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authorsmatz <smatz@openttd.org>2008-02-04 23:24:22 +0000
committersmatz <smatz@openttd.org>2008-02-04 23:24:22 +0000
commit146779b1586dd5e4da4810d468951d16ded562a5 (patch)
tree2aad26d071f88c07f9a43a628d9c823e1e9339eb
parent23c669fe50138f6a029d6c7b979aa26067982bb7 (diff)
downloadopenttd-146779b1586dd5e4da4810d468951d16ded562a5.tar.xz
(svn r12062) -Fix: possible deadlock when there are no houses available to build at given tile
-Fix: houses with zero probability could be built
-rw-r--r--src/town_cmd.cpp98
1 files changed, 50 insertions, 48 deletions
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index b688d100e..31cbe3ea1 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -1748,7 +1748,7 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
{
HouseID houses[HOUSE_MAX];
int num = 0;
- uint cumulative_probs[HOUSE_MAX];
+ uint probs[HOUSE_MAX];
uint probability_max = 0;
/* Generate a list of all possible houses that can be built. */
@@ -1756,26 +1756,31 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
hs = GetHouseSpecs(i);
/* Verify that the candidate house spec matches the current tile status */
if ((~hs->building_availability & bitmask) == 0 && hs->enabled) {
- if (_loaded_newgrf_features.has_newhouses) {
- probability_max += hs->probability;
- cumulative_probs[num] = probability_max;
- }
+ /* Without NewHouses, all houses have probability '1' */
+ uint cur_prob = (_loaded_newgrf_features.has_newhouses ? hs->probability : 1);
+ probability_max += cur_prob;
+ probs[num] = cur_prob;
houses[num++] = (HouseID)i;
}
}
uint maxz = GetTileMaxZ(tile);
- for (;;) {
- if (_loaded_newgrf_features.has_newhouses) {
- uint r = RandomRange(probability_max);
- for (i = 0; i < num; i++) if (cumulative_probs[i] >= r) break;
-
- house = houses[i];
- } else {
- house = houses[RandomRange(num)];
+ while (probability_max > 0) {
+ uint r = RandomRange(probability_max);
+ for (i = 0; i < num; i++) {
+ if (probs[i] > r) break;
+ r -= probs[i];
}
+ house = houses[i];
+ probability_max -= probs[i];
+
+ /* remove tested house from the set */
+ num--;
+ houses[i] = houses[num];
+ probs[i] = probs[num];
+
hs = GetHouseSpecs(house);
if (_loaded_newgrf_features.has_newhouses) {
@@ -1810,60 +1815,57 @@ static bool BuildTownHouse(Town *t, TileIndex tile)
if (noslope && slope != SLOPE_FLAT) continue;
if (hs->building_flags & TILE_SIZE_2x2) {
- if (CheckFree2x2Area(tile, maxz, noslope) ||
- CheckFree2x2Area(tile += TileDiffXY(-1, 0), maxz, noslope) ||
- CheckFree2x2Area(tile += TileDiffXY( 0, -1), maxz, noslope) ||
- CheckFree2x2Area(tile += TileDiffXY( 1, 0), maxz, noslope)) {
- break;
+ if (!CheckFree2x2Area(tile, maxz, noslope) &&
+ !CheckFree2x2Area(tile += TileDiffXY(-1, 0), maxz, noslope) &&
+ !CheckFree2x2Area(tile += TileDiffXY( 0, -1), maxz, noslope) &&
+ !CheckFree2x2Area(tile += TileDiffXY( 1, 0), maxz, noslope)) {
+ /* return to the original tile */
+ tile += TileDiffXY(0, 1);
+ continue; /* continue the while() loop */
}
- /* return to original tile */
- tile += TileDiffXY(0, 1);
} else if (hs->building_flags & TILE_SIZE_2x1) {
/* 'tile' is already checked above - CanBuildHouseHere() and slope test */
- if (CheckBuildHouseSameZ(tile + TileDiffXY(1, 0), maxz, noslope)) break;
-
- if (CheckBuildHouseSameZ(tile + TileDiffXY(-1, 0), maxz, noslope)) {
+ if (!CheckBuildHouseSameZ(tile + TileDiffXY(1, 0), maxz, noslope)) {
+ if (!CheckBuildHouseSameZ(tile + TileDiffXY(-1, 0), maxz, noslope)) continue;
tile += TileDiffXY(-1, 0);
- break;
}
} else if (hs->building_flags & TILE_SIZE_1x2) {
- if (CheckBuildHouseSameZ(tile + TileDiffXY(0, 1), maxz, noslope)) break;
-
- if (CheckBuildHouseSameZ(tile + TileDiffXY(0, -1), maxz, noslope)) {
+ if (!CheckBuildHouseSameZ(tile + TileDiffXY(0, 1), maxz, noslope)) {
+ if (!CheckBuildHouseSameZ(tile + TileDiffXY(0, -1), maxz, noslope)) continue;
tile += TileDiffXY(0, -1);
- break;
}
- } else {
- break;
}
- }
- }
- t->num_houses++;
- IncreaseBuildingCount(t, house);
+ /* build the house */
+ t->num_houses++;
+ IncreaseBuildingCount(t, house);
- /* Special houses that there can be only one of. */
- t->flags12 |= oneof;
+ /* Special houses that there can be only one of. */
+ t->flags12 |= oneof;
- {
- byte construction_counter = 0, construction_stage = 0;
+ {
+ byte construction_counter = 0, construction_stage = 0;
- if (_generating_world) {
- uint32 r = Random();
+ if (_generating_world) {
+ uint32 r = Random();
- construction_stage = TOWN_HOUSE_COMPLETED;
- if (Chance16(1, 7)) construction_stage = GB(r, 0, 2);
+ construction_stage = TOWN_HOUSE_COMPLETED;
+ if (Chance16(1, 7)) construction_stage = GB(r, 0, 2);
- if (construction_stage == TOWN_HOUSE_COMPLETED) {
- ChangePopulation(t, hs->population);
- } else {
- construction_counter = GB(r, 2, 2);
+ if (construction_stage == TOWN_HOUSE_COMPLETED) {
+ ChangePopulation(t, hs->population);
+ } else {
+ construction_counter = GB(r, 2, 2);
+ }
+ }
+ MakeTownHouse(tile, t->index, construction_counter, construction_stage, house, Random());
}
+
+ return true;
}
- MakeTownHouse(tile, t->index, construction_counter, construction_stage, house, Random());
}
- return true;
+ return false;
}