diff --git a/tools/bin2cpp/bin2cpp.cpp b/tools/bin2cpp/bin2cpp.cpp
index 31273e7748..e62f86b9a5 100644
--- a/tools/bin2cpp/bin2cpp.cpp
+++ b/tools/bin2cpp/bin2cpp.cpp
@@ -105,8 +105,8 @@ int main(int argc, char* argv[])
 
 	strcpy(srcfile,argv[ARG_SRCFILE]);
 
-	int srcfn_len = strlen( srcfile );
-	if( srcfile[srcfn_len-4] != '.' )
+	const size_t srcfn_len = strlen( srcfile );
+	if( srcfn_len < 4 || srcfile[srcfn_len-4] != '.' )
 	{
 		printf( "ERROR : Malformed source filename.  I'm a crap utility and I demand 3-letter extensions only!\n" );
 		return 18;
@@ -166,7 +166,7 @@ int main(int argc, char* argv[])
 	}
 
 	{
-		int len = strlen(fnameonly);
+		int len = static_cast<int>(strlen(fnameonly));
 		const char* fnlast = &fnameonly[len];
 		while( --fnlast, --len, (len >= 0 && (*fnlast != '/')) );