From 56d2bf77bae50bb1cb0eab01841cd1a9e7057f30 Mon Sep 17 00:00:00 2001
From: Adrian Frühwirth
Date: Thu, 17 May 2018 12:40:02 +0200
Subject: SCUMM: Ensure pointer returned by getResourceAddress() is usable

In some cases the pointer returned is used directly without further
error checking.
As most instances already assert() in this case this commit simply
adds asserts where missing and deemed appropriate.
---
 engines/scumm/object.cpp               | 18 ++++++++++++------
 engines/scumm/players/player_ad.cpp    |  1 +
 engines/scumm/players/player_towns.cpp |  3 +++
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/engines/scumm/object.cpp b/engines/scumm/object.cpp
index f4aea93b8b..df0b3e1035 100644
--- a/engines/scumm/object.cpp
+++ b/engines/scumm/object.cpp
@@ -45,6 +45,7 @@ void ScummEngine::addObjectToInventory(uint obj, uint room) {
 		idx = getObjectIndex(obj);
 		assert(idx >= 0);
 		ptr = getResourceAddress(rtFlObject, _objs[idx].fl_object_index) + 8;
+		assert(ptr);
 		size = READ_BE_UINT32(ptr + 4);
 	} else {
 		findObjectInRoom(&foir, foCodeHeader, obj, room);
@@ -742,6 +743,7 @@ void ScummEngine::resetRoomObjects() {
 	const CodeHeader *cdhd;
 
 	room = getResourceAddress(rtRoom, _roomResource);
+	assert(room);
 
 	if (_numObjectsInRoom == 0)
 		return;
@@ -756,7 +758,7 @@ void ScummEngine::resetRoomObjects() {
 	assert(searchptr);
 
 	// Load in new room objects
-	ResourceIterator	obcds(searchptr, false);
+	ResourceIterator obcds(searchptr, false);
 	for (i = 0; i < _numObjectsInRoom; i++) {
 		od = &_objs[findLocalObjectSlot()];
 
@@ -784,7 +786,7 @@ void ScummEngine::resetRoomObjects() {
 	}
 
 	searchptr = room;
-	ResourceIterator	obims(room, false);
+	ResourceIterator obims(room, false);
 	for (i = 0; i < _numObjectsInRoom; i++) {
 		ptr = obims.findNext(MKTAG('O','B','I','M'));
 		if (ptr == NULL)
@@ -810,6 +812,7 @@ void ScummEngine_v3old::resetRoomObjects() {
 	const byte *room, *ptr;
 
 	room = getResourceAddress(rtRoom, _roomResource);
+	assert(room);
 
 	if (_numObjectsInRoom == 0)
 		return;
@@ -854,6 +857,7 @@ void ScummEngine_v4::resetRoomObjects() {
 	const byte *room;
 
 	room = getResourceAddress(rtRoom, _roomResource);
+	assert(room);
 
 	if (_numObjectsInRoom == 0)
 		return;
@@ -861,7 +865,7 @@ void ScummEngine_v4::resetRoomObjects() {
 	if (_numObjectsInRoom > _numLocalObjects)
 		error("More than %d objects in room %d", _numLocalObjects, _roomResource);
 
-	ResourceIterator	obcds(room, true);
+	ResourceIterator obcds(room, true);
 	for (i = 0; i < _numObjectsInRoom; i++) {
 		od = &_objs[findLocalObjectSlot()];
 
@@ -878,7 +882,7 @@ void ScummEngine_v4::resetRoomObjects() {
 		}
 	}
 
-	ResourceIterator	obims(room, true);
+	ResourceIterator obims(room, true);
 	for (i = 0; i < _numObjectsInRoom; i++) {
 		// In the PC Engine version of Loom, there aren't image blocks
 		// for all objects.
@@ -979,10 +983,12 @@ void ScummEngine::resetRoomObject(ObjectData *od, const byte *room, const byte *
 	assert(room);
 
 	if (searchptr == NULL) {
-		if (_game.version == 8)
+		if (_game.version == 8) {
 			searchptr = getResourceAddress(rtRoomScripts, _roomResource);
-		else
+			assert(searchptr);
+		} else {
 			searchptr = room;
+		}
 	}
 
 	cdhd = (const CodeHeader *)findResourceData(MKTAG('C','D','H','D'), searchptr + od->OBCDoffset);
diff --git a/engines/scumm/players/player_ad.cpp b/engines/scumm/players/player_ad.cpp
index 7f0f449a92..40f4ec93c9 100644
--- a/engines/scumm/players/player_ad.cpp
+++ b/engines/scumm/players/player_ad.cpp
@@ -97,6 +97,7 @@ void Player_AD::startSound(int sound) {
 
 	// Query the sound resource
 	const byte *res = _vm->getResourceAddress(rtSound, sound);
+	assert(res);
 
 	if (res[2] == 0x80) {
 		// Stop the current sounds
diff --git a/engines/scumm/players/player_towns.cpp b/engines/scumm/players/player_towns.cpp
index 16080205c0..a1add906bb 100644
--- a/engines/scumm/players/player_towns.cpp
+++ b/engines/scumm/players/player_towns.cpp
@@ -236,6 +236,8 @@ void Player_Towns_v1::setMusicVolume(int vol) {
 
 void Player_Towns_v1::startSound(int sound) {
 	uint8 *ptr = _vm->getResourceAddress(rtSound, sound);
+	assert(ptr);
+
 	if (_vm->_game.version != 3)
 		ptr += 2;
 
@@ -620,6 +622,7 @@ int Player_Towns_v2::getSoundStatus(int sound) const {
 
 void Player_Towns_v2::startSound(int sound) {
 	uint8 *ptr = _vm->getResourceAddress(rtSound, sound);
+	assert(ptr);
 
 	if (READ_BE_UINT32(ptr) == MKTAG('T','O','W','S')) {
 		_soundOverride[sound].type = 7;
-- 
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