Added librarys and test application

include/entityx/3rdparty/simplesignal.h

@@ -0,0 +1,580 @@
+// CC0 Public Domain: http://creativecommons.org/publicdomain/zero/1.0/
+#ifndef SIMPLE_SIGNAL_H__
+#define SIMPLE_SIGNAL_H__
+
+#include <assert.h>
+#include <stdint.h>
+#include <vector>
+#include <functional>
+
+namespace Simple {
+
+namespace Lib {
+
+/// ProtoSignal is the template implementation for callback list.
+template <typename, typename>
+class ProtoSignal;  // undefined
+
+/// CollectorInvocation invokes signal handlers differently depending on return
+/// type.
+template <typename, typename>
+struct CollectorInvocation;
+
+/// CollectorLast returns the result of the last signal handler from a signal
+/// emission.
+template <typename Result>
+struct CollectorLast {
+  typedef Result CollectorResult;
+  explicit CollectorLast() : last_() {}
+  inline bool operator()(Result r) {
+    last_ = r;
+    return true;
+  }
+  CollectorResult result() { return last_; }
+
+ private:
+  Result last_;
+};
+
+/// CollectorDefault implements the default signal handler collection behaviour.
+template <typename Result>
+struct CollectorDefault : CollectorLast<Result> {};
+
+/// CollectorDefault specialisation for signals with void return type.
+template <>
+struct CollectorDefault<void> {
+  typedef void CollectorResult;
+  void result() {}
+  inline bool operator()(void) { return true; }
+};
+
+/// CollectorInvocation specialisation for regular signals.
+template <class Collector, class R, class... Args>
+struct CollectorInvocation<Collector, R(Args...)> {
+  inline bool invoke(Collector &collector, const std::function<R(Args...)> &cbf,
+                     Args... args) {
+    return collector(cbf(args...));
+  }
+};
+
+/// CollectorInvocation specialisation for signals with void return type.
+template <class Collector, class... Args>
+struct CollectorInvocation<Collector, void(Args...)> {
+  inline bool invoke(Collector &collector,
+                     const std::function<void(Args...)> &cbf, Args... args) {
+    cbf(args...);
+    return collector();
+  }
+};
+
+/// ProtoSignal template specialised for the callback signature and collector.
+template <class Collector, class R, class... Args>
+class ProtoSignal<R(Args...), Collector> : private CollectorInvocation<
+                                               Collector, R(Args...)> {
+ protected:
+  typedef std::function<R(Args...)> CbFunction;
+  typedef typename CbFunction::result_type Result;
+  typedef typename Collector::CollectorResult CollectorResult;
+
+ private:
+  /// SignalLink implements a doubly-linked ring with ref-counted nodes
+  /// containing the signal handlers.
+  struct SignalLink {
+    SignalLink *next, *prev;
+    CbFunction function;
+    int ref_count;
+    explicit SignalLink(const CbFunction &cbf)
+        : next(0), prev(0), function(cbf), ref_count(1) {}
+    /*dtor*/ ~SignalLink() { assert(ref_count == 0); }
+    void incref() {
+      ref_count += 1;
+      assert(ref_count > 0);
+    }
+    void decref() {
+      ref_count -= 1;
+      if (!ref_count)
+        delete this;
+      else
+        assert(ref_count > 0);
+    }
+    void unlink() {
+      function = nullptr;
+      if (next) next->prev = prev;
+      if (prev) prev->next = next;
+      decref();
+      // leave intact ->next, ->prev for stale iterators
+    }
+    size_t add_before(const CbFunction &cb) {
+      SignalLink *link = new SignalLink(cb);
+      link->prev = prev;  // link to last
+      link->next = this;
+      prev->next = link;  // link from last
+      prev = link;
+      static_assert(sizeof(link) == sizeof(size_t), "sizeof size_t");
+      return size_t(link);
+    }
+    bool deactivate(const CbFunction &cbf) {
+      if (cbf == function) {
+        function = 0;  // deactivate static head
+        return true;
+      }
+      for (SignalLink *link = this->next ? this->next : this; link != this;
+           link = link->next)
+        if (cbf == link->function) {
+          link->unlink();  // deactivate and unlink sibling
+          return true;
+        }
+      return false;
+    }
+    bool remove_sibling(size_t id) {
+      for (SignalLink *link = this->next ? this->next : this; link != this;
+           link = link->next)
+        if (id == size_t(link)) {
+          link->unlink();  // deactivate and unlink sibling
+          return true;
+        }
+      return false;
+    }
+  };
+  SignalLink *callback_ring_;  // linked ring of callback nodes
+  /*copy-ctor*/ ProtoSignal(const ProtoSignal &) = delete;
+  ProtoSignal &operator=(const ProtoSignal &) = delete;
+  void ensure_ring() {
+    if (!callback_ring_) {
+      callback_ring_ = new SignalLink(CbFunction());  // ref_count = 1
+      callback_ring_->incref();  // ref_count = 2, head of ring, can be
+                                 // deactivated but not removed
+      callback_ring_->next = callback_ring_;  // ring head initialization
+      callback_ring_->prev = callback_ring_;  // ring tail initialization
+    }
+  }
+
+ public:
+  /// ProtoSignal constructor, connects default callback if non-0.
+  ProtoSignal(const CbFunction &method) : callback_ring_(0) {
+    if (method != 0) {
+      ensure_ring();
+      callback_ring_->function = method;
+    }
+  }
+  /// ProtoSignal destructor releases all resources associated with this signal.
+  ~ProtoSignal() {
+    if (callback_ring_) {
+      while (callback_ring_->next != callback_ring_)
+        callback_ring_->next->unlink();
+      assert(callback_ring_->ref_count >= 2);
+      callback_ring_->decref();
+      callback_ring_->decref();
+    }
+  }
+  /// Operator to add a new function or lambda as signal handler, returns a
+  /// handler connection ID.
+  size_t connect(const CbFunction &cb) {
+    ensure_ring();
+    return callback_ring_->add_before(cb);
+  }
+  /// Operator to remove a signal handler through it connection ID, returns if a
+  /// handler was removed.
+  bool disconnect(size_t connection) {
+    return callback_ring_ ? callback_ring_->remove_sibling(connection) : false;
+  }
+  /// Emit a signal, i.e. invoke all its callbacks and collect return types with
+  /// the Collector.
+  CollectorResult emit(Args... args) {
+    Collector collector;
+    if (!callback_ring_) return collector.result();
+    SignalLink *link = callback_ring_;
+    link->incref();
+    do {
+      if (link->function != 0) {
+        const bool continue_emission =
+            this->invoke(collector, link->function, args...);
+        if (!continue_emission) break;
+      }
+      SignalLink *old = link;
+      link = old->next;
+      link->incref();
+      old->decref();
+    } while (link != callback_ring_);
+    link->decref();
+    return collector.result();
+  }
+  // Number of connected slots.
+  std::size_t size() {
+    std::size_t size = 0;
+    SignalLink *link = callback_ring_;
+    link->incref();
+    do {
+      if (link->function != 0) {
+        size++;
+      }
+      SignalLink *old = link;
+      link = old->next;
+      link->incref();
+      old->decref();
+    } while (link != callback_ring_);
+    return size;
+  }
+};
+
+}  // Lib
+   // namespace Simple
+
+/**
+ * Signal is a template type providing an interface for arbitrary callback
+ * lists.
+ * A signal type needs to be declared with the function signature of its
+ * callbacks,
+ * and optionally a return result collector class type.
+ * Signal callbacks can be added with operator+= to a signal and removed with
+ * operator-=, using
+ * a callback connection ID return by operator+= as argument.
+ * The callbacks of a signal are invoked with the emit() method and arguments
+ * according to the signature.
+ * The result returned by emit() depends on the signal collector class. By
+ * default, the result of
+ * the last callback is returned from emit(). Collectors can be implemented to
+ * accumulate callback
+ * results or to halt a running emissions in correspondance to callback results.
+ * The signal implementation is safe against recursion, so callbacks may be
+ * removed and
+ * added during a signal emission and recursive emit() calls are also safe.
+ * The overhead of an unused signal is intentionally kept very low, around the
+ * size of a single pointer.
+ * Note that the Signal template types is non-copyable.
+ */
+template <typename SignalSignature,
+          class Collector = Lib::CollectorDefault<
+              typename std::function<SignalSignature>::result_type>>
+struct Signal /*final*/ : Lib::ProtoSignal<SignalSignature, Collector> {
+  typedef Lib::ProtoSignal<SignalSignature, Collector> ProtoSignal;
+  typedef typename ProtoSignal::CbFunction CbFunction;
+  /// Signal constructor, supports a default callback as argument.
+  Signal(const CbFunction &method = CbFunction()) : ProtoSignal(method) {}
+};
+
+/// This function creates a std::function by binding @a object to the member
+/// function pointer @a method.
+template <class Instance, class Class, class R, class... Args>
+std::function<R(Args...)> slot(Instance &object, R (Class::*method)(Args...)) {
+  return [&object, method](Args... args) { return (object.*method)(args...); };
+}
+
+/// This function creates a std::function by binding @a object to the member
+/// function pointer @a method.
+template <class Class, class R, class... Args>
+std::function<R(Args...)> slot(Class *object, R (Class::*method)(Args...)) {
+  return [object, method](Args... args) { return (object->*method)(args...); };
+}
+
+/// Keep signal emissions going while all handlers return !0 (true).
+template <typename Result>
+struct CollectorUntil0 {
+  typedef Result CollectorResult;
+  explicit CollectorUntil0() : result_() {}
+  const CollectorResult &result() { return result_; }
+  inline bool operator()(Result r) {
+    result_ = r;
+    return result_ ? true : false;
+  }
+
+ private:
+  CollectorResult result_;
+};
+
+/// Keep signal emissions going while all handlers return 0 (false).
+template <typename Result>
+struct CollectorWhile0 {
+  typedef Result CollectorResult;
+  explicit CollectorWhile0() : result_() {}
+  const CollectorResult &result() { return result_; }
+  inline bool operator()(Result r) {
+    result_ = r;
+    return result_ ? false : true;
+  }
+
+ private:
+  CollectorResult result_;
+};
+
+/// CollectorVector returns the result of the all signal handlers from a signal
+/// emission in a std::vector.
+template <typename Result>
+struct CollectorVector {
+  typedef std::vector<Result> CollectorResult;
+  const CollectorResult &result() { return result_; }
+  inline bool operator()(Result r) {
+    result_.push_back(r);
+    return true;
+  }
+
+ private:
+  CollectorResult result_;
+};
+
+}  // Simple
+
+#endif  // SIMPLE_SIGNAL_H__
+
+#ifdef ENABLE_SIMPLE_SIGNAL_TESTS
+
+#include <string>
+#include <stdarg.h>
+#include <time.h>
+#include <sys/time.h>
+
+#ifdef __MACH__
+#include <mach/clock.h>
+#include <mach/mach.h>
+#endif
+
+static std::string string_printf(const char *format, ...)
+    __attribute__((__format__(__printf__, 1, 2)));
+static std::string string_printf(const char *format, ...) {
+  std::string result;
+  char *str = 0;
+  va_list args;
+  va_start(args, format);
+  if (vasprintf(&str, format, args) >= 0) result = str;
+  va_end(args);
+  if (str) free(str);
+  return result;
+}
+
+static uint64_t timestamp_benchmark() {
+  struct timespec tp = {0, 0};
+
+#ifdef __MACH__  // OS X does not have clock_gettime, use clock_get_time
+  clock_serv_t cclock;
+  mach_timespec_t mts;
+  host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
+  clock_get_time(cclock, &mts);
+  mach_port_deallocate(mach_task_self(), cclock);
+  tp.tv_sec = mts.tv_sec;
+  tp.tv_nsec = mts.tv_nsec;
+#else
+  clock_gettime(CLOCK_REALTIME, &tp);
+#endif
+  uint64_t stamp = tp.tv_sec * 1000000000ULL + tp.tv_nsec;
+  return stamp;
+}
+
+struct TestCounter {
+  static uint64_t get();
+  static void set(uint64_t);
+  static void add2(void *, uint64_t);
+};
+
+namespace {  // Anon
+void (*test_counter_add2)(void *, uint64_t) =
+    TestCounter::add2;  // external symbol to prevent easy inlining
+static uint64_t test_counter_var = 0;
+}  // Anon
+
+class BasicSignalTests {
+  static std::string accu;
+  struct Foo {
+    char foo_bool(float f, int i, std::string s) {
+      accu += string_printf("Foo: %.2f\n", f + i + s.size());
+      return true;
+    }
+  };
+  static char float_callback(float f, int, std::string) {
+    accu += string_printf("float: %.2f\n", f);
+    return 0;
+  }
+
+ public:
+  static void run() {
+    accu = "";
+    Simple::Signal<char(float, int, std::string)> sig1;
+    size_t id1 = sig1.connect(float_callback);
+    size_t id2 = sig1.connect([](float, int i, std::string) {
+      accu += string_printf("int: %d\n", i);
+      return 0;
+    });
+    size_t id3 = sig1.connect([](float, int, const std::string &s) {
+      accu += string_printf("string: %s\n", s.c_str());
+      return 0;
+    });
+    sig1.emit(.3, 4, "huhu");
+    bool success;
+    success = sig1.disconnect(id1);
+    assert(success == true);
+    success = sig1.disconnect(id1);
+    assert(success == false);
+    success = sig1.disconnect(id2);
+    assert(success == true);
+    success = sig1.disconnect(id3);
+    assert(success == true);
+    success = sig1.disconnect(id3);
+    assert(success == false);
+    success = sig1.disconnect(id2);
+    assert(success == false);
+    Foo foo;
+    sig1.connect(Simple::slot(foo, &Foo::foo_bool));
+    sig1.connect(Simple::slot(&foo, &Foo::foo_bool));
+    sig1.emit(.5, 1, "12");
+
+    Simple::Signal<void(std::string, int)> sig2;
+    sig2.connect([](std::string msg,
+                    int) { accu += string_printf("msg: %s", msg.c_str()); });
+    sig2.connect([](std::string,
+                    int d) { accu += string_printf(" *%d*\n", d); });
+    sig2.emit("in sig2", 17);
+
+    accu += "DONE";
+
+    const char *expected =
+        "float: 0.30\n"
+        "int: 4\n"
+        "string: huhu\n"
+        "Foo: 3.50\n"
+        "Foo: 3.50\n"
+        "msg: in sig2 *17*\n"
+        "DONE";
+    assert(accu == expected);
+  }
+};
+std::string BasicSignalTests::accu;
+
+class TestCollectorVector {
+  static int handler1() { return 1; }
+  static int handler42() { return 42; }
+  static int handler777() { return 777; }
+
+ public:
+  static void run() {
+    Simple::Signal<int(), Simple::CollectorVector<int>> sig_vector;
+    sig_vector.connect(handler777);
+    sig_vector.connect(handler42);
+    sig_vector.connect(handler1);
+    sig_vector.connect(handler42);
+    sig_vector.connect(handler777);
+    std::vector<int> results = sig_vector.emit();
+    const std::vector<int> reference = {777, 42, 1, 42, 777, };
+    assert(results == reference);
+  }
+};
+
+class TestCollectorUntil0 {
+  bool check1, check2;
+  TestCollectorUntil0() : check1(0), check2(0) {}
+  bool handler_true() {
+    check1 = true;
+    return true;
+  }
+  bool handler_false() {
+    check2 = true;
+    return false;
+  }
+  bool handler_abort() { abort(); }
+
+ public:
+  static void run() {
+    TestCollectorUntil0 self;
+    Simple::Signal<bool(), Simple::CollectorUntil0<bool>> sig_until0;
+    sig_until0.connect(Simple::slot(self, &TestCollectorUntil0::handler_true));
+    sig_until0.connect(Simple::slot(self, &TestCollectorUntil0::handler_false));
+    sig_until0.connect(Simple::slot(self, &TestCollectorUntil0::handler_abort));
+    assert(!self.check1 && !self.check2);
+    const bool result = sig_until0.emit();
+    assert(!result && self.check1 && self.check2);
+  }
+};
+
+class TestCollectorWhile0 {
+  bool check1, check2;
+  TestCollectorWhile0() : check1(0), check2(0) {}
+  bool handler_0() {
+    check1 = true;
+    return false;
+  }
+  bool handler_1() {
+    check2 = true;
+    return true;
+  }
+  bool handler_abort() { abort(); }
+
+ public:
+  static void run() {
+    TestCollectorWhile0 self;
+    Simple::Signal<bool(), Simple::CollectorWhile0<bool>> sig_while0;
+    sig_while0.connect(Simple::slot(self, &TestCollectorWhile0::handler_0));
+    sig_while0.connect(Simple::slot(self, &TestCollectorWhile0::handler_1));
+    sig_while0.connect(Simple::slot(self, &TestCollectorWhile0::handler_abort));
+    assert(!self.check1 && !self.check2);
+    const bool result = sig_while0.emit();
+    assert(result == true && self.check1 && self.check2);
+  }
+};
+
+static void bench_simple_signal() {
+  Simple::Signal<void(void *, uint64_t)> sig_increment;
+  sig_increment.connect(test_counter_add2);
+  const uint64_t start_counter = TestCounter::get();
+  const uint64_t benchstart = timestamp_benchmark();
+  uint64_t i;
+  for (i = 0; i < 999999; i++) {
+    sig_increment.emit(0, 1);
+  }
+  const uint64_t benchdone = timestamp_benchmark();
+  const uint64_t end_counter = TestCounter::get();
+  assert(end_counter - start_counter == i);
+  printf("OK\n  Benchmark: Simple::Signal: %fns per emission (size=%zu): ",
+         size_t(benchdone - benchstart) * 1.0 / size_t(i),
+         sizeof(sig_increment));
+}
+
+static void bench_callback_loop() {
+  void (*counter_increment)(void *, uint64_t) = test_counter_add2;
+  const uint64_t start_counter = TestCounter::get();
+  const uint64_t benchstart = timestamp_benchmark();
+  uint64_t i;
+  for (i = 0; i < 999999; i++) {
+    counter_increment(0, 1);
+  }
+  const uint64_t benchdone = timestamp_benchmark();
+  const uint64_t end_counter = TestCounter::get();
+  assert(end_counter - start_counter == i);
+  printf("OK\n  Benchmark: callback loop: %fns per round: ",
+         size_t(benchdone - benchstart) * 1.0 / size_t(i));
+}
+
+uint64_t TestCounter::get() { return test_counter_var; }
+
+void TestCounter::set(uint64_t v) { test_counter_var = v; }
+
+void TestCounter::add2(void *, uint64_t v) { test_counter_var += v; }
+
+int main(int argc, char *argv[]) {
+  printf("Signal/Basic Tests: ");
+  BasicSignalTests::run();
+  printf("OK\n");
+
+  printf("Signal/CollectorVector: ");
+  TestCollectorVector::run();
+  printf("OK\n");
+
+  printf("Signal/CollectorUntil0: ");
+  TestCollectorUntil0::run();
+  printf("OK\n");
+
+  printf("Signal/CollectorWhile0: ");
+  TestCollectorWhile0::run();
+  printf("OK\n");
+
+  printf("Signal/Benchmark: Simple::Signal: ");
+  bench_simple_signal();
+  printf("OK\n");
+
+  printf("Signal/Benchmark: callback loop: ");
+  bench_callback_loop();
+  printf("OK\n");
+
+  return 0;
+}
+
+#endif  // DISABLE_TESTS
+
+// g++ -Wall -O2 -std=gnu++0x -pthread simplesignal.cc -lrt && ./a.out