time_cache.h

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/*
 * Copyright (c) 2008, Willow Garage, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of the Willow Garage, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * 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
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#ifndef TF2_TIME_CACHE_H
#define TF2_TIME_CACHE_H

#include "transform_storage.h"

#include <deque>

#include <sstream>

#include <ros/message_forward.h>
#include <ros/time.h>

#include <boost/shared_ptr.hpp>

namespace geometry_msgs
{
ROS_DECLARE_MESSAGE(TransformStamped);
}

namespace tf2
{

typedef std::pair<ros::Time, CompactFrameID> P_TimeAndFrameID;

class TimeCacheInterface
{
public:
  virtual bool getData(ros::Time time, TransformStorage & data_out, std::string* error_str = 0)=0; //returns false if data unavailable (should be thrown as lookup exception

  virtual bool insertData(const TransformStorage& new_data)=0;

  virtual void clearList()=0;

  virtual CompactFrameID getParent(ros::Time time, std::string* error_str) = 0;

  virtual P_TimeAndFrameID getLatestTimeAndParent() = 0;



  virtual unsigned int getListLength()=0;

  virtual ros::Time getLatestTimestamp()=0;

  virtual ros::Time getOldestTimestamp()=0;
};

typedef boost::shared_ptr<TimeCacheInterface> TimeCacheInterfacePtr;

class TimeCache : public TimeCacheInterface
{
 public:
  static const int MIN_INTERPOLATION_DISTANCE = 5; 
  static const unsigned int MAX_LENGTH_LINKED_LIST = 1000000; 
  static const int64_t DEFAULT_MAX_STORAGE_TIME = 10ULL * 1000000000LL; 

  TimeCache(ros::Duration  max_storage_time = ros::Duration().fromNSec(DEFAULT_MAX_STORAGE_TIME));



  virtual bool getData(ros::Time time, TransformStorage & data_out, std::string* error_str = 0);
  virtual bool insertData(const TransformStorage& new_data);
  virtual void clearList();
  virtual CompactFrameID getParent(ros::Time time, std::string* error_str);
  virtual P_TimeAndFrameID getLatestTimeAndParent();

  virtual unsigned int getListLength();
  virtual ros::Time getLatestTimestamp();
  virtual ros::Time getOldestTimestamp();
  

private:
  typedef std::deque<TransformStorage> L_TransformStorage;
  L_TransformStorage storage_;

  ros::Duration max_storage_time_;


  //Assumes storage is already locked for it
  inline uint8_t findClosest(TransformStorage*& one, TransformStorage*& two, ros::Time target_time, std::string* error_str);

  inline void interpolate(const TransformStorage& one, const TransformStorage& two, ros::Time time, TransformStorage& output);


  void pruneList();



};

class StaticCache : public TimeCacheInterface
{
 public:

  virtual bool getData(ros::Time time, TransformStorage & data_out, std::string* error_str = 0); //returns false if data unavailable (should be thrown as lookup exception
  virtual bool insertData(const TransformStorage& new_data);
  virtual void clearList();
  virtual CompactFrameID getParent(ros::Time time, std::string* error_str);
  virtual P_TimeAndFrameID getLatestTimeAndParent();


  virtual unsigned int getListLength();
  virtual ros::Time getLatestTimestamp();
  virtual ros::Time getOldestTimestamp();
  

private:
  TransformStorage  storage_;
};

}

#endif // TF2_TIME_CACHE_H