From c005878776c65a1f6ee8beda82a272eb67b57441 Mon Sep 17 00:00:00 2001
From: 0xdeadbeer <64986162+0xdeadbeer@users.noreply.github.com>
Date: Tue, 21 Nov 2023 19:00:24 +0100
Subject: [PATCH] 03: optimize hashmap value allocation

---
 03-network/server/src/hashmap.c | 28 ++++++++++++++++---------
 03-network/server/src/hashmap.h |  2 +-
 03-network/server/src/main.c    | 36 +++++++++++++++++++++------------
 3 files changed, 43 insertions(+), 23 deletions(-)

diff --git a/03-network/server/src/hashmap.c b/03-network/server/src/hashmap.c
index 7c03681..a458183 100644
--- a/03-network/server/src/hashmap.c
+++ b/03-network/server/src/hashmap.c
@@ -22,21 +22,31 @@ int find_empty_slot(void **map, int slots) {
     return slot;
 }
 
-int allocate_value(void ***map, int *slots, int bytes) {
-    int empty_slot = find_empty_slot(*map, *slots); 
+// If there's Nx fewer used slots than total slots in the map, find the first possible one.
+// Else reallocate the map and use the end slot 
+// Then allocate an object of size BYTES and add it into the map.
+int allocate_value(void ***map, int *total_slots, int *used_slots, int bytes) {
+    int half_slots = (*total_slots) / 2;
+    int empty_slot = 0; 
+    
+    if (*used_slots < half_slots) {
+        empty_slot = find_empty_slot(*map, *used_slots); 
+        goto jump;   
+    } 
 
-    if (empty_slot == *slots) {
-        (*slots)++;
-        *map = realloc(*map, sizeof(void *)*(*slots));
-    }
+    empty_slot = *total_slots;
+    (*total_slots)++;
+    *map = realloc(*map, sizeof(void *)*(*total_slots));
 
-    if (*map == NULL)
+jump: 
+    if (*map == NULL) 
         return MEMERR; 
 
-    void *new_value = calloc(1, bytes);
+    void *new_value = calloc(1, bytes); 
     if (new_value == NULL) 
-        return MEMERR;
+        return MEMERR; 
 
+    (*used_slots)++;
     (*map)[empty_slot] = new_value;
 
     return empty_slot;
diff --git a/03-network/server/src/hashmap.h b/03-network/server/src/hashmap.h
index 1d97232..5beed26 100644
--- a/03-network/server/src/hashmap.h
+++ b/03-network/server/src/hashmap.h
@@ -4,6 +4,6 @@
 #include "structs.h"
 
 int find_empty_slot(void **map, int slots);
-int allocate_value(void ***map, int *slots, int bytes);
+int allocate_value(void ***map, int *total_slots, int *used_slots, int bytes);
 
 #endif
diff --git a/03-network/server/src/main.c b/03-network/server/src/main.c
index e300282..f13f5a4 100644
--- a/03-network/server/src/main.c
+++ b/03-network/server/src/main.c
@@ -11,11 +11,13 @@
 #define DEBUG 0x0010
 #define PORT 9080
 
-int objects_count = 0;
 struct object **objects_map;
+int objects_map_size = 0;
+int objects_count = 0;
 
-int connections_count = 0; 
 struct connection **connections_map;
+int connections_map_size = 0; 
+int connections_count = 0; 
 
 void handle_player_input(struct object *obj, char *message) {
     uint8_t action = message[0];
@@ -26,8 +28,9 @@ void handle_player_input(struct object *obj, char *message) {
     if (action & LEFT_MOVEMENT)
         obj->x -= MOVEMENT_SPEED; 
 
-    if (action & JUMP_MOVEMENT) {
-        obj->force -= MOVEMENT_SPEED; 
+    if (obj->colliding && (action & JUMP_MOVEMENT)) {
+        obj->force -= MOVEMENT_SPEED * 3; 
+        obj->y += obj->force;
         obj->colliding = 0;
     }
 
@@ -35,12 +38,14 @@ void handle_player_input(struct object *obj, char *message) {
 }
 
 void handle_player_physics(struct object *obj) {
-    if (obj->y < 200) 
-        obj->force += GRAVITY; 
-    else {
-        obj->colliding = 1; 
-        obj->y = 200;
-    }
+    int touching_ground = obj->y >= 200;
+
+    if (touching_ground) {
+        obj->force = 0; 
+        obj->y = 200; 
+        obj->colliding = 1;
+    } else 
+        obj->force += GRAVITY;
 
     obj->y += obj->force;
 }
@@ -48,7 +53,7 @@ void handle_player_physics(struct object *obj) {
 int broadcast_event(int format, int object_id) {
     struct object *obj = objects_map[object_id];
 
-    for (int iter = 0; iter < connections_count; iter++) {
+    for (int iter = 0; iter < connections_map_size; iter++) {
         struct connection *con = connections_map[iter]; 
         if (con == NULL) 
             continue; 
@@ -120,8 +125,13 @@ int handle_player(void *data) {
 
     SDLNet_FreeSocketSet(set);
     SDLNet_TCP_Close(connection_data->socket);
+
     objects_map[connection_data->obj_id] = NULL;
+    objects_count--;
+
     connections_map[connection_data->id] = NULL;
+    connections_count--;
+
     free(obj);
     free(data);
 
@@ -186,13 +196,13 @@ int main(int argc, char *argv[]) {
 
         fprintf(stdout, "Notice: accepted a connection from client!\n"); 
 
-        int new_object_slot = allocate_value((void ***) &objects_map, &objects_count, sizeof(struct object));
+        int new_object_slot = allocate_value((void ***) &objects_map, &objects_map_size, &objects_count, sizeof(struct object));
         if (new_object_slot == MEMERR) {
             fprintf(stderr, "MEMERR: failed allocating memory for new object\n");
             return STDERR;
         }
 
-        int new_connection_slot = allocate_value((void ***) &connections_map, &connections_count, sizeof(struct connection));
+        int new_connection_slot = allocate_value((void ***) &connections_map, &connections_map_size, &connections_count, sizeof(struct connection));
         if (new_connection_slot == MEMERR) {
             fprintf(stderr, "MEMERR: failed allocating memory for new connection\n");
             return STDERR;