Correct wrapping of player infosets collection.

Author: tturocy

src/pygambit/gambit.pxd

@@ -145,6 +145,17 @@ cdef extern from "games/game.h":
         bint Precedes(c_GameNode) except +
 
     cdef cppclass c_GamePlayerRep "GamePlayerRep":
+        cppclass Infosets:
+            cppclass iterator:
+                c_GameInfoset operator *()
+                iterator operator++()
+                bint operator ==(iterator)
+                bint operator !=(iterator)
+
+            int size() except +
+            iterator begin() except +
+            iterator end() except +
+
         c_Game GetGame() except +
         int GetNumber() except +
         int IsChance() except +
@@ -155,8 +166,8 @@ cdef extern from "games/game.h":
         int NumStrategies() except +
         c_GameStrategy GetStrategy(int) except +IndexError
 
-        int NumInfosets() except +
         c_GameInfoset GetInfoset(int) except +IndexError
+        Infosets GetInfosets() except +
 
     cdef cppclass c_GameOutcomeRep "GameOutcomeRep":
         c_Game GetGame() except +

src/pygambit/player.pxi

@@ -42,11 +42,11 @@ class PlayerInfosets:
 
     def __len__(self) -> int:
         """The number of information sets at which the player has the decision."""
-        return self.player.deref().NumInfosets()
+        return self.player.deref().GetInfosets().size()
 
     def __iter__(self) -> typing.Iterator[Infoset]:
-        for i in range(self.player.deref().NumInfosets()):
-            yield Infoset.wrap(self.player.deref().GetInfoset(i + 1))
+        for infoset in self.player.deref().GetInfosets():
+            yield Infoset.wrap(infoset)
 
     def __getitem__(self, index: typing.Union[int, str]) -> Infoset:
         if isinstance(index, str):