Fix nullpointer access in special layer draw function.

3 files changed, 51 insertions, 4 deletions

diff --git a/src/resources/map/maplayer.cpp b/src/resources/map/maplayer.cpp
index 95e835302..deaeab9de 100644
--- a/src/resources/map/maplayer.cpp
+++ b/src/resources/map/maplayer.cpp
@@ -391,7 +391,7 @@ void MapLayer::drawSpecialLayer(Graphics *const graphics,
     const MapItem *item0 = mSpecialLayer->mTiles[ptr + startX];
     if (!item0 || item0->mType == MapItemType::EMPTY)
     {
-        x0 += mSpecialLayer->mCache[ptr + startX];
+        x0 += mSpecialLayer->mCache[ptr + startX] + 1;
     }
     for (int x = x0; x < endX1; x++)
     {
@@ -414,7 +414,7 @@ void MapLayer::drawSpecialLayer(Graphics *const graphics,
     item0 = mTempLayer->mTiles[ptr + startX];
     if (!item0 || item0->mType == MapItemType::EMPTY)
     {
-        x0 += mTempLayer->mCache[ptr + startX];
+        x0 += mTempLayer->mCache[ptr + startX] + 1;
     }
     for (int x = x0; x < endX1; x++)
     {
diff --git a/src/resources/map/maplayer_unittest.cc b/src/resources/map/maplayer_unittest.cc
index 103d019cd..bd58d998c 100644
--- a/src/resources/map/maplayer_unittest.cc
+++ b/src/resources/map/maplayer_unittest.cc
@@ -2117,8 +2117,14 @@ TEST_CASE("MapLayer drawSpecialLayer (tempLayer)")
         layer->setTempLayer(map->getTempLayer());
         TileInfo *const tiles = layer->getTiles();
         specialLayer = map->getTempLayer();
+        const int *const cache = specialLayer->getCache();
+        REQUIRE(cache[0] == 10000);
+        REQUIRE(cache[1] == 10000);
+
         specialLayer->setTile(1, 0, MapItemType::ARROW_UP);
         specialLayer->updateCache();
+        REQUIRE(cache[0] == 0);
+        REQUIRE(cache[1] == 10000);
 
         layer->drawSpecialLayer(mock,
             0,
diff --git a/src/resources/map/speciallayer_unittest.cc b/src/resources/map/speciallayer_unittest.cc
index 3e1b42043..b74ade7dc 100644
--- a/src/resources/map/speciallayer_unittest.cc
+++ b/src/resources/map/speciallayer_unittest.cc
@@ -62,8 +62,9 @@ TEST_CASE("SpecialLayer updateCache")
     {
         layer = new SpecialLayer("test",
             1, 1);
-        layer->setTile(0, 0, MapItemType::ARROW_UP);
         const int *const cache = layer->getCache();
+        REQUIRE(cache[0] == 10000);
+        layer->setTile(0, 0, MapItemType::ARROW_UP);
         layer->updateCache();
         REQUIRE(cache[0] == 10000);
     }
@@ -72,8 +73,10 @@ TEST_CASE("SpecialLayer updateCache")
     {
         layer = new SpecialLayer("test",
             2, 1);
-        layer->setTile(0, 0, MapItemType::ARROW_UP);
         const int *const cache = layer->getCache();
+        REQUIRE(cache[0] == 10000);
+        REQUIRE(cache[1] == 10000);
+        layer->setTile(0, 0, MapItemType::ARROW_UP);
         layer->updateCache();
         REQUIRE(cache[0] == 10000);
         REQUIRE(cache[1] == 10000);
@@ -143,6 +146,44 @@ TEST_CASE("SpecialLayer updateCache")
         REQUIRE(cache[2] == 10000);
     }
 
+    SECTION("simple 7")
+    {
+        layer = new SpecialLayer("test",
+            3, 1);
+        const int *const cache = layer->getCache();
+        layer->updateCache();
+        REQUIRE(cache[0] == 10000);
+        REQUIRE(cache[1] == 10000);
+        REQUIRE(cache[2] == 10000);
+    }
+
+    SECTION("simple 8")
+    {
+        layer = new SpecialLayer("test",
+            3, 1);
+        layer->setTile(0, 0, MapItemType::EMPTY);
+        layer->setTile(1, 0, MapItemType::EMPTY);
+        layer->setTile(2, 0, MapItemType::EMPTY);
+        const int *const cache = layer->getCache();
+        layer->updateCache();
+        REQUIRE(cache[0] == 10000);
+        REQUIRE(cache[1] == 10000);
+        REQUIRE(cache[2] == 10000);
+    }
+
+    SECTION("simple 9")
+    {
+        layer = new SpecialLayer("test",
+            2, 1);
+        const int *const cache = layer->getCache();
+        REQUIRE(cache[0] == 10000);
+        REQUIRE(cache[1] == 10000);
+        layer->setTile(1, 0, MapItemType::ARROW_UP);
+        layer->updateCache();
+        REQUIRE(cache[0] == 0);
+        REQUIRE(cache[1] == 10000);
+    }
+
     SECTION("normal 1")
     {
         layer = new SpecialLayer("test",