From a50a0c5b0d2f4a409800e628c2019c5950760c76 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Sat, 23 Feb 2019 09:20:30 +0100
Subject: [PATCH] - fixed: empty strings cannot be substituted.

---
 src/utility/zstring.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/utility/zstring.cpp b/src/utility/zstring.cpp
index fa56229ad..d4ad5ec89 100644
--- a/src/utility/zstring.cpp
+++ b/src/utility/zstring.cpp
@@ -1039,6 +1039,7 @@ void FString::Substitute (const char *oldstr, const char *newstr)
 
 void FString::Substitute (const char *oldstr, const char *newstr, size_t oldstrlen, size_t newstrlen)
 {
+	if (oldstr == nullptr || newstr == nullptr || *oldstr == 0) return;
 	LockBuffer();
 	for (size_t checkpt = 0; checkpt < Len(); )
 	{