From 387100e78f7cf7c7378d9c324f14718d28f6cb9c Mon Sep 17 00:00:00 2001
From: Christian Heller <c.heller@plomlompom.de>
Date: Sat, 27 Apr 2019 11:54:54 +0200
Subject: [PATCH] Use trivially re-seedable PRNG.

---
 new/example_server.py     |  2 +-
 new/plomrogue/commands.py |  7 ++++++-
 new/plomrogue/game.py     | 31 +++++++++++++++++++++++++------
 3 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/new/example_server.py b/new/example_server.py
index c078d88..87c368f 100755
--- a/new/example_server.py
+++ b/new/example_server.py
@@ -19,5 +19,5 @@ if os.path.exists(game_file_name):
             print("FILE INPUT LINE %5s: %s" % (i, line), end='')
             game.io.handle_input(line, store=False)
 else:
-    game.io.handle_input('GEN_WORLD Y:16,X:16 bar')
+    game.io.handle_input('GEN_WORLD Y:16,X:16 42')
 game.io.run_loop_with_server()
diff --git a/new/plomrogue/commands.py b/new/plomrogue/commands.py
index 1e0cad0..ef18bbb 100644
--- a/new/plomrogue/commands.py
+++ b/new/plomrogue/commands.py
@@ -4,12 +4,16 @@ from plomrogue.misc import quote, stringify_yx
 
 def cmd_GEN_WORLD(game, yx, seed):
     game.world.make_new(yx, seed)
-cmd_GEN_WORLD.argtypes = 'yx_tuple:pos string'
+cmd_GEN_WORLD.argtypes = 'yx_tuple:pos int:nonneg'
 
 def cmd_GET_GAMESTATE(game, connection_id):
     """Send game state to caller."""
     game.send_gamestate(connection_id)
 
+def cmd_SEED(game, seed):
+    game.world.rand.prngod_seed = seed
+cmd_SEED.argtypes = 'int:nonneg'
+
 def cmd_MAP(game, map_pos, size):
     """Create new map of size at position map_pos, and only '?' cells."""
     game.world.new_map(map_pos, size)
@@ -90,6 +94,7 @@ def cmd_SAVE(game):
     save_file_name = game.io.game_file_name + '.save'
     with open(save_file_name, 'w') as f:
         write(f, 'TURN %s' % game.world.turn)
+        write(f, 'SEED %s' % game.world.rand.prngod_seed)
         for map_pos in game.world.maps:
             write(f, 'MAP ' + stringify_yx(map_pos) + ' ' +
                   stringify_yx(game.world.maps[(0,0)].size))
diff --git a/new/plomrogue/game.py b/new/plomrogue/game.py
index f86383d..79a381b 100755
--- a/new/plomrogue/game.py
+++ b/new/plomrogue/game.py
@@ -4,7 +4,7 @@ from plomrogue.errors import ArgError, GameError
 from plomrogue.commands import (cmd_GEN_WORLD, cmd_GET_GAMESTATE,
                                 cmd_MAP, cmd_MAP, cmd_THING_TYPE,
                                 cmd_THING_POS, cmd_THING_INVENTORY,
-                                cmd_THING_HEALTH,
+                                cmd_THING_HEALTH, cmd_SEED,
                                 cmd_GET_PICKABLE_ITEMS,
                                 cmd_TERRAIN_LINE, cmd_PLAYER_ID,
                                 cmd_TURN, cmd_SWITCH_PLAYER, cmd_SAVE)
@@ -17,6 +17,23 @@ import random
 
 
 
+class PRNGod(random.Random):
+
+    def seed(self, seed):
+        self.prngod_seed = seed
+
+    def getstate(self):
+        return self.prngod_seed
+
+    def setstate(seed):
+        self.seed(seed)
+
+    def random(self):
+        self.prngod_seed = ((self.prngod_seed * 1103515245) + 12345) % 2**32
+        return (self.prngod_seed >> 16) / (2**16 - 1)
+
+
+
 class WorldBase:
 
     def __init__(self, game):
@@ -50,6 +67,7 @@ class World(WorldBase):
         self.player_id = 0
         self.player_is_alive = True
         self.maps = {}
+        self.rand = PRNGod(0)
 
     @property
     def player(self):
@@ -85,7 +103,7 @@ class World(WorldBase):
             for pos in self.maps[(0,0)]:
                 if self.maps[(0,0)][pos] == '.' and \
                    len(self.things_at_pos(((0,0), pos))) == 0 and \
-                   random.random() > 0.999:
+                   self.rand.random() > 0.999:
                     self.add_thing_at('food', ((0,0), pos))
             for thing in self.things[:player_i]:
                 thing.proceed()
@@ -104,8 +122,8 @@ class World(WorldBase):
         def add_thing_at_random(type_):
             while True:
                 new_pos = ((0,0),
-                           (random.randint(0, yx[0] -1),
-                            random.randint(0, yx[1] -1)))
+                           (self.rand.randint(0, yx[0] -1),
+                            self.rand.randint(0, yx[1] -1)))
                 if self.maps[new_pos[0]][new_pos[1]] != '.':
                     continue
                 if len(self.things_at_pos(new_pos)) > 0:
@@ -113,7 +131,7 @@ class World(WorldBase):
                 return self.add_thing_at(type_, new_pos)
 
         self.things = []
-        random.seed(seed)
+        self.rand.seed(seed)
         self.turn = 0
         self.maps = {}
         self.new_map((0,0), yx)
@@ -129,7 +147,7 @@ class World(WorldBase):
             map_ = self.maps[map_pos]
             if (0,0) == map_pos:
                 for pos in map_:
-                    map_[pos] = random.choice(('.', '.', '.', '.', 'x'))
+                    map_[pos] = self.rand.choice(('.', '.', '.', '.', 'x'))
             else:
                 for pos in map_:
                     map_[pos] = '~'
@@ -157,6 +175,7 @@ class Game:
                       'DROP': Task_DROP}
         self.commands = {'GEN_WORLD': cmd_GEN_WORLD,
                          'GET_GAMESTATE': cmd_GET_GAMESTATE,
+                         'SEED': cmd_SEED,
                          'MAP': cmd_MAP,
                          'THING_TYPE': cmd_THING_TYPE,
                          'THING_POS': cmd_THING_POS,
-- 
2.30.2