dist(), att_reacting_units() and s_commod() are only interested in
cost, not the actual path. BestLandPath() and BestDistPath() compute
both cost and path. Use path_find() directly instead.
Destinations are no longer treated as unreachable when the best path
is longer than 1023 characters.
Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
s_commod() could incorrectly claim success when the sink ended up with
at least as many supplies than were missing initially. This caused a
number of problems:
* shp_torp() let a ship with two shells fire a torpedo, resulting in
-1 shells, which then made item_prewrite() oops. Affected missions
and return fire, but not the torpedo command.
* shp_missile_defense() let a ship with one shell use missile defense,
resulting in -1 shells, and the same item_prewrite() oops.
* Land units were considered in supply even when they had not quite
enough supplies. Such land units could defend without penalty,
attack and react. Commands load and lload weren't affected, because
they use lnd_in_supply(), which doesn't use s_commod().
Broken in 98f24d5c, v4.3.20.
Change s_commod() not to use the supply sink as source. As explained
in the message of the commit before the previous one, using the sink
as source makes it impossible for callers to safely keep a copy of the
sink across a supply call. All current users do that. Some were safe
anyway, some were not:
* fort_fire() was safe, because a fort draws shells only when it has
none.
* shp_fire() was unsafe for ships with capability supply and ammo use
greater than 1. No such ship exists in the stock game.
* shp_dchrg() was unsafe for ships with both capabilities dchrg and
supply. Same for shp_torp() and capability torp, and
shp_missile_defense() and capability anti-missile. No such ship
exists in the stock game.
* lnd_fire(), supp() and get_dlist() were safe, because they draw
shells only when they have less than their ammo need, and then they
don't supply any.
* mission_pln_equip() was unsafe when equipping planes with shells in
supply sources.
* landmine() was unsafe for land units with both capability engineer
and supply. No such land units exist in the stock game.
* load() and lload() were unsafe for loadable supply units, but the
supply use there was disabled in commit 65410d16 because of another
bug.
* ask_olist() and att_reacting_units() were safe, because
lnd_can_attack() excludes supply units.
In the stock game, planes flying interception or support missions,
abms intercepting ballistic missiles, launch of missiles or anti-sats
could conjure up shells, triggering a seqno mismatch oops.
In games with unusual customizations, this could also happen with
supply ships firing guns or torpedoes, dropping depth charges, or
shooting down marine missiles, and in the lmine command.
To implement the supply from self avoidance described in the previous
commit's message, s_commod() needs to be redesigned along the same
principles: take the sink as argument, update and put it. Also take
an item limit argument, and return whether supply request was fully
met.
Update sct_supply(), shp_supply(), lnd_supply() and
lnd_could_be_supplied(). The former three become straighforward
wrappers.
supply_commod() and try_supply_commod() are now unused, remove them.
The automatic supply interface has design flaws that make it hard to
use correctly. Its current uses are in fact all wrong (until commit
0179fd86, the update had a few uses that might have been correct).
Some of the bugs can only bite with land unit capability combinations
that don't exist in the stock game, though.
Automatic supply draws supplies from supply sources in range. Since
that can update any supply source in range, all copies of potential
supply sources a caller may keep can get invalidated. Writing back
such an invalid copy wipes out the deduction of supplies and mobility
from a source, triggering a seqno mismatch oops.
This commit redesigns the interface so that callers can safely keep a
copy of the object drawing the supplies (the "supply sink"). The idea
is to pass the sink to the supply code, so it can avoid using it as
source. The actual avoiding will be implemented in a later commit.
Copies other than the supply sink still need to be eliminated. See
commit 65410d16 for an example.
Other improvements to help avoid common errors:
* Supply functions are commonly used to ensure the sink has a certain
amount of supplies. A common error is to fetch that amount
regardless of how many the sink already has. It's more convenient
for such users to pass how many they need to have instead of how
many to get.
* A common use of supply functions is to get supplies for immediate
use. If that use turns out not to be possible after all, the
supplies need to be added somewhere, which is all too easy to
forget. Many bugs of this kind have been fixed over time, and there
are still some left. This class of bugs can be avoided by adding
the supplies to the sink automatically.
In fact, this commit fixes precisely such bugs in mission_pln_equip()
and shp_missile_defense(): plane interception and support missions,
missile interception (abms), launch of ballistic missiles and
anti-sats could all lose shells, or supply more than needed.
Replace supply_commod() by new sct_supply(), shp_supply(),
lnd_supply(), and resupply_all() by new lnd_supply_all(). Simplify
users accordingly.
There's just one use of resupply_commod() left, in landmine(). Use
lnd_supply_all() there, and remove resupply_commod().
Automatic supply always leaves enough food to avoid starvation in
supply sources, except for one case: when drawing supplies from the
sector containing the sink.
This behavior contradicted info supply. However, do_feed() used to
rely on it (it would have wiped out food without it). Supply use
there was removed in commit 7da69c92, so we can now fix this.
Affected by this is the automatic food supply of land units in combat,
and the food supply in commands supply, load and lload. Except supply
is disabled due to bugs in the last two.
When a supply request got served completely from a remote sector after
some other source had already provided some of it, the sector was
charged mobility for the complete amount instead of just the part it
actually provided.
Its implementation in s_commod() increases lnd_seqno even when
!actually_doit, which can cause spurious seqno oopses in callers of
lnd_could_be_supplied(). I can't be bothered to clean up this mess
right now, because recursive resupply is too dumb to be really useful
anyway: each step uses the first source it finds, without
consideration of mobility cost.
Being in supply is relevant for defending and reacting units. The
code used has_supply() to check that.
Contrary to its name, has_supply() does not check whether the land
unit has enough supplies to be in supply, but whether it has or could
draw enough. So, defending and reacting units did not actually draw
any missing supplies.
Fix that in get_dlist() and att_reacting_units() by calling
resupply_all(), then checking with new lnd_in_supply() instead of
has_supply(). The fix of att_reacting_units() is complicated by the
fact that it is also used in the strength command, and should keep not
drawing supplies there.
Rename has_supply() to lnd_could_be_supplied(). Replace its uses
immediately after resupply_all() by lnd_in_supply().
Running supply recursively here is problematic, because it can draw
supplies from the outer supply's destination, which can then end up
with less than it asked for.
Serving as supply source never puts a unit that is in supply out of
supply. So, the recursive supply here denies the sink its supplies to
put a supply unit somewhere else back in supply. That's robbing Peter
to pay Paul. Drop it.
The common supply code does not supply a land unit from the ship
carrying it, only resupply_all() does that, since 4.3.14. It would be
nice to fix the inconsistency by always supplying land units that way,
but that's relatively costly now, because of the supply code's design.
Just drop it for now.
Affects load and lload (except resupply is disabled there because it's
buggy), supply, assault and board.
Before s_commod() attempts to recursively supply a supply unit it
wants to use as supply source, it zaps the unit's load. When
actually_doit is false, it later restores the old load by overwriting
the change with a saved copy of the unit. That triggers a seqno
mismatch oops.
Avoid that by copying the new sequence number to the saved copy.
Change supply_commod() and try_supply_commod() not to call s_commod()
when zero units are wanted.
This isn't just for efficiency, it's also for limiting exposure to
supply bugs a bit.
The abstract idea of tying ships and land units to a logistical tether
is sound, the concrete implementation as option FUEL is flawed. It
adds too much busy-work to the game to be enjoyable. It hasn't been
enabled in a public game for years. The code implementing it is ugly,
repetitive, and a burden to maintain.
Remove selector fuel from ship_ca[] and land_ca[], and selectors
fuelc, fuelu from mchr_ca[] and lchr_ca[]. Remove fields fuelc, fuelu
from ship.config and land.config.
Remove command fuel from player_coms[].
Deprecate edit key 'B' in doship(), dounit(), and don't show it in
pr_ship(), pr_land().
Drop opt_FUEL code from build_ship(), shi(), sdump(), ship_damage(),
show_ship_stats(), do_mob_ship(), nav_ship(), build_land(), land(),
ldump(), land_damage(), show_land_stats(), do_mob_land(),
resupply_all(), resupply_commod(), get_minimum(), has_supply(),
unit_list(), vers().
Remove opt_FUEL, fuel_mult, struct shpstr member shp_fuel, struct
mchrstr members m_fuelc and m_fuelu, M_OILER, struct lndstr member
lnd_fuel, struct lchrstr members l_fuelc and l_fuelu, fuel(), and
auto_fuel_ship().
struct lndstr members lnd_spy, lnd_rad, lnd_ammo, lnd_fuelc,
lnd_fuelu, lnd_maxlight, lnd_maxlight are mere copies of struct
lchrstr members l_spy, l_rad, l_ammo, l_fuelc, l_fuelu, l_nxlight,
l_nland. Remove them.
Make land unit selectors spy, rmax, ammo, fuelc, fuelu, maxlight
virtual.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
move costs, but failed to make A* use these costs. This broke land
unit path finding. Fix:
(MOB_ROAD, MOB_MOVE, MOB_MARCH): Split MOB_ROAD into MOB_MOVE and
MOB_MARCH. Users changed.
(lnd_mobcost, sector_mcost): Move minimum mobcost logic to
sector_mcost(), where it is visible to A*. Also fixes unit reaction
path cost.
(lnd_path): Fix confusing message: don't claim there's no path when
all we really know is that there's no railway.
(feed_ship, feed_land): Use it.
(do_feed): Use it. Estimate of food needed was one too large for
integer food needs. Used to round fractional food need to nearest
instead of up for supply_commod(), which could cause starvation.
(s_commod, get_minimum): Use it. Estimate of food needed was one too
large for integer food needs. s_commod() used to reserve one more
than get_minimum() would have returned; it's now the same.
(famine_victims): New.
(feed_people): Use it. This rounds victim fractions down instead of
up. It also dosn't flush needs <=1 to zero. Doesn't change
starvation, as do_feed() always produces at least one emergency food.
Does change food consumption.
(starve_some): New.
(feed_people): Use it.
(feed_ship): Use feed_people(). This rounds victim fractions down
instead of up.
(feed_land): Use feed_people(). Rounding of victim fractions
unchanged. Feeds all people not just mil; closes#913997.
(starv_people): New.
(starv_sects, starv_ships, starv_units): Use it. Fixes starve land to
talk about people instead of mil.
(starv_sects): Use famine_victims() rather than feed_people(). Take
emergency food into account, because feed_people() doesn't. Don't aim
for one extra food, for consistency with starv_ships() and
starv_units().
(feed_people): Remove useless parameter. Simplify.
(starv_ships, starv_ships): Use famine_victims() rather than
feed_ship() and feed_land().
(feed_ship, feed_land): Remove useless parameters. Internal linkage.
Simplify.
(feed_land): Call resupply_commod() only if there's a food shortage.
Don't scrounge lnd_ship for food, resupply_commod() already does.
(ltend, multifire, quite_bigdef, mine, landmine)
(do_loan, prod, printdiff, sell, sona, stre)
(tend, fire_dchrg, vers, work, ac_planedamage)
(ac_shipflak, ask_off, get_mine_dsupport, att_fight)
(ask_move_in_off, detonate, sd, land_gun)
(land_unitgun, lnd_fort_interdiction, lnd_fortify)
(perform_mission, pln_mine, pln_mobcost)
(retreat_ship1, retreat_land1, shp_sweep)
(shp_fort_interdiction, shp_missle_defense)
(new_work, growfood, upd_land, land_repair)
(get_materials, do_mob_ship, do_mob_land)
(load_it, unload_it, prod_plane, produce)
(guerrilla, upd_buildeff, spread_fallout)
(upd_ship, ship_repair, min, dmin, MIN):
Remove min() and dmin() functions and replace
with a MIN macro in misc.h. Remove local MIN
macros and use the new one in misc.h. This
change removes the need for the special
case for _WIN32.
(fuel, look_ship, multifire, mission, sona)
(plane_sona, ef_open, player_accept, player_main)
(ac_dog, att_get_combat, calc_mobcost)
(ask_move_in_off, intelligence_report)
(build_mission_list_type, perform_mission)
(show_mission, use_supply, dodistribute)
(allocate_memory, max, dmax, MAX):
Remove max() and dmax() functions and replace
with a MAX macro in misc.h. Remove local MAX
macros and use the new one in misc.h. This
change removes the need for the special
case for _WIN32.
I_BAR, I_FOOD, I_OIL, I_LCM, I_HCM, I_UW, I_RAD, I_MAX): Turn macros
into enumeration constants.
(i_type): New. Use where appropriate. No functional changes, except
that I_NONE is now catched properly in a few places.
