Fix detection of empty datasets

Author: franzpoeschel

include/openPMD/Dataset.hpp

@@ -55,5 +55,7 @@ class Dataset
     uint8_t rank;
     std::optional<size_t> joinedDimension;
     std::string options = "{}"; //!< backend-dependent JSON configuration
+
+    bool empty() const;
 };
 } // namespace openPMD

src/Dataset.cpp

@@ -49,4 +49,17 @@ Dataset &Dataset::extend(Extent newExtents)
     extent = newExtents;
     return *this;
 }
+
+bool Dataset::empty() const
+{
+    for (size_t i = 0; i < extent.size(); ++i)
+    {
+        if (extent[i] == 0 &&
+            (!joinedDimension.has_value() || joinedDimension.value() != i))
+        {
+            return true;
+        }
+    }
+    return false;
+}
 } // namespace openPMD

src/RecordComponent.cpp

@@ -95,10 +95,7 @@ RecordComponent &RecordComponent::resetDataset(Dataset d)
     }
     // if( d.extent.empty() )
     //    throw std::runtime_error("Dataset extent must be at least 1D.");
-    if (std::any_of(
-            d.extent.begin(), d.extent.end(), [](Extent::value_type const &i) {
-                return i == 0u;
-            }))
+    if (d.empty())
         return makeEmpty(std::move(d));
 
     rc.m_isEmpty = false;

src/backend/PatchRecordComponent.cpp

@@ -48,10 +48,7 @@ PatchRecordComponent &PatchRecordComponent::resetDataset(Dataset d)
             "written.");
     if (d.extent.empty())
         throw std::runtime_error("Dataset extent must be at least 1D.");
-    if (std::any_of(
-            d.extent.begin(), d.extent.end(), [](Extent::value_type const &i) {
-                return i == 0u;
-            }))
+    if (d.empty())
         throw std::runtime_error(
             "Dataset extent must not be zero in any dimension.");
 

test/ParallelIOTest.cpp

@@ -1887,7 +1887,7 @@ void joined_dim(std::string const &ext)
 
         auto it = s.writeIterations()[100];
 
-        Dataset numParticlesDS(determineDatatype<patchType>(), {1});
+        Dataset numParticlesDS(determineDatatype<patchType>(), {0});
         numParticlesDS.joinedDimension = 0;
         auto numParticles =
             it.particles["e"]
@@ -1900,7 +1900,7 @@ void joined_dim(std::string const &ext)
 
         auto patchOffset = it.particles["e"].particlePatches["offset"]["x"];
         auto patchExtent = it.particles["e"].particlePatches["extent"]["x"];
-        Dataset particlePatchesDS(determineDatatype<float>(), {1});
+        Dataset particlePatchesDS(determineDatatype<float>(), {0});
         particlePatchesDS.joinedDimension = 0;
         patchOffset.resetDataset(particlePatchesDS);
         patchExtent.resetDataset(particlePatchesDS);

test/SerialIOTest.cpp

@@ -7263,7 +7263,7 @@ void joined_dim(std::string const &ext)
 
         auto it = s.writeIterations()[100];
 
-        Dataset numParticlesDS(determineDatatype<patchType>(), {1});
+        Dataset numParticlesDS(determineDatatype<patchType>(), {0});
         numParticlesDS.joinedDimension = 0;
         auto numParticles =
             it.particles["e"]
@@ -7276,7 +7276,7 @@ void joined_dim(std::string const &ext)
 
         auto patchOffset = it.particles["e"].particlePatches["offset"]["x"];
         auto patchExtent = it.particles["e"].particlePatches["extent"]["x"];
-        Dataset particlePatchesDS(determineDatatype<float>(), {1});
+        Dataset particlePatchesDS(determineDatatype<float>(), {0});
         particlePatchesDS.joinedDimension = 0;
         patchOffset.resetDataset(particlePatchesDS);
         patchExtent.resetDataset(particlePatchesDS);