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(svn r2022) Revise CmdRemoveSingleSignal: Check parameters for validity and simplify the function

release/0.4.5
tron 2005-03-18 07:37:32 +00:00
parent ad579912f4
commit e5036891f6
1 changed files with 15 additions and 37 deletions
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52
rail_cmd.c
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@ -1083,52 +1083,30 @@ int32 CmdBuildSignalTrack(int x, int y, uint32 flags, uint32 p1, uint32 p2)
}
/* Remove signals
* p1 bits 0..2 = track
* p1 bits 0-2 = track, valid values: 0-5
* p2 = unused
*/
int32 CmdRemoveSingleSignal(int x, int y, uint32 flags, uint32 p1, uint32 p2)
{
TileInfo ti;
uint tile;
int track = p1 & 0x7;
byte a,b,c,d;
TileIndex tile = TILE_FROM_XY(x, y);
uint track = p1 & 0x7;
if (!(track < 6) || // only 6 possible track-combinations
!IsTileType(tile, MP_RAILWAY) ||
!EnsureNoVehicle(tile))
return CMD_ERROR;
if ((_map5[tile] & RAIL_TYPE_MASK) != RAIL_TYPE_SIGNALS ||
(_map3_lo[tile] & _signals_table_both[track]) == 0) // signals on track?
return CMD_ERROR;
if (!CheckTileOwnership(tile)) return CMD_ERROR;
SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
FindLandscapeHeight(&ti, x, y);
tile = ti.tile;
/* No vehicle behind. */
if (!EnsureNoVehicle(tile))
return CMD_ERROR;
/* Signals can only exist on railways */
if (ti.type != MP_RAILWAY)
return CMD_ERROR;
/* Map5 mode is 0x40 when there's signals */
if ((ti.map5 & RAIL_TYPE_MASK) != RAIL_TYPE_SIGNALS)
return CMD_ERROR;
/* Who owns the tile? */
if (_current_player != OWNER_WATER && !CheckTileOwnership(tile))
return CMD_ERROR;
// calculate already built signals
a = _signals_table[track]; // signal for this track in one direction
b = _signals_table[track + 8]; // signal for this track in the other direction
c = a | b;
d = _map3_lo[tile] & c;
/* no signals on selected track? */
if (d == 0)
return CMD_ERROR;
/* Do it? */
if (flags & DC_EXEC) {
_map3_lo[tile] &= ~c;
_map3_lo[tile] &= ~_signals_table_both[track];
/* removed last signal from tile? */
if ((_map3_lo[tile] & 0xF0) == 0) {