Modernize: C++11/14 (#826)

Perform some modernizations, guided by clang-tidy (v10).

Author: ax3l

.clang-tidy

@@ -1,6 +1,6 @@
-# Future consideration: cppcoreguidelines-*,clang-analyzer-*,google-*,hicpp-*,llvm-*,misc-*,modernize-*,readability-*,-clang-diagnostic-unused-command-line-argument,-*-namespace-comment*,-*-braces-around-statements,-google-readability-todo,-readability-inconsistent-declaration-parameter-name,-readability-named-parameter
+# Future consideration: cppcoreguidelines-*,clang-analyzer-*,google-*,hicpp-*,llvm-*,misc-*,readability-*,-clang-diagnostic-unused-command-line-argument,-*-namespace-comment*,-*-braces-around-statements,-google-readability-todo,-readability-inconsistent-declaration-parameter-name,-readability-named-parameter
 # FIXME: all performance-* reports
 # FIXME: all cert-* reports
 # FIXME: all bugprone-* reports
-Checks: -*,bugprone-*,-bugprone-unhandled-self-assignment,-bugprone-parent-virtual-call,-bugprone-narrowing-conversions,-bugprone-exception-escape,-bugprone-string-literal-with-embedded-nul,cppcoreguidelines-slicing,mpi-*,readability-non-const-parameter,modernize-use-override,modernize-use-equals-default
+Checks: -*,bugprone-*,-bugprone-unhandled-self-assignment,-bugprone-parent-virtual-call,-bugprone-narrowing-conversions,-bugprone-exception-escape,-bugprone-string-literal-with-embedded-nul,cppcoreguidelines-slicing,mpi-*,readability-non-const-parameter,modernize-*,-modernize-use-trailing-return-type,-modernize-use-bool-literals,-modernize-avoid-c-arrays
 HeaderFilterRegex: '((^(?!\/share\/openPMD\/).*)*include\/openPMD\/.+\.hpp|src\/^(?!binding).+\.cpp$)'

examples/5_write_parallel.cpp

@@ -46,7 +46,7 @@ int main(int argc, char *argv[])
     {
         // global data set to write: [MPI_Size * 10, 300]
         // each rank writes a 10x300 slice with its MPI rank as values
-        float const value = float(mpi_size);
+        auto const value = float(mpi_size);
         std::vector<float> local_data(
             10 * 300, value);
         if( 0 == mpi_rank )

examples/8a_benchmark_write1D2D_parallel.cpp

@@ -151,7 +151,7 @@ class TestInput
           return;
 
         // many small writes
-        srand(time(NULL) * (m_MPIRank  + m_MPISize) );
+        srand(time(nullptr) * (m_MPIRank  + m_MPISize) );
 
         auto nBlocks = GetSeg();
         if ((rankCount / nBlocks) <= 1)
@@ -165,7 +165,7 @@ class TestInput
            if ((rankCount % nBlocks != 0) && (i == (nBlocks -1)))
                blockSize = rankCount - blockSize * (nBlocks -1);
 
-           m_InRankDistribution.push_back(std::make_pair(rankOffset + counter, blockSize));
+           m_InRankDistribution.emplace_back(rankOffset + counter, blockSize);
            counter += blockSize;
         }
     }
@@ -248,7 +248,7 @@ class TestInput
             Offset meshOffset;
             auto const blockSize = getNthMeshExtent(n, meshOffset, meshExtent);
             if( blockSize > 0ul ) {
-                double const value = double(1.0*n + 0.0001*step);
+                auto const value = double(1.0*n + 0.0001*step);
                 auto A = createData<double>( blockSize, value, false ) ;
                 compA.storeChunk( A, meshOffset, meshExtent );
             }
@@ -414,8 +414,8 @@ class TestInput
     {
         unsigned long result = m_Ratio;
 
-        for (unsigned int  i=0; i<m_GlobalMesh.size(); i++)
-          result *= m_GlobalMesh[i];
+        for (unsigned long i : m_GlobalMesh)
+          result *= i;
 
         return result;
     }
@@ -512,7 +512,7 @@ main( int argc, char *argv[] )
     }
 
     if( argc >= 3 )
-        input.m_Bulk = strtoul( argv[2], NULL, 0 );
+        input.m_Bulk = strtoul( argv[2], nullptr, 0 );
 
     if( argc >= 4 )
         input.m_Seg = atoi( argv[3] );

src/IO/ADIOS/ADIOS2IOHandler.cpp

@@ -21,18 +21,19 @@
 
 #include "openPMD/IO/ADIOS/ADIOS2IOHandler.hpp"
 
-#include <algorithm>
-#include <iostream>
-#include <iterator>
-#include <set>
-#include <string>
-
 #include "openPMD/Datatype.hpp"
 #include "openPMD/IO/ADIOS/ADIOS2FilePosition.hpp"
 #include "openPMD/IO/ADIOS/ADIOS2IOHandler.hpp"
 #include "openPMD/auxiliary/Environment.hpp"
 #include "openPMD/auxiliary/Filesystem.hpp"
 #include "openPMD/auxiliary/StringManip.hpp"
+
+#include <algorithm>
+#include <iostream>
+#include <iterator>
+#include <memory>
+#include <set>
+#include <string>
 #include <type_traits>
 
 
@@ -695,8 +696,8 @@ ADIOS2IOHandlerImpl::getFileData( InvalidatableFile file )
     {
         return *m_fileData
                     .emplace( std::move( file ),
-                              std::unique_ptr< detail::BufferedActions >{
-                                  new detail::BufferedActions{*this, file}} )
+                              std::make_unique< detail::BufferedActions >(
+                                  *this, file) )
                     .first->second;
     }
     else
@@ -1205,7 +1206,7 @@ namespace detail
                                       ") not found in backend." );
         }
 
-        Datatype ret =
+        auto ret =
             switchType< Datatype >(
                 type,
                 detail::AttributeReader{},

src/IO/HDF5/HDF5IOHandler.cpp

@@ -917,13 +917,13 @@ HDF5IOHandlerImpl::writeAttribute(Writable* writable,
         }
         case DT::UCHAR:
         {
-            unsigned char u = att.get< unsigned char >();
+            auto u = att.get< unsigned char >();
             status = H5Awrite(attribute_id, dataType, &u);
             break;
         }
         case DT::SHORT:
         {
-            short i = att.get< short >();
+            auto i = att.get< short >();
             status = H5Awrite(attribute_id, dataType, &i);
             break;
         }
@@ -941,49 +941,49 @@ HDF5IOHandlerImpl::writeAttribute(Writable* writable,
         }
         case DT::LONGLONG:
         {
-            long long i = att.get< long long >();
+            auto i = att.get< long long >();
             status = H5Awrite(attribute_id, dataType, &i);
             break;
         }
         case DT::USHORT:
         {
-            unsigned short u = att.get< unsigned short >();
+            auto u = att.get< unsigned short >();
             status = H5Awrite(attribute_id, dataType, &u);
             break;
         }
         case DT::UINT:
         {
-            unsigned int u = att.get< unsigned int >();
+            auto u = att.get< unsigned int >();
             status = H5Awrite(attribute_id, dataType, &u);
             break;
         }
         case DT::ULONG:
         {
-            unsigned long u = att.get< unsigned long >();
+            auto u = att.get< unsigned long >();
             status = H5Awrite(attribute_id, dataType, &u);
             break;
         }
         case DT::ULONGLONG:
         {
-            unsigned long long u = att.get< unsigned long long >();
+            auto u = att.get< unsigned long long >();
             status = H5Awrite(attribute_id, dataType, &u);
             break;
         }
         case DT::FLOAT:
         {
-            float f = att.get< float >();
+            auto f = att.get< float >();
             status = H5Awrite(attribute_id, dataType, &f);
             break;
         }
         case DT::DOUBLE:
         {
-            double d = att.get< double >();
+            auto d = att.get< double >();
             status = H5Awrite(attribute_id, dataType, &d);
             break;
         }
         case DT::LONG_DOUBLE:
         {
-            long double d = att.get< long double >();
+            auto d = att.get< long double >();
             status = H5Awrite(attribute_id, dataType, &d);
             break;
         }

src/IO/JSON/JSONFilePosition.cpp

@@ -1,9 +1,11 @@
 #include "openPMD/IO/JSON/JSONFilePosition.hpp"
 
+#include <utility>
+
 
 namespace openPMD
 {
     JSONFilePosition::JSONFilePosition( json::json_pointer ptr):
-        id( ptr )
+        id( std::move( ptr ) )
     {}
 }

src/ParticleSpecies.cpp

@@ -121,7 +121,7 @@ ParticleSpecies::flush(std::string const& path)
             patch.second.flush(patch.first);
     } else
     {
-        iterator it = find("position");
+        auto it = find("position");
         if ( it != end() )
             it->second.setUnitDimension({{UnitDimension::L, 1}});
         it = find("positionOffset");

src/auxiliary/Date.cpp

@@ -20,6 +20,7 @@
  */
 #include "openPMD/auxiliary/Date.hpp"
 
+#include <array>
 #include <ctime>
 #include <string>
 #include <sstream>
@@ -32,18 +33,18 @@ namespace auxiliary
     std::string getDateString( std::string const & format )
     {
         constexpr size_t maxLen = 30u;
-        char buffer [maxLen];
+        std::array< char, maxLen > buffer;
 
         time_t rawtime;
         time( &rawtime );
         struct tm* timeinfo;
         // https://github.com/openPMD/openPMD-api/pull/657#issuecomment-574424885
         timeinfo = localtime( &rawtime );  // lgtm[cpp/potentially-dangerous-function]
 
-        strftime( buffer, maxLen, format.c_str(), timeinfo );
+        strftime( buffer.data(), maxLen, format.c_str(), timeinfo );
 
         std::stringstream dateString;
-        dateString << buffer;
+        dateString << buffer.data();
 
         return dateString.str();
     }

src/binding/python/Attributable.cpp

@@ -125,7 +125,7 @@ bool setAttributeFromBufferInfo(
          * - not strided with paddings
          * - not a view in another buffer that results in striding
          */
-        Py_buffer* view = new Py_buffer();
+        auto* view = new Py_buffer();
         int flags = PyBUF_STRIDES | PyBUF_FORMAT;
         if( PyObject_GetBuffer( a.ptr(), view, flags ) != 0 )
         {

src/binding/python/RecordComponent.cpp

@@ -264,7 +264,7 @@ store_chunk(RecordComponent & r, py::array & a, Offset const & offset, Extent co
      * - not strided with paddings
      * - not a view in another buffer that results in striding
      */
-    Py_buffer* view = new Py_buffer();
+    auto* view = new Py_buffer();
     int flags = PyBUF_STRIDES | PyBUF_FORMAT;
     if( PyObject_GetBuffer( a.ptr(), view, flags ) != 0 )
     {