Experimental definition of Players collection as a member of GameRep

Author: tturocy

src/games/file.cc

@@ -428,7 +428,7 @@ void ParsePayoffBody(GameFileLexer &p_parser, Game &p_nfg)
 {
   const StrategySupportProfile profile(p_nfg);
   for (auto iter : StrategyContingencies(profile)) {
-    for (auto player : p_nfg->GetPlayers()) {
+    for (const auto &player : p_nfg->GetPlayers()) {
       p_parser.ExpectCurrentToken(TOKEN_NUMBER, "numerical payoff");
       iter->GetOutcome()->SetPayoff(player, Number(p_parser.GetLastText()));
       p_parser.GetNextToken();

src/games/game.cc

@@ -41,7 +41,7 @@ namespace Gambit {
 
 GameOutcomeRep::GameOutcomeRep(GameRep *p_game, int p_number) : m_game(p_game), m_number(p_number)
 {
-  for (const auto &player : p_game->GetPlayers()) {
+  for (const auto &player : m_game->m_players) {
     m_payoffs[player] = Number();
   }
 }
@@ -199,15 +199,6 @@ size_t GamePlayerRep::NumSequences() const
 //                            class GameRep
 //========================================================================
 
-Array<GamePlayer> GameRep::GetPlayers() const
-{
-  Array<GamePlayer> ret(NumPlayers());
-  for (size_t pl = 1; pl <= NumPlayers(); pl++) {
-    ret[pl] = GetPlayer(pl);
-  }
-  return ret;
-}
-
 Array<GameStrategy> GameRep::GetStrategies() const
 {
   Array<GameStrategy> ret(MixedProfileLength());

src/games/game.h

@@ -433,6 +433,63 @@ class GameRep : public BaseGameRep {
   //@}
 
 public:
+  class Players {
+    Game m_game{nullptr};
+
+  public:
+    class iterator {
+      Game m_game{nullptr};
+      size_t m_index{0};
+
+    public:
+      using iterator_category = std::bidirectional_iterator_tag;
+      using difference_type = std::ptrdiff_t;
+      using value_type = GamePlayer;
+      using pointer = value_type *;
+      using reference = value_type &;
+
+      iterator() = default;
+      iterator(const Game &p_game, size_t p_index = 0) : m_game(p_game), m_index(p_index) {}
+      iterator(const iterator &) = default;
+      ~iterator() = default;
+      iterator &operator=(const iterator &) = default;
+
+      bool operator==(const iterator &p_iter) const
+      {
+        return m_game == p_iter.m_game && m_index == p_iter.m_index;
+      }
+      bool operator!=(const iterator &p_iter) const
+      {
+        return m_game != p_iter.m_game || m_index != p_iter.m_index;
+      }
+
+      iterator &operator++()
+      {
+        m_index++;
+        return *this;
+      }
+      iterator &operator--()
+      {
+        m_index--;
+        return *this;
+      }
+      GamePlayer operator*() const { return m_game->m_players.at(m_index); }
+    };
+
+    Players() = default;
+    explicit Players(const Game &p_game) : m_game(p_game) {}
+    Players(const Players &) = default;
+    ~Players() = default;
+    Players &operator=(const Players &) = default;
+
+    size_t size() const { return m_game->m_players.size(); }
+
+    iterator begin() const { return {m_game, 0}; }
+    iterator end() const { return {m_game, (m_game) ? m_game->m_players.size() : 0}; }
+    iterator cbegin() const { return {m_game, 0}; }
+    iterator cend() const { return {m_game, (m_game) ? m_game->m_players.size() : 0}; }
+  };
+
   /// @name Lifecycle
   //@{
   /// Clean up the game
@@ -599,7 +656,7 @@ class GameRep : public BaseGameRep {
   /// Returns the pl'th player in the game
   GamePlayer GetPlayer(int pl) const { return m_players.at(pl - 1); }
   /// Returns the set of players in the game
-  Array<GamePlayer> GetPlayers() const;
+  Players GetPlayers() const { return Players(this); }
   /// Returns the chance (nature) player
   virtual GamePlayer GetChance() const = 0;
   /// Creates a new player in the game, with no moves

src/games/stratspt.h

@@ -102,7 +102,7 @@ class StrategySupportProfile {
   /// Returns the number of players in the game
   int NumPlayers() const { return m_nfg->NumPlayers(); }
   /// Returns the set of players in the game
-  Array<GamePlayer> GetPlayers() const { return m_nfg->GetPlayers(); }
+  GameRep::Players GetPlayers() const { return m_nfg->GetPlayers(); }
   /// Returns the set of strategies in the support for a player
   Support GetStrategies(const GamePlayer &p_player) const { return {this, p_player}; }
 

src/pygambit/gambit.pxd

@@ -167,6 +167,16 @@ cdef extern from "games/game.h":
         c_GameAction GetPriorAction() except +
 
     cdef cppclass c_GameRep "GameRep":
+        cppclass Players:
+            cppclass iterator:
+                c_GamePlayer operator *()
+                iterator operator++()
+                bint operator ==(iterator)
+                bint operator !=(iterator)
+            int size() except +
+            iterator begin() except +
+            iterator end() except +
+
         int IsTree() except +
 
         string GetTitle() except +
@@ -177,7 +187,7 @@ cdef extern from "games/game.h":
 
         int NumPlayers() except +
         c_GamePlayer GetPlayer(int) except +IndexError
-        Array[c_GamePlayer] GetPlayers() except +
+        Players GetPlayers() except +
         c_GamePlayer GetChance() except +
         c_GamePlayer NewPlayer() except +
 

src/solvers/enumpoly/gameseq.h

@@ -269,7 +269,7 @@ class GameSequenceForm {
 
   Contingencies GetContingencies() const { return {this}; }
 
-  Array<GamePlayer> GetPlayers() const { return m_support.GetGame()->GetPlayers(); }
+  GameRep::Players GetPlayers() const { return m_support.GetGame()->GetPlayers(); }
 
   Infosets GetInfosets() const { return {this}; }