(svn r20477) -Codechange: remove some airport-related constants/functions and add some documentation

4 files changed, 36 insertions, 69 deletions

diff --git a/src/aircraft_cmd.cpp b/src/aircraft_cmd.cpp
index 6664cef72..6dc0e05ee 100644
--- a/src/aircraft_cmd.cpp
+++ b/src/aircraft_cmd.cpp
@@ -71,14 +71,6 @@ void Aircraft::UpdateDeltaXY(Direction direction)
 	this->y_extent      = GB(x, 24, 8);
 }
 
-
-/**
- * this maps the terminal to its corresponding state and block flag
- *  currently set for 10 terms, 4 helipads
- */
-static const byte _airport_terminal_state[] = {2, 3, 4, 5, 6, 7, 19, 20, 0, 0, 8, 9, 21, 22};
-static const byte _airport_terminal_flag[] =  {0, 1, 2, 3, 4, 5, 22, 23, 0, 0, 6, 7, 24, 25};
-
 static bool AirportMove(Aircraft *v, const AirportFTAClass *apc);
 static bool AirportSetBlocks(Aircraft *v, const AirportFTA *current_pos, const AirportFTAClass *apc);
 static bool AirportHasBlock(Aircraft *v, const AirportFTA *current_pos, const AirportFTAClass *apc);
@@ -1638,7 +1630,6 @@ static AircraftStateHandler * const _aircraft_state_handlers[] = {
 	AircraftEventHandler_AtTerminal,     // TERM7          = 19
 	AircraftEventHandler_AtTerminal,     // TERM8          = 20
 	AircraftEventHandler_AtTerminal,     // HELIPAD3       = 21
-	AircraftEventHandler_AtTerminal,     // HELIPAD4       = 22
 };
 
 static void AirportClearBlock(const Aircraft *v, const AirportFTAClass *apc)
@@ -1780,14 +1771,39 @@ static bool AirportSetBlocks(Aircraft *v, const AirportFTA *current_pos, const A
 	return true;
 }
 
+/**
+ * Combination of aircraft state for going to a certain terminal and the
+ * airport flag for that terminal block.
+ */
+struct MovementTerminalMapping {
+	AirportMovementStates state; ///< Aircraft movement state when going to this terminal.
+	uint64 airport_flag;         ///< Bitmask in the airport flags that need to be free for this terminal.
+};
+
+/** A list of all valid terminals and their associated blocks. */
+static const MovementTerminalMapping _airport_terminal_mapping[] = {
+	{TERM1, TERM1_block},
+	{TERM2, TERM2_block},
+	{TERM3, TERM3_block},
+	{TERM4, TERM4_block},
+	{TERM5, TERM5_block},
+	{TERM6, TERM6_block},
+	{TERM7, TERM7_block},
+	{TERM8, TERM8_block},
+	{HELIPAD1, HELIPAD1_block},
+	{HELIPAD2, HELIPAD2_block},
+	{HELIPAD3, HELIPAD3_block},
+};
+
 static bool FreeTerminal(Aircraft *v, byte i, byte last_terminal)
 {
+	assert(last_terminal <= lengthof(_airport_terminal_mapping));
 	Station *st = Station::Get(v->targetairport);
 	for (; i < last_terminal; i++) {
-		if (!HasBit(st->airport.flags, _airport_terminal_flag[i])) {
+		if ((st->airport.flags & _airport_terminal_mapping[i].airport_flag) == 0) {
 			/* TERMINAL# HELIPAD# */
-			v->state = _airport_terminal_state[i]; // start moving to that terminal/helipad
-			SetBit(st->airport.flags, _airport_terminal_flag[i]); // occupy terminal/helipad
+			v->state = _airport_terminal_mapping[i].state; // start moving to that terminal/helipad
+			SETBITS(st->airport.flags, _airport_terminal_mapping[i].airport_flag); // occupy terminal/helipad
 			return true;
 		}
 	}
@@ -1850,58 +1866,15 @@ static bool AirportFindFreeTerminal(Aircraft *v, const AirportFTAClass *apc)
 	return FreeTerminal(v, 0, GetNumTerminals(apc));
 }
 
-static uint GetNumHelipads(const AirportFTAClass *apc)
-{
-	uint num = 0;
-
-	for (uint i = apc->helipads[0]; i > 0; i--) num += apc->helipads[i];
-
-	return num;
-}
-
-
 static bool AirportFindFreeHelipad(Aircraft *v, const AirportFTAClass *apc)
 {
 	/* if an airport doesn't have helipads, use terminals */
 	if (apc->helipads == NULL) return AirportFindFreeTerminal(v, apc);
 
-	/* if there are more helicoptergroups, pick one, just as in AirportFindFreeTerminal() */
-	if (apc->helipads[0] > 1) {
-		const Station *st = Station::Get(v->targetairport);
-		const AirportFTA *temp = apc->layout[v->pos].next;
-
-		while (temp != NULL) {
-			if (temp->heading == 255) {
-				if (!(st->airport.flags & temp->block)) {
-
-					/* read which group do we want to go to?
-					 * (the first free group) */
-					uint target_group = temp->next_position + 1;
-
-					/* at what terminal does the group start?
-					 * that means, sum up all terminals of
-					 * groups with lower number */
-					uint group_start = 0;
-					for (uint i = 1; i < target_group; i++) {
-						group_start += apc->helipads[i];
-					}
-
-					uint group_end = group_start + apc->helipads[target_group];
-					if (FreeTerminal(v, group_start, group_end)) return true;
-				}
-			} else {
-				/* once the heading isn't 255, we've exhausted the possible blocks.
-				 * So we cannot move */
-				return false;
-			}
-			temp = temp->next;
-		}
-	} else {
-		/* only 1 helicoptergroup, check all helipads
-		 * The blocks for helipads start after the last terminal (MAX_TERMINALS) */
-		return FreeTerminal(v, MAX_TERMINALS, GetNumHelipads(apc) + MAX_TERMINALS);
-	}
-	return false; // it shouldn't get here anytime, but just to be sure
+	assert(apc->helipads[0] == 1);
+	/* only 1 helicoptergroup, check all helipads
+	 * The blocks for helipads start after the last terminal (MAX_TERMINALS) */
+	return FreeTerminal(v, MAX_TERMINALS, apc->helipads[1] + MAX_TERMINALS);
 }
 
 static bool AircraftEventHandler(Aircraft *v, int loop)
diff --git a/src/airport.cpp b/src/airport.cpp
index 6be9c0039..bb4957681 100644
--- a/src/airport.cpp
+++ b/src/airport.cpp
@@ -393,7 +393,6 @@ static const char * const _airport_heading_strings[] = {
 	"TERM7",
 	"TERM8",
 	"HELIPAD3",
-	"HELIPAD4",
 	"DUMMY" // extra heading for 255
 };
 
diff --git a/src/airport.h b/src/airport.h
index e91bdb1bd..b96c0939f 100644
--- a/src/airport.h
+++ b/src/airport.h
@@ -16,8 +16,8 @@
 #include "tile_type.h"
 
 /** Some airport-related constants */
-static const uint MAX_TERMINALS =  10;                       ///< maximum number of terminals per airport
-static const uint MAX_HELIPADS  =   4;                       ///< maximum number of helipads per airport
+static const uint MAX_TERMINALS =   8;                       ///< maximum number of terminals per airport
+static const uint MAX_HELIPADS  =   3;                       ///< maximum number of helipads per airport
 static const uint MAX_ELEMENTS  = 255;                       ///< maximum number of aircraft positions at airport
 
 static const uint NUM_AIRPORTTILES       = 256;              ///< total number of airport tiles
@@ -78,8 +78,7 @@ enum AirportMovementStates {
 	TERM7          = 19,
 	TERM8          = 20,
 	HELIPAD3       = 21,
-	HELIPAD4       = 22,
-	MAX_HEADINGS   = 22,
+	MAX_HEADINGS   = 21,
 };
 
 /* Movement Blocks on Airports
@@ -113,10 +112,7 @@ static const uint64
 	/* blocks for new airports */
 	TERM7_block              = 1ULL << 22,
 	TERM8_block              = 1ULL << 23,
-	TERM9_block              = 1ULL << 24,
 	HELIPAD3_block           = 1ULL << 24,
-	TERM10_block             = 1ULL << 25,
-	HELIPAD4_block           = 1ULL << 25,
 	HANGAR1_AREA_block       = 1ULL << 26,
 	OUT_WAY2_block           = 1ULL << 27,
 	IN_WAY2_block            = 1ULL << 28,
diff --git a/src/newgrf_engine.cpp b/src/newgrf_engine.cpp
index 92f6f0eb2..fd8835b8a 100644
--- a/src/newgrf_engine.cpp
+++ b/src/newgrf_engine.cpp
@@ -242,7 +242,7 @@ static byte MapAircraftMovementState(const Aircraft *v)
 		case HELIPAD1:
 		case HELIPAD2:
 		case HELIPAD3:
-		case HELIPAD4: // Will only occur for helicopters.
+			/* Will only occur for helicopters.*/
 			if (amdflag & AMED_HELI_LOWER) return AMS_TTDP_HELI_LAND_AIRPORT; // Descending.
 			if (amdflag & AMED_SLOWTURN)   return AMS_TTDP_FLIGHT_TO_TOWER;   // Still hasn't started descent.
 			return AMS_TTDP_TO_JUNCTION; // On the ground.
@@ -340,7 +340,6 @@ static byte MapAircraftMovementAction(const Aircraft *v)
 		case TERM7:
 		case TERM8:
 		case HELIPAD3:
-		case HELIPAD4:
 			return (v->current_order.IsType(OT_LOADING)) ? AMA_TTDP_ON_PAD3 : AMA_TTDP_LANDING_TO_PAD3;
 
 		case TAKEOFF:      // Moving to takeoff position