Mercurial > public > cpp-enigma

changeset 13:b9d124a15926

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
To improve cache performance, the enigma machine rotors are now stored together with the reflector in a vector.
author Brian Neal <bgneal@gmail.com>
date Mon, 02 Jul 2012 19:14:36 -0500
parents 424111a36ed7
children 919b7a0d1802
files enigma/machine.cpp enigma/machine.h enigma/tests/test_plugboard.t.h
diffstat 3 files changed, 71 insertions(+), 48 deletions(-) [+]
line wrap: on
line diff
--- a/enigma/machine.cpp	Sun Jul 01 12:53:10 2012 -0500
+++ b/enigma/machine.cpp	Mon Jul 02 19:14:36 2012 -0500
@@ -18,10 +18,14 @@
       const rotor_vector& rv,
       std::shared_ptr<rotor> reflector,
       const plugboard& pb)
- : rotors(rv),
-   reflector(reflector),
+ : rotors(),
    pb(pb)
 {
+   rotors.push_back(*reflector);
+   for (const auto& r : rv)
+   {
+      rotors.push_back(*r);
+   }
    rotor_count_check();
 }
 
@@ -30,10 +34,14 @@
 enigma_machine::enigma_machine(
       const rotor_vector& rv,
       std::shared_ptr<rotor> reflector)
- : rotors(rv),
-   reflector(reflector),
+ : rotors(),
    pb()
 {
+   rotors.push_back(*reflector);
+   for (const auto& r : rv)
+   {
+      rotors.push_back(*r);
+   }
    rotor_count_check();
 }
 
@@ -45,26 +53,28 @@
       const std::string& reflector_name,
       const std::string& plugboard_settings)
  : rotors(),
-   reflector(create_reflector(reflector_name.c_str())),
    pb(plugboard_settings)
 {
+   const auto ukw(create_reflector(reflector_name.c_str()));
+   rotors.push_back(*ukw);
    for (const auto& name : rotor_types)
    {
-      rotors.push_back(create_rotor(name.c_str()));
+      const auto r(create_rotor(name.c_str()));
+      rotors.push_back(*r);
    }
    rotor_count_check();
 
    // if ring settings are supplied, there has to be one for each rotor
    if (!ring_settings.empty())
    {
-      if (rotors.size() != ring_settings.size())
+      if (rotors.size() - 1 != ring_settings.size())
       {
          throw enigma_machine_error("rotor/ring setting count mismatch");
       }
 
-      for (std::size_t i = 0; i < rotors.size(); ++i)
+      for (std::size_t i = 1; i < rotors.size(); ++i)
       {
-         rotors[i]->set_ring_setting(ring_settings[i]);
+         rotors[i].set_ring_setting(ring_settings[i - 1]);
       }
    }
 }
@@ -73,22 +83,24 @@
 
 void enigma_machine::rotor_count_check()
 {
-   if (rotors.size() != 3 && rotors.size() != 4)
+   // the first rotor is actually the reflector; so we should have a total
+   // of 4 or 5 rotors
+   if (rotors.size() != 4 && rotors.size() != 5)
    {
       throw enigma_machine_error("rotor count");
    }
 
-   if (rotors.size() == 3)
+   if (rotors.size() == 4)
    {
-      r_rotor = rotors[2].get();
-      m_rotor = rotors[1].get();
-      l_rotor = rotors[0].get();
+      r_rotor = &rotors[3];
+      m_rotor = &rotors[2];
+      l_rotor = &rotors[1];
    }
    else
    {
-      r_rotor = rotors[3].get();
-      m_rotor = rotors[2].get();
-      l_rotor = rotors[1].get();
+      r_rotor = &rotors[4];
+      m_rotor = &rotors[3];
+      l_rotor = &rotors[2];
    }
 }
 
@@ -98,11 +110,11 @@
 {
    std::ostringstream os;
 
-   os << reflector->name() << ' ';
+   os << rotors[0].name() << ' ';
 
-   for (const auto& r : rotors)
+   for (std::size_t i = 1; i < rotors.size(); ++i)
    {
-      os << r->name() << '/' << r->get_ring_setting() << ' ';
+      os << rotors[i].name() << '/' << rotors[i].get_ring_setting() << ' ';
    }
 
    os << get_display() << ' ' << (army ? pb.army_str() : pb.navy_str());
--- a/enigma/machine.h	Sun Jul 01 12:53:10 2012 -0500
+++ b/enigma/machine.h	Mon Jul 02 19:14:36 2012 -0500
@@ -47,22 +47,22 @@
       // set the rotor display (starting position) - 3 rotor version
       void set_display(char left, char mid, char right)
       {
-         assert(rotors.size() == 3);
+         assert(rotors.size() == 4);
 
-         rotors[0]->set_display(left);
-         rotors[1]->set_display(mid);
-         rotors[2]->set_display(right);
+         rotors[1].set_display(left);
+         rotors[2].set_display(mid);
+         rotors[3].set_display(right);
       }
 
       // set the rotor display (starting position) - 4 rotor version
       void set_display(char c0, char c1, char c2, char c3)
       {
-         assert(rotors.size() == 4);
+         assert(rotors.size() == 5);
 
-         rotors[0]->set_display(c0);
-         rotors[1]->set_display(c1);
-         rotors[2]->set_display(c2);
-         rotors[3]->set_display(c3);
+         rotors[1].set_display(c0);
+         rotors[2].set_display(c1);
+         rotors[3].set_display(c2);
+         rotors[4].set_display(c3);
       }
 
       // Set the rotor display (starting position) using a string; the
@@ -70,11 +70,11 @@
       // enigma_machine_error exception will be thrown:
       void set_display(const std::string& val)
       {
-         if (val.size() == 3 && rotors.size() == 3)
+         if (val.size() == 3 && rotors.size() == 4)
          {
             set_display(val[0], val[1], val[2]);
          }
-         else if (val.size() == 4 && rotors.size() == 4)
+         else if (val.size() == 4 && rotors.size() == 5)
          {
             set_display(val[0], val[1], val[2], val[3]);
          }
@@ -88,9 +88,9 @@
       std::string get_display() const
       {
          std::string result;
-         for (const auto& r : rotors)
+         for (std::size_t i = 1; i < rotors.size(); ++i)
          {
-            result += r->get_display();
+            result += rotors[i].get_display();
          }
          return result;
       }
@@ -143,8 +143,9 @@
       std::string navy_str() const { return str(false); }
 
    private:
-      rotor_vector rotors;
-      std::shared_ptr<rotor> reflector;
+      // Note that to improve cache performance, the rotors and reflectors are stored
+      // in a contiguous vector.
+      std::vector<rotor> rotors;    // rotor & reflector array
       plugboard pb;
       rotor* r_rotor;      // rightmost rotor
       rotor* m_rotor;      // 2nd to right rotor
@@ -188,21 +189,31 @@
       // Returns a lamp number to light (an integer 0-25).
       int electric_signal(int signal_num)
       {
-         int pos = pb.signal(signal_num);
+         int n = pb.signal(signal_num);
 
-         for (auto r = rotors.rbegin(); r != rotors.rend(); ++r)
+         if (rotors.size() == 4)    // 3 rotors + reflector
          {
-            pos = (*r)->signal_in(pos);
+            n = rotors[3].signal_in(n);
+            n = rotors[2].signal_in(n);
+            n = rotors[1].signal_in(n);
+            n = rotors[0].signal_in(n);   // reflector
+            n = rotors[1].signal_out(n);
+            n = rotors[2].signal_out(n);
+            n = rotors[3].signal_out(n);
          }
-
-         pos = reflector->signal_in(pos);
-
-         for (const auto& r : rotors)
+         else  // Kriegsmarine 4 rotor + reflector
          {
-            pos = r->signal_out(pos);
+            n = rotors[4].signal_in(n);
+            n = rotors[3].signal_in(n);
+            n = rotors[2].signal_in(n);
+            n = rotors[1].signal_in(n);
+            n = rotors[0].signal_in(n);   // reflector
+            n = rotors[1].signal_out(n);
+            n = rotors[2].signal_out(n);
+            n = rotors[3].signal_out(n);
+            n = rotors[4].signal_out(n);
          }
-
-         return pb.signal(pos);
+         return pb.signal(n);
       }
 
       std::string str(bool army) const;
--- a/enigma/tests/test_plugboard.t.h	Sun Jul 01 12:53:10 2012 -0500
+++ b/enigma/tests/test_plugboard.t.h	Mon Jul 02 19:14:36 2012 -0500
@@ -143,7 +143,7 @@
    void test_get_wiring()
    {
       plugboard pb;
-      alpha_int_array w(pb.get_wiring());
+      auto w(pb.get_wiring());
 
       for (int i = 0; i < 26; ++i)
       {
@@ -161,7 +161,7 @@
       std::swap(w[8], w[20]);
       std::swap(w[24], w[25]);
 
-      alpha_int_array w1(pb.get_wiring());
+      auto w1(pb.get_wiring());
       for (int i = 0; i < 26; ++i)
       {
          TS_ASSERT_EQUALS(w[i], w1[i]);
@@ -182,7 +182,7 @@
       plugboard pb;
       pb.set_wiring(w);
 
-      alpha_int_array w2 = pb.get_wiring();
+      auto w2 = pb.get_wiring();
       TS_ASSERT_EQUALS(w, w2);
    }