CGE2: Fix a crash when detecting an empty set of VOL files

1 files changed, 12 insertions, 2 deletions

diff --git a/engines/cge2/fileio.cpp b/engines/cge2/fileio.cpp
index 6f8009716b..acb5bb870f 100644
--- a/engines/cge2/fileio.cpp
+++ b/engines/cge2/fileio.cpp
@@ -116,7 +116,10 @@ BtPage *ResourceManager::getPage(int level, uint16 pageId) {
 	if (_buff[level]._pageNo != pageId) {
 		int32 pos = pageId * kBtSize;
 		_buff[level]._pageNo = pageId;
-		assert(_catFile->size() > pos);
+
+		if (_catFile->size() <= pos)
+			return nullptr;
+
 		// In the original, there was a check verifying if the
 		// purpose was to write a new file. This should only be
 		// to create a new file, thus it was removed.
@@ -139,6 +142,9 @@ BtKeypack *ResourceManager::find(const char *key) {
 	uint16 nxt = kBtValRoot;
 	while (!_catFile->eos()) {
 		BtPage *pg = getPage(lev, nxt);
+		if (!pg)
+			return nullptr;
+
 		// search
 		if (pg->_header._down != kBtValNone) {
 			int i;
@@ -170,7 +176,11 @@ BtKeypack *ResourceManager::find(const char *key) {
 }
 
 bool ResourceManager::exist(const char *name) {
-	return scumm_stricmp(find(name)->_key, name) == 0;
+	BtKeypack *result = find(name);
+	if (!result)
+		return false;
+
+	return scumm_stricmp(result->_key, name) == 0;
 }
 
 uint16 ResourceManager::catRead(byte *buf, uint16 length) {