Added librarys and test application

include/entityx/help/NonCopyable.h

@@ -0,0 +1,20 @@
+//  Inspired heavily by boost::noncopyable
+
+#pragma once
+
+namespace entityx {
+namespace help {
+
+class NonCopyable {
+protected:
+  NonCopyable() = default;
+  ~NonCopyable() = default;
+
+
+  NonCopyable(const NonCopyable&) = delete;
+  NonCopyable& operator = (const NonCopyable &) = delete;
+};
+
+
+}  // namespace help
+}  // namespace entityx

include/entityx/help/Pool.cc

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2012-2014 Alec Thomas <alec@swapoff.org>
+ * All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.
+ *
+ * Author: Alec Thomas <alec@swapoff.org>
+ */
+
+#include "entityx/help/Pool.h"
+
+namespace entityx {
+
+BasePool::~BasePool() {
+  for (char *ptr : blocks_) {
+    delete[] ptr;
+  }
+}
+
+}  // namespace entityx

include/entityx/help/Pool.h

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2012-2014 Alec Thomas <alec@swapoff.org>
+ * All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.
+ *
+ * Author: Alec Thomas <alec@swapoff.org>
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <cassert>
+#include <vector>
+
+namespace entityx {
+
+/**
+ * Provides a resizable, semi-contiguous pool of memory for constructing
+ * objects in. Pointers into the pool will be invalided only when the pool is
+ * destroyed.
+ *
+ * The semi-contiguous nature aims to provide cache-friendly iteration.
+ *
+ * Lookups are O(1).
+ * Appends are amortized O(1).
+ */
+class BasePool {
+ public:
+  explicit BasePool(std::size_t element_size, std::size_t chunk_size = 8192)
+      : element_size_(element_size), chunk_size_(chunk_size), capacity_(0) {}
+  virtual ~BasePool();
+
+  std::size_t size() const { return size_; }
+  std::size_t capacity() const { return capacity_; }
+  std::size_t chunks() const { return blocks_.size(); }
+
+  /// Ensure at least n elements will fit in the pool.
+  inline void expand(std::size_t n) {
+    if (n >= size_) {
+      if (n >= capacity_) reserve(n);
+      size_ = n;
+    }
+  }
+
+  inline void reserve(std::size_t n) {
+    while (capacity_ < n) {
+      char *chunk = new char[element_size_ * chunk_size_];
+      blocks_.push_back(chunk);
+      capacity_ += chunk_size_;
+    }
+  }
+
+  inline void *get(std::size_t n) {
+    assert(n < size_);
+    return blocks_[n / chunk_size_] + (n % chunk_size_) * element_size_;
+  }
+
+  inline const void *get(std::size_t n) const {
+    assert(n < size_);
+    return blocks_[n / chunk_size_] + (n % chunk_size_) * element_size_;
+  }
+
+  virtual void destroy(std::size_t n) = 0;
+
+ protected:
+  std::vector<char *> blocks_;
+  std::size_t element_size_;
+  std::size_t chunk_size_;
+  std::size_t size_ = 0;
+  std::size_t capacity_;
+};
+
+
+/**
+ * Implementation of BasePool that provides type-"safe" deconstruction of
+ * elements in the pool.
+ */
+template <typename T, std::size_t ChunkSize = 8192>
+class Pool : public BasePool {
+ public:
+  Pool() : BasePool(sizeof(T), ChunkSize) {}
+  virtual ~Pool() {
+    // Component destructors *must* be called by owner.
+  }
+
+  virtual void destroy(std::size_t n) override {
+    assert(n < size_);
+    T *ptr = static_cast<T*>(get(n));
+    ptr->~T();
+  }
+};
+
+}  // namespace entityx

include/entityx/help/Pool_test.cc

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2012-2014 Alec Thomas <alec@swapoff.org>
+ * All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.
+ *
+ * Author: Alec Thomas <alec@swapoff.org>
+ */
+
+#define CATCH_CONFIG_MAIN
+
+#include <vector>
+#include "entityx/3rdparty/catch.hpp"
+#include "entityx/help/Pool.h"
+
+struct Position {
+  explicit Position(int *ptr = nullptr) : ptr(ptr) {
+    if (ptr) (*ptr)++;
+  }
+  ~Position() {
+    if (ptr) (*ptr)++;
+  }
+
+  float x, y;
+  int *ptr;
+};
+
+
+TEST_CASE("TestPoolReserve") {
+  entityx::Pool<Position, 8> pool;
+  REQUIRE(0 ==  pool.capacity());
+  REQUIRE(0 ==  pool.chunks());
+  pool.reserve(8);
+  REQUIRE(0 ==  pool.size());
+  REQUIRE(8 ==  pool.capacity());
+  REQUIRE(1 ==  pool.chunks());
+  pool.reserve(16);
+  REQUIRE(0 ==  pool.size());
+  REQUIRE(16 ==  pool.capacity());
+  REQUIRE(2 ==  pool.chunks());
+}
+
+TEST_CASE("TestPoolPointers") {
+  entityx::Pool<Position, 8> pool;
+  std::vector<char*> ptrs;
+  for (int i = 0; i < 4; i++) {
+    pool.expand(i * 8 + 8);
+    // NOTE: This is an attempt to ensure non-contiguous allocations from
+    // arena allocators.
+    ptrs.push_back(new char[8 * sizeof(Position)]);
+  }
+  char *p0 = static_cast<char*>(pool.get(0));
+  char *p7 = static_cast<char*>(pool.get(7));
+  char *p8 = static_cast<char*>(pool.get(8));
+  char *p16 = static_cast<char*>(pool.get(16));
+  char *p24 = static_cast<char*>(pool.get(24));
+
+  void *expected_p7 = p0 + 7 * sizeof(Position);
+  REQUIRE(expected_p7 == static_cast<void*>(p7));
+  void *extrapolated_p8 = p0 + 8 * sizeof(Position);
+  REQUIRE(extrapolated_p8 !=  static_cast<void*>(p8));
+  void *extrapolated_p16 = p8 + 8 * sizeof(Position);
+  REQUIRE(extrapolated_p16 !=  static_cast<void*>(p16));
+  void *extrapolated_p24 = p16 + 8 * sizeof(Position);
+  REQUIRE(extrapolated_p24 !=  static_cast<void*>(p24));
+}
+
+TEST_CASE("TestDeconstruct") {
+  entityx::Pool<Position, 8> pool;
+  pool.expand(8);
+
+  void *p0 = pool.get(0);
+
+  int counter = 0;
+  new(p0) Position(&counter);
+  REQUIRE(1 ==  counter);
+  pool.destroy(0);
+  REQUIRE(2 ==  counter);
+}

include/entityx/help/Timer.cc

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2013 Antony Woods <antony@teamwoods.org>
+ * All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.
+ *
+ * Author: Antony Woods <antony@teamwoods.org>
+ */
+
+#include "entityx/help/Timer.h"
+
+namespace entityx {
+namespace help {
+
+Timer::Timer() {
+  _start = std::chrono::system_clock::now();
+}
+
+Timer::~Timer() {
+}
+
+void Timer::restart() {
+  _start = std::chrono::system_clock::now();
+}
+
+double Timer::elapsed() {
+  return std::chrono::duration<double>(std::chrono::system_clock::now() - _start).count();
+}
+
+}  // namespace help
+}  // namespace entityx

include/entityx/help/Timer.h

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2013 Antony Woods <antony@teamwoods.org>
+ * All rights reserved.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution.
+ *
+ * Author: Antony Woods <antony@teamwoods.org>
+ */
+#pragma once
+
+#include <chrono>
+
+namespace entityx {
+namespace help {
+
+class Timer {
+public:
+  Timer();
+  ~Timer();
+
+  void restart();
+  double elapsed();
+private:
+  std::chrono::time_point<std::chrono::system_clock> _start;
+};
+
+}  // namespace help
+}  // namespace entityx