# HG changeset patch
# User Brian Neal <bgneal@gmail.com>
# Date 1340159528 18000
# Node ID f3af458a5d2d841c3a9e09d1d239d559a1649e6a
# Parent  160e1bd599653363ea17766c1bc4ba8f264972cb
Add methods to Plugboard to support hill-climbing.

diff -r 160e1bd59965 -r f3af458a5d2d enigma/plugboard.py
--- a/enigma/plugboard.py	Tue Jun 19 19:02:37 2012 -0500
+++ b/enigma/plugboard.py	Tue Jun 19 21:32:08 2012 -0500
@@ -8,6 +8,7 @@
 """
 
 import collections
+import copy
 from itertools import chain
 import string
 
@@ -55,6 +56,11 @@
         # construct wiring mapping table with default 1-1 mappings
         self.wiring_map = list(range(26))
 
+        # construct backup storage for the wiring map; this is useful when
+        # hill-climbing and is used when the Plugboard is used as a context
+        # manager
+        self._backup_map = list(range(26))
+
         # use settings if provided
         if not wiring_pairs:
             return
@@ -173,3 +179,62 @@
 
         """
         return self.wiring_map[n]
+
+    # Support for hill-climbing algorithms:
+
+    def get_wiring(self):
+        """Returns a deep copy of the internal wiring map."""
+        return copy.deepcopy(self.wiring_map)
+
+    def is_wired(self, n):
+        """Returns True if connection n has a cable attached; 0 <= n < 26."""
+        return self.wiring_map[n] != n
+
+    def is_free(self, n):
+        """Returns True if connection n has no cable attached; 0 <= n < 26."""
+        return self.wiring_map[n] == n
+
+    def __enter__(self):
+        """Saves the current state of the wiring map."""
+        for n in range(26):
+            self._backup_map[n] = self.wiring_map[n]
+        return self
+
+    def __exit__(self, *exc_info):
+        """Restores the saved state of the wiring map."""
+        for n in range(26):
+            self.wiring_map[n] = self._backup_map[n]
+
+    def connection(self, n):
+        """Returns plug number [0-25] for what is connected to plug n [0-25]."""
+        return self.wiring_map[n]
+
+    def disconnect(self, n):
+        """Removes cable from plug number n [0-25]."""
+        x = self.wiring_map[n]
+        self.wiring_map[x] = x
+        self.wiring_map[n] = n
+
+    def connect(self, x, y):
+        """Connects plug x to plug y, removing any existing connections first.
+        
+        x and y must be in [0-25].
+
+        """
+        # disconnect any existing connections
+        m = self.wiring_map[x]
+        n = self.wiring_map[y]
+        self.wiring_map[m] = m
+        self.wiring_map[n] = n
+
+        self.wiring_map[x] = y
+        self.wiring_map[y] = x
+
+    def is_connected(self, x, y):
+        """Returns True if x is connected to y.
+
+        x and y must be in [0-25].
+
+        """
+        return self.wiring_map[x] == y and self.wiring_map[y] == x
+