--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/newgrf_spritegroup.cpp	Wed Jan 10 18:12:09 2007 +0000
@@ -0,0 +1,233 @@
+/* $Id$ */
+
+#include "stdafx.h"
+#include "openttd.h"
+#include "variables.h"
+#include "macros.h"
+#include "oldpool.h"
+#include "newgrf_spritegroup.h"
+#include "date.h"
+
+static void SpriteGroupPoolCleanBlock(uint start_item, uint end_item);
+
+static uint _spritegroup_count = 0;
+STATIC_OLD_POOL(SpriteGroup, SpriteGroup, 9, 250, NULL, SpriteGroupPoolCleanBlock)
+
+static void DestroySpriteGroup(SpriteGroup *group)
+{
+	/* Free dynamically allocated memory */
+	/* XXX Cast away the consts due to MSVC being buggy... */
+	switch (group->type) {
+		case SGT_REAL:
+			free((SpriteGroup**)group->g.real.loaded);
+			free((SpriteGroup**)group->g.real.loading);
+			break;
+
+		case SGT_DETERMINISTIC:
+			free(group->g.determ.adjusts);
+			free(group->g.determ.ranges);
+			break;
+
+		case SGT_RANDOMIZED:
+			free((SpriteGroup**)group->g.random.groups);
+			break;
+
+		default:
+			break;
+	}
+}
+
+static void SpriteGroupPoolCleanBlock(uint start_item, uint end_item)
+{
+	uint i;
+
+	for (i = start_item; i <= end_item; i++) {
+		DestroySpriteGroup(GetSpriteGroup(i));
+	}
+}
+
+
+/* Allocate a new SpriteGroup */
+SpriteGroup *AllocateSpriteGroup(void)
+{
+	/* This is totally different to the other pool allocators, as we never remove an item from the pool. */
+	if (_spritegroup_count == GetSpriteGroupPoolSize()) {
+		if (!AddBlockToPool(&_SpriteGroup_pool)) return NULL;
+	}
+
+	return GetSpriteGroup(_spritegroup_count++);
+}
+
+
+void InitializeSpriteGroupPool(void)
+{
+	CleanPool(&_SpriteGroup_pool);
+
+	_spritegroup_count = 0;
+}
+
+
+static inline uint32 GetVariable(const ResolverObject *object, byte variable, byte parameter, bool *available)
+{
+	/* Return common variables */
+	switch (variable) {
+		case 0x00: return max(_date - DAYS_TILL_ORIGINAL_BASE_YEAR, 0);
+		case 0x01: return clamp(_cur_year, ORIGINAL_BASE_YEAR, ORIGINAL_MAX_YEAR) - ORIGINAL_BASE_YEAR;
+		case 0x02: return _cur_month;
+		case 0x03: return _opt.landscape;
+		case 0x09: return _date_fract;
+		case 0x0A: return _tick_counter;
+		case 0x0C: return object->callback;
+		case 0x10: return object->callback_param1;
+		case 0x11: return 0;
+		case 0x18: return object->callback_param2;
+		case 0x1A: return -1;
+		case 0x1B: return GB(_display_opt, 0, 6);
+		case 0x1C: return object->last_value;
+		case 0x20: return _opt.landscape == LT_HILLY ? _opt.snow_line : 0xFF;
+
+		/* Not a common variable, so evalute the feature specific variables */
+		default: return object->GetVariable(object, variable, parameter, available);
+	}
+}
+
+
+/* Evaluate an adjustment for a variable of the given size. This is a bit of
+ * an unwieldy macro, but it saves triplicating the code. */
+#define BUILD_EVAL_ADJUST(size, usize) \
+static inline usize EvalAdjust_ ## size(const DeterministicSpriteGroupAdjust *adjust, usize last_value, int32 value) \
+{ \
+	value >>= adjust->shift_num; \
+	value  &= adjust->and_mask; \
+\
+	if (adjust->type != DSGA_TYPE_NONE) value += (size)adjust->add_val; \
+\
+	switch (adjust->type) { \
+		case DSGA_TYPE_DIV:  value /= (size)adjust->divmod_val; break; \
+		case DSGA_TYPE_MOD:  value %= (usize)adjust->divmod_val; break; \
+		case DSGA_TYPE_NONE: break; \
+	} \
+\
+	/* Get our value to the correct range */ \
+	value = (usize)value; \
+\
+	switch (adjust->operation) { \
+		case DSGA_OP_ADD:  return last_value + value; \
+		case DSGA_OP_SUB:  return last_value - value; \
+		case DSGA_OP_SMIN: return min(last_value, value); \
+		case DSGA_OP_SMAX: return max(last_value, value); \
+		case DSGA_OP_UMIN: return min((usize)last_value, (usize)value); \
+		case DSGA_OP_UMAX: return max((usize)last_value, (usize)value); \
+		case DSGA_OP_SDIV: return last_value / value; \
+		case DSGA_OP_SMOD: return last_value % value; \
+		case DSGA_OP_UDIV: return (usize)last_value / (usize)value; \
+		case DSGA_OP_UMOD: return (usize)last_value % (usize)value; \
+		case DSGA_OP_MUL:  return last_value * value; \
+		case DSGA_OP_AND:  return last_value & value; \
+		case DSGA_OP_OR:   return last_value | value; \
+		case DSGA_OP_XOR:  return last_value ^ value; \
+		default:           return value; \
+	} \
+}
+
+
+BUILD_EVAL_ADJUST(int8, uint8)
+BUILD_EVAL_ADJUST(int16, uint16)
+BUILD_EVAL_ADJUST(int32, uint32)
+
+
+static inline const SpriteGroup *ResolveVariable(const SpriteGroup *group, ResolverObject *object)
+{
+	static SpriteGroup nvarzero;
+	int32 last_value = object->last_value;
+	int32 value = -1;
+	uint i;
+
+	object->scope = group->g.determ.var_scope;
+
+	for (i = 0; i < group->g.determ.num_adjusts; i++) {
+		DeterministicSpriteGroupAdjust *adjust = &group->g.determ.adjusts[i];
+
+		/* Try to get the variable. We shall assume it is available, unless told otherwise. */
+		bool available = true;
+		value = GetVariable(object, adjust->variable, adjust->parameter, &available);
+
+		if (!available) {
+			/* Unsupported property: skip further processing and return either
+			 * the group from the first range or the default group. */
+			return Resolve(group->g.determ.num_ranges > 0 ? group->g.determ.ranges[0].group : group->g.determ.default_group, object);
+		}
+
+		switch (group->g.determ.size) {
+			case DSG_SIZE_BYTE:  value = EvalAdjust_int8(adjust, last_value, value); break;
+			case DSG_SIZE_WORD:  value = EvalAdjust_int16(adjust, last_value, value); break;
+			case DSG_SIZE_DWORD: value = EvalAdjust_int32(adjust, last_value, value); break;
+			default: NOT_REACHED(); break;
+		}
+		last_value = value;
+	}
+
+	if (group->g.determ.num_ranges == 0) {
+		/* nvar == 0 is a special case -- we turn our value into a callback result */
+		nvarzero.type = SGT_CALLBACK;
+		nvarzero.g.callback.result = GB(value, 0, 15);
+		return &nvarzero;
+	}
+
+	for (i = 0; i < group->g.determ.num_ranges; i++) {
+		if (group->g.determ.ranges[i].low <= (uint32)value && (uint32)value <= group->g.determ.ranges[i].high) {
+			return Resolve(group->g.determ.ranges[i].group, object);
+		}
+	}
+
+	return Resolve(group->g.determ.default_group, object);
+}
+
+
+static inline const SpriteGroup *ResolveRandom(const SpriteGroup *group, ResolverObject *object)
+{
+	uint32 mask;
+	byte index;
+
+	object->scope = group->g.random.var_scope;
+
+	if (object->trigger != 0) {
+		/* Handle triggers */
+		/* Magic code that may or may not do the right things... */
+		byte waiting_triggers = object->GetTriggers(object);
+		byte match = group->g.random.triggers & (waiting_triggers | object->trigger);
+		bool res;
+
+		res = (group->g.random.cmp_mode == RSG_CMP_ANY) ?
+			(match != 0) : (match == group->g.random.triggers);
+
+		if (res) {
+			waiting_triggers &= ~match;
+			object->reseed |= (group->g.random.num_groups - 1) << group->g.random.lowest_randbit;
+		} else {
+			waiting_triggers |= object->trigger;
+		}
+
+		object->SetTriggers(object, waiting_triggers);
+	}
+
+	mask  = (group->g.random.num_groups - 1) << group->g.random.lowest_randbit;
+	index = (object->GetRandomBits(object) & mask) >> group->g.random.lowest_randbit;
+
+	return Resolve(group->g.random.groups[index], object);
+}
+
+
+/* ResolverObject (re)entry point */
+const SpriteGroup *Resolve(const SpriteGroup *group, ResolverObject *object)
+{
+	/* We're called even if there is no group, so quietly return nothing */
+	if (group == NULL) return NULL;
+
+	switch (group->type) {
+		case SGT_REAL:          return object->ResolveReal(object, group);
+		case SGT_DETERMINISTIC: return ResolveVariable(group, object);
+		case SGT_RANDOMIZED:    return ResolveRandom(group, object);
+		default:                return group;
+	}
+}