pool.hh

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//
// Copyright (c) 2018 CNRS
// Author: Joseph Mirabel
//
//
 
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// 1. Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
// DAMAGE.
 
#ifndef HPP_PINOCCHIO_POOL_HH
#define HPP_PINOCCHIO_POOL_HH
 
#include <boost/thread/condition_variable.hpp>
#include <boost/thread/mutex.hpp>
#include <hpp/pinocchio/config.hh>
#include <vector>
 
namespace hpp {
namespace pinocchio {
 
template <typename T>
class HPP_PINOCCHIO_DLLAPI Pool {
 public:
  T* acquire() {
    boost::mutex::scoped_lock lock(mutex_);
    condVariable_.wait(lock, OneIsAvailable(*this));
    T* ret = NULL;
    std::swap(ret, Ts_[lastFree_]);
    lastFree_++;
    return ret;
  }
 
  void release(T* t) {
    boost::mutex::scoped_lock lock(mutex_);
    // At least one T* is not free.
    assert(lastFree_ > 0);
    assert(Ts_[lastFree_ - 1] == NULL);
    Ts_[lastFree_ - 1] = t;
    lastFree_--;
    condVariable_.notify_one();
  }
 
  bool available() const { return OneIsAvailable(*this)(); }
 
  std::size_t size() const { return Ts_.size(); }
 
  void clear() {
    boost::mutex::scoped_lock lock(mutex_);
    if (lastFree_ > 0)
      throw std::logic_error("Cannot free pool when some objects are in use.");
    for (std::size_t i = 0; i < size(); ++i) delete Ts_[i];
    Ts_.resize(0);
  }
 
  void push_back(T* t) {
    boost::mutex::scoped_lock lock(mutex_);
    Ts_.push_back(t);
  }
 
  template <class InputIterator>
  void push_back(InputIterator first, InputIterator last) {
    boost::mutex::scoped_lock lock(mutex_);
    Ts_.insert(Ts_.end(), first, last);
  }
 
  ~Pool() { clear(); }
 
  Pool() : lastFree_(0) {}
 
 private:
  struct OneIsAvailable {
    const Pool& p;
    OneIsAvailable(const Pool& pool) : p(pool) {}
    bool operator()() { return p.lastFree_ < p.size(); }
  };
 
  boost::mutex mutex_;
  boost::condition_variable condVariable_;
  std::vector<T*> Ts_;
  std::size_t lastFree_;
};  // class Pool
}  // namespace pinocchio
}  // namespace hpp
 
#endif  // HPP_PINOCCHIO_DEVICE_HH