Improvements to matchmaking system

hm_lobbyserver/src/game.c

@@ -15,11 +15,11 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include <stdio.h>
-#include <stdarg.h>
-#include <memory.h>
-#include <malloc.h>
 #include <ev.h>
+#include <malloc.h>
+#include <memory.h>
+#include <stdarg.h>
+#include <stdio.h>
 
 #include <hmbase.h>
 
@@ -30,51 +30,58 @@ struct playerlist_s {
   struct playerlist_s *next;
 };
 
-static struct playerlist_s *queue = NULL;
 static int gamehandle = 0;
+struct playerlist_s *queue = NULL;
+struct playerlist_s *tail = NULL; // Pointer to the last element
 
-void mm_push(struct conn_client_s *c)
-{
-    struct playerlist_s *p;
-
-    p = malloc(sizeof(*p));
-
+// Add a player to the matchmaking queue
+void mm_push(struct conn_client_s *c) {
+  struct playerlist_s *p = malloc(sizeof(*p));
   p->player = c;
-    p->next = queue;
+  p->next = NULL;
 
+  if (queue == NULL) {
     queue = p;
+  } else {
+    tail->next = p;
+  }
+
+  tail = p; // Update the tail pointer
 }
 
-struct conn_client_s *mm_pop()
-{
-    struct conn_client_s *c;
-    struct playerlist_s *p;
+// Remove a player from the matchmaking queue
+struct conn_client_s *mm_pop() {
+  if (queue == NULL)
+    return NULL;
 
-    p = queue;
-    c = queue->player;
+  struct playerlist_s *temp = queue;
+  struct conn_client_s *c = temp->player;
 
   queue = queue->next;
-    free(p);
+  if (queue == NULL) {
+    tail = NULL; // If the queue is empty after pop, reset the tail pointer
+  }
+  free(temp);
 
   return c;
 }
 
-int matchmaking(struct conn_client_s *player1)
-{
-    struct conn_client_s *player2;	
+// Matchmaking
+int matchmaking(struct conn_client_s *player) {
+  // Add the player to the queue
+  mm_push(player);
 
-    // first player
-    if(queue == NULL) {
-        mm_push(player1);
-        return 0;
-    }
+  while (queue != NULL && queue->next != NULL) {
+    struct conn_client_s *player1 = mm_pop();
+    struct conn_client_s *player2 = mm_pop();
 
-    player2 = mm_pop();
-
-    if(player1 && player2) {
+    if (player1 && player2) {
       start_game(player1, player2, gamehandle++);
-        return 0;
+    } else {
+      // This block should  never be reached in this setup
+      return -1;
+    }
   }
 
-    return -1;
+  return 0;
 }