From 25a39fdc6100c6f8db66023fdafb3d87bab40990 Mon Sep 17 00:00:00 2001
From: Gerhard Hoffmann <g.hoffmann@atb-online.eu>
Date: Wed, 31 Jan 2024 15:09:42 +0100
Subject: [PATCH] Fix getPaymentMethodId(): check for valid iterator.

---
 library/src/utilities.cpp | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/library/src/utilities.cpp b/library/src/utilities.cpp
index c02c6a5..2ac7ddd 100644
--- a/library/src/utilities.cpp
+++ b/library/src/utilities.cpp
@@ -354,22 +354,24 @@ bool Utilities::isCarryOverNotSet(Configuration const *cfg, PaymentMethod paymen
 }
 
 PaymentMethod Utilities::getPaymentMethodId(Configuration const *cfg) {
-    if (cfg->PaymentOption.size() != 1) {
+    if (cfg->PaymentOption.size() == 0) {
         return PaymentMethod::Undefined;
     }
 
     std::multimap<int, ATBPaymentOption>::const_iterator it =
         cfg->PaymentOption.cbegin();
 
-    switch (it->first) {
-    case PaymentMethod::Linear:
-        return PaymentMethod::Linear;
-    case PaymentMethod::Steps:
-        return PaymentMethod::Steps;
-    case PaymentMethod::Degressive:
-        return PaymentMethod::Degressive;
-    case PaymentMethod::Progressive:
-        return PaymentMethod::Progressive;
+    if (it != cfg->PaymentOption.cend()) {
+        switch (it->first) {
+        case PaymentMethod::Linear:
+            return PaymentMethod::Linear;
+        case PaymentMethod::Steps:
+            return PaymentMethod::Steps;
+        case PaymentMethod::Degressive:
+            return PaymentMethod::Degressive;
+        case PaymentMethod::Progressive:
+            return PaymentMethod::Progressive;
+        }
     }
 
     return PaymentMethod::Undefined;