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author | rubidium <rubidium@openttd.org> | 2010-05-12 18:31:39 +0000 |
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committer | rubidium <rubidium@openttd.org> | 2010-05-12 18:31:39 +0000 |
commit | 863ff6522b671ce69a1265fe246149b25e83a847 (patch) | |
tree | dea696bc261a69f8c6b499d8111a9f1c3c1680d6 /src/town.h | |
parent | 0d9281dde3ca4001a2e25ea0f2945ca4ebdab9f9 (diff) | |
download | openttd-863ff6522b671ce69a1265fe246149b25e83a847.tar.xz |
(svn r19798) -Codechange: generalise the waypoint naming method
Diffstat (limited to 'src/town.h')
-rw-r--r-- | src/town.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/src/town.h b/src/town.h index d589d8f1e..b1cae99cc 100644 --- a/src/town.h +++ b/src/town.h @@ -258,4 +258,68 @@ static inline uint TileHash2Bit(uint x, uint y) return GB(TileHash(x, y), 0, 2); } +/** + * Set the default name for a depot/waypoint + * @tparam T The type/class to make a default name for + * @param obj The object/instance we want to find the name for + */ +template <class T> +void MakeDefaultName(T *obj) +{ + /* We only want to set names if it hasn't been set before. */ + assert(obj->name == NULL); + + obj->town = ClosestTownFromTile(obj->xy, UINT_MAX); + + /* Find first unused number belonging to this town. This can never fail, + * as long as there can be at most 65535 waypoints/depots in total. + * + * This does 'n * m' search, but with 32bit 'used' bitmap, it needs at + * most 'n * (1 + ceil(m / 32))' steps (n - number of waypoints in pool, + * m - number of waypoints near this town). + * Usually, it needs only 'n' steps. + * + * If it wasn't using 'used' and 'idx', it would just search for increasing 'next', + * but this way it is faster */ + + uint32 used = 0; // bitmap of used waypoint numbers, sliding window with 'next' as base + uint32 next = 0; // first number in the bitmap + uint32 idx = 0; // index where we will stop + uint32 cid = 0; // current index, goes to T::GetPoolSize()-1, then wraps to 0 + + do { + T *lobj = T::GetIfValid(cid); + + /* check only valid waypoints... */ + if (lobj != NULL && obj != lobj) { + /* only objects with 'generic' name within the same city and with the same type*/ + if (lobj->name == NULL && lobj->town == obj->town && lobj->IsOfType(obj)) { + /* if lobj->town_cn < next, uint will overflow to '+inf' */ + uint i = (uint)lobj->town_cn - next; + + if (i < 32) { + SetBit(used, i); // update bitmap + if (i == 0) { + /* shift bitmap while the lowest bit is '1'; + * increase the base of the bitmap too */ + do { + used >>= 1; + next++; + } while (HasBit(used, 0)); + /* when we are at 'idx' again at end of the loop and + * 'next' hasn't changed, then no object had town_cn == next, + * so we can safely use it */ + idx = cid; + } + } + } + } + + cid++; + if (cid == T::GetPoolSize()) cid = 0; // wrap to zero... + } while (cid != idx); + + obj->town_cn = (uint16)next; // set index... +} + #endif /* TOWN_H */ |