DPL Analysis: fix bug in soa::Table::sliceBy(), add a test (#7357)

Author: aalkin

Framework/Core/src/ASoA.cxx

@@ -111,15 +111,14 @@ arrow::Status getSliceFor(int value, char const* key, std::shared_ptr<arrow::Tab
   auto values = static_cast<arrow::NumericArray<arrow::Int32Type>>(pair.field(0)->data());
   auto counts = static_cast<arrow::NumericArray<arrow::Int64Type>>(pair.field(1)->data());
 
-  int slice;
-  for (slice = 0; slice < values.length(); ++slice) {
+  for (auto slice = 0; slice < values.length(); ++slice) {
     if (values.Value(slice) == value) {
-      offset = slice;
-      output = input->Slice(slice, counts.Value(slice));
+      output = input->Slice(offset, counts.Value(slice));
       return arrow::Status::OK();
     }
+    offset += counts.Value(slice);
   }
-  output = input->Slice(0, 0);
+  output = input->Slice(offset, 0);
   return arrow::Status::OK();
 }
 

Framework/Core/test/test_ASoA.cxx

@@ -826,3 +826,34 @@ BOOST_AUTO_TEST_CASE(TestListColumns)
     ++s;
   }
 }
+
+BOOST_AUTO_TEST_CASE(TestSliceBy)
+{
+  TableBuilder b;
+  auto writer = b.cursor<Origins>();
+  for (auto i = 0; i < 20; ++i) {
+    writer(0, i, i % 3 == 0);
+  }
+  auto origins = b.finalize();
+  Origins o{origins};
+
+  TableBuilder w;
+  auto writer_w = w.cursor<References>();
+  auto step = -1;
+  for (auto i = 0; i < 5 * 20; ++i) {
+    if (i % 5 == 0) {
+      ++step;
+    }
+    writer_w(0, step);
+  }
+  auto refs = w.finalize();
+  References r{refs};
+
+  for (auto& oi : o) {
+    auto slice = r.sliceBy(test::originId, oi.globalIndex());
+    BOOST_CHECK_EQUAL(slice.size(), 5);
+    for (auto& ri : slice) {
+      BOOST_CHECK_EQUAL(ri.originId(), oi.globalIndex());
+    }
+  }
+}