McParticleUtils: Fix py3 compilation.

Fix compilation with python 3.

PhysicsAnalysis/TruthParticleID/McParticleUtils/CMakeLists.txt

@@ -15,6 +15,7 @@ atlas_depends_on_subdirs( PUBLIC
                           PRIVATE
                           AtlasTest/TestTools
                           Control/StoreGate
+                          Control/RootUtils
                           TestPolicy )
 
 # External dependencies:
@@ -32,7 +33,7 @@ atlas_add_library( McParticleUtils
                    INCLUDE_DIRS ${HEPMC_INCLUDE_DIRS}
                    PRIVATE_INCLUDE_DIRS ${Boost_INCLUDE_DIRS} ${HEPPDT_INCLUDE_DIRS} ${PYTHON_INCLUDE_DIRS} ${CLHEP_INCLUDE_DIRS} ${CPPUNIT_INCLUDE_DIRS}
                    PRIVATE_DEFINITIONS ${CLHEP_DEFINITIONS}
-                   LINK_LIBRARIES ${HEPMC_LIBRARIES} AthenaKernel AthContainers EventKernel GaudiKernel AnalysisUtilsLib StoreGateLib SGtests
+                   LINK_LIBRARIES ${HEPMC_LIBRARIES} AthenaKernel AthContainers EventKernel GaudiKernel AnalysisUtilsLib StoreGateLib SGtests RootUtils
                    PRIVATE_LINK_LIBRARIES ${Boost_LIBRARIES} ${HEPPDT_LIBRARIES} ${PYTHON_LIBRARIES} ${CLHEP_LIBRARIES} ${CPPUNIT_LIBRARIES} )
 
 # Install files from the package:

PhysicsAnalysis/TruthParticleID/McParticleUtils/python/DecayParser.py

-# Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+# Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 
 # @file: McParticleUtils/python/DecayParser.py
 # @purpose: implement the parsing/tokenization of decay-patterns' strings
 # @author:  Sebastien Binet <binet@cern.ch>
 
+from __future__ import print_function
+
 import re
 
 _slot_separator = "+"
@@ -16,7 +18,7 @@ def py_parse (cmd):
     cmd = re.sub(pattern=" ",
                  repl="",
                  string=cmd)
-##     print "=> [%s]"%cmd
+##     print ("=> [%s]"%cmd)
 
     if cmd == _decay_arrow:
         # special case of a single arrow without any parent nor child:
@@ -25,7 +27,7 @@ def py_parse (cmd):
     buf = cmd.split (_decay_arrow)
     assert (len(buf)==2)
     
-##     print "==> buf:",buf
+##     print ("==> buf:",buf)
     parents = process_block (buf[0])
     children= process_block (buf[1])
     
@@ -39,14 +41,14 @@ def process_block (cmd):
 
 
 if __name__ == "__main__":
-    print ":"*80
-    print "::: tests..."
+    print (":"*80)
+    print ("::: tests...")
     for cmd in ("-1|-2|-3|-4|-5|-6|21 + 1|2|3|4|5|6|21 -> ",
                 "-> 91|92|94"
                 ):
-        print "::: testing [%s]..." % cmd
-        print "::: result:",py_parse (cmd)
+        print ("::: testing [%s]..." % cmd)
+        print ("::: result:",py_parse (cmd))
 
-    print "::: bye."
-    print ":"*80
+    print ("::: bye.")
+    print (":"*80)
     

PhysicsAnalysis/TruthParticleID/McParticleUtils/src/DecayParser.cxx

 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
 */
 
 /////////////////////////////////////////////////////////////////// 
@@ -10,6 +10,7 @@
 
 // Python includes
 #include "Python.h"
+#include "RootUtils/PyGetString.h"
 
 // STL includes
 #include <iostream>
@@ -160,14 +161,22 @@ void DecayParser::parse( const std::string& inputCmd )
 
   PyObject *sc = PyTuple_GET_ITEM (res, 0);
   Py_XINCREF (sc);
+#if PY_MAJOR_VERSION < 3
   if (!sc || !PyInt_Check (sc)) {
+#else
+  if (!sc || !PyLong_Check (sc)) {
+#endif
     Py_XDECREF (sc);
     Py_DECREF  (res);
     std::string error = "corrupted return code";
     throw std::runtime_error (error);
   }
 
+#if PY_MAJOR_VERSION < 3
   Py_ssize_t status = PyInt_AsSsize_t (sc);
+#else
+  Py_ssize_t status = PyLong_AsSsize_t (sc);
+#endif
   if (status != 0) {
     Py_DECREF (sc);
     Py_DECREF (res);
@@ -409,7 +418,7 @@ py_to_cpp (PyObject* candidates,
 	return false;
       }
 
-      parsed[i][j] = std::string(PyString_AS_STRING(pdgid));
+      parsed[i][j] = RootUtils::PyGetString (pdgid).first;
     }
 
     Py_DECREF (cand);