Fix bugs found in beta

README.md

@@ -4,27 +4,47 @@ The [TrueOG Network](https://trueog.net) fork of [Duels](https://github.com/Real
 
 Changes from Duels:
 
-- Added a chat wizard for setting a bounty amount post-duel command in the GUI by @NotAlexNoyle
-- Remove update checker by @NotAlexNoyle
-- Only start Duels from one world, configurable in config.yml by @NotAlexNoyle
-- Inventory loss bug fixes by @szumielxd
-- Essentials API NPE fix by @skbeh
-- Update deprecated pickup API by @NotAlexNoyle
-- Added an option to hide the Duel winning title message by @NotAlexNoyle
-- Added an option to hide the bet winning title message by @NotAlexNoyle
-- Prevent players from stealing Duels items from the inventory by @dwaslashe
-- Prevent players from stealing Duels items from the ground by @SrBedrock
-- Whitelist arenas/worlds and fix duel transportation, with [PetTeleport-OG](https://github.com/true-og/PetTeleport-OG) and [HorseTp-OG](https://github.com/true-og/HorseTp-OG) support by @NotAlexNoyle
-- Add [EternalCombat](https://github.com/EternalCodeTeam/EternalCombat) support by @NotAlexNoyle
-- Replace BountyHunters hook with [PlayerBounties-OG](https://github.com/true-og/PlayerBounties-OG) support by @NotAlexNoyle
-- Replaced Vault hook with [DiamondBank-OG](https://github.com/true-og/DiamondBank-OG) API by @NotAlexNoyle
-- Removed Multiverse hook; world whitelisting now uses plain Bukkit world names with [MyWorlds](https://github.com/true-og/MyWorlds) listed as a soft-depend to ensure managed worlds load before Duels by @NotAlexNoyle
-- Bundled live TrueOG Network config files for plug-and-play deployment by @NotAlexNoyle
-- Bundled default kits (chain, iron, diamond, leather, netherite, debuff, nodebuff) in the plugin jar by @NotAlexNoyle
-- Removed WorldGuard region restrictions inside duel arenas by @NotAlexNoyle
-- Fixed victory message formatting by @NotAlexNoyle
-- Fixed kits equipping into an empty inventory caused by a delayed inventory reset wiping the kit by @NotAlexNoyle
-- Added separate configurable end-of-match broadcast commands for bet and no-bet duels by @NotAlexNoyle
+#### @NotAlexNoyle
+
+- Added a chat wizard for setting a bounty amount post-duel command in the GUI
+- Remove update checker
+- Only start Duels from one world, configurable in config.yml
+- Update deprecated pickup API
+- Added an option to hide the Duel winning title message
+- Added an option to hide the bet winning title message
+- Whitelist arenas/worlds and fix duel transportation, with [PetTeleport-OG](https://github.com/true-og/PetTeleport-OG) and [HorseTp-OG](https://github.com/true-og/HorseTp-OG) support
+- Add [EternalCombat](https://github.com/EternalCodeTeam/EternalCombat) support
+- Replace BountyHunters hook with [PlayerBounties-OG](https://github.com/true-og/PlayerBounties-OG) support
+- Replaced Vault hook with [DiamondBank-OG](https://github.com/true-og/DiamondBank-OG) API
+- Removed Multiverse hook; world whitelisting now uses plain Bukkit world names with [MyWorlds](https://github.com/true-og/MyWorlds) listed as a soft-depend to ensure managed worlds load before Duels
+- Bundled live TrueOG Network config files for plug-and-play deployment
+- Bundled default kits (chain, iron, diamond, leather, netherite, debuff, nodebuff) in the plugin jar
+- Removed WorldGuard region restrictions inside duel arenas
+- Fixed victory message formatting
+- Fixed kits equipping into an empty inventory caused by a delayed inventory reset wiping the kit
+- Added separate configurable end-of-match broadcast commands for bet and no-bet duels
+- Fixed diamond bet payouts so the total bounty equals the bet amount (the loser pays the winner, instead of both staking and the winner receiving double)
+- Added a message telling the bet maker when their opponent cannot afford the bet
+- Pluralize "Diamond"/"Diamonds" in messages based on the amount
+- Fixed a bug where a selected kit could not be de-selected, blocking own-inventory duels
+- Select a random kit and arena if none are selected
+- Strip kit-item NBT from outgoing packets via [ProtocolLib](https://github.com/dmulloy2/ProtocolLib) so legacy clients (1.8+ through ViaVersion) can eat, draw bows, and hold items without desync, while keeping kit-item protection intact
+
+#### @szumielxd
+
+- Inventory loss bug fixes
+
+#### @skbeh
+
+- Essentials API NPE fix
+
+#### @dwaslashe
+
+- Prevent players from stealing Duels items from the inventory
+
+#### @SrBedrock
+
+- Prevent players from stealing Duels items from the ground
 
 ---
 

build.gradle.kts

@@ -114,6 +114,7 @@ project(":duels-plugin") {
             isTransitive = false
         }
 
+        compileOnly(localJar("ProtocolLib/ProtocolLib-5.0"))
         compileOnly(localJar("MVdWPlaceholderAPI-3.1.1"))
         compileOnly(localJar("CombatTagPlus"))
         compileOnly(localJar("PvPManager-3.7.16"))

duels-plugin/src/main/java/me/realized/duels/DuelsPlugin.java

@@ -32,6 +32,7 @@ import me.realized.duels.kit.KitManagerImpl;
 import me.realized.duels.listeners.DamageListener;
 import me.realized.duels.listeners.EnderpearlListener;
 import me.realized.duels.listeners.KitItemListener;
+import me.realized.duels.listeners.KitItemPacketListener;
 import me.realized.duels.listeners.KitOptionsListener;
 import me.realized.duels.listeners.LingerPotionListener;
 import me.realized.duels.listeners.PotionListener;
@@ -171,6 +172,17 @@ public class DuelsPlugin extends JavaPlugin implements Duels, LogSource {
         }
 
         new KitItemListener(this);
+
+        // Strip kit-item NBT from outgoing packets so legacy (ViaVersion) clients don't desync the
+        // held slot. Only needed when kit-item protection is on (otherwise no tag is ever applied).
+        if (configuration.isProtectKitItems() && getServer().getPluginManager().isPluginEnabled("ProtocolLib")) {
+            try {
+                new KitItemPacketListener(this);
+            } catch (final Throwable ex) {
+                Log.warn("Failed to register ProtocolLib kit-item listener: " + ex.getMessage());
+            }
+        }
+
         new DamageListener(this);
         new PotionListener(this);
         new TeleportListener(this);

duels-plugin/src/main/java/me/realized/duels/config/Lang.java

@@ -107,17 +107,48 @@ public class Lang extends AbstractConfiguration<DuelsPlugin> implements Reloadab
             replacers = (Object[]) replacers[0];
         }
 
+        Long diamondCount = null;
+
         for (int i = 0; i < replacers.length; i += 2) {
             if (i + 1 >= replacers.length) {
                 break;
             }
 
-            message = message.replace("%" + replacers[i].toString() + "%", String.valueOf(replacers[i + 1]));
+            final String key = replacers[i].toString();
+            final Object value = replacers[i + 1];
+
+            // Track the Diamond count so "Diamond(s)" can be pluralized to match.
+            if (key.equals("bet_amount") || key.equals("money")) {
+                final Long parsed = toLong(value);
+
+                if (parsed != null) {
+                    diamondCount = parsed;
+                }
+            }
+
+            message = message.replace("%" + key + "%", String.valueOf(value));
+        }
+
+        // Resolve "Diamond(s)" to "Diamond" or "Diamonds" based on the amount.
+        if (message.contains("Diamond(s)") && diamondCount != null) {
+            message = message.replace("Diamond(s)", diamondCount == 1 ? "Diamond" : "Diamonds");
         }
 
         return message;
     }
 
+    private Long toLong(final Object value) {
+        if (value instanceof Number) {
+            return ((Number) value).longValue();
+        }
+
+        try {
+            return (long) Double.parseDouble(String.valueOf(value));
+        } catch (NumberFormatException ex) {
+            return null;
+        }
+    }
+
     public String getMessage(final String key, final Object... replacers) {
         final String message = getMessage(key);
         return message != null ? replace(message, replacers) : null;

duels-plugin/src/main/java/me/realized/duels/data/ItemData.java

@@ -9,6 +9,7 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
+import me.realized.duels.DuelsPlugin;
 import me.realized.duels.util.EnumUtil;
 import me.realized.duels.util.collection.StreamUtil;
 import me.realized.duels.util.compat.CompatUtil;
@@ -67,7 +68,13 @@ public class ItemData {
 
         final String dumped = YamlUtil.yamlDump(item);
         ItemStack item = YamlUtil.bukkitYamlLoadAs(dumped, ItemStack.class);
-        return kitItem ? Identifiers.addIdentifier(item) : item;
+
+        // Only stamp the custom NBT identifier when kit-item protection is actually enabled.
+        // The tag is purely for KitItemListener; when protection is off it adds nothing but
+        // can trip up legacy clients via ViaVersion/ViaBackwards (held-item "bobbing", bows not
+        // staying drawn, food not consuming) due to client/server NBT mismatch on the held slot.
+        final boolean protect = DuelsPlugin.getInstance().getConfiguration().isProtectKitItems();
+        return kitItem && protect ? Identifiers.addIdentifier(item) : item;
     }
 
     public ItemStack toItemStack() {

duels-plugin/src/main/java/me/realized/duels/duel/DuelManager.java

@@ -10,6 +10,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.ThreadLocalRandom;
 
 import org.bukkit.Bukkit;
 import org.bukkit.Color;
@@ -58,7 +59,9 @@ import me.realized.duels.hook.hooks.McMMOHook;
 import me.realized.duels.hook.hooks.PvPManagerHook;
 import me.realized.duels.hook.hooks.worldguard.WorldGuardHook;
 import me.realized.duels.inventories.InventoryManager;
+import me.realized.duels.api.kit.Kit;
 import me.realized.duels.kit.KitImpl;
+import me.realized.duels.kit.KitManagerImpl;
 import me.realized.duels.player.PlayerInfo;
 import me.realized.duels.player.PlayerInfoManager;
 import me.realized.duels.queue.Queue;
@@ -86,6 +89,7 @@ public class DuelManager implements Loadable {
     private final Lang lang;
     private final UserManagerImpl userDataManager;
     private final ArenaManagerImpl arenaManager;
+    private final KitManagerImpl kitManager;
     private final PlayerInfoManager playerManager;
     private final InventoryManager inventoryManager;
 
@@ -109,6 +113,7 @@ public class DuelManager implements Loadable {
         this.lang = plugin.getLang();
         this.userDataManager = plugin.getUserManager();
         this.arenaManager = plugin.getArenaManager();
+        this.kitManager = plugin.getKitManager();
         this.playerManager = plugin.getPlayerManager();
         this.inventoryManager = plugin.getInventoryManager();
 
@@ -198,10 +203,7 @@ public class DuelManager implements Loadable {
     private void handleTie(final Player player, final ArenaImpl arena, final MatchImpl match, boolean alive) {
         arena.remove(player);
 
-        // Refund the player's bet in the case of a tie.
-        if (diamondBank != null && match.getBet() > 0) {
-            diamondBank.add(match.getBet(), player);
-        }
+        // No bet is escrowed up-front, so a tie requires no refund.
 
         if (mcMMO != null) {
             mcMMO.enableSkills(player);
@@ -248,15 +250,23 @@ public class DuelManager implements Loadable {
 
         final String opponentName = opponent != null ? opponent.getName() : lang.getMessage("GENERAL.none");
 
-        if (diamondBank != null && match.getBet() > 0) {
-            final int amount = match.getBet() * 2;
-            diamondBank.add(amount, player);
-            lang.sendMessage(player, "DUEL.reward.money.message", "name", opponentName, "money", amount);
+        if (diamondBank != null && opponent != null && match.getBet() > 0) {
+            final int amount = match.getBet();
 
-            final String title = lang.getMessage("DUEL.reward.money.title", "name", opponentName, "money", amount);
+            // Transfer the bet from the loser to the winner: total payout equals the bet amount.
+            if (diamondBank.remove(amount, opponent)) {
+                if (diamondBank.add(amount, player)) {
+                    lang.sendMessage(player, "DUEL.reward.money.message", "name", opponentName, "money", amount);
 
-            if (title != null && config.isVictoryTitleEnabled()) {
-                Titles.send(player, title, null, 0, 20, 50);
+                    final String title = lang.getMessage("DUEL.reward.money.title", "name", opponentName, "money", amount);
+
+                    if (title != null && config.isVictoryTitleEnabled()) {
+                        Titles.send(player, title, null, 0, 20, 50);
+                    }
+                } else {
+                    // Pay-out failed: refund the loser so no Diamonds are lost.
+                    diamondBank.add(amount, opponent);
+                }
             }
         }
 
@@ -288,12 +298,17 @@ public class DuelManager implements Loadable {
     }
 
     public void startMatch(final Player first, final Player second, final Settings settings, final Map<UUID, List<ItemStack>> items, final Queue source) {
-        final KitImpl kit = settings.getKit();
+        KitImpl kit = settings.getKit();
 
+        // If neither a kit nor own inventory was chosen, fall back to a random kit.
         if (!settings.isOwnInventory() && kit == null) {
-            lang.sendMessage(Arrays.asList(first, second), "DUEL.start-failure.mode-unselected");
-            refundItems(items, first, second);
-            return;
+            kit = randomKit();
+
+            if (kit == null) {
+                lang.sendMessage(Arrays.asList(first, second), "DUEL.start-failure.mode-unselected");
+                refundItems(items, first, second);
+                return;
+            }
         }
 
         if (first.isDead() || second.isDead()) {
@@ -348,10 +363,33 @@ public class DuelManager implements Loadable {
 
         final int bet = settings.getBet();
 
-        if (bet > 0 && (diamondBank == null || !diamondBank.has(bet, first, second))) {
-            lang.sendMessage(Arrays.asList(first, second), "DUEL.start-failure.not-enough-money", "bet_amount", bet);
-            refundItems(items, first, second);
-            return;
+        if (bet > 0) {
+            if (diamondBank == null) {
+                lang.sendMessage(Arrays.asList(first, second), "DUEL.start-failure.not-enough-money", "bet_amount", bet);
+                refundItems(items, first, second);
+                return;
+            }
+
+            final boolean firstHas = diamondBank.has(bet, first);
+            final boolean secondHas = diamondBank.has(bet, second);
+
+            if (!firstHas || !secondHas) {
+                // Tell whoever is short that they can't afford it, and tell the solvent player which opponent fell short.
+                if (!firstHas) {
+                    lang.sendMessage(first, "DUEL.start-failure.not-enough-money", "bet_amount", bet);
+                } else {
+                    lang.sendMessage(first, "DUEL.start-failure.opponent-not-enough-money", "name", second.getName(), "bet_amount", bet);
+                }
+
+                if (!secondHas) {
+                    lang.sendMessage(second, "DUEL.start-failure.not-enough-money", "bet_amount", bet);
+                } else {
+                    lang.sendMessage(second, "DUEL.start-failure.opponent-not-enough-money", "name", first.getName(), "bet_amount", bet);
+                }
+
+                refundItems(items, first, second);
+                return;
+            }
         }
 
         final Map<UUID, PreDuelState> states = captureStates(first, second);
@@ -363,12 +401,6 @@ public class DuelManager implements Loadable {
             return;
         }
 
-        if (bet > 0 && !diamondBank.remove(bet, first, second)) {
-            lang.sendMessage(Arrays.asList(first, second), "DUEL.start-failure.not-enough-money", "bet_amount", bet);
-            refundItems(items, first, second);
-            return;
-        }
-
         final MatchImpl match = arena.startMatch(kit, items, settings.getBet(), source);
         addPlayers(match, arena, kit, arena.getPositions(), states, first, second);
 
@@ -389,6 +421,16 @@ public class DuelManager implements Loadable {
         }
     }
 
+    private KitImpl randomKit() {
+        final List<Kit> kits = kitManager.getKits();
+
+        if (kits.isEmpty()) {
+            return null;
+        }
+
+        return (KitImpl) kits.get(ThreadLocalRandom.current().nextInt(kits.size()));
+    }
+
     private boolean isBlacklistedWorld(final Player player) {
         return !config.isDuelingWorld(player);
     }

duels-plugin/src/main/java/me/realized/duels/gui/settings/buttons/RequestSendButton.java

@@ -33,12 +33,7 @@ public class RequestSendButton extends BaseButton {
             return;
         }
 
-        if (!settings.isOwnInventory() && settings.getKit() == null) {
-            player.closeInventory();
-            lang.sendMessage(player, "ERROR.duel.mode-unselected");
-            return;
-        }
-
+        // No kit / own-inventory selected is allowed: a random kit is chosen when the match starts.
         player.closeInventory();
         requestManager.send(player, target, settings);
     }

duels-plugin/src/main/java/me/realized/duels/listeners/KitItemPacketListener.java

@@ -0,0 +1,93 @@
+package me.realized.duels.listeners;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.ProtocolLibrary;
+import com.comphenix.protocol.ProtocolManager;
+import com.comphenix.protocol.events.ListenerPriority;
+import com.comphenix.protocol.events.PacketAdapter;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.events.PacketEvent;
+import com.comphenix.protocol.reflect.StructureModifier;
+import java.util.ArrayList;
+import java.util.List;
+import me.realized.duels.DuelsPlugin;
+import me.realized.duels.util.Log;
+import me.realized.duels.util.compat.Identifiers;
+import org.bukkit.Material;
+import org.bukkit.inventory.ItemStack;
+
+/**
+ * Strips the Duels kit-item NBT identifier from outgoing item packets so legacy
+ * clients (1.8-1.12 routed through ViaVersion/ViaBackwards) never receive the
+ * custom tag. Without this, the client/server NBT mismatch on the held slot makes
+ * the held item "bob", bows fail to stay drawn, and food fail to be consumed.
+ *
+ * The tag stays on the server-side {@link ItemStack}, so {@link KitItemListener}
+ * protection is unaffected: it reads items from the server inventory, not packets.
+ * Stripping for every client is safe because nothing client-side ever consumes the tag.
+ */
+public class KitItemPacketListener {
+
+    public KitItemPacketListener(final DuelsPlugin plugin) {
+        final ProtocolManager manager = ProtocolLibrary.getProtocolManager();
+
+        manager.addPacketListener(new PacketAdapter(plugin, ListenerPriority.NORMAL,
+            PacketType.Play.Server.SET_SLOT, PacketType.Play.Server.WINDOW_ITEMS) {
+
+            @Override
+            public void onPacketSending(final PacketEvent event) {
+                final PacketContainer packet = event.getPacket();
+
+                if (event.getPacketType() == PacketType.Play.Server.SET_SLOT) {
+                    final StructureModifier<ItemStack> items = packet.getItemModifier();
+                    final ItemStack sanitized = sanitize(items.read(0));
+
+                    if (sanitized != null) {
+                        items.write(0, sanitized);
+                    }
+
+                    return;
+                }
+
+                // WINDOW_ITEMS: the whole inventory contents as a list.
+                final StructureModifier<List<ItemStack>> modifier = packet.getItemListModifier();
+                final List<ItemStack> contents = modifier.read(0);
+
+                if (contents == null || contents.isEmpty()) {
+                    return;
+                }
+
+                boolean changed = false;
+                final List<ItemStack> copy = new ArrayList<>(contents.size());
+
+                for (final ItemStack item : contents) {
+                    final ItemStack sanitized = sanitize(item);
+
+                    if (sanitized != null) {
+                        copy.add(sanitized);
+                        changed = true;
+                    } else {
+                        copy.add(item);
+                    }
+                }
+
+                if (changed) {
+                    modifier.write(0, copy);
+                }
+            }
+        });
+
+        Log.info("Registered ProtocolLib listener to strip kit-item NBT for legacy client compatibility.");
+    }
+
+    /**
+     * @return a tag-free clone if the item carries the kit identifier, otherwise null (no change needed).
+     */
+    private ItemStack sanitize(final ItemStack item) {
+        if (item == null || item.getType() == Material.AIR || !item.hasItemMeta() || !Identifiers.hasIdentifier(item)) {
+            return null;
+        }
+
+        return Identifiers.removeIdentifier(item.clone());
+    }
+}

duels-plugin/src/main/java/me/realized/duels/setting/Settings.java

@@ -108,6 +108,12 @@ public class Settings {
 
     public void setOwnInventory(final boolean ownInventory) {
         this.ownInventory = ownInventory;
+
+        // Own inventory and a selected kit are mutually exclusive, so enabling
+        // own inventory must clear any remembered kit (otherwise the kit wins at match start).
+        if (ownInventory) {
+            this.kit = null;
+        }
     }
 
     // Don't copy the gui since it won't be required to start a match

duels-plugin/src/main/resources/lang.yml

@@ -243,7 +243,7 @@ COMMAND:
     create-queue: '{PREFIX} &7Created a queue with kit &d%kit% &7and a bet of &B%bet_amount% Diamond(s) &7.'
     delete-queue: '{PREFIX} &7Deleted a queue with kit &d%kit% &7and a bet of &B%bet_amount% Diamond(s) &7.'
     add-sign: '{PREFIX} &7Created queue sign at &3%location% &7with kit &d%kit% &7and bet &B%bet_amount% Diamond(s)&7.'
-    del-sign: '{PREFIX} &7Deleted queue sign at &3%location% &7with kit &d%kit% &7and bet &B%bet_amount Diamond(s)%&7.'
+    del-sign: '{PREFIX} &7Deleted queue sign at &3%location% &7with kit &d%kit% &7and bet &B%bet_amount% Diamond(s)&7.'
     set-lobby: '{PREFIX} &7Duel lobby set at your current location.'
     lobby: '{PREFIX} &7You have been teleported to lobby!'
     edit: '{PREFIX} &7Following action has been executed for &6%name%&7: &6%action% %amount% %type%'
@@ -294,7 +294,8 @@ DUEL:
     no-arena-available: '{FAIL_PREFIX} No arenas are currently available. Please try again later.'
     arena-in-use: '{FAIL_PREFIX} That arena is already in use. Please select a different arena.'
     arena-not-applicable: '{FAIL_PREFIX} You cannot use kit %kit% on this arena.'
-    not-enough-money: '{FAIL_PREFIX} &cYou or your opponent does not have &B%bet_amount% Diamond(s)&c.'
+    not-enough-money: '{FAIL_PREFIX} &cYou do not have &B%bet_amount% Diamond(s)&c.'
+    opponent-not-enough-money: '{FAIL_PREFIX} &c%name% does not have &B%bet_amount% Diamond(s)&c to cover that bet.'
   prevent:
     item-drop: '&cYou cannot drop items while in a duel.'
     command: '&cYou cannot use ''%command%'' while in a duel.'

duels-plugin/src/main/resources/plugin.yml

@@ -1,7 +1,7 @@
 name: Duels-OG
 main: me.realized.duels.DuelsPlugin
 version: @VERSION@
-softdepend: [BetterChairs-OG, CombatLogX, CombatTagPlus, DiamondBank-OG, Essentials, EternalCombat, Factions, GameModeInventories-OG, LeaderHeads, mcMMO, MVdWPlaceholderAPI, MyWorlds, PlaceholderAPI, PvPManager, SimpleClans, WorldGuard]
+softdepend: [BetterChairs-OG, CombatLogX, CombatTagPlus, DiamondBank-OG, Essentials, EternalCombat, Factions, GameModeInventories-OG, LeaderHeads, mcMMO, MVdWPlaceholderAPI, MyWorlds, PlaceholderAPI, ProtocolLib, PvPManager, SimpleClans, WorldGuard]
 # MyWorlds added as soft-depend due to locations being null when Duels is loaded before managed worlds.
 # Add any world management plugins to softdepend list if arena doesn't load properly in the generated world.
 api-version: 1.14

libs/ProtocolLib/License.txt

@@ -0,0 +1,339 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The licenses for most software are designed to take away your
+freedom to share and change it.  By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users.  This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it.  (Some other Free Software Foundation software is covered by
+the GNU Lesser General Public License instead.)  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+  To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have.  You must make sure that they, too, receive or can get the
+source code.  And you must show them these terms so they know their
+rights.
+
+  We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+  Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software.  If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
+that any problems introduced by others will not reflect on the original
+authors' reputations.
+
+  Finally, any free program is threatened constantly by software
+patents.  We wish to avoid the danger that redistributors of a free
+program will individually obtain patent licenses, in effect making the
+program proprietary.  To prevent this, we have made it clear that any
+patent must be licensed for everyone's free use or not licensed at all.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                    GNU GENERAL PUBLIC LICENSE
+   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+  0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
+under the terms of this General Public License.  The "Program", below,
+refers to any such program or work, and a "work based on the Program"
+means either the Program or any derivative work under copyright law:
+that is to say, a work containing the Program or a portion of it,
+either verbatim or with modifications and/or translated into another
+language.  (Hereinafter, translation is included without limitation in
+the term "modification".)  Each licensee is addressed as "you".
+
+Activities other than copying, distribution and modification are not
+covered by this License; they are outside its scope.  The act of
+running the Program is not restricted, and the output from the Program
+is covered only if its contents constitute a work based on the
+Program (independent of having been made by running the Program).
+Whether that is true depends on what the Program does.
+
+  1. You may copy and distribute verbatim copies of the Program's
+source code as you receive it, in any medium, provided that you
+conspicuously and appropriately publish on each copy an appropriate
+copyright notice and disclaimer of warranty; keep intact all the
+notices that refer to this License and to the absence of any warranty;
+and give any other recipients of the Program a copy of this License
+along with the Program.
+
+You may charge a fee for the physical act of transferring a copy, and
+you may at your option offer warranty protection in exchange for a fee.
+
+  2. You may modify your copy or copies of the Program or any portion
+of it, thus forming a work based on the Program, and copy and
+distribute such modifications or work under the terms of Section 1
+above, provided that you also meet all of these conditions:
+
+    a) You must cause the modified files to carry prominent notices
+    stating that you changed the files and the date of any change.
+
+    b) You must cause any work that you distribute or publish, that in
+    whole or in part contains or is derived from the Program or any
+    part thereof, to be licensed as a whole at no charge to all third
+    parties under the terms of this License.
+
+    c) If the modified program normally reads commands interactively
+    when run, you must cause it, when started running for such
+    interactive use in the most ordinary way, to print or display an
+    announcement including an appropriate copyright notice and a
+    notice that there is no warranty (or else, saying that you provide
+    a warranty) and that users may redistribute the program under
+    these conditions, and telling the user how to view a copy of this
+    License.  (Exception: if the Program itself is interactive but
+    does not normally print such an announcement, your work based on
+    the Program is not required to print an announcement.)
+
+These requirements apply to the modified work as a whole.  If
+identifiable sections of that work are not derived from the Program,
+and can be reasonably considered independent and separate works in
+themselves, then this License, and its terms, do not apply to those
+sections when you distribute them as separate works.  But when you
+distribute the same sections as part of a whole which is a work based
+on the Program, the distribution of the whole must be on the terms of
+this License, whose permissions for other licensees extend to the
+entire whole, and thus to each and every part regardless of who wrote it.
+
+Thus, it is not the intent of this section to claim rights or contest
+your rights to work written entirely by you; rather, the intent is to
+exercise the right to control the distribution of derivative or
+collective works based on the Program.
+
+In addition, mere aggregation of another work not based on the Program
+with the Program (or with a work based on the Program) on a volume of
+a storage or distribution medium does not bring the other work under
+the scope of this License.
+
+  3. You may copy and distribute the Program (or a work based on it,
+under Section 2) in object code or executable form under the terms of
+Sections 1 and 2 above provided that you also do one of the following:
+
+    a) Accompany it with the complete corresponding machine-readable
+    source code, which must be distributed under the terms of Sections
+    1 and 2 above on a medium customarily used for software interchange; or,
+
+    b) Accompany it with a written offer, valid for at least three
+    years, to give any third party, for a charge no more than your
+    cost of physically performing source distribution, a complete
+    machine-readable copy of the corresponding source code, to be
+    distributed under the terms of Sections 1 and 2 above on a medium
+    customarily used for software interchange; or,
+
+    c) Accompany it with the information you received as to the offer
+    to distribute corresponding source code.  (This alternative is
+    allowed only for noncommercial distribution and only if you
+    received the program in object code or executable form with such
+    an offer, in accord with Subsection b above.)
+
+The source code for a work means the preferred form of the work for
+making modifications to it.  For an executable work, complete source
+code means all the source code for all modules it contains, plus any
+associated interface definition files, plus the scripts used to
+control compilation and installation of the executable.  However, as a
+special exception, the source code distributed need not include
+anything that is normally distributed (in either source or binary
+form) with the major components (compiler, kernel, and so on) of the
+operating system on which the executable runs, unless that component
+itself accompanies the executable.
+
+If distribution of executable or object code is made by offering
+access to copy from a designated place, then offering equivalent
+access to copy the source code from the same place counts as
+distribution of the source code, even though third parties are not
+compelled to copy the source along with the object code.
+
+  4. You may not copy, modify, sublicense, or distribute the Program
+except as expressly provided under this License.  Any attempt
+otherwise to copy, modify, sublicense or distribute the Program is
+void, and will automatically terminate your rights under this License.
+However, parties who have received copies, or rights, from you under
+this License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+  5. You are not required to accept this License, since you have not
+signed it.  However, nothing else grants you permission to modify or
+distribute the Program or its derivative works.  These actions are
+prohibited by law if you do not accept this License.  Therefore, by
+modifying or distributing the Program (or any work based on the
+Program), you indicate your acceptance of this License to do so, and
+all its terms and conditions for copying, distributing or modifying
+the Program or works based on it.
+
+  6. Each time you redistribute the Program (or any work based on the
+Program), the recipient automatically receives a license from the
+original licensor to copy, distribute or modify the Program subject to
+these terms and conditions.  You may not impose any further
+restrictions on the recipients' exercise of the rights granted herein.
+You are not responsible for enforcing compliance by third parties to
+this License.
+
+  7. If, as a consequence of a court judgment or allegation of patent
+infringement or for any other reason (not limited to patent issues),
+conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot
+distribute so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you
+may not distribute the Program at all.  For example, if a patent
+license would not permit royalty-free redistribution of the Program by
+all those who receive copies directly or indirectly through you, then
+the only way you could satisfy both it and this License would be to
+refrain entirely from distribution of the Program.
+
+If any portion of this section is held invalid or unenforceable under
+any particular circumstance, the balance of the section is intended to
+apply and the section as a whole is intended to apply in other
+circumstances.
+
+It is not the purpose of this section to induce you to infringe any
+patents or other property right claims or to contest validity of any
+such claims; this section has the sole purpose of protecting the
+integrity of the free software distribution system, which is
+implemented by public license practices.  Many people have made
+generous contributions to the wide range of software distributed
+through that system in reliance on consistent application of that
+system; it is up to the author/donor to decide if he or she is willing
+to distribute software through any other system and a licensee cannot
+impose that choice.
+
+This section is intended to make thoroughly clear what is believed to
+be a consequence of the rest of this License.
+
+  8. If the distribution and/or use of the Program is restricted in
+certain countries either by patents or by copyrighted interfaces, the
+original copyright holder who places the Program under this License
+may add an explicit geographical distribution limitation excluding
+those countries, so that distribution is permitted only in or among
+countries not thus excluded.  In such case, this License incorporates
+the limitation as if written in the body of this License.
+
+  9. The Free Software Foundation may publish revised and/or new versions
+of the General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+Each version is given a distinguishing version number.  If the Program
+specifies a version number of this License which applies to it and "any
+later version", you have the option of following the terms and conditions
+either of that version or of any later version published by the Free
+Software Foundation.  If the Program does not specify a version number of
+this License, you may choose any version ever published by the Free Software
+Foundation.
+
+  10. If you wish to incorporate parts of the Program into other free
+programs whose distribution conditions are different, write to the author
+to ask for permission.  For software which is copyrighted by the Free
+Software Foundation, write to the Free Software Foundation; we sometimes
+make exceptions for this.  Our decision will be guided by the two goals
+of preserving the free status of all derivatives of our free software and
+of promoting the sharing and reuse of software generally.
+
+                            NO WARRANTY
+
+  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
+FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
+OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
+PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
+OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
+TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
+PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
+REPAIR OR CORRECTION.
+
+  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
+REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
+INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
+OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
+TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
+YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
+PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGES.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+Also add information on how to contact you by electronic and paper mail.
+
+If the program is interactive, make it output a short notice like this
+when it starts in an interactive mode:
+
+    Gnomovision version 69, Copyright (C) year name of author
+    Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, the commands you use may
+be called something other than `show w' and `show c'; they could even be
+mouse-clicks or menu items--whatever suits your program.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the program, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the program
+  `Gnomovision' (which makes passes at compilers) written by James Hacker.
+
+  <signature of Ty Coon>, 1 April 1989
+  Ty Coon, President of Vice
+
+This General Public License does not permit incorporating your program into
+proprietary programs.  If your program is a subroutine library, you may
+consider it more useful to permit linking proprietary applications with the
+library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.