initial code repo

[stor4nfv.git] / src / ceph / src / dmclock / support / src / heap.h

diff --git a/src/ceph/src/dmclock/support/src/heap.h b/src/ceph/src/dmclock/support/src/heap.h
new file mode 100644 (file)
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+++ b/src/ceph/src/dmclock/support/src/heap.h
@@ -0,0 +1,240 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+/*
+ * Copyright (C) 2016 Red Hat Inc.
+ */
+
+
+#pragma once
+
+
+#include <vector>
+#include <ostream>
+
+#include "assert.h"
+
+
+namespace crimson {
+
+  /*
+   * T : type of data held in the heap.
+   *
+   * C : class that implements operator() with two arguments and
+   * returns a boolean when the first argument is greater than (higher
+   * in priority than) the second.
+   */
+  template<typename T, typename C>
+  class Heap {
+
+  public:
+
+    class iterator {
+
+      friend Heap<T,C>;
+
+      Heap<T,C>& heap;
+      int        index;
+
+      iterator(Heap<T,C>& _heap, int _index) :
+       heap(_heap),
+       index(_index)
+      {
+       // empty
+      }
+
+    public:
+
+      iterator(iterator&& other) :
+       heap(other.heap),
+       index(other.index)
+      {
+       // empty
+      }
+
+      iterator& operator++() {
+       ++index;
+       return *this;
+      }
+
+      bool operator==(const iterator& other) const {
+       return index == other.index;
+      }
+
+      bool operator!=(const iterator& other) const {
+       return !(*this == other);
+      }
+
+      T& operator*() {
+       return heap.data[index];
+      }
+
+      // the item this iterator refers to
+      void increase() {
+       heap.siftUp(index);
+      }
+    }; // class iterator
+
+    friend iterator;
+
+  protected:
+
+    std::vector<T> data;
+    int count;
+    C comparator;
+
+    // parent(0) should be a negative value, which it is due to
+    // truncating towards negative infinity
+    static inline int parent(int i) { return (i - 1) / 2; }
+
+    static inline int lhs(int i) { return 2*i + 1; }
+
+    static inline int rhs(int i) { return 2*i + 2; }
+
+    void siftUp(int i) {
+      assert(i < count);
+
+      while (i > 0) {
+       int pi = parent(i);
+       if (!comparator(data[i], data[pi])) {
+         break;
+       }
+
+       std::swap(data[i], data[pi]);
+       i = pi;
+      }
+    }
+
+    void siftDown(int i) {
+      while (i < count) {
+       int li = lhs(i);
+       int ri = rhs(i);
+
+       if (li < count) {
+         if (comparator(data[li], data[i])) {
+           if (ri < count && comparator(data[ri], data[li])) {
+             std::swap(data[i], data[ri]);
+             i = ri;
+           } else {
+             std::swap(data[i], data[li]);
+             i = li;
+           }
+         } else if (ri < count && comparator(data[ri], data[i])) {
+           std::swap(data[i], data[ri]);
+           i = ri;
+         } else {
+           break;
+         }
+       } else {
+         break;
+       }
+      }
+    }
+
+
+  public:
+
+    Heap() :
+      count(0)
+    {
+      // empty
+    }
+
+    Heap(const Heap<T,C>& other) {
+      data.resize(other.data.size());
+      for (int i = 0; i < other.count; ++i) {
+       data[i] = other.data[i];
+      }
+      count = other.count;
+    }
+
+    const Heap<T,C>& operator=(const Heap<T,C>& other) {
+      data.resize(other.data.size());
+      for (int i = 0; i < other.count; ++i) {
+       data[i] = other.data[i];
+      }
+      count = other.count;
+      return *this;
+    }
+
+    bool empty() const { return 0 == count; }
+
+    T& top() { return data[0]; }
+
+    void push(T item) {
+      int i = count++;
+      data.push_back(item);
+      siftUp(i);
+    }
+
+    void pop() {
+      data[0] = data[--count];
+      data.resize(count);
+      siftDown(0);
+    }
+
+    void updateTop() {
+      siftDown(0);
+    }
+
+    void clear() {
+      count = 0;
+      data.resize(0);
+    }
+
+    iterator begin() {
+      return iterator(*this, 0);
+    }
+
+    iterator end() {
+      return iterator(*this, count);
+    }
+
+    std::ostream& displaySorted(std::ostream& out,
+                               std::function<bool(const T&)> filter,
+                               bool insert_line_breaks = true) const {
+      Heap<T,C> temp = *this;
+
+      bool first = true;
+      out << "[ ";
+
+      while(!temp.empty()) {
+       const T& top = temp.top();
+       if (filter(top)) {
+         if (!first) {
+           out << ", ";
+         }
+         if (insert_line_breaks) {
+           out << std::endl << "    ";
+         }
+         out << temp.top();
+         first = false;
+       }
+       temp.pop();
+      }
+
+      out << " ]";
+      if (insert_line_breaks) {
+       out << std::endl;
+      }
+      return out;
+    }
+
+    template<typename T1, typename T2>
+    friend std::ostream& operator<<(std::ostream&, const Heap<T1,T2>&);
+  }; // class Heap
+
+
+  template<typename T1, typename T2>
+  std::ostream& operator<<(std::ostream& out, const Heap<T1,T2>& h) {
+    out << "[ ";
+    if (h.count) {
+      out << h.data[0];
+    }
+    for (int i = 1; i < h.count; i++) {
+      out << ", " << h.data[i];
+    }
+    out << " ]";
+    return out;
+  }
+} // namespace