--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/newgrf_generic.cpp	Fri Feb 22 00:25:54 2008 +0000
@@ -0,0 +1,179 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "variables.h"
+#include "landscape.h"
+#include "debug.h"
+#include "newgrf.h"
+#include "newgrf_callbacks.h"
+#include "newgrf_commons.h"
+#include "newgrf_spritegroup.h"
+#include "newgrf_generic.h"
+#include "tile_map.h"
+#include <list>
+
+
+struct GenericCallback {
+	const GRFFile *file;
+	const SpriteGroup *group;
+
+	GenericCallback(const GRFFile *file, const SpriteGroup *group) :
+		file(file),
+		group(group)
+	{ }
+};
+
+typedef std::list<GenericCallback> GenericCallbackList;
+
+static GenericCallbackList _gcl[GSF_END];
+
+
+/**
+ * Reset all generic feature callback sprite groups.
+ */
+void ResetGenericCallbacks()
+{
+	for (uint8 feature = 0; feature < lengthof(_gcl); feature++) {
+		_gcl[feature].clear();
+	}
+}
+
+
+/**
+ * Add a generic feature callback sprite group to the appropriate feature list.
+ * @param feature
+ * @param file
+ * @param group
+ */
+void AddGenericCallback(uint8 feature, const GRFFile *file, const SpriteGroup *group)
+{
+	if (feature >= lengthof(_gcl)) {
+		grfmsg(5, "AddGenericCallback: Unsupported feature 0x%02X", feature);
+		return;
+	}
+
+	/* Generic feature callbacks are evaluated in reverse (i.e. the last group
+	 * to be added is evaluated first, etc) thus we push the group to the
+	 * beginning of the list so a standard iterator will do the right thing. */
+	_gcl[feature].push_front(GenericCallback(file, group));
+}
+
+
+static uint32 GenericCallbackGetRandomBits(const ResolverObject *object)
+{
+	return 0;
+}
+
+
+static uint32 GenericCallbackGetTriggers(const ResolverObject *object)
+{
+	return 0;
+}
+
+
+static void GenericCallbackSetTriggers(const ResolverObject *object, int triggers)
+{
+	return;
+}
+
+
+static uint32 GenericCallbackGetVariable(const ResolverObject *object, byte variable, byte parameter, bool *available)
+{
+	switch (variable) {
+		case 0x40: return object->u.generic.cargo_type;
+
+		case 0x80: return object->u.generic.cargo_type;
+		case 0x81: return object->u.generic.cargo_type;
+		case 0x82: return object->u.generic.default_selection;
+		case 0x83: return object->u.generic.src_industry;
+		case 0x84: return object->u.generic.dst_industry;
+		case 0x85: return object->u.generic.distance;
+		case 0x86: return object->u.generic.event;
+		case 0x87: return object->u.generic.count;
+		case 0x88: return object->u.generic.station_size;
+
+		default: break;
+	}
+
+	DEBUG(grf, 1, "Unhandled generic feature property 0x%02X", variable);
+
+	*available = false;
+	return 0;
+}
+
+
+static const SpriteGroup *GenericCallbackResolveReal(const ResolverObject *object, const SpriteGroup *group)
+{
+	if (group->g.real.num_loaded == 0) return NULL;
+
+	return group->g.real.loaded[0];
+}
+
+
+static inline void NewGenericResolver(ResolverObject *res)
+{
+	res->GetRandomBits = &GenericCallbackGetRandomBits;
+	res->GetTriggers   = &GenericCallbackGetTriggers;
+	res->SetTriggers   = &GenericCallbackSetTriggers;
+	res->GetVariable   = &GenericCallbackGetVariable;
+	res->ResolveReal   = &GenericCallbackResolveReal;
+
+	res->callback        = CBID_NO_CALLBACK;
+	res->callback_param1 = 0;
+	res->callback_param2 = 0;
+	res->last_value      = 0;
+	res->trigger         = 0;
+	res->reseed          = 0;
+}
+
+
+/** Follow a generic feature callback list and return the first successful
+ * answer
+ * @param feature GRF Feature of callback
+ * @param object  pre-populated resolver object
+ * @param file    address of GRFFile object if file reference is needed, NULL is valid
+ * @return callback value if successful or CALLBACK_FAILED
+ */
+static uint16 GetGenericCallbackResult(uint8 feature, ResolverObject *object, const GRFFile **file)
+{
+	assert(feature < lengthof(_gcl));
+
+	/* Test each feature callback sprite group. */
+	for (GenericCallbackList::const_iterator it = _gcl[feature].begin(); it != _gcl[feature].end(); ++it) {
+		const SpriteGroup *group = it->group;
+		group = Resolve(group, object);
+		if (group == NULL || group->type != SGT_CALLBACK) continue;
+
+		/* Return NewGRF file if necessary */
+		if (file != NULL) *file = it->file;
+
+		return group->g.callback.result;
+	}
+
+	/* No callback returned a valid result, so we've failed. */
+	return CALLBACK_FAILED;
+}
+
+
+/**
+ * 'Execute' an AI purchase selection callback
+ */
+uint16 GetAiPurchaseCallbackResult(uint8 feature, CargoID cargo_type, uint8 default_selection, IndustryType src_industry, IndustryType dst_industry, uint8 distance, AIConstructionEvent event, uint8 count, uint8 station_size, const GRFFile **file)
+{
+	ResolverObject object;
+
+	NewGenericResolver(&object);
+
+	object.callback = CBID_GENERIC_AI_PURCHASE_SELECTION;
+	object.u.generic.cargo_type        = cargo_type;
+	object.u.generic.default_selection = default_selection;
+	object.u.generic.src_industry      = src_industry;
+	object.u.generic.dst_industry      = dst_industry;
+	object.u.generic.distance          = distance;
+	object.u.generic.event             = event;
+	object.u.generic.count             = count;
+	object.u.generic.station_size      = station_size;
+
+	return GetGenericCallbackResult(feature, &object, file);
+}