(svn r15027) -Merge: tomatos and bananas left to be, here is NoAI for all to see.

NoAI is an API (a framework) to build your own AIs in. See:
   http://wiki.openttd.org/wiki/index.php/AI:Main_Page
 With many thanks to:
  - glx and Rubidium for their syncing, feedback and hard work
  - Yexo for his feedback, patches, and AIs which tested the system very deep
  - Morloth for his feedback and patches
  - TJIP for hosting a challenge which kept NoAI on track
  - All AI authors for testing our AI API, and all other people who helped in one way or another
-Remove: all old AIs and their cheats/hacks

src/ai/api/ai_bridge.cpp

@@ -0,0 +1,177 @@
+/* $Id$ */
+
+/** @file ai_bridge.cpp Implementation of AIBridge. */
+
+#include "ai_bridge.hpp"
+#include "ai_rail.hpp"
+#include "../ai_instance.hpp"
+#include "../../openttd.h"
+#include "../../bridge_map.h"
+#include "../../strings_func.h"
+#include "../../core/alloc_func.hpp"
+#include "../../economy_func.h"
+#include "../../settings_type.h"
+#include "../../road_map.h"
+#include "table/strings.h"
+
+/* static */ bool AIBridge::IsValidBridge(BridgeID bridge_id)
+{
+	return bridge_id < MAX_BRIDGES;
+}
+
+/* static */ bool AIBridge::IsBridgeTile(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return false;
+	return ::IsBridgeTile(tile);
+}
+
+static void _DoCommandReturnBuildBridge2(class AIInstance *instance)
+{
+	if (!AIBridge::_BuildBridgeRoad2()) {
+		AIObject::SetLastCommandRes(false);
+		AIInstance::DoCommandReturn(instance);
+		return;
+	}
+
+	/* This can never happen, as in test-mode this callback is never executed,
+	*  and in execute-mode, the other callback is called. */
+	NOT_REACHED();
+}
+
+static void _DoCommandReturnBuildBridge1(class AIInstance *instance)
+{
+	if (!AIBridge::_BuildBridgeRoad1()) {
+		AIObject::SetLastCommandRes(false);
+		AIInstance::DoCommandReturn(instance);
+		return;
+	}
+
+	/* This can never happen, as in test-mode this callback is never executed,
+	*  and in execute-mode, the other callback is called. */
+	NOT_REACHED();
+}
+
+/* static */ bool AIBridge::BuildBridge(AIVehicle::VehicleType vehicle_type, BridgeID bridge_id, TileIndex start, TileIndex end)
+{
+	EnforcePrecondition(false, start != end);
+	EnforcePrecondition(false, ::IsValidTile(start) && ::IsValidTile(end));
+	EnforcePrecondition(false, TileX(start) == TileX(end) || TileY(start) == TileY(end));
+	EnforcePrecondition(false, vehicle_type == AIVehicle::VEHICLE_ROAD || vehicle_type == AIVehicle::VEHICLE_RAIL || vehicle_type == AIVehicle::VEHICLE_WATER);
+	EnforcePrecondition(false, vehicle_type != AIVehicle::VEHICLE_RAIL || AIRail::IsRailTypeAvailable(AIRail::GetCurrentRailType()));
+
+	uint type = 0;
+	switch (vehicle_type) {
+		case AIVehicle::VEHICLE_ROAD:
+			type |= (TRANSPORT_ROAD << 15);
+			type |= (RoadTypeToRoadTypes((::RoadType)AIObject::GetRoadType()) << 8);
+			break;
+		case AIVehicle::VEHICLE_RAIL:
+			type |= (TRANSPORT_RAIL << 15);
+			type |= (AIRail::GetCurrentRailType() << 8);
+			break;
+		case AIVehicle::VEHICLE_WATER:
+			type |= (TRANSPORT_WATER << 15);
+			break;
+		default: NOT_REACHED();
+	}
+
+	/* For rail and water we do nothing special */
+	if (vehicle_type == AIVehicle::VEHICLE_RAIL || vehicle_type == AIVehicle::VEHICLE_WATER) {
+		return AIObject::DoCommand(end, start, type | bridge_id, CMD_BUILD_BRIDGE);
+	}
+
+	AIObject::SetCallbackVariable(0, start);
+	if (!AIObject::DoCommand(end, start, type | bridge_id, CMD_BUILD_BRIDGE, NULL, &_DoCommandReturnBuildBridge1)) return false;
+
+	/* In case of test-mode, test if we can build both road pieces */
+	return _BuildBridgeRoad1();
+}
+
+/* static */ bool AIBridge::_BuildBridgeRoad1()
+{
+	/* Build the piece of road on the 'start' side of the bridge */
+	TileIndex end = AIObject::GetCallbackVariable(0);
+	TileIndex start = AIBridge::GetOtherBridgeEnd(end);
+
+	DiagDirection dir_1 = (DiagDirection)((::TileX(start) == ::TileX(end)) ? (::TileY(start) < ::TileY(end) ? DIAGDIR_NW : DIAGDIR_SE) : (::TileX(start) < ::TileX(end) ? DIAGDIR_NE : DIAGDIR_SW));
+	DiagDirection dir_2 = ::ReverseDiagDir(dir_1);
+
+	if (!AIObject::DoCommand(start + ::TileOffsByDiagDir(dir_1), ::DiagDirToRoadBits(dir_2) | (AIObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD, NULL, &_DoCommandReturnBuildBridge2)) return false;
+
+	/* In case of test-mode, test the other road piece too */
+	return _BuildBridgeRoad2();
+}
+
+/* static */ bool AIBridge::_BuildBridgeRoad2()
+{
+	/* Build the piece of road on the 'end' side of the bridge */
+	TileIndex end = AIObject::GetCallbackVariable(0);
+	TileIndex start = AIBridge::GetOtherBridgeEnd(end);
+
+	DiagDirection dir_1 = (DiagDirection)((::TileX(start) == ::TileX(end)) ? (::TileY(start) < ::TileY(end) ? DIAGDIR_NW : DIAGDIR_SE) : (::TileX(start) < ::TileX(end) ? DIAGDIR_NE : DIAGDIR_SW));
+	DiagDirection dir_2 = ::ReverseDiagDir(dir_1);
+
+	return AIObject::DoCommand(end + ::TileOffsByDiagDir(dir_2), ::DiagDirToRoadBits(dir_1) | (AIObject::GetRoadType() << 4), 0, CMD_BUILD_ROAD);
+}
+
+/* static */ bool AIBridge::RemoveBridge(TileIndex tile)
+{
+	EnforcePrecondition(false, IsBridgeTile(tile));
+	return AIObject::DoCommand(tile, 0, 0, CMD_LANDSCAPE_CLEAR);
+}
+
+/* static */ const char *AIBridge::GetName(BridgeID bridge_id)
+{
+	if (!IsValidBridge(bridge_id)) return NULL;
+
+	static const int len = 64;
+	char *bridge_name = MallocT<char>(len);
+
+	::GetString(bridge_name, ::GetBridgeSpec(bridge_id)->transport_name[0], &bridge_name[len - 1]);
+	return bridge_name;
+}
+
+/* static */ int32 AIBridge::GetMaxSpeed(BridgeID bridge_id)
+{
+	if (!IsValidBridge(bridge_id)) return -1;
+
+	return ::GetBridgeSpec(bridge_id)->speed;
+}
+
+/* static */ Money AIBridge::GetPrice(BridgeID bridge_id, uint length)
+{
+	if (!IsValidBridge(bridge_id)) return -1;
+
+	return length * _price.build_bridge * ::GetBridgeSpec(bridge_id)->price >> 8;
+}
+
+/* static */ int32 AIBridge::GetMaxLength(BridgeID bridge_id)
+{
+	if (!IsValidBridge(bridge_id)) return -1;
+
+	uint max = ::GetBridgeSpec(bridge_id)->max_length;
+	if (max >= 16 && _settings_game.construction.longbridges) max = 100;
+	return max + 2;
+}
+
+/* static */ int32 AIBridge::GetMinLength(BridgeID bridge_id)
+{
+	if (!IsValidBridge(bridge_id)) return -1;
+
+	return ::GetBridgeSpec(bridge_id)->min_length + 2;
+}
+
+/* static */ int32 AIBridge::GetYearAvailable(BridgeID bridge_id)
+{
+	if (!IsValidBridge(bridge_id)) return -1;
+
+	return ::GetBridgeSpec(bridge_id)->avail_year;
+}
+
+/* static */ TileIndex AIBridge::GetOtherBridgeEnd(TileIndex tile)
+{
+	if (!::IsValidTile(tile)) return INVALID_TILE;
+	if (!IsBridgeTile(tile)) return INVALID_TILE;
+
+	return ::GetOtherBridgeEnd(tile);
+}