Fix entities with an index greater than 2047 corrupting the client's heap if sent over the network

Resolves #191

CHANGELOG.md

@@ -19,6 +19,7 @@
 * Fixed game_player_equip crashing when given a null activator [#189](https://github.com/SamVanheer/halflife-updated/issues/189)
 * Fixed Hornet gun recharging to full ammo after loading a save game [#190](https://github.com/SamVanheer/halflife-updated/issues/190)
 * Fixed explosives that impact the underside of a brush dealing damage to entities on the other side of that brush (halflife issue [#3244](https://github.com/ValveSoftware/halflife/issues/3244))
+* Fixed entities with an index greater than 2047 corrupting the client's heap if sent over the network [#191](https://github.com/SamVanheer/halflife-updated/issues/191)
 
 ### New features
 
@@ -27,6 +28,7 @@
 * When using `impulse 107` to get the name of a texture the texture type (as used in `materials.txt`) will also be printed
 * Made `PM_FindTextureType` const correct
 * Added `WRITE_FLOAT` function corresponding to the client's `READ_FLOAT` function
+* Set maximum edicts to 2048 in liblist.gam [#181](https://github.com/SamVanheer/halflife-updated/issues/181)
 
 ## Changes in V1.0.0 Beta 013
 

common/com_model.h

@@ -12,7 +12,7 @@
 #define STUDIO_RENDER 1
 #define STUDIO_EVENTS 2
 
-#define MAX_EDICTS 900
+#define MAX_EDICTS 2048
 
 #define MAX_MODEL_NAME 64
 #define MAX_MAP_HULLS 4

dlls/client.cpp

@@ -26,6 +26,7 @@
 #include "extdll.h"
 #include "util.h"
 #include "cbase.h"
+#include "com_model.h"
 #include "saverestore.h"
 #include "player.h"
 #include "spectator.h"
@@ -1084,6 +1085,15 @@ we could also use the pas/ pvs that we set in SetupVisibility, if we wanted to.
 */
 int AddToFullPack(struct entity_state_s* state, int e, edict_t* ent, edict_t* host, int hostflags, int player, unsigned char* pSet)
 {
+	// Entities with an index greater than this will corrupt the client's heap because 
+	// the index is sent with only 11 bits of precision (2^11 == 2048).
+	// So we don't send them, just like having too many entities would result
+	// in the entity not being sent.
+	if (e >= MAX_EDICTS)
+	{
+		return 0;
+	}
+
 	int i;
 
 	auto entity = reinterpret_cast<CBaseEntity*>(GET_PRIVATE(ent));