, const DomainNameServiceQuery::Result& result) { - return accumulator + result.weight; - } - }; + struct GetWeight { + GetWeight() {} - struct WeightToProbability { - WeightToProbability(int total) : total(total) {} - - double operator()(const DomainNameServiceQuery::Result& result) { - return result.weight / boost::numeric_cast<double>(total); + int operator()(const DomainNameServiceQuery::Result& result) { + return result.weight + 1 /* easy hack to account for '0' weights getting at least some weight */; } - int total; }; } @@ -50,15 +45,15 @@ void DomainNameServiceQuery::sortResults(std::vector<DomainNameServiceQuery::Res while (i != queries.end()) { std::vector<DomainNameServiceQuery::Result>::iterator next = std::upper_bound(i, queries.end(), *i, comparator); if (std::distance(i, next) > 1) { - int weightSum = std::accumulate(i, next, 0, WeightAccumulator()); - std::vector<double> probabilities; - std::transform(i, next, std::back_inserter(probabilities), WeightToProbability(weightSum > 0 ? weightSum : 1)); - - // Shuffling the result array and the probabilities in parallel - for (size_t j = 0; j < probabilities.size(); ++j) { - int selectedIndex = generator.generateWeighedRandomNumber(probabilities.begin() + j, probabilities.end()); + std::vector<int> weights; + std::transform(i, next, std::back_inserter(weights), GetWeight()); + for (size_t j = 0; j < weights.size() - 1; ++j) { + std::vector<int> cumulativeWeights; + std::partial_sum(weights.begin() + j, weights.end(), std::back_inserter(cumulativeWeights)); + int randomNumber = generator.generateRandomInteger(cumulativeWeights.back()); + int selectedIndex = std::lower_bound(cumulativeWeights.begin(), cumulativeWeights.end(), randomNumber) - cumulativeWeights.begin(); std::swap(i[j], i[j + selectedIndex]); - std::swap(probabilities.begin()[j], probabilities.begin()[j + selectedIndex]); + std::swap(weights.begin()[j], weights.begin()[j + selectedIndex]); } } i = next; diff --git a/Swiften/Network/UnitTest/DomainNameServiceQueryTest.cpp b/Swiften/Network/UnitTest/DomainNameServiceQueryTest.cpp index aefd815..53b9413 100644 --- a/Swiften/Network/UnitTest/DomainNameServiceQueryTest.cpp +++ b/Swiften/Network/UnitTest/DomainNameServiceQueryTest.cpp @@ -16,14 +16,14 @@ using namespace Swift; namespace { struct RandomGenerator1 : public RandomGenerator { - virtual int generateWeighedRandomNumber(std::vector<double>::const_iterator, std::vector<double>::const_iterator) { + virtual int generateRandomInteger(int) { return 0; } }; struct RandomGenerator2 : public RandomGenerator { - virtual int generateWeighedRandomNumber(std::vector<double>::const_iterator probabilities_begin, std::vector<double>::const_iterator probabilities_end) { - return std::max_element(probabilities_begin, probabilities_end) - probabilities_begin; + virtual int generateRandomInteger(int i) { + return i; } }; } @@ -70,9 +70,9 @@ class DomainNameServiceQueryTest : public CppUnit::TestFixture { CPPUNIT_ASSERT_EQUAL(std::string("server5.com"), results[0].hostname); CPPUNIT_ASSERT_EQUAL(std::string("server7.com"), results[1].hostname); - CPPUNIT_ASSERT_EQUAL(std::string("server4.com"), results[2].hostname); - CPPUNIT_ASSERT_EQUAL(std::string("server6.com"), results[3].hostname); - CPPUNIT_ASSERT_EQUAL(std::string("server2.com"), results[4].hostname); + CPPUNIT_ASSERT_EQUAL(std::string("server2.com"), results[2].hostname); + CPPUNIT_ASSERT_EQUAL(std::string("server4.com"), results[3].hostname); + CPPUNIT_ASSERT_EQUAL(std::string("server6.com"), results[4].hostname); CPPUNIT_ASSERT_EQUAL(std::string("server1.com"), results[5].hostname); CPPUNIT_ASSERT_EQUAL(std::string("server3.com"), results[6].hostname); } |