diff --git a/src/Makefile.am b/src/Makefile.am
index c89aa097..8dfe3daf 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -197,7 +197,6 @@ SRCS =  option_processing.cc\
 	NullSinkStreamFilter.cc NullSinkStreamFilter.h\
 	uri.cc uri.h\
 	uri_split.c uri_split.h\
-	Triplet.h\
 	cookie_helper.cc cookie_helper.h\
 	json.cc json.h\
 	JsonParser.cc JsonParser.h\
diff --git a/src/RequestGroupMan.cc b/src/RequestGroupMan.cc
index 437cc69b..0d8fb484 100644
--- a/src/RequestGroupMan.cc
+++ b/src/RequestGroupMan.cc
@@ -70,7 +70,6 @@
 #include "Segment.h"
 #include "DlAbortEx.h"
 #include "uri.h"
-#include "Triplet.h"
 #include "Signature.h"
 #include "OutputFile.h"
 #include "download_helper.h"
@@ -920,45 +919,44 @@ bool RequestGroupMan::doesOverallUploadSpeedExceed()
 void RequestGroupMan::getUsedHosts
 (std::vector<std::pair<size_t, std::string> >& usedHosts)
 {
-  // vector of triplet which consists of use count, -download speed,
+  // vector of tuple which consists of use count, -download speed,
   // hostname. We want to sort by least used and faster download
   // speed. We use -download speed so that we can sort them using
   // operator<().
-  std::vector<Triplet<size_t, int, std::string> > tempHosts;
-  for(RequestGroupList::const_iterator i = requestGroups_.begin(),
-        eoi = requestGroups_.end(); i != eoi; ++i) {
-    const std::shared_ptr<RequestGroup>& rg = *i;
-    const FileEntry::InFlightRequestSet& inFlightReqs =
+  std::vector<std::tuple<size_t, int, std::string> > tempHosts;
+  for(const auto& rg : requestGroups_) {
+    const auto& inFlightReqs =
       rg->getDownloadContext()->getFirstFileEntry()->getInFlightRequests();
-    for(FileEntry::InFlightRequestSet::iterator j =
-          inFlightReqs.begin(), eoj = inFlightReqs.end(); j != eoj; ++j) {
+    for(const auto& req : inFlightReqs) {
       uri_split_result us;
-      if(uri_split(&us, (*j)->getUri().c_str()) == 0) {
-        std::vector<Triplet<size_t, int, std::string> >::iterator k;
-        std::vector<Triplet<size_t, int, std::string> >::iterator eok =
-          tempHosts.end();
+      if(uri_split(&us, req->getUri().c_str()) == 0) {
         std::string host = uri::getFieldString(us, USR_HOST,
-                                               (*j)->getUri().c_str());
-        for(k =  tempHosts.begin(); k != eok; ++k) {
-          if((*k).third == host) {
-            ++(*k).first;
+                                               req->getUri().c_str());
+        auto k = tempHosts.begin();
+        auto eok = tempHosts.end();
+        for(; k != eok; ++k) {
+          if(std::get<2>(*k) == host) {
+            ++std::get<0>(*k);
             break;
           }
         }
         if(k == eok) {
           std::string protocol = uri::getFieldString(us, USR_SCHEME,
-                                                     (*j)->getUri().c_str());
-          std::shared_ptr<ServerStat> ss = findServerStat(host, protocol);
+                                                     req->getUri().c_str());
+          auto ss = findServerStat(host, protocol);
           int invDlSpeed = (ss && ss->isOK()) ?
             -(static_cast<int>(ss->getDownloadSpeed())) : 0;
-          tempHosts.push_back(makeTriplet(1, invDlSpeed, host));
+          tempHosts.emplace_back(1, invDlSpeed, host);
         }
       }
     }
   }
   std::sort(tempHosts.begin(), tempHosts.end());
   std::transform(tempHosts.begin(), tempHosts.end(),
-                 std::back_inserter(usedHosts), Tuple2Pair<1, 3>());
+                 std::back_inserter(usedHosts),
+                 [](const std::tuple<size_t, int, std::string>& x) {
+                   return std::make_pair(std::get<0>(x), std::get<2>(x));
+                 });
 }
 
 void RequestGroupMan::setUriListParser
diff --git a/src/Triplet.h b/src/Triplet.h
deleted file mode 100644
index ef6ced6c..00000000
--- a/src/Triplet.h
+++ /dev/null
@@ -1,150 +0,0 @@
-/* <!-- copyright */
-/*
- * aria2 - The high speed download utility
- *
- * Copyright (C) 2010 Tatsuhiro Tsujikawa
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * In addition, as a special exception, the copyright holders give
- * permission to link the code of portions of this program with the
- * OpenSSL library under certain conditions as described in each
- * individual source file, and distribute linked combinations
- * including the two.
- * You must obey the GNU General Public License in all respects
- * for all of the code used other than OpenSSL.  If you modify
- * file(s) with this exception, you may extend this exception to your
- * version of the file(s), but you are not obligated to do so.  If you
- * do not wish to do so, delete this exception statement from your
- * version.  If you delete this exception statement from all source
- * files in the program, then also delete it here.
- */
-/* copyright --> */
-#ifndef D_TRIPLET_H
-#define D_TRIPLET_H
-
-#include <cstdlib>
-#include <utility>
-
-namespace aria2 {
-
-template<typename T1, typename T2, typename T3>
-struct Triplet {
-  typedef T1 first_type;
-  typedef T2 second_type;
-  typedef T3 third_type;
-
-  T1 first;
-  T2 second;
-  T3 third;
-
-  Triplet() {}
-
-  Triplet(const T1& t1, const T2& t2, const T3& t3):
-    first(t1), second(t2), third(t3) {}
-
-  template<typename U1, typename U2, typename U3>
-  Triplet(const Triplet<U1, U2, U3>& t):
-    first(t.first), second(t.second), third(t.third) {}
-
-  Triplet& operator=(const Triplet& tri)
-  {
-    if(this != &tri) {
-      first = tri.first;
-      second = tri.second;
-      third = tri.third;
-    }
-    return *this;
-  }
-};
-
-template<typename T1, typename T2, typename T3>
-bool operator<(const Triplet<T1, T2, T3>& lhs, const Triplet<T1, T2, T3>& rhs)
-{
-  return lhs.first < rhs.first ||
-    (!(rhs.first < lhs.first) && (lhs.second < rhs.second ||
-                                  (!(rhs.second < lhs.second) &&
-                                   lhs.third < rhs.third)));
-}
-
-template<typename T1, typename T2, typename T3>
-Triplet<T1, T2, T3> makeTriplet(const T1& t1, const T2& t2, const T3& t3)
-{
-  return Triplet<T1, T2, T3>(t1, t2, t3);
-}
-
-template<class Tuple, size_t N>
-struct TupleNthType;
-
-template<class Tuple>
-struct TupleNthType<Tuple, 1> {
-  typedef typename Tuple::first_type type;
-};
-
-template<class Tuple>
-struct TupleNthType<Tuple, 2> {
-  typedef typename Tuple::second_type type;
-};
-
-template<class Tuple>
-struct TupleNthType<Tuple, 3> {
-  typedef typename Tuple::third_type type;
-};
-
-template<size_t N>
-struct TupleGet;
-
-template<>
-struct TupleGet<1> {
-  template<class Tuple>
-  static typename TupleNthType<Tuple, 1>::type get(const Tuple& tri)
-  {
-    return tri.first;
-  }
-};
-
-template<>
-struct TupleGet<2> {
-  template<class Tuple>
-  static typename TupleNthType<Tuple, 2>::type get(const Tuple& tri)
-  {
-    return tri.second;
-  }
-};
-
-template<>
-struct TupleGet<3> {
-  template<class Tuple>
-  static typename TupleNthType<Tuple, 3>::type get(const Tuple& tri)
-  {
-    return tri.third;
-  }
-};
-
-template<size_t N1, size_t N2>
-class Tuple2Pair {
-public:
-  template<class Tuple>
-  std::pair<typename TupleNthType<Tuple, N1>::type,
-            typename TupleNthType<Tuple, N2>::type>
-  operator()(const Tuple& tri) const
-  {
-    return std::make_pair(TupleGet<N1>::get(tri), TupleGet<N2>::get(tri));
-  }
-};
-
-} // namespace aria2
-
-#endif // D_TRIPLET_H
diff --git a/test/Makefile.am b/test/Makefile.am
index 085bee05..384efe86 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -71,7 +71,6 @@ aria2c_SOURCES = AllTest.cc\
 	UriTest.cc\
 	UriSplitTest.cc\
 	MockSegment.h\
-	TripletTest.cc\
 	CookieHelperTest.cc\
 	JsonTest.cc\
 	ValueBaseJsonParserTest.cc\
diff --git a/test/TripletTest.cc b/test/TripletTest.cc
deleted file mode 100644
index 10dbee82..00000000
--- a/test/TripletTest.cc
+++ /dev/null
@@ -1,77 +0,0 @@
-#include "Triplet.h"
-
-#include <cppunit/extensions/HelperMacros.h>
-
-namespace aria2 {
-
-class TripletTest:public CppUnit::TestFixture {
-
-  CPPUNIT_TEST_SUITE(TripletTest);
-  CPPUNIT_TEST(testLess);
-  CPPUNIT_TEST(testTupleGet);
-  CPPUNIT_TEST(testTupleNthType);
-  CPPUNIT_TEST(testTuple2Pair);
-  CPPUNIT_TEST_SUITE_END();
-public:
-  void setUp() {}
-
-  void tearDown() {}
-
-  void testLess();
-  void testTupleGet();
-  void testTupleNthType();
-  void testTuple2Pair();
-};
-
-CPPUNIT_TEST_SUITE_REGISTRATION(TripletTest);
-
-void TripletTest::testLess()
-{
-  Triplet<int, int, int> tri1(0, 1, 1);
-  Triplet<int, int, int> tri2(1, 0, 0);
-  CPPUNIT_ASSERT(!(tri1 < tri1));
-  CPPUNIT_ASSERT(tri1 < tri2);
-  CPPUNIT_ASSERT(!(tri2 < tri1));
-
-  Triplet<int, int, int> tri3(0, 0, 1);
-  Triplet<int, int, int> tri4(0, 1, 0);
-  CPPUNIT_ASSERT(tri3 < tri4);
-  CPPUNIT_ASSERT(!(tri4 < tri3));
-
-  Triplet<int, int, int> tri5(0, 0, 0);
-  Triplet<int, int, int> tri6(0, 0, 1);
-  CPPUNIT_ASSERT(tri5 < tri6);
-  CPPUNIT_ASSERT(!(tri6 < tri5));
-}
-
-void TripletTest::testTupleGet()
-{
-  Triplet<int, double, std::string> x(1, 3.14, "foo");
-  CPPUNIT_ASSERT_EQUAL(1, (TupleGet<1>::get(x)));
-  CPPUNIT_ASSERT_EQUAL((double)3.14, (TupleGet<2>::get(x)));
-  CPPUNIT_ASSERT_EQUAL(std::string("foo"), (TupleGet<3>::get(x)));
-}
-
-void TripletTest::testTupleNthType()
-{
-  TupleNthType<Triplet<int, double, std::string>, 1>::type x = 1;
-  CPPUNIT_ASSERT_EQUAL(1, x);
-  TupleNthType<Triplet<int, double, std::string>, 2>::type y = 3.14;
-  CPPUNIT_ASSERT_EQUAL((double)3.14, y);
-  TupleNthType<Triplet<int, double, std::string>, 3>::type z = "foo";
-  CPPUNIT_ASSERT_EQUAL(std::string("foo"), z);
-}
-
-void TripletTest::testTuple2Pair()
-{
-  Triplet<int, double, std::string> x(1, 3.14, "foo");
-  std::pair<int, double> p1 = Tuple2Pair<1, 2>()(x);
-  CPPUNIT_ASSERT_EQUAL(1, p1.first);
-  CPPUNIT_ASSERT_EQUAL((double)3.14, p1.second);
-
-  std::pair<double, std::string> p2 = Tuple2Pair<2, 3>()(x);
-  CPPUNIT_ASSERT_EQUAL((double)3.14, p2.first);
-  CPPUNIT_ASSERT_EQUAL(std::string("foo"), p2.second);
-}
-
-} // namespace aria2