From adf929fef5022c0b6583e9fc6fde559c71ab0fad Mon Sep 17 00:00:00 2001
From: Darkvater <darkvater@openttd.org>
Date: Fri, 6 May 2005 16:13:44 +0000
Subject: [PATCH] (svn r2274) - Codechange: some comments, parentheses and
 EngineID typedef for engine_type

---
 train_cmd.c |  4 ++--
 variables.h |  1 +
 vehicle.h   | 10 +++++-----
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/train_cmd.c b/train_cmd.c
index 94008418b2..80400faf9b 100644
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -955,7 +955,7 @@ int32 CmdSellRailWagon(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 
 			/* 2. We are selling the first engine, some special action might be required
 				* here, so take attention */
-			if (flags & DC_EXEC && v == first) {
+			if ((flags & DC_EXEC) && v == first) {
 				Vehicle *new_f = first->next;
 
 				/* 2.1 If the first wagon is sold, update the first-> pointers to NULL */
@@ -1043,7 +1043,7 @@ int32 CmdSellRailWagon(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 			}
 
 			/* 3. If it is still a valid train after selling, update its acceleration */
-			if (flags & DC_EXEC && first != NULL && first->subtype == TS_Front_Engine) UpdateTrainAcceleration(first);
+			if ((flags & DC_EXEC) && first != NULL && first->subtype == TS_Front_Engine) UpdateTrainAcceleration(first);
 		} break;
 	}
 	return cost;
diff --git a/variables.h b/variables.h
index afd37d4f9f..71939cfd85 100644
--- a/variables.h
+++ b/variables.h
@@ -9,6 +9,7 @@
 #endif
 
 typedef uint16 UnitID;   //! All unitnumber stuff is of this type (or anyway, should be)
+typedef uint16 EngineID; //! All enginenumbers should be of this type
 
 // Prices and also the fractional part.
 VARDEF Prices _price;
diff --git a/vehicle.h b/vehicle.h
index e8f45cb05b..d0e99e9699 100644
--- a/vehicle.h
+++ b/vehicle.h
@@ -26,9 +26,9 @@ enum VehStatus {
 
 // 1 and 3 do not appear to be used
 typedef enum TrainSubtypes {
-	TS_Front_Engine = 0,
-	TS_Not_First = 2,
-	TS_Free_Car = 4,
+	TS_Front_Engine = 0, // Leading engine of a train
+	TS_Not_First = 2,    // Wagon or additional engine
+	TS_Free_Car = 4,     // First in a wagon chain (in depot)
 } TrainSubtype;
 
 /* Effect vehicle types */
@@ -161,7 +161,7 @@ struct Vehicle {
 	byte z_height;		// z-height of vehicle sprite
 	int8 x_offs;			// x offset for vehicle sprite
 	int8 y_offs;			// y offset for vehicle sprite
-	uint16 engine_type;
+	EngineID engine_type;
 
 	// for randomized variational spritegroups
 	// bitmask used to resolve them; parts of it get reseeded when triggers
@@ -366,7 +366,7 @@ static inline uint16 GetVehiclePoolSize(void)
 /**
  * Check if a Vehicle really exists.
  */
-static inline bool IsValidVehicle(Vehicle* v)
+static inline bool IsValidVehicle(const Vehicle *v)
 {
 	return v->type != 0;
 }