DataFormats: add operator< to DataDescription and DataOrigin

This is needed in case we want to sort them.

Author: ktf

DataFormats/Headers/include/Headers/DataHeader.h

@@ -205,20 +205,35 @@ struct DescriptorCompareTraits {
   static bool compare(const T &lh, const T &rh, Length N) {
     return std::memcmp(lh.str, rh.str, N) == 0;
   }
+  template <typename T, typename Length>
+  static bool lessThen(const T& lh, const T& rh, Length N)
+  {
+    return std::memcmp(lh.str, rh.str, N) < 0;
+  }
 };
 template<>
 struct DescriptorCompareTraits<1> {
   template<typename T, typename Length>
   static bool compare(const T &lh, const T &rh, Length) {
     return lh.itg[0] == rh.itg[0];
   }
+  template <typename T, typename Length>
+  static bool lessThen(const T& lh, const T& rh, Length)
+  {
+    return lh.itg[0] < rh.itg[0];
+  }
 };
 template<>
 struct DescriptorCompareTraits<2> {
   template<typename T, typename Length>
   static bool compare(const T &lh, const T &rh, Length) {
     return (lh.itg[0] == rh.itg[0]) && (lh.itg[1] == rh.itg[1]);
   }
+  template <typename T, typename Length>
+  static bool lessThen(const T& lh, const T& rh, Length)
+  {
+    return std::tie(lh.itg[0], lh.itg[1]) < std::tie(rh.itg[0], rh.itg[1]);
+  }
 };
 
 //__________________________________________________________________________________________________
@@ -293,6 +308,7 @@ struct Descriptor {
   }
 
   bool operator==(const Descriptor& other) const {return DescriptorCompareTraits<arraySize>::compare(*this,other, N);}
+  bool operator<(const Descriptor& other) const { return DescriptorCompareTraits<arraySize>::lessThen(*this, other, N); }
   bool operator!=(const Descriptor& other) const {return not this->operator==(other);}
 
   // explicitly forbid comparison with e.g. const char* strings

DataFormats/Headers/test/testDataHeader.cxx

@@ -132,6 +132,11 @@ namespace o2 {
       BOOST_CHECK(desc.as<std::string>().length() == 6);
       BOOST_CHECK(runtimeDesc.as<std::string>().length() == 16);
       BOOST_CHECK(DataDescription("INVALIDDATA").as<std::string>().length() == 11);
+
+      BOOST_CHECK(DataDescription("A") < DataDescription("B"));
+      BOOST_CHECK(DataDescription("AA") < DataDescription("AB"));
+      BOOST_CHECK(DataDescription("AAA") < DataDescription("AAB"));
+      BOOST_CHECK(DataDescription("AAA") < DataDescription("ABA"));
     }
 
     BOOST_AUTO_TEST_CASE(DataOrigin_test)
@@ -141,12 +146,56 @@ namespace o2 {
       using TestDescriptorT = Descriptor<descriptorSize>;
       BOOST_CHECK(TestDescriptorT::size == descriptorSize);
       BOOST_CHECK(TestDescriptorT::bitcount == descriptorSize * 8);
-      BOOST_CHECK(sizeof(TestDescriptorT::ItgType)*TestDescriptorT::arraySize == descriptorSize);
+      BOOST_CHECK(sizeof(TestDescriptorT::ItgType) * TestDescriptorT::arraySize == descriptorSize);
       BOOST_CHECK(TestDescriptorT::size == sizeof(DataOrigin));
 
       // we want to explicitely have the size of DataOrigin to be 4
       static_assert(sizeof(DataOrigin) == 4,
                     "DataOrigin struct must be of size 4");
+
+      // Check that ordering works.
+      BOOST_CHECK(DataOrigin("A") < DataOrigin("B"));
+      BOOST_CHECK(DataOrigin("AA") < DataOrigin("AB"));
+      BOOST_CHECK(DataOrigin("AAA") < DataOrigin("AAB"));
+      BOOST_CHECK(DataOrigin("AAA") < DataOrigin("ABA"));
+      std::vector<DataOrigin> v1 = { DataOrigin("B"), DataOrigin("C"), DataOrigin("A") };
+      std::sort(v1.begin(), v1.end());
+      BOOST_CHECK_EQUAL(v1[0], DataOrigin("A"));
+      BOOST_CHECK_EQUAL(v1[1], DataOrigin("B"));
+      BOOST_CHECK_EQUAL(v1[2], DataOrigin("C"));
+      std::vector<DataOrigin> v2 = { DataOrigin("A"), DataOrigin("B") };
+      std::sort(v2.begin(), v2.end());
+      BOOST_CHECK_EQUAL(v2[0], DataOrigin("A"));
+      BOOST_CHECK_EQUAL(v2[1], DataOrigin("B"));
+
+      using CustomHeader = std::tuple<DataOrigin, DataDescription>;
+      std::vector<CustomHeader> v3{ CustomHeader{ "TST", "B" }, CustomHeader{ "TST", "A" } };
+      std::sort(v3.begin(), v3.end());
+      auto h0 = CustomHeader{ "TST", "A" };
+      auto h1 = CustomHeader{ "TST", "B" };
+      BOOST_CHECK(v3[0] == h0);
+      BOOST_CHECK(v3[1] == h1);
+
+      using CustomHeader2 = std::tuple<DataOrigin, DataDescription, int>;
+      std::vector<CustomHeader2> v4{ CustomHeader2{ "TST", "A", 1 }, CustomHeader2{ "TST", "A", 0 } };
+      std::sort(v4.begin(), v4.end());
+      auto hh0 = CustomHeader2{ "TST", "A", 0 };
+      auto hh1 = CustomHeader2{ "TST", "A", 1 };
+      BOOST_CHECK(v4[0] == hh0);
+      BOOST_CHECK(v4[1] == hh1);
+
+      struct CustomHeader3 {
+        DataOrigin origin;
+        DataDescription desc;
+        uint64_t subSpec;
+        int isOut;
+      };
+      std::vector<CustomHeader3> v5{ CustomHeader3{ "TST", "A", 0, 1 }, CustomHeader3{ "TST", "A", 0, 0 } };
+      std::sort(v5.begin(), v5.end(), [](CustomHeader3 const& lhs, CustomHeader3 const& rhs) {
+        return std::tie(lhs.origin, lhs.desc, rhs.subSpec, lhs.isOut) < std::tie(rhs.origin, rhs.desc, rhs.subSpec, rhs.isOut);
+      });
+      BOOST_CHECK(v5[0].isOut == 0);
+      BOOST_CHECK(v5[1].isOut == 1);
     }
 
     BOOST_AUTO_TEST_CASE(BaseHeader_test)