add missing max_size implementation, add collection methods and ali…

…ases to `UserDataCollection`

include/podio/CollectionBase.h

@@ -55,6 +55,9 @@ class CollectionBase {
   /// number of elements in the collection
   virtual size_t size() const = 0;
 
+  /// maximal number of elements in the collection
+  virtual std::size_t max_size() const = 0;
+
   /// Is the collection empty
   virtual bool empty() const = 0;
 

include/podio/UserDataCollection.h

@@ -77,6 +77,12 @@ class UserDataCollection : public CollectionBase {
   VectorMembersInfo m_vecmem_info{};
 
 public:
+  using value_type = typename decltype(_vec)::value_type;
+  using const_iterator = typename decltype(_vec)::const_iterator;
+  using iterator = typename decltype(_vec)::iterator;
+  using difference_type = typename decltype(_vec)::difference_type;
+  using size_type = typename decltype(_vec)::size_type;
+
   UserDataCollection() = default;
   /// Constructor from an existing vector (which will be moved from!)
   UserDataCollection(std::vector<BasicType>&& vec) : _vec(std::move(vec)) {
@@ -133,6 +139,11 @@ class UserDataCollection : public CollectionBase {
     return _vec.size();
   }
 
+  /// maximal number of elements in the collection
+  size_t max_size() const override {
+    return _vec.max_size();
+  }
+
   /// Is the collection empty
   bool empty() const override {
     return _vec.empty();
@@ -206,6 +217,12 @@ class UserDataCollection : public CollectionBase {
   typename std::vector<BasicType>::const_iterator end() const {
     return _vec.end();
   }
+  typename std::vector<BasicType>::const_iterator cbegin() const {
+    return _vec.cbegin();
+  }
+  typename std::vector<BasicType>::const_iterator cend() const {
+    return _vec.cend();
+  }
 
   typename std::vector<BasicType>::reference operator[](size_t idx) {
     return _vec[idx];

python/templates/Collection.cc.jinja2

@@ -59,6 +59,10 @@ std::size_t {{ collection_type }}::size() const {
   return m_storage.entries.size();
 }
 
+std::size_t {{ collection_type }}::max_size() const {
+  return m_storage.entries.max_size();
+}
+
 bool {{ collection_type }}::empty() const {
   return m_storage.entries.empty();
 }

python/templates/Collection.h.jinja2

@@ -89,7 +89,7 @@ public:
   std::size_t size() const final;
 
   /// maximal number of elements in the collection
-  std::size_t max_size() const;
+  std::size_t max_size() const final;
 
   /// Is the collection empty
   bool empty() const final;