(svn r662) [newgrf] Moved grfspecial.c to newgrf.c/newgrf.h

1 files changed, 2122 insertions, 0 deletions

diff --git a/newgrf.c b/newgrf.c
new file mode 100644
index 000000000..5563f8d8e
--- /dev/null
+++ b/newgrf.c
@@ -0,0 +1,2122 @@
+#include "stdafx.h"
+
+#include <stdarg.h>
+
+#include "ttd.h"
+#include "gfx.h"
+#include "fileio.h"
+#include "engine.h"
+#include "station.h"
+#include "sprite.h"
+#include "newgrf.h"
+
+/* TTDPatch extended GRF format codec
+ * (c) Petr Baudis 2004 (GPL'd)
+ * Changes by Florian octo Forster are (c) by the OpenTTD development team.
+ *
+ * Contains portions of documentation by TTDPatch team.
+ * Thanks especially to Josef Drexler for the documentation as well as a lot
+ * of help at #tycoon. Also thanks to Michael Blunck for is GRF files which
+ * served as subject to the initial testing of this codec. */
+
+extern int _skip_sprites;
+extern int _replace_sprites_count[16];
+extern int _replace_sprites_offset[16];
+extern int _traininfo_vehicle_pitch;
+
+static struct GRFFile *_cur_grffile;
+static int _cur_spriteid;
+static int _cur_stage;
+extern int _custom_sprites_base;
+
+static int32 _paramlist[0x7f];
+static int _param_max;
+
+/* 32 * 8 = 256 flags. Apparently TTDPatch uses this many.. */
+static uint32 _ttdpatch_flags[8];
+
+
+enum grfspec_feature {
+	GSF_TRAIN,
+	GSF_ROAD,
+	GSF_SHIP,
+	GSF_AIRCRAFT,
+	GSF_STATION,
+	GSF_BRIDGE,
+	GSF_TOWNHOUSE,
+};
+
+
+typedef void (*SpecialSpriteHandler)(byte *buf, int len);
+
+static const int _vehcounts[4] = {
+	/* GSF_TRAIN */    NUM_TRAIN_ENGINES,
+	/* GSF_ROAD */     NUM_ROAD_ENGINES,
+	/* GSF_SHIP */     NUM_SHIP_ENGINES,
+	/* GSF_AIRCRAFT */ NUM_AIRCRAFT_ENGINES
+};
+
+static const int _vehshifts[4] = {
+	/* GSF_TRAIN */    0,
+	/* GSF_ROAD */     ROAD_ENGINES_INDEX,
+	/* GSF_SHIP */     SHIP_ENGINES_INDEX,
+	/* GSF_AIRCRAFT */ AIRCRAFT_ENGINES_INDEX,
+};
+
+
+/* Debugging messages policy:
+ *
+ * These should be the severities used for direct DEBUG() calls
+ * (there is room for exceptions, but you have to have a good cause):
+ *
+ * 0..2 - dedicated to grfmsg()
+ * 3
+ * 4
+ * 5
+ * 6 - action handler entry reporting - one per action
+ * 7 - basic action progress reporting - in loops, only single one allowed
+ * 8 - more detailed progress reporting - less important stuff, in deep loops etc
+ * 9 - extremely detailed progress reporting - detailed reports inside of deep loops and so
+ */
+
+
+enum grfmsg_severity {
+	GMS_NOTICE,
+	GMS_WARN,
+	GMS_ERROR,
+	GMS_FATAL,
+};
+
+static void CDECL grfmsg(enum grfmsg_severity severity, const char *str, ...)
+{
+	static const char * const severitystr[4] = { "Notice", "Warning", "Error", "Fatal" };
+	int export_severity = 0;
+	char buf[1024];
+	va_list va;
+
+	va_start(va, str);
+	vsprintf(buf, str, va);
+	va_end(va);
+
+	export_severity = 2 - (severity == GMS_FATAL ? 2 : severity);
+	DEBUG(grf, export_severity) ("[%s][%s] %s", _cur_grffile->filename, severitystr[severity], buf);
+}
+
+
+#define check_length(real, wanted, where) \
+do { \
+	if (real < wanted) { \
+		grfmsg(GMS_ERROR, "%s: Invalid special sprite length %d (expected %d)!", where, real, wanted); \
+		return; \
+	} \
+} while (0)
+
+
+static byte INLINE grf_load_byte(byte **buf)
+{
+	return *(*buf)++;
+}
+
+static uint16 grf_load_word(byte **buf)
+{
+	uint16 val;
+	byte *p = *buf;
+	val = p[0];
+	val |= p[1] << 8;
+	*buf = p + 2;
+	return val;
+}
+
+static uint16 grf_load_dword(byte **buf)
+{
+	uint32 val;
+	byte *p = *buf;
+	val = p[0];
+	val |= p[1] << 8;
+	val |= p[2] << 16;
+	val |= p[3] << 24;
+	*buf = p + 4;
+	return val;
+}
+
+
+static struct GRFFile *GetFileByGRFID(uint32 grfid)
+{
+	struct GRFFile *file;
+
+	file = _first_grffile;
+	while ((file != NULL) && (file->grfid != grfid))
+		file = file->next;
+
+	return file;
+}
+
+static struct GRFFile *GetFileByFilename(const char *filename)
+{
+	struct GRFFile *file;
+
+	file = _first_grffile;
+	while ((file != NULL) && strcmp(file->filename, filename))
+		file = file->next;
+
+	return file;
+}
+
+
+typedef bool (*VCI_Handler)(uint engine, int numinfo, int prop, byte **buf, int len);
+
+#define FOR_EACH_OBJECT for (i = 0; i < numinfo; i++)
+
+static void dewagonize(int condition, int engine)
+{
+	EngineInfo *ei = &_engine_info[engine];
+	RailVehicleInfo *rvi = &_rail_vehicle_info[engine];
+
+	if (condition != 0) {
+		ei->unk2 &= ~0x80;
+		rvi->flags &= ~2;
+	} else {
+		ei->unk2 |= 0x80;
+		rvi->flags |= 2;
+	}
+}
+
+static bool RailVehicleChangeInfo(uint engine, int numinfo, int prop, byte **bufp, int len)
+{
+	EngineInfo *ei = &_engine_info[engine];
+	RailVehicleInfo *rvi = &_rail_vehicle_info[engine];
+	byte *buf = *bufp;
+	int i;
+	bool ret = false;
+
+	switch (prop) {
+		case 0x05: {	/* Track type */
+			FOR_EACH_OBJECT {
+				uint8 tracktype = grf_load_byte(&buf);
+
+				ei[i].railtype_climates &= 0xf;
+				ei[i].railtype_climates |= tracktype << 4;
+			}
+		}	break;
+		case 0x08: {	/* AI passenger service */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+		}	break;
+		case 0x09: {	/* Speed */
+			FOR_EACH_OBJECT {
+				uint16 speed = grf_load_word(&buf);
+
+				rvi[i].max_speed = speed;
+				dewagonize(speed, engine + i);
+			}
+		}	break;
+		case 0x0B: {	/* Power */
+			FOR_EACH_OBJECT {
+				uint16 power = grf_load_word(&buf);
+
+				rvi[i].power = power;
+				dewagonize(power, engine + i);
+			}
+		}	break;
+		case 0x0D: {	/* Running cost factor */
+			FOR_EACH_OBJECT {
+				uint8 runcostfact = grf_load_byte(&buf);
+
+				rvi[i].running_cost_base = runcostfact;
+				dewagonize(runcostfact, engine + i);
+			}
+		}	break;
+		case 0x0E: {	/* Running cost base */
+			FOR_EACH_OBJECT {
+				uint32 base = grf_load_dword(&buf);
+
+				switch (base) {
+				case 0x4C30:
+					rvi[i].engclass = 0;
+					break;
+				case 0x4C36:
+					rvi[i].engclass = 1;
+					break;
+				case 0x4C3C:
+					rvi[i].engclass = 2;
+					break;
+				}
+				dewagonize(base, engine + i);
+			}
+		}	break;
+		case 0x12: {	/* Sprite ID */
+			FOR_EACH_OBJECT {
+				uint8 spriteid = grf_load_byte(&buf);
+
+				if (spriteid == 0xFD && rvi[i].image_index != 0xFD)
+					_engine_original_sprites[engine + i] = rvi[i].image_index;
+				rvi[i].image_index = spriteid;
+			}
+		}	break;
+		case 0x13: {	/* Dual-headed */
+			FOR_EACH_OBJECT {
+				uint8 dual = grf_load_byte(&buf);
+
+				if (dual != 0) {
+					rvi[i].flags |= 1;
+				} else {
+					rvi[i].flags &= ~1;
+				}
+			}
+		}	break;
+		case 0x14: {	/* Cargo capacity */
+			FOR_EACH_OBJECT {
+				uint8 capacity = grf_load_byte(&buf);
+
+				rvi[i].capacity = capacity;
+			}
+		}	break;
+		case 0x15: {	/* Cargo type */
+			FOR_EACH_OBJECT {
+				uint8 ctype = grf_load_byte(&buf);
+
+				rvi[i].cargo_type = ctype;
+			}
+		}	break;
+		case 0x16: {	/* Weight */
+			FOR_EACH_OBJECT {
+				uint8 weight = grf_load_byte(&buf);
+
+				rvi[i].weight = weight;
+			}
+		}	break;
+		case 0x17: {	/* Cost factor */
+			FOR_EACH_OBJECT {
+				uint8 cfactor = grf_load_byte(&buf);
+
+				rvi[i].base_cost = cfactor;
+			}
+		}	break;
+		case 0x18: {	/* AI rank */
+			/* TODO: _railveh_score should be merged to _rail_vehicle_info. */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+		}	break;
+		case 0x19: { /* Engine traction type */
+			/* TODO: What do the individual numbers mean?
+			 * XXX: And in what base are they, in fact? --pasky */
+			FOR_EACH_OBJECT {
+				uint8 traction = grf_load_byte(&buf);
+				int engclass;
+
+				if (traction <= 0x07)
+					engclass = 0;
+				else if (traction <= 0x27)
+					engclass = 1;
+				else if (traction <= 0x31)
+					engclass = 2;
+				else
+					break;
+
+				rvi[i].engclass = engclass;
+			}
+		}	break;
+		case 0x1D: {	/* Refit cargo */
+			FOR_EACH_OBJECT {
+				uint32 refit_mask = grf_load_dword(&buf);
+
+				_engine_refit_masks[engine + i] = refit_mask;
+			}
+		}	break;
+
+		/* TODO */
+		/* Fall-through for unimplemented two bytes long properties. */
+		case 0x1B:	/* Powered wagons power bonus */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+		/* Fall-through for unimplemented one byte long properties. */
+		case 0x1A:	/* Sort order */
+		case 0x1C:	/* Refit cost */
+		case 0x1E:	/* Callback */
+		case 0x1F:	/* Tractive effort */
+		case 0x21:	/* Shorter tenders */
+		case 0x22:	/* Visual */
+		case 0x23: {/* Powered wagons weight bonus */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+		}	break;
+		default:
+			ret = true;
+	}
+	*bufp = buf;
+	return ret;
+}
+
+static bool RoadVehicleChangeInfo(uint engine, int numinfo, int prop, byte **bufp, int len)
+{
+	RoadVehicleInfo *rvi = &_road_vehicle_info[engine];
+	byte *buf = *bufp;
+	int i;
+	bool ret = false;
+
+	switch (prop) {
+		case 0x08: {	/* Speed */
+			FOR_EACH_OBJECT {
+				uint8 speed = grf_load_byte(&buf);
+
+				rvi[i].max_speed = speed; // ?? units
+			}
+		}	break;
+		case 0x09: {	/* Running cost factor */
+			FOR_EACH_OBJECT {
+				uint8 runcost = grf_load_byte(&buf);
+
+				rvi[i].running_cost = runcost;
+			}
+		}	break;
+		case 0x0A:	/* Running cost base */
+			/* TODO: I have no idea. --pasky */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+			break;
+		case 0x0E: {	/* Sprite ID */
+			FOR_EACH_OBJECT {
+				uint8 spriteid = grf_load_byte(&buf);
+
+				if (spriteid == 0xFF)
+					spriteid = 0xFD; // cars have different custom id in the GRF file
+
+				// This is currently not used but there's no reason
+				// in not having it here for the future.
+				if (spriteid == 0xFD && rvi[i].image_index != 0xFD)
+					_engine_original_sprites[ROAD_ENGINES_INDEX + engine + i] = rvi[i].image_index;
+
+				rvi[i].image_index = spriteid;
+			}
+		}	break;
+		case 0x0F: {	/* Cargo capacity */
+			FOR_EACH_OBJECT {
+				uint16 capacity = grf_load_word(&buf);
+
+				rvi[i].capacity = capacity;
+			}
+		}	break;
+		case 0x10: { /* Cargo type */
+			FOR_EACH_OBJECT {
+				uint8 cargo = grf_load_byte(&buf);
+
+				rvi[i].cargo_type = cargo;
+			}
+		}	break;
+		case 0x11: {	/* Cost factor */
+			FOR_EACH_OBJECT {
+				uint8 cost_factor = grf_load_byte(&buf);
+
+				rvi[i].base_cost = cost_factor; // ?? is it base_cost?
+			}
+		}	break;
+		case 0x12: {	/* SFX */
+			FOR_EACH_OBJECT {
+				uint8 sfx = grf_load_byte(&buf);
+
+				rvi[i].sfx = sfx;
+			}
+		}	break;
+		case 0x13:      /* Power in 10hp */
+		case 0x14:      /* Weight in 1/4 tons */
+		case 0x15:      /* Speed in mph*0.8 */
+			/* TODO: Support for road vehicles realistic power
+			 * computations (called rvpower in TTDPatch) is just
+			 * missing in OTTD yet. --pasky */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+			break;
+		case 0x16: {	/* Cargos available for refitting */
+			FOR_EACH_OBJECT {
+				uint32 refit_mask = grf_load_dword(&buf);
+
+				_engine_refit_masks[ROAD_ENGINES_INDEX + engine + i] = refit_mask;
+			}
+		}	break;
+		case 0x17:      /* Callback */
+		case 0x18:      /* Tractive effort */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = true;
+			break;
+		default:
+			ret = true;
+	}
+
+	*bufp = buf;
+	return ret;
+}
+
+static bool ShipVehicleChangeInfo(uint engine, int numinfo, int prop, byte **bufp, int len)
+{
+	ShipVehicleInfo *svi = &_ship_vehicle_info[engine];
+	byte *buf = *bufp;
+	int i;
+	bool ret = false;
+
+	//printf("e %x prop %x?\n", engine, prop);
+	switch (prop) {
+		case 0x08: {	/* Sprite ID */
+			FOR_EACH_OBJECT {
+				uint8 spriteid = grf_load_byte(&buf);
+
+				if (spriteid == 0xFF)
+					spriteid = 0xFD; // ships have different custom id in the GRF file
+
+				// This is currently not used but there's no reason
+				// in not having it here for the future.
+				if (spriteid == 0xFD && svi[i].image_index != 0xFD)
+					_engine_original_sprites[SHIP_ENGINES_INDEX + engine + i] = svi[i].image_index;
+
+				svi[i].image_index = spriteid;
+			}
+		}	break;
+		case 0x09: {	/* Refittable */
+			FOR_EACH_OBJECT {
+				uint8 refittable = grf_load_byte(&buf);
+
+				svi[i].refittable = refittable;
+			}
+		}	break;
+		case 0x0A: {	/* Cost factor */
+			FOR_EACH_OBJECT {
+				uint8 cost_factor = grf_load_byte(&buf);
+
+				svi[i].base_cost = cost_factor; // ?? is it base_cost?
+			}
+		}	break;
+		case 0x0B: {	/* Speed */
+			FOR_EACH_OBJECT {
+				uint8 speed = grf_load_byte(&buf);
+
+				svi[i].max_speed = speed; // ?? units
+			}
+		}	break;
+		case 0x0C: { /* Cargo type */
+			FOR_EACH_OBJECT {
+				uint8 cargo = grf_load_byte(&buf);
+
+				// XXX: Need to consult this with patchman yet.
+#if 0
+				// Documentation claims this is already the
+				// per-landscape cargo type id, but newships.grf
+				// assume otherwise.
+				cargo = local_cargo_id_ctype[cargo];
+#endif
+				svi[i].cargo_type = cargo;
+			}
+		}	break;
+		case 0x0D: {	/* Cargo capacity */
+			FOR_EACH_OBJECT {
+				uint16 capacity = grf_load_word(&buf);
+
+				svi[i].capacity = capacity;
+			}
+		}	break;
+		case 0x0F: {	/* Running cost factor */
+			FOR_EACH_OBJECT {
+				uint8 runcost = grf_load_byte(&buf);
+
+				svi[i].running_cost = runcost;
+			}
+		} break;
+		case 0x10: {	/* SFX */
+			FOR_EACH_OBJECT {
+				uint8 sfx = grf_load_byte(&buf);
+
+				svi[i].sfx = sfx;
+			}
+		}	break;
+		case 0x11: {	/* Cargos available for refitting */
+			FOR_EACH_OBJECT {
+				uint32 refit_mask = grf_load_dword(&buf);
+
+				_engine_refit_masks[SHIP_ENGINES_INDEX + engine + i] = refit_mask;
+			}
+		}	break;
+		case 0x12: { /* Callback TODO */
+			ret = true;
+		}	break;
+		default:
+			ret = true;
+	}
+
+	*bufp = buf;
+	return ret;
+}
+
+static bool AircraftVehicleChangeInfo(uint engine, int numinfo, int prop, byte **bufp, int len)
+{
+	AircraftVehicleInfo *avi = &_aircraft_vehicle_info[engine];
+	byte *buf = *bufp;
+	int i;
+	bool ret = false;
+
+	//printf("e %x prop %x?\n", engine, prop);
+	switch (prop) {
+		case 0x08: {	/* Sprite ID */
+			FOR_EACH_OBJECT {
+				uint8 spriteid = grf_load_byte(&buf);
+
+				if (spriteid == 0xFF)
+					spriteid = 0xFD; // ships have different custom id in the GRF file
+
+				// This is currently not used but there's no reason
+				// in not having it here for the future.
+				if (spriteid == 0xFD && avi[i].image_index != 0xFD)
+					_engine_original_sprites[AIRCRAFT_ENGINES_INDEX + engine + i] = avi[i].image_index;
+
+				avi[i].image_index = spriteid;
+			}
+		}	break;
+		case 0x09: {	/* Helicopter */
+			FOR_EACH_OBJECT {
+				uint8 heli = grf_load_byte(&buf);
+
+				avi[i].subtype = (heli == 0) ? 0 : 1;
+			}
+		}	break;
+		case 0x0A: {	/* Large */
+			FOR_EACH_OBJECT {
+				uint8 large = grf_load_byte(&buf);
+
+				avi[i].subtype = (large == 1) ? 3 : 1;
+			}
+		}	break;
+		case 0x0B: {	/* Cost factor */
+			FOR_EACH_OBJECT {
+				uint8 cost_factor = grf_load_byte(&buf);
+
+				avi[i].base_cost = cost_factor; // ?? is it base_cost?
+			}
+		}	break;
+		case 0x0C: {	/* Speed */
+			FOR_EACH_OBJECT {
+				uint8 speed = grf_load_byte(&buf);
+
+				avi[i].max_speed = speed; // ?? units
+			}
+		}	break;
+		case 0x0D: {	/* Acceleration */
+			FOR_EACH_OBJECT {
+				uint8 accel = grf_load_byte(&buf);
+
+				avi[i].acceleration = accel;
+			}
+		} break;
+		case 0x0E: {	/* Running cost factor */
+			FOR_EACH_OBJECT {
+				uint8 runcost = grf_load_byte(&buf);
+
+				avi[i].running_cost = runcost;
+			}
+		} break;
+		case 0x0F: {	/* Passenger capacity */
+			FOR_EACH_OBJECT {
+				uint16 capacity = grf_load_word(&buf);
+
+				avi[i].passanger_capacity = capacity;
+			}
+		}	break;
+		case 0x11: {	/* Mail capacity */
+			FOR_EACH_OBJECT {
+				uint8 capacity = grf_load_byte(&buf);
+
+				avi[i].mail_capacity = capacity;
+			}
+		}	break;
+		case 0x12: {	/* SFX */
+			FOR_EACH_OBJECT {
+				uint8 sfx = grf_load_byte(&buf);
+
+				avi[i].sfx = sfx;
+			}
+		}	break;
+		case 0x13: {	/* Cargos available for refitting */
+			FOR_EACH_OBJECT {
+				uint32 refit_mask = grf_load_dword(&buf);
+
+				_engine_refit_masks[AIRCRAFT_ENGINES_INDEX + engine + i] = refit_mask;
+			}
+		}	break;
+		case 0x14: { /* Callback TODO */
+			ret = true;
+		}	break;
+		default:
+			ret = true;
+	}
+
+	*bufp = buf;
+	return ret;
+}
+
+static bool StationChangeInfo(uint stid, int numinfo, int prop, byte **bufp, int len)
+{
+	byte *buf = *bufp;
+	int i;
+	int ret = 0;
+
+	/* This is one single huge TODO. It doesn't handle anything more than
+	 * just waypoints for now. */
+
+	//printf("sci %d %d [0x%02x]\n", stid, numinfo, prop);
+	switch (prop) {
+		case 0x08:
+		{	/* Class ID */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+				uint32 classid;
+
+				/* classid, for a change, is always little-endian */
+				classid = *(buf++) << 24;
+				classid |= *(buf++) << 16;
+				classid |= *(buf++) << 8;
+				classid |= *(buf++);
+
+				switch (classid) {
+					case 'DFLT':
+						stat->sclass = STAT_CLASS_DFLT;
+						break;
+					case 'WAYP':
+						stat->sclass = STAT_CLASS_WAYP;
+						break;
+					default:
+						/* TODO: No support for custom
+						 * classes for now, so stuff
+						 * everything to the single
+						 * default one. --pasky */
+						stat->sclass = STAT_CLASS_DFLT;
+						//stat->sclass = STAT_CLASS_CUSTOM;
+						break;
+				}
+			}
+			break;
+		}
+		case 0x09:
+		{	/* Define sprite layout */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+				int t;
+
+				stat->tiles = grf_load_byte(&buf);
+				for (t = 0; t < stat->tiles; t++) {
+					DrawTileSprites *dts = &stat->renderdata[t];
+					int seq_count = 0;
+
+					if (t >= 8) {
+						grfmsg(GMS_WARN, "StationChangeInfo: Sprite %d>=8, skipping.", t);
+						grf_load_dword(&buf); // at least something
+						continue;
+					}
+
+					dts->ground_sprite = grf_load_dword(&buf);
+					if (!dts->ground_sprite) {
+						static const DrawTileSeqStruct empty = {0x80};
+						dts->seq = &empty;
+						continue;
+					}
+
+					dts->seq = NULL;
+					while (buf < *bufp + len) {
+						DrawTileSeqStruct *dtss;
+
+						// no relative bounding box support
+						dts->seq = realloc((void*)dts->seq, ++seq_count * sizeof(DrawTileSeqStruct));
+						dtss = (DrawTileSeqStruct*) &dts->seq[seq_count - 1];
+
+						dtss->delta_x = grf_load_byte(&buf);
+						if ((byte) dtss->delta_x == 0x80) break;
+						dtss->delta_y = grf_load_byte(&buf);
+						dtss->delta_z = grf_load_byte(&buf);
+						dtss->width = grf_load_byte(&buf);
+						dtss->height = grf_load_byte(&buf);
+						dtss->unk = grf_load_byte(&buf);
+						dtss->image = grf_load_dword(&buf) - 0x42d;
+					}
+				}
+			}
+			break;
+		}
+		case 0x0a:
+		{	/* Copy sprite layout */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+				byte srcid = grf_load_byte(&buf);
+				struct StationSpec *srcstat = &_cur_grffile->stations[srcid];
+				int t;
+
+				stat->tiles = srcstat->tiles;
+				for (t = 0; t < stat->tiles; t++) {
+					DrawTileSprites *dts = &stat->renderdata[t];
+					DrawTileSprites *sdts = &srcstat->renderdata[t];
+					DrawTileSeqStruct const *sdtss = sdts->seq;
+					int seq_count = 0;
+
+					dts->ground_sprite = sdts->ground_sprite;
+					if (!dts->ground_sprite) {
+						static const DrawTileSeqStruct empty = {0x80};
+						dts->seq = &empty;
+						continue;
+					}
+
+					dts->seq = NULL;
+					while (1) {
+						DrawTileSeqStruct *dtss;
+
+						// no relative bounding box support
+						dts->seq = realloc((void*)dts->seq, ++seq_count * sizeof(DrawTileSeqStruct));
+						dtss = (DrawTileSeqStruct*) &dts->seq[seq_count - 1];
+						*dtss = *sdtss;
+						if ((byte) dtss->delta_x == 0x80) break;
+						sdtss++;
+					}
+				}
+			}
+			break;
+		}
+		case 0x0b:
+		{	/* Callback */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = 1;
+			break;
+		}
+		case 0x0C:
+		{	/* Platforms number */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+
+				stat->allowed_platforms = ~grf_load_byte(&buf);
+			}
+			break;
+		}
+		case 0x0D:
+		{	/* Platforms length */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+
+				stat->allowed_lengths = ~grf_load_byte(&buf);
+			}
+			break;
+		}
+		case 0x0e:
+		{	/* Define custom layout */
+			FOR_EACH_OBJECT {
+				struct StationSpec *stat = &_cur_grffile->stations[stid + i];
+
+				while (buf < *bufp + len) {
+					byte length = grf_load_byte(&buf);
+					byte number = grf_load_byte(&buf);
+					StationLayout layout;
+					int l, p;
+
+					if (length == 0 || number == 0) break;
+
+					//debug("l %d > %d ?", length, stat->lengths);
+					if (length > stat->lengths) {
+						stat->platforms = realloc(stat->platforms, length);
+						memset(stat->platforms + stat->lengths, 0, length - stat->lengths);
+
+						stat->layouts = realloc(stat->layouts, length * sizeof(*stat->layouts));
+						memset(stat->layouts + stat->lengths, 0,
+						       (length - stat->lengths) * sizeof(*stat->layouts));
+
+						stat->lengths = length;
+					}
+					l = length - 1; // index is zero-based
+
+					//debug("p %d > %d ?", number, stat->platforms[l]);
+					if (number > stat->platforms[l]) {
+						stat->layouts[l] = realloc(stat->layouts[l],
+						                               number * sizeof(**stat->layouts));
+						// We expect NULL being 0 here, but C99 guarantees that.
+						memset(stat->layouts[l] + stat->platforms[l], 0,
+						       (number - stat->platforms[l]) * sizeof(**stat->layouts));
+
+						stat->platforms[l] = number;
+					}
+
+					layout = malloc(length * number);
+					for (l = 0; l < length; l++)
+						for (p = 0; p < number; p++)
+							layout[l * number + p] = grf_load_byte(&buf);
+
+					l--;
+					p--;
+					free(stat->layouts[l][p]);
+					stat->layouts[l][p] = layout;
+				}
+			}
+			break;
+		}
+		case 0x0f:
+		{	/* Copy custom layout */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			ret = 1;
+			break;
+		}
+		case 0x10:
+		{	/* Little/lots cargo threshold */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_word(&buf);
+			}
+			ret = 1;
+			break;
+		}
+		case 0x11:
+		{	/* Pylon placement */
+			/* TODO; makes sense only for electrified tracks */
+			FOR_EACH_OBJECT {
+				grf_load_word(&buf);
+			}
+			ret = 1;
+			break;
+		}
+		case 0x12:
+		{	/* Cargo types for random triggers */
+			/* TODO */
+			FOR_EACH_OBJECT {
+				grf_load_dword(&buf);
+			}
+			ret = 1;
+			break;
+		}
+		default:
+			ret = 1;
+			break;
+	}
+
+	*bufp = buf;
+	return ret;
+}
+
+#undef shift_buf
+
+
+/* Action 0x00 */
+static void VehicleChangeInfo(byte *buf, int len)
+{
+	byte *bufend = buf + len;
+	int i;
+
+	/* <00> <feature> <num-props> <num-info> <id> (<property <new-info>)...
+	 *
+	 * B feature       0, 1, 2 or 3 for trains, road vehicles, ships or planes
+	 *                 4 for defining new train station sets
+	 * B num-props     how many properties to change per vehicle/station
+	 * B num-info      how many vehicles/stations to change
+	 * B id            ID of first vehicle/station to change, if num-info is
+	 *                 greater than one, this one and the following
+	 *                 vehicles/stations will be changed
+	 * B property      what property to change, depends on the feature
+	 * V new-info      new bytes of info (variable size; depends on properties) */
+	/* TODO: Bridges, town houses. */
+
+	static const VCI_Handler handler[7] = {
+		/* GSF_TRAIN */    RailVehicleChangeInfo,
+		/* GSF_ROAD */     RoadVehicleChangeInfo,
+		/* GSF_SHIP */     ShipVehicleChangeInfo,
+		/* GSF_AIRCRAFT */ AircraftVehicleChangeInfo,
+		/* GSF_STATION */  StationChangeInfo,
+		/* GSF_BRIDGE */   NULL,
+		/* GSF_TOWNHOUSE */NULL,
+	};
+
+	uint8 feature;
+	uint8 numprops;
+	uint8 numinfo;
+	byte engine;
+	EngineInfo *ei;
+
+	if (len == 1) {
+		DEBUG(grf, 8) ("Silently ignoring one-byte special sprite 0x00.");
+		return;
+	}
+
+	check_length(len, 6, "VehicleChangeInfo");
+	feature = buf[1];
+	numprops = buf[2];
+	numinfo = buf[3];
+	engine = buf[4];
+
+	DEBUG(grf, 6) ("VehicleChangeInfo: Feature %d, %d properties, to apply to %d+%d",
+	               feature, numprops, engine, numinfo);
+
+	if (feature > GSF_STATION) {
+		grfmsg(GMS_WARN, "VehicleChangeInfo: Unsupported feature %d, skipping.", feature);
+		return;
+	}
+
+	if (feature != GSF_STATION)
+		ei = &_engine_info[engine + _vehshifts[feature]];
+
+	buf += 5;
+
+	while (numprops-- && buf < bufend) {
+		uint8 prop = grf_load_byte(&buf);
+
+		if (feature == GSF_STATION)
+			// stations don't share those common properties
+			goto run_handler;
+
+		switch (prop) {
+		case 0x00: { /* Introduction date */
+			FOR_EACH_OBJECT {
+				uint16 date = grf_load_word(&buf);
+
+				ei[i].base_intro = date;
+			}
+		}	break;
+		case 0x02: { /* Decay speed */
+			FOR_EACH_OBJECT {
+				uint8 decay = grf_load_byte(&buf);
+
+				ei[i].unk2 &= 0x80;
+				ei[i].unk2 |= decay & 0x7f;
+			}
+		}	break;
+		case 0x03: { /* Vehicle life */
+			FOR_EACH_OBJECT {
+				uint8 life = grf_load_byte(&buf);
+
+				ei[i].lifelength = life;
+			}
+		}	break;
+		case 0x04: { /* Model life */
+			FOR_EACH_OBJECT {
+				uint8 life = grf_load_byte(&buf);
+
+				ei[i].base_life = life;
+			}
+		}	break;
+		case 0x06: { /* Climates available */
+			FOR_EACH_OBJECT {
+				uint8 climates = grf_load_byte(&buf);
+
+				ei[i].railtype_climates &= 0xf0;
+				ei[i].railtype_climates |= climates;
+			}
+		}	break;
+		case 0x07: { /* Loading speed */
+			/* TODO */
+			/* Hyronymus explained me what does
+			 * this mean and insists on having a
+			 * credit ;-). --pasky */
+			/* TODO: This needs to be supported by
+			 * LoadUnloadVehicle() first. */
+			FOR_EACH_OBJECT {
+				grf_load_byte(&buf);
+			}
+			goto ignoring;
+		}
+		default: {
+run_handler:
+			if (handler[feature](engine, numinfo, prop, &buf, bufend - buf)) {
+ignoring:
+				grfmsg(GMS_NOTICE, "VehicleChangeInfo: Ignoring property %x (not implemented).", prop);
+			}
+			break;
+		}
+		}
+	}
+#undef shift_buf
+}
+
+#undef FOR_EACH_OBJECT
+
+
+/* Action 0x01 */
+static void NewSpriteSet(byte *buf, int len)
+{
+	/* <01> <feature> <num-sets> <num-ent>
+	 *
+	 * B feature       feature to define sprites for
+	 *                 0, 1, 2, 3: veh-type, 4: train stations
+	 * B num-sets      number of sprite sets
+	 * B num-ent       how many entries per sprite set
+	 *                 For vehicles, this is the number of different
+	 *                         vehicle directions in each sprite set
+	 *                         Set num-dirs=8, unless your sprites are symmetric.
+	 *                         In that case, use num-dirs=4.
+	 *                 For stations, must be 12 (hex) for the eighteen
+	 *                         different sprites that make up a station */
+	/* TODO: No stations support. */
+	uint8 feature;
+
+	check_length(len, 4, "NewSpriteSet");
+	feature = buf[1];
+
+	_cur_grffile->spriteset_start = _cur_spriteid + 1;
+	_cur_grffile->spriteset_feature = feature;
+	_cur_grffile->spriteset_numsets = buf[2];
+	_cur_grffile->spriteset_numents = buf[3];
+}
+
+/* Action 0x02 */
+static void NewSpriteGroup(byte *buf, int len)
+{
+	byte *bufend = buf + len;
+
+	/* <02> <feature> <set-id> <type/num-entries> <feature-specific-data...>
+	 *
+	 * B feature       see action 1
+	 * B set-id        ID of this particular definition
+	 * B type/num-entries
+	 *                 if 80 or greater, this is a randomized or variational
+	 *                 list definition, see below
+	 *                 otherwise it specifies a number of entries, the exact
+	 *                 meaning depends on the feature
+	 * V feature-specific-data (huge mess, don't even look it up --pasky) */
+	/* TODO: No 0x80-types (ugh). */
+	/* TODO: Also, empty sprites aren't handled for now. Need to investigate
+	 * the "opacity" rules for these, that is which sprite to fall back to
+	 * when. --pasky */
+	uint8 feature;
+	uint8 setid;
+	/* XXX: For stations, these two are "little cargo" and "lotsa cargo" sets. */
+	uint8 numloaded;
+	uint8 numloading;
+	struct SpriteGroup *group;
+	struct RealSpriteGroup *rg;
+	byte *loaded_ptr;
+	byte *loading_ptr;
+	int i;
+
+	check_length(len, 5, "NewSpriteGroup");
+	feature = buf[1];
+	setid = buf[2];
+	numloaded = buf[3];
+	numloading = buf[4];
+
+	if (numloaded == 0x81 || numloaded == 0x82) {
+		struct DeterministicSpriteGroup *dg;
+		uint16 groupid;
+		int i;
+
+		// Ok, this is gonna get a little wild, so hold your breath...
+
+		/* This stuff is getting actually evaluated in
+		 * EvalDeterministicSpriteGroup(). */
+
+		buf += 4; len -= 4;
+		check_length(len, 6, "NewSpriteGroup 0x81/0x82");
+
+		if (setid >= _cur_grffile->spritegroups_count) {
+			_cur_grffile->spritegroups_count = setid + 1;
+			_cur_grffile->spritegroups = realloc(_cur_grffile->spritegroups, _cur_grffile->spritegroups_count * sizeof(struct SpriteGroup));
+		}
+
+		group = &_cur_grffile->spritegroups[setid];
+		memset(group, 0, sizeof(struct SpriteGroup));
+		group->type = SGT_DETERMINISTIC;
+		dg = &group->g.determ;
+
+		/* XXX: We don't free() anything, assuming that if there was
+		 * some action here before, it got associated by action 3.
+		 * We should perhaps keep some refcount? --pasky */
+
+		dg->var_scope = numloaded == 0x82 ? VSG_SCOPE_PARENT : VSG_SCOPE_SELF;
+		dg->variable = grf_load_byte(&buf);
+
+		dg->shift_num = grf_load_byte(&buf);
+		dg->and_mask = grf_load_byte(&buf);
+		dg->operation = dg->shift_num >> 6; /* w00t */
+		dg->shift_num &= 0x3F;
+		if (dg->operation != DSG_OP_NONE) {
+			dg->add_val = grf_load_byte(&buf);
+			dg->divmod_val = grf_load_byte(&buf);
+		}
+
+		/* (groupid & 0x8000) means this is callback result; we happily
+		 * ignore that for now. */
+
+		dg->num_ranges = grf_load_byte(&buf);
+		dg->ranges = calloc(dg->num_ranges, sizeof(*dg->ranges));
+		for (i = 0; i < dg->num_ranges; i++) {
+			groupid = grf_load_word(&buf);
+			if (groupid & 0x8000 || groupid >= _cur_grffile->spritegroups_count) {
+				/* This doesn't exist for us. */
+				grf_load_word(&buf); // skip range
+				i--; dg->num_ranges--;
+				continue;
+			}
+			/* XXX: If multiple surreal sets attach a surreal
+			 * set this way, we are in trouble. */
+			dg->ranges[i].group = _cur_grffile->spritegroups[groupid];
+			dg->ranges[i].low = grf_load_byte(&buf);
+			dg->ranges[i].high = grf_load_byte(&buf);
+		}
+
+		groupid = grf_load_word(&buf);
+		if (groupid & 0x8000 || groupid >= _cur_grffile->spritegroups_count) {
+			/* This spritegroup stinks. */
+			free(dg->ranges), dg->ranges = NULL;
+			grfmsg(GMS_WARN, "NewSpriteGroup(%02x:0x%x): Default groupid %04x is cargo callback or unknown, ignoring spritegroup.", setid, numloaded, groupid);
+			return;
+		}
+
+		dg->default_group = malloc(sizeof(*dg->default_group));
+		memcpy(dg->default_group, &_cur_grffile->spritegroups[groupid], sizeof(*dg->default_group));
+
+		return;
+
+	} else if (numloaded == 0x80 || numloaded == 0x83) {
+		struct RandomizedSpriteGroup *rg;
+		int i;
+
+		/* This stuff is getting actually evaluated in
+		 * EvalRandomizedSpriteGroup(). */
+
+		buf += 4;
+		len -= 4;
+		check_length(len, 6, "NewSpriteGroup 0x80/0x83");
+
+		if (setid >= _cur_grffile->spritegroups_count) {
+			_cur_grffile->spritegroups_count = setid + 1;
+			_cur_grffile->spritegroups = realloc(_cur_grffile->spritegroups, _cur_grffile->spritegroups_count * sizeof(struct SpriteGroup));
+		}
+
+		group = &_cur_grffile->spritegroups[setid];
+		memset(group, 0, sizeof(*group));
+		group->type = SGT_RANDOMIZED;
+		rg = &group->g.random;
+
+		/* XXX: We don't free() anything, assuming that if there was
+		 * some action here before, it got associated by action 3.
+		 * We should perhaps keep some refcount? --pasky */
+
+		rg->var_scope = numloaded == 0x83 ? VSG_SCOPE_PARENT : VSG_SCOPE_SELF;
+
+		rg->triggers = grf_load_byte(&buf);
+		rg->cmp_mode = rg->triggers & 0x80;
+		rg->triggers &= 0x7F;
+
+		rg->lowest_randbit = grf_load_byte(&buf);
+		rg->num_groups = grf_load_byte(&buf);
+
+		rg->groups = calloc(rg->num_groups, sizeof(*rg->groups));
+		for (i = 0; i < rg->num_groups; i++) {
+			uint16 groupid = grf_load_word(&buf);
+
+			if (groupid & 0x8000 || groupid >= _cur_grffile->spritegroups_count) {
+				/* This doesn't exist for us. */
+				i--;
+				rg->num_groups--;
+				continue;
+			}
+			/* XXX: If multiple surreal sets attach a surreal
+			 * set this way, we are in trouble. */
+			rg->groups[i] = _cur_grffile->spritegroups[groupid];
+		}
+
+		return;
+	}
+
+	if (!_cur_grffile->spriteset_start) {
+		grfmsg(GMS_ERROR, "NewSpriteGroup: No sprite set to work on! Skipping.");
+		return;
+	}
+
+	if (_cur_grffile->spriteset_feature != feature) {
+		grfmsg(GMS_ERROR, "NewSpriteGroup: Group feature %x doesn't match set feature %x! Playing it risky and trying to use it anyway.", feature, _cur_grffile->spriteset_feature);
+		// return; // XXX: we can't because of MB's newstats.grf --pasky
+	}
+
+	check_length(bufend - buf, 5, "NewSpriteGroup");
+	buf += 5;
+	check_length(bufend - buf, 2 * numloaded, "NewSpriteGroup");
+	loaded_ptr = buf;
+	loading_ptr = buf + 2 * numloaded;
+
+	if (numloaded > 16) {
+		grfmsg(GMS_WARN, "NewSpriteGroup: More than 16 sprites in group %x, skipping the rest.", setid);
+		numloaded = 16;
+	}
+	if (numloading > 16) {
+		grfmsg(GMS_WARN, "NewSpriteGroup: More than 16 sprites in group %x, skipping the rest.", setid);
+		numloading = 16;
+	}
+
+	if (setid >= _cur_grffile->spritegroups_count) {
+		_cur_grffile->spritegroups_count = setid + 1;
+		_cur_grffile->spritegroups = realloc(_cur_grffile->spritegroups, _cur_grffile->spritegroups_count * sizeof(struct SpriteGroup));
+	}
+	group = &_cur_grffile->spritegroups[setid];
+	memset(group, 0, sizeof(struct SpriteGroup));
+	group->type = SGT_REAL;
+	rg = &group->g.real;
+
+	rg->sprites_per_set = _cur_grffile->spriteset_numents;
+	rg->loaded_count  = numloaded;
+	rg->loading_count = numloading;
+
+	DEBUG(grf, 6) ("NewSpriteGroup: New SpriteGroup 0x%02hhx, %u views, %u loaded, %u loading, sprites %u - %u",
+			setid, rg->sprites_per_set, rg->loaded_count, rg->loading_count,
+			_cur_grffile->spriteset_start - _cur_grffile->sprite_offset,
+			_cur_grffile->spriteset_start + (_cur_grffile->spriteset_numents * (numloaded + numloading)) - _cur_grffile->sprite_offset);
+
+	for (i = 0; i < numloaded; i++) {
+		uint16 spriteset_id = grf_load_word(&loaded_ptr);
+		rg->loaded[i] = _cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents;
+		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loaded[%i]  = %u (subset %u)", i, rg->loaded[i], spriteset_id);
+	}
+
+	for (i = 0; i < numloading; i++) {
+		uint16 spriteset_id = grf_load_word(&loading_ptr);
+		rg->loading[i] = _cur_grffile->spriteset_start + spriteset_id * _cur_grffile->spriteset_numents;
+		DEBUG(grf, 8) ("NewSpriteGroup: + rg->loading[%i] = %u (subset %u)", i, rg->loading[i], spriteset_id);
+	}
+}
+
+/* Action 0x03 */
+static void NewVehicle_SpriteGroupMapping(byte *buf, int len)
+{
+	/* <03> <feature> <n-id> <ids>... <num-cid> [<cargo-type> <cid>]... <def-cid>
+	 * id-list	:= [<id>] [id-list]
+	 * cargo-list	:= <cargo-type> <cid> [cargo-list]
+	 *
+	 * B feature       see action 0
+	 * B n-id          bits 0-6: how many IDs this definition applies to
+	 *                 bit 7: if set, this is a wagon override definition (see below)
+	 * B ids           the IDs for which this definition applies
+	 * B num-cid       number of cargo IDs (sprite group IDs) in this definition
+	 *                 can be zero, in that case the def-cid is used always
+	 * B cargo-type    type of this cargo type (e.g. mail=2, wood=7, see below)
+	 * W cid           cargo ID (sprite group ID) for this type of cargo
+	 * W def-cid       default cargo ID (sprite group ID) */
+	/* TODO: Bridges, town houses. */
+	/* TODO: Multiple cargo support could be useful even for trains/cars -
+	 * cargo id 0xff is used for showing images in the build train list. */
+
+	static byte *last_engines;
+	static int last_engines_count;
+	uint8 feature;
+	uint8 idcount;
+	bool wagover;
+	uint8 cidcount;
+	int c, i;
+
+	check_length(len, 7, "VehicleMapSpriteGroup");
+	feature = buf[1];
+	idcount = buf[2] & 0x7F;
+	wagover = (buf[2] & 0x80) == 0x80;
+	check_length(len, 3 + idcount, "VehicleMapSpriteGroup");
+	cidcount = buf[3 + idcount];
+	check_length(len, 4 + idcount + cidcount * 3, "VehicleMapSpriteGroup");
+
+	DEBUG(grf, 6) ("VehicleMapSpriteGroup: Feature %d, %d ids, %d cids, wagon override %d.",
+			feature, idcount, cidcount, wagover);
+
+	if (feature > GSF_STATION) {
+		grfmsg(GMS_WARN, "VehicleMapSpriteGroup: Unsupported feature %d, skipping.", feature);
+		return;
+	}
+
+
+	if (feature == GSF_STATION) {
+		// We do things differently for stations.
+
+		for (i = 0; i < idcount; i++) {
+			uint8 stid = buf[3 + i];
+			struct StationSpec *stat = &_cur_grffile->stations[stid];
+			byte *bp = &buf[4 + idcount];
+
+			for (c = 0; c < cidcount; c++) {
+				uint8 ctype = grf_load_byte(&bp);
+				uint16 groupid = grf_load_word(&bp);
+
+				if (groupid >= _cur_grffile->spritegroups_count) {
+					grfmsg(GMS_WARN, "VehicleMapSpriteGroup: Spriteset %x out of range %x, skipping.",
+					       groupid, _cur_grffile->spritegroups_count);
+					return;
+				}
+
+				if (ctype != 0xFF) {
+					/* TODO: No support for any other cargo. */
+					continue;
+				}
+
+				stat->spritegroup[1] = _cur_grffile->spritegroups[groupid];
+			}
+		}
+
+		{
+			byte *bp = buf + 4 + idcount + cidcount * 3;
+			uint16 groupid = grf_load_word(&bp);
+
+			if (groupid >= _cur_grffile->spritegroups_count) {
+				grfmsg(GMS_WARN, "VehicleMapSpriteGroup: Spriteset %x out of range %x, skipping.",
+				       groupid, _cur_grffile->spritegroups_count);
+				return;
+			}
+
+			for (i = 0; i < idcount; i++) {
+				uint8 stid = buf[3 + i];
+				struct StationSpec *stat = &_cur_grffile->stations[stid];
+
+				stat->spritegroup[0] = _cur_grffile->spritegroups[groupid];
+				stat->grfid = _cur_grffile->grfid;
+				SetCustomStation(stid, stat);
+				stat->sclass = STAT_CLASS_NONE;
+			}
+		}
+		return;
+	}
+
+
+	/* If ``n-id'' (or ``idcount'') is zero, this is a ``feature
+	 * callback''. I have no idea how this works, so we will ignore it for
+	 * now.  --octo */
+	if (idcount == 0) {
+		grfmsg(GMS_NOTICE, "NewMapping: Feature callbacks not implemented yet.");
+		return;
+	}
+
+	// FIXME: Tropicset contains things like:
+	// 03 00 01 19 01 00 00 00 00 - this is missing one 00 at the end,
+	// what should we exactly do with that? --pasky
+
+	if (!_cur_grffile->spriteset_start || !_cur_grffile->spritegroups) {
+		grfmsg(GMS_WARN, "VehicleMapSpriteGroup: No sprite set to work on! Skipping.");
+		return;
+	}
+
+	if (!wagover && last_engines_count != idcount) {
+		last_engines = realloc(last_engines, idcount);
+		last_engines_count = idcount;
+	}
+
+	if (wagover) {
+		if (last_engines_count == 0) {
+			grfmsg(GMS_ERROR, "VehicleMapSpriteGroup: WagonOverride: No engine to do override with.");
+			return;
+		}
+		DEBUG(grf, 6) ("VehicleMapSpriteGroup: WagonOverride: %u engines, %u wagons.",
+				last_engines_count, idcount);
+	}
+
+
+	for (i = 0; i < idcount; i++) {
+		uint8 engine_id = buf[3 + i];
+		uint8 engine = engine_id + _vehshifts[feature];
+		byte *bp = &buf[4 + idcount];
+
+		if (engine_id > _vehcounts[feature]) {
+			grfmsg(GMS_ERROR, "Id %u for feature %x is out of bounds.",
+					engine_id, feature);
+			return;
+		}
+
+		DEBUG(grf, 7) ("VehicleMapSpriteGroup: [%d] Engine %d...", i, engine);
+
+		for (c = 0; c < cidcount; c++) {
+			uint8 ctype = grf_load_byte(&bp);
+			uint16 groupid = grf_load_word(&bp);
+
+			DEBUG(grf, 8) ("VehicleMapSpriteGroup: * [%d] Cargo type %x, group id %x", c, ctype, groupid);
+
+			if (groupid >= _cur_grffile->spritegroups_count) {
+				grfmsg(GMS_WARN, "VehicleMapSpriteGroup: Spriteset %x out of range %x, skipping.", groupid, _cur_grffile->spritegroups_count);
+				return;
+			}
+
+			if (ctype == 0xFF)
+				ctype = CID_PURCHASE;
+
+			if (wagover) {
+				// TODO: No multiple cargo types per vehicle yet. --pasky
+				SetWagonOverrideSprites(engine, &_cur_grffile->spritegroups[groupid], last_engines, last_engines_count);
+			} else {
+				SetCustomEngineSprites(engine, ctype, &_cur_grffile->spritegroups[groupid]);
+				last_engines[i] = engine;
+			}
+		}
+	}
+
+	{
+		byte *bp = buf + 4 + idcount + cidcount * 3;
+		uint16 groupid = grf_load_word(&bp);
+
+		DEBUG(grf, 8) ("-- Default group id %x", groupid);
+
+		for (i = 0; i < idcount; i++) {
+			uint8 engine = buf[3 + i] + _vehshifts[feature];
+
+			// Don't tell me you don't love duplicated code!
+			if (groupid >= _cur_grffile->spritegroups_count) {
+				grfmsg(GMS_WARN, "VehicleMapSpriteGroup: Spriteset %x out of range %x, skipping.", groupid, _cur_grffile->spritegroups_count);
+				return;
+			}
+
+			if (wagover) {
+				// TODO: No multiple cargo types per vehicle yet. --pasky
+				SetWagonOverrideSprites(engine, &_cur_grffile->spritegroups[groupid], last_engines, last_engines_count);
+			} else {
+				SetCustomEngineSprites(engine, CID_DEFAULT, &_cur_grffile->spritegroups[groupid]);
+				last_engines[i] = engine;
+			}
+		}
+	}
+}
+
+/* Action 0x04 */
+static void VehicleNewName(byte *buf, int len)
+{
+	/* <04> <veh-type> <language-id> <num-veh> <offset> <data...>
+	 *
+	 * B veh-type      see action 0
+	 * B language-id   language ID with bit 7 cleared (see below)
+	 * B num-veh       number of vehicles which are getting a new name
+	 * B offset        number of the first vehicle that gets a new name
+	 * S data          new texts, each of them zero-terminated, after
+	 *                 which the next name begins. */
+	/* TODO: No support for changing non-vehicle text. Perhaps we shouldn't
+	 * implement it at all, but it could be useful for some "modpacks"
+	 * (completely new scenarios changing all graphics and logically also
+	 * factory names etc). We should then also support all languages (by
+	 * name), not only the original four ones. --pasky */
+	/* TODO: Support for custom station class/type names. */
+
+	uint8 feature;
+	uint8 lang;
+	uint8 id;
+	uint8 endid;
+
+	check_length(len, 6, "VehicleNewName");
+	feature = buf[1];
+	lang = buf[2];
+	id = buf[4] + _vehshifts[feature];
+	endid = id + buf[3];
+
+	DEBUG(grf, 6) ("VehicleNewName: About to rename engines %d..%d (feature %d) in language 0x%x.",
+	               id, endid, feature, lang);
+
+	if (lang & 0x80) {
+		grfmsg(GMS_WARN, "VehicleNewName: No support for changing in-game texts. Skipping.");
+		return;
+	}
+
+	if (!(lang & 3)) {
+		/* XXX: If non-English name, silently skip it. */
+		DEBUG(grf, 7) ("VehicleNewName: Skipping non-English name.");
+		return;
+	}
+
+	buf += 5, len -= 5;
+	for (; id < endid && len > 0; id++) {
+		int ofs = strlen(buf) + 1;
+
+		if (ofs < 128) {
+			DEBUG(grf, 8) ("VehicleNewName: %d <- %s", id, buf);
+			SetCustomEngineName(id, buf);
+		} else {
+			DEBUG(grf, 7) ("VehicleNewName: Too long a name (%d)", ofs);
+		}
+		buf += ofs, len -= ofs;
+	}
+}
+
+/* Action 0x05 */
+static void GraphicsNew(byte *buf, int len)
+{
+	/* <05> <graphics-type> <num-sprites> <other data...>
+	 *
+	 * B graphics-type What set of graphics the sprites define.
+	 * B num-sprites   How many sprites are in this set?
+	 * V other data    Graphics type specific data.  Currently unused. */
+	/* TODO */
+
+	uint8 type;
+	uint8 num;
+
+	check_length(len, 2, "GraphicsNew");
+	type = buf[0];
+	num = buf[1];
+
+	grfmsg(GMS_NOTICE, "GraphicsNew: Custom graphics (type %x) sprite block of length %d (unimplemented, ignoring).\n",
+	       type, num);
+}
+
+/* Action 0x06 */
+static void CfgApply(byte *buf, int len)
+{
+	/* <06> <param-num> <param-size> <offset> ... <FF>
+	 *
+	 * B param-num     Number of parameter to substitute (First = "zero")
+	 *                 Ignored if that parameter was not specified in newgrf.cfg
+	 * B param-size    How many bytes to replace.  If larger than 4, the
+	 *                 bytes of the following parameter are used.  In that
+	 *                 case, nothing is applied unless *all* parameters
+	 *                 were specified.
+	 * B offset        Offset into data from beginning of next sprite
+	 *                 to place where parameter is to be stored. */
+	/* TODO */
+	grfmsg(GMS_NOTICE, "CfgApply: Ignoring (not implemented).\n");
+}
+
+/* Action 0x07 */
+/* Action 0x09 */
+static void SkipIf(byte *buf, int len)
+{
+	/* <07/09> <param-num> <param-size> <condition-type> <value> <num-sprites>
+	 *
+	 * B param-num
+	 * B param-size
+	 * B condition-type
+	 * V value
+	 * B num-sprites */
+	/* TODO: More params. More condition types. */
+	uint8 param;
+	uint8 paramsize;
+	uint8 condtype;
+	uint8 numsprites;
+	int param_val = 0, cond_val = 0;
+	bool result;
+
+	check_length(len, 6, "SkipIf");
+	param = buf[1];
+	paramsize = buf[2];
+	condtype = buf[3];
+
+	if (condtype < 2) {
+		/* Always 1 for bit tests, the given value should
+		 * be ignored. */
+		paramsize = 1;
+	}
+
+	buf += 4;
+	if (paramsize == 4)
+		cond_val = grf_load_dword(&buf);
+	else if (paramsize == 2)
+		cond_val = grf_load_word(&buf);
+	else if (paramsize == 1)
+		cond_val = grf_load_byte(&buf);
+
+	switch (param) {
+		case 0x83:    /* current climate, 0=temp, 1=arctic, 2=trop, 3=toyland */
+			param_val = _opt.landscape;
+			break;
+		case 0x84:    /* .grf loading stage, 0=initialization, 1=activation */
+			param_val = _cur_stage;
+			break;
+		case 0x85:    /* TTDPatch flags, only for bit tests */
+			param_val = _ttdpatch_flags[cond_val / 0x20];
+			cond_val %= 0x20;
+			break;
+		case 0x86:    /* road traffic side, bit 4 clear=left, set=right */
+			param_val = _opt.road_side << 4;
+			break;
+		case 0x88: {  /* see if specified GRFID is active */
+			struct GRFFile *file;
+
+			file = GetFileByGRFID(cond_val);
+			param_val = (file != NULL);
+		}	break;
+		case 0x8B:    /* TTDPatch version */
+			param_val = 0xFFFF;
+			break;
+		case 0x8D:    /* TTD Version, 00=DOS, 01=Windows */
+			param_val = 1;
+			break;
+		case 0x8E:
+			param_val = _traininfo_vehicle_pitch;
+			break;
+		/* TODO */
+		case 0x8F:    /* Track type cost multipliers */
+		default:
+			if (param >= 0x80) {
+				/* In-game variable. */
+				grfmsg(GMS_WARN, "Unsupported in-game variable %x. Ignoring test.", param);
+			} else {
+				/* Parameter. */
+				param_val = _paramlist[param];
+			}
+			return;
+	}
+
+	switch (condtype) {
+		case 0: result = (param_val & (1 << cond_val));
+			break;
+		case 1: result = !(param_val & (1 << cond_val));
+			break;
+		/* TODO: For the following, make it to work with paramsize>1. */
+		case 2: result = (param_val == cond_val);
+			break;
+		case 3: result = (param_val != cond_val);
+			break;
+		case 4: result = (param_val < cond_val);
+			break;
+		case 5: result = (param_val > cond_val);
+			break;
+		case 6: result = param_val; /* GRFID is active (only for param-num=88) */
+			break;
+		case 7: result = !param_val; /* GRFID is not active (only for param-num=88) */
+			break;
+		default:
+			grfmsg(GMS_WARN, "Unsupported test %d. Ignoring.", condtype);
+			return;
+	}
+
+	if (result == 0) {
+		grfmsg(GMS_NOTICE, "Not skipping sprites, test was false.");
+		return;
+	}
+
+	numsprites = grf_load_byte(&buf);
+	grfmsg(GMS_NOTICE, "Skipping %d->+%d sprites, test was true.", _cur_spriteid - _custom_sprites_base, numsprites);
+	_skip_sprites = numsprites;
+	if (_skip_sprites == 0) {
+		/* Zero means there are no sprites to skip, so
+		 * we use -1 to indicate that all further
+		 * sprites should be skipped. */
+		_skip_sprites = -1;
+	}
+}
+
+static void GRFInfo(byte *buf, int len)
+{
+	/* <08> <version> <grf-id> <name> <info>
+	 *
+	 * B version       newgrf version, currently 06
+	 * 4*B grf-id      globally unique ID of this .grf file
+	 * S name          name of this .grf set
+	 * S info          string describing the set, and e.g. author and copyright */
+	/* TODO: Check version. (We should have own versioning done somehow.) */
+	uint8 version;
+	uint32 grfid;
+	char *name;
+	char *info;
+
+	check_length(len, 9, "GRFInfo");
+	version = buf[1];
+	/* this is de facto big endian - grf_load_dword() unsuitable */
+	grfid = buf[2] << 24 | buf[3] << 16 | buf[4] << 8 | buf[5];
+	name = buf + 6;
+	info = name + strlen(name) + 1;
+
+	_cur_grffile->grfid = grfid;
+	_cur_grffile->flags |= 0x0001; /* set active flag */
+
+	DEBUG(grf, 1) ("[%s] Loaded GRFv%d set %08lx - %s:\n%s\n",
+	               _cur_grffile->filename, version, grfid, name, info);
+}
+
+static void SpriteReplace(byte *buf, int len)
+{
+	/* <0A> <num-sets> <set1> [<set2> ...]
+	 * <set>: <num-sprites> <first-sprite>
+	 *
+	 * B num-sets      How many sets of sprites to replace.
+	 * Each set:
+	 * B num-sprites   How many sprites are in this set
+	 * W first-sprite  First sprite number to replace */
+	uint8 num_sets;
+	int i;
+
+	buf++; /* skip action byte */
+	num_sets = grf_load_byte(&buf);
+
+	if (num_sets > 16) {
+		grfmsg(GMS_ERROR, "SpriteReplace: Too many sets (%d), taking only the first 16!", num_sets);
+	}
+
+	for (i = 0; i < 16; i++) {
+		if (i < num_sets) {
+			uint8 num_sprites = grf_load_byte(&buf);
+			uint16 first_sprite = grf_load_word(&buf);
+
+			_replace_sprites_count[i] = num_sprites;
+			_replace_sprites_offset[i] = first_sprite;
+			grfmsg(GMS_NOTICE, "SpriteReplace: [Set %d] Changing %d sprites, beginning with %d",
+					i, num_sprites, first_sprite);
+		} else {
+			_replace_sprites_count[i] = 0;
+			_replace_sprites_offset[i] = 0;
+		}
+	}
+}
+
+static void GRFError(byte *buf, int len)
+{
+	/* <0B> <severity> <language-id> <message-id> [<message...> 00] [<data...>] 00 [<parnum>]
+	 *
+	 * B severity      00: notice, contine loading grf file
+	 *                 01: warning, continue loading grf file
+	 *                 02: error, but continue loading grf file, and attempt
+	 *                     loading grf again when loading or starting next game
+	 *                 03: error, abort loading and prevent loading again in
+	 *                     the future (only when restarting the patch)
+	 * B language-id   see action 4, use 1F for built-in error messages
+	 * B message-id    message to show, see below
+	 * S message       for custom messages (message-id FF), text of the message
+	 *                 not present for built-in messages.
+	 * V data          additional data for built-in (or custom) messages
+	 * B parnum        see action 6, only used with built-in message 03 */
+	/* TODO: For now we just show the message, sometimes incomplete and never translated. */
+
+	static const char * const msgstr[4] = {
+		"Requires at least pseudo-TTDPatch version %s.",
+		"This file is for %s version of TTD.",
+		"Designed to be used with %s.",
+		"Invalid parameter %s.",
+	};
+	uint8 severity;
+	uint8 msgid;
+
+	check_length(len, 6, "GRFError");
+	severity = buf[1];
+	msgid = buf[3];
+
+	// Undocumented TTDPatch feature.
+	if ((severity & 0x80) == 0 && _cur_stage == 0)
+		return;
+	severity &= 0x7F;
+
+	if (msgid == 0xFF) {
+		grfmsg(severity, "%s", buf+4);
+	} else {
+		grfmsg(severity, msgstr[msgid], buf+4);
+	}
+}
+
+static void GRFComment(byte *buf, int len)
+{
+	/* <0C> [<ignored...>]
+	 *
+	 * V ignored       Anything following the 0C is ignored */
+}
+
+/* Action 0x0D */
+static void ParamSet(byte *buf, int len)
+{
+	/* <0D> <target> <operation> <source1> <source2> [<data>]
+	 *
+	 * B target        parameter number where result is stored
+	 * B operation     operation to perform, see below
+	 * B source1       first source operand
+	 * B source2       second source operand
+	 * D data          data to use in the calculation, not necessary
+	 *                 if both source1 and source2 refer to actual parameters
+	 *
+	 * Operations
+	 * 00      Set parameter equal to source1
+	 * 01      Addition, source1 + source2
+	 * 02      Subtraction, source1 - source2
+	 * 03      Unsigned multiplication, source1 * source2 (both unsigned)
+	 * 04      Signed multiplication, source1 * source2 (both signed)
+	 * 05      Unsigned bit shift, source1 by source2 (source2 taken to be a
+	 *         signed quantity; left shift if positive and right shift if
+	 *         negative, source1 is unsigned)
+	 * 06      Signed bit shift, source1 by source2
+	 *         (source2 like in 05, and source1 as well)
+	 */
+
+	byte target;
+	byte oper;
+	uint16 src1;
+	uint16 src2;
+	uint16 data = 0;
+	int32 *dest;
+
+	check_length(len, 5, "ParamSet");
+	buf++;
+	target = grf_load_byte(&buf);
+	oper = grf_load_byte(&buf);
+	src1 = grf_load_byte(&buf);
+	src2 = grf_load_byte(&buf);
+
+	if (len >= 8)
+		data = grf_load_dword(&buf);
+
+	/* You can add 80 to the operation to make it apply only if the target
+	 * is not defined yet.  In this respect, a parameter is taken to be
+	 * defined if any of the following applies:
+	 * - it has been set to any value in the newgrf(w).cfg parameter list
+	 * - it OR A PARAMETER WITH HIGHER NUMBER has been set to any value by
+	 *   an earlier action D */
+	if (oper & 0x80) {
+		if (_param_max < target)
+			oper &= 0x7F;
+		else
+			return;
+	}
+
+	/* The source1 and source2 operands refer to the grf parameter number
+	 * like in action 6 and 7.  In addition, they can refer to the special
+	 * variables available in action 7, or they can be FF to use the value
+	 * of <data>.  If referring to parameters that are undefined, a value
+	 * of 0 is used instead.  */
+	if (src1 == 0xFF) {
+		src1 = data;
+	} else {
+		src1 = _param_max >= src1 ? _paramlist[src1] : 0;
+	}
+
+	if (src2 == 0xFF) {
+		src2 = data;
+	} else {
+		src2 = _param_max >= src2 ? _paramlist[src2] : 0;
+	}
+
+	/* TODO: You can access the parameters of another GRF file by using
+	 * source2=FE, source1=the other GRF's parameter number and data=GRF
+	 * ID.  This is only valid with operation 00 (set).  If the GRF ID
+	 * cannot be found, a value of 0 is used for the parameter value
+	 * instead. */
+
+	/* TODO: The target operand can also refer to the special variables
+	 * from action 7, but at the moment the only variable that is valid to
+	 * write is 8E. */
+
+	if (target == 0x8E) {
+		dest = &_traininfo_vehicle_pitch;
+	} else {
+		if (_param_max < target)
+			_param_max = target;
+		dest = &_paramlist[target];
+	}
+
+	/* FIXME: No checking for overflows. */
+	switch (oper) {
+		case 0x00:
+			*dest = src1;
+			break;
+		case 0x01:
+			*dest = src1 + src2;
+			break;
+		case 0x02:
+			*dest = src1 - src2;
+			break;
+		case 0x03:
+			*dest = ((uint32) src1) * ((uint32) src2);
+			break;
+		case 0x04:
+			*dest = ((int32) src1) * ((int32) src2);
+			break;
+		case 0x05:
+			if (src2 & 0x8000) /* src2 is "negative" */
+				*dest = src1 >> -((int16) src2);
+			else
+				*dest = src1 << src2;
+			break;
+		case 0x06:
+			if (src2 & 0x8000) /* src2 is "negative" */
+				*dest = ((int16) src1) >> -((int16) src2);
+			else
+				*dest = ((int16) src1) << src2;
+			break;
+		default:
+			grfmsg(GMS_ERROR, "ParamSet: Unknown operation %d, skipping.", oper);
+	}
+}
+
+static void GRFInhibit(byte *buf, int len)
+{
+	/* <0E> <num> <grfids...>
+	 *
+	 * B num           Number of GRFIDs that follow
+	 * D grfids        GRFIDs of the files to deactivate */
+
+	byte num;
+	int i;
+
+	check_length(len, 1, "GRFInhibit");
+	buf++, len--;
+	num = grf_load_byte(&buf); len--;
+	check_length(len, 4 * num, "GRFInhibit");
+
+	for (i = 0; i < num; i++) {
+		uint32 grfid = grf_load_dword(&buf);
+		struct GRFFile *file = GetFileByGRFID(grfid);
+
+		/* Unset activation flag */
+		if (file != NULL) {
+			grfmsg(GMS_NOTICE, "GRFInhibit: Deactivating file ``%s''", file->filename);
+			file->flags &= 0xFFFE;
+		}
+	}
+}
+
+
+static void InitializeGRFSpecial(void)
+{
+	/* FIXME: We should rather reflect reality in _ttdpatch_flags[]. */
+
+	_ttdpatch_flags[1] = (1 << 0x08)  /* mammothtrains */
+	                   | (1 << 0x0B)  /* subsidiaries */
+	                   | (1 << 0x14)  /* bridgespeedlimits */
+	                   | (1 << 0x16)  /* eternalgame */
+	                   | (1 << 0x17)  /* newtrains */
+	                   | (1 << 0x18)  /* newrvs */
+	                   | (1 << 0x19)  /* newships */
+	                   | (1 << 0x1A)  /* newplanes */
+			   | (1 << 0x1B); /* signalsontrafficside */
+	                   /* Uncomment following if you want to fool the GRF file.
+	                    * Some GRF files will refuse to load without this
+	                    * but you can still squeeze something from them even
+	                    * without the support - i.e. USSet. --pasky */
+			   //| (1 << 0x1C); /* electrifiedrailway */
+
+	_ttdpatch_flags[2] = (1 << 0x0D)  /* buildonslopes */
+	                   | (1 << 0x16)  /* canals */
+	                   | (1 << 0x17); /* newstartyear */
+}
+
+void InitNewGRFFile(const char *filename, int sprite_offset)
+{
+	struct GRFFile *newfile;
+
+	newfile = calloc(1, sizeof(struct GRFFile));
+
+	if (newfile == NULL)
+		error ("Out of memory");
+
+	newfile->filename = strdup(filename);
+	newfile->sprite_offset = sprite_offset;
+
+	if (_first_grffile == NULL) {
+		_cur_grffile = newfile;
+		_first_grffile = newfile;
+	} else {
+		_cur_grffile->next = newfile;
+		_cur_grffile = newfile;
+	}
+}
+
+
+/* Here we perform initial decoding of some special sprites (as are they
+ * described at http://www.ttdpatch.net/src/newgrf.txt, but this is only a very
+ * partial implementation yet). */
+/* XXX: We consider GRF files trusted. It would be trivial to exploit OTTD by
+ * a crafted invalid GRF file. We should tell that to the user somehow, or
+ * better make this more robust in the future. */
+
+void DecodeSpecialSprite(const char *filename, int num, int spriteid, int stage)
+{
+#define NUM_ACTIONS 0xF
+	static const SpecialSpriteHandler handlers[NUM_ACTIONS] = {
+		/* 0x0 */ VehicleChangeInfo,
+		/* 0x1 */ NewSpriteSet,
+		/* 0x2 */ NewSpriteGroup,
+		/* 0x3 */ NewVehicle_SpriteGroupMapping,
+		/* 0x4 */ VehicleNewName,
+		/* 0x5 */ GraphicsNew,
+		/* 0x6 */ CfgApply,
+		/* 0x7 */ SkipIf,
+		/* 0x8 */ GRFInfo,
+		/* 0x9 */ SkipIf,
+		/* 0xa */ SpriteReplace,
+		/* 0xb */ GRFError,
+		/* 0xc */ GRFComment,
+		/* 0xd */ ParamSet,
+		/* 0xe */ GRFInhibit,
+	};
+	static int initialized;
+	byte action;
+	byte *buf = malloc(num);
+	int i;
+
+	if (buf == NULL) error("DecodeSpecialSprite: Could not allocate memory");
+
+	if (initialized == 0) {
+		InitializeGRFSpecial();
+		initialized = 1;
+	}
+
+	_cur_stage = stage;
+	_cur_spriteid = spriteid;
+
+	for (i = 0; i != num; i++)
+		buf[i] = FioReadByte();
+
+	action = buf[0];
+
+	/* XXX: There is a difference between staged loading in TTDPatch and
+	 * here.  In TTDPatch, for some reason actions 1 and 2 are carried out
+	 * during stage 0, whilst action 3 is carried out during stage 1 (to
+	 * "resolve" cargo IDs... wtf). This is a little problem, because cargo
+	 * IDs are valid only within a given set (action 1) block, and may be
+	 * overwritten after action 3 associates them. But overwriting happens
+	 * in an earlier stage than associating, so...  We just process actions
+	 * 1 and 2 in stage 1 now, let's hope that won't get us into problems.
+	 * --pasky */
+
+	if (stage == 0) {
+		/* During initialization, actions 0, 1, 2, 3, 4, 5 and 7 are ignored. */
+
+		if ((action == 0x00) || (action == 0x01) || (action == 0x02) || (action == 0x03)
+		    || (action == 0x04) || (action == 0x05) || (action == 0x07)) {
+			DEBUG (grf, 7) ("DecodeSpecialSprite: Action: %x, Stage 0, Skipped", action);
+			/* Do nothing. */
+
+		} else if (action < NUM_ACTIONS) {
+			DEBUG (grf, 7) ("DecodeSpecialSprite: Action: %x, Stage 0", action);
+ 			handlers[action](buf, num);
+
+		} else {
+			grfmsg(GMS_WARN, "Unknown special sprite action %x, skipping.", action);
+		}
+
+	} else if (stage == 1) {
+		/* A .grf file is activated only if it was active when the game was
+		 * started.  If a game is loaded, only its active .grfs will be
+		 * reactivated, unless "loadallgraphics on" is used.  A .grf file is
+		 * considered active if its action 8 has been processed, i.e. its
+		 * action 8 hasn't been skipped using an action 7.
+		 *
+		 * During activation, only actions 0, 1, 2, 3, 4, 5, 7, 8, 9, 0A and 0B are
+		 * carried out.  All others are ignored, because they only need to be
+		 * processed once at initialization.  */
+
+		if ((_cur_grffile == NULL) || strcmp(_cur_grffile->filename, filename))
+			_cur_grffile = GetFileByFilename(filename);
+
+		if (_cur_grffile == NULL)
+			error("File ``%s'' lost in cache.\n", filename);
+
+		if (!(_cur_grffile->flags & 0x0001)) {
+			DEBUG (grf, 7) ("DecodeSpecialSprite: Action: %x, Stage 1, Not activated", action);
+			/* Do nothing. */
+
+		} else if ((action == 0x00) || (action == 0x01) || (action == 0x02) || (action == 0x03)
+			   || (action == 0x04) || (action == 0x05) || (action == 0x07) || (action == 0x08)
+			   || (action == 0x09) || (action == 0x0A) || (action == 0x0B)) {
+			DEBUG (grf, 7) ("DecodeSpecialSprite: Action: %x, Stage 1", action);
+			handlers[action](buf, num);
+
+		} else if (action < NUM_ACTIONS) {
+			DEBUG (grf, 7) ("DecodeSpecialSprite: Action: %x, Stage 1, Skipped", action);
+			/* Do nothing. */
+
+		} else {
+			grfmsg(GMS_WARN, "Unknown special sprite action %x, skipping.", action);
+		}
+
+	} else {
+		error("Invalid stage %d", stage);
+	}
+
+	free(buf);
+#undef NUM_ACTIONS
+}