From 126669e10d9de26ae4c6d44958a4e7f9e8abeed5 Mon Sep 17 00:00:00 2001
From: Peter Nelson <peter1138@openttd.org>
Date: Tue, 9 Sep 2025 18:00:54 +0100
Subject: [PATCH] Codechange: Make GetRail/RoadTypeInfoIndex() a member method.

This follows a similar pattern used for cargoes, houses and objects.

Also fixes incorrect documentation of GetRoadTypeInfoIndex().
---
 src/newgrf_railtype.cpp |  2 +-
 src/newgrf_roadtype.cpp |  2 +-
 src/rail.cpp            | 12 ++++++++++++
 src/rail.h              | 15 ++-------------
 src/road.cpp            | 12 ++++++++++++
 src/road.h              | 15 ++-------------
 6 files changed, 30 insertions(+), 28 deletions(-)

diff --git a/src/newgrf_railtype.cpp b/src/newgrf_railtype.cpp
index 0d215971b8..67754addb2 100644
--- a/src/newgrf_railtype.cpp
+++ b/src/newgrf_railtype.cpp
@@ -35,7 +35,7 @@
 			case 0x43: return TimerGameCalendar::date.base();
 			case 0x44: return to_underlying(HouseZone::TownEdge);
 			case 0x45: {
-				auto rt = GetRailTypeInfoIndex(this->rti);
+				RailType rt = this->rti->Index();
 				uint8_t local = GetReverseRailTypeTranslation(rt, this->ro.grffile);
 				if (local == 0xFF) local = 0xFE;
 				return 0xFFFF | local << 16;
diff --git a/src/newgrf_roadtype.cpp b/src/newgrf_roadtype.cpp
index e48a67b11a..6b40a1e0d8 100644
--- a/src/newgrf_roadtype.cpp
+++ b/src/newgrf_roadtype.cpp
@@ -69,7 +69,7 @@ uint32_t GetTrackTypes(TileIndex tile, const GRFFile *grffile)
 			case 0x43: return TimerGameCalendar::date.base();
 			case 0x44: return to_underlying(HouseZone::TownEdge);
 			case 0x45: {
-				auto rt = GetRoadTypeInfoIndex(this->rti);
+				RoadType rt = this->rti->Index();
 				uint8_t local = GetReverseRoadTypeTranslation(rt, this->ro.grffile);
 				if (local == 0xFF) local = 0xFE;
 				if (RoadTypeIsRoad(rt)) {
diff --git a/src/rail.cpp b/src/rail.cpp
index d9e41087e3..590676aa87 100644
--- a/src/rail.cpp
+++ b/src/rail.cpp
@@ -19,6 +19,18 @@
 
 #include "safeguards.h"
 
+/**
+ * Get the RailType for this RailTypeInfo.
+ * @return RailType in static RailTypeInfo definitions.
+ */
+RailType RailTypeInfo::Index() const
+{
+	extern RailTypeInfo _railtypes[RAILTYPE_END];
+	size_t index = this - _railtypes;
+	assert(index < RAILTYPE_END);
+	return static_cast<RailType>(index);
+}
+
 /**
  * Return the rail type of tile, or INVALID_RAILTYPE if this is no rail tile.
  */
diff --git a/src/rail.h b/src/rail.h
index 4a294e213d..631a7989d0 100644
--- a/src/rail.h
+++ b/src/rail.h
@@ -286,6 +286,8 @@ public:
 	{
 		return 82 * this->fallback_railtype;
 	}
+
+	RailType Index() const;
 };
 
 
@@ -301,19 +303,6 @@ inline const RailTypeInfo *GetRailTypeInfo(RailType railtype)
 	return &_railtypes[railtype];
 }
 
-/**
- * Returns the railtype for a Railtype information.
- * @param rti Pointer to static RailTypeInfo
- * @return Railtype in static railtype definitions
- */
-inline RailType GetRailTypeInfoIndex(const RailTypeInfo *rti)
-{
-	extern RailTypeInfo _railtypes[RAILTYPE_END];
-	size_t index = rti - _railtypes;
-	assert(index < RAILTYPE_END && rti == _railtypes + index);
-	return static_cast<RailType>(index);
-}
-
 /**
  * Returns all compatible railtypes for a set of railtypes.
  * @param railtypes Set of railtypes to get the compatible railtypes from.
diff --git a/src/road.cpp b/src/road.cpp
index 5b796f12ea..51bdf1900d 100644
--- a/src/road.cpp
+++ b/src/road.cpp
@@ -23,6 +23,18 @@
 
 #include "safeguards.h"
 
+/**
+ * Get the RoadType for this RoadTypeInfo.
+ * @return RoadType in static RoadTypeInfo definitions.
+ */
+RoadType RoadTypeInfo::Index() const
+{
+	extern RoadTypeInfo _roadtypes[ROADTYPE_END];
+	size_t index = this - _roadtypes;
+	assert(index < ROADTYPE_END);
+	return static_cast<RoadType>(index);
+}
+
 /**
  * Return if the tile is a valid tile for a crossing.
  *
diff --git a/src/road.h b/src/road.h
index 76355d216e..a3c689419f 100644
--- a/src/road.h
+++ b/src/road.h
@@ -185,6 +185,8 @@ public:
 	{
 		return this->group[ROTSG_GROUND] != nullptr;
 	}
+
+	RoadType Index() const;
 };
 
 /**
@@ -231,19 +233,6 @@ inline const RoadTypeInfo *GetRoadTypeInfo(RoadType roadtype)
 	return &_roadtypes[roadtype];
 }
 
-/**
- * Returns the railtype for a Railtype information.
- * @param rti Pointer to static RailTypeInfo
- * @return Railtype in static railtype definitions
- */
-inline RoadType GetRoadTypeInfoIndex(const RoadTypeInfo *rti)
-{
-	extern RoadTypeInfo _roadtypes[ROADTYPE_END];
-	size_t index = rti - _roadtypes;
-	assert(index < ROADTYPE_END && rti == _roadtypes + index);
-	return static_cast<RoadType>(index);
-}
-
 /**
  * Checks if an engine of the given RoadType got power on a tile with a given
  * RoadType. This would normally just be an equality check, but for electrified