icp.cpp

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// icp.cpp,v 1.3 2003/11/22 23:21:31 parsons Exp

// ============================================================================
//
// = LIBRARY
//    TAO/examples/Advanced/ch_12
//
// = FILENAME
//    icp.cpp
//
// = AUTHORS
//   Source code used in TAO has been modified and adapted from the
//   code provided in the book, "Advanced CORBA Programming with C++"
//   by Michi Henning and Steve Vinoski. Copyright
//   1999. Addison-Wesley, Reading, MA.  Used with permission of
//   Addison-Wesley.
//
//   Modified for TAO by Mike Moran <[e-mail]>
//
// ============================================================================

#include    <string>
#include    <map>
#include    <algorithm>
#include    <iostream>
#include    "icp.h"

using namespace std;

// The following header is #included automatically by ACE+TAO.
// Therefore, they don't need to be included explicitly.
//#include    <stdlib.h>

enum DeviceType { thermometer, thermostat };

struct DeviceState 
{                // State for a device
  DeviceType type;
  const char *model;
  string location;
  short nominal_temp;   // For thermostats only
};

typedef map<unsigned long, DeviceState> StateMap;

const size_t MAXSTR = 32;       // Max len of string including NUL

const short MIN_TEMP = 40;      // 40 F ==  4.44 C
const short MAX_TEMP = 90;      // 90 F == 32.22 C
const short DFLT_TEMP = 68;     // 68 F == 20.00 C

static StateMap dstate;         // Map of known devices

// ICP_online () simulates adding a new device to the network by
// adding it to the dstate map.
//
// For this simple simulation, devices with odd asset numbers
// are thermometers and devices with even asset numbers
// are thermostats.
//
// Thermostats get an initial nominal temperature of DFLT_TEMP.
// The location string is intentionally left blank because it
// must be programmed by the controller after putting the device
// on-line  (as should be the nominal temperature).
//
// If a device with the specified ID is already on-line, the
// return value is -1. A zero return value indicates success.

extern "C"
int
ICP_online (unsigned long id)
{
  // Look for id in state map.
  StateMap::iterator pos = dstate.find (id);
  if (pos != dstate.end ())
    return -1;                          // Already exists
    
  // Fill in state.
  DeviceState ds;
  ds.type =  (id % 2) ? thermometer : thermostat;
  ds.model =  (ds.type == thermometer)
    ? "Sens-A-Temp" : "Select-A-Temp";
  ds.nominal_temp = DFLT_TEMP;

  // Insert new device into map
  dstate[id] = ds;

  return 0;
}

// ICP_offline () simulates removing a device from the network by
// removing it from the dstate map. If the device isn't known, the
// return value is -1. A zero return value indicates success.

extern "C"
int
ICP_offline (unsigned long id)
{
  // Look for id in state map
  StateMap::iterator pos = dstate.find (id);

  if (pos == dstate.end ())
    return -1;                              // No such device
  dstate.erase (id);
  return 0;
}

// vary_temp () simulates the variation in actual temperature around a
// thermostat.The function randomly varies the temperature as a
// percentage of calls as follows:
//
//      3 degrees too cold:      5%
//      3 degrees too hot:       5%
//      2 degrees too cold:     10%
//      2 degrees too hot:      10%
//      1 degree too cold:      15%
//      1 degree too hot:       15%
//      exact temperature:      40%

static
short
vary_temp (short temp)
{
  long r = lrand48 () % 50;
  long delta;
  if  (r < 5)
    delta = 3;
  else if  (r < 15)
    delta = 2;
  else if  (r < 30)
    delta = 1;
  else
    delta = 0;
  if  (lrand48 () % 2)
    delta = -delta;
  return temp + delta;
}

// Function object. Locates a thermostat that is in the same room as
// the device at position pos.

class ThermostatInSameRoom 
{
public:
  ThermostatInSameRoom (const StateMap::iterator &pos):
    m_pos (pos) {}
  bool operator () (pair<const unsigned long, DeviceState> &p) const
  {
    return p.second.type == thermostat
      && p.second.location == m_pos->second.location;
  }
private:
  const StateMap::iterator & m_pos;
};

// actual_temp () is a helper function to determine the actual
// temperature returned by a particular thermometer or thermostat.
// The pos argument indicates the device.
// 
// The function locates all thermostats that are in the same room
// as the device denoted by pos and computes the average of all
// the thermostats' nominal temperatures.  (If no thermostats are
// in the same room as the device, the function assumes that the
// average of the nominal temperatures is DFLT_TEMP.)
//
// The returned temperature varies from the average as
// determined by vary_temp ().

static
short
actual_temp (const StateMap::iterator & pos)
{
  long sum = 0;
  long count = 0;
  StateMap::iterator where = find_if (dstate.begin (), dstate.end (),
                                      ThermostatInSameRoom (pos));
  while  (where != dstate.end ()) 
    {
      count++;
      sum += where->second.nominal_temp;
      where = find_if (++where, dstate.end (),
                       ThermostatInSameRoom (pos));
    }

  return vary_temp (count == 0 ? DFLT_TEMP : sum / count);
}

// ICP_get () returns an attribute value of the device with the given
// id. The attribute is named by the attr parameter. The value is
// copied into the buffer pointed to by the value pointer. The len
// parameter is the size of the passed buffer, so ICP_get can avoid
// overrunning the buffer.
//
// By default, thermometers report a temperature that varies somewhat
// around DFLT_TEMP. However, if there is another thermostat in the
// same room as the the thermometer, the thermometer reports a
// temperature that varies around that thermostat's temperature. For
// several thermostats that are in the same room, the thermometer
// reports around the average nominal temperature of all the
// thermostats.
//
// Attempts to read from a non-existent device or to read a
// non-existent attribute return -1. A return value of zero indicates
// success. If the supplied buffer is too short to hold a value,
// ICP_get () silently truncates the value and returns success.

extern "C"
int
ICP_get (unsigned long id,
         const char * attr,
         void *value,
         size_t len)
{
  // Look for id in state map
  StateMap::iterator pos = dstate.find (id);
  if (pos == dstate.end ())
    return -1;                              // No such device

  // Depending on the attribute, return the
  // corresponding piece of state.
  if  (strcmp (attr, "model") == 0) 
    {
      strncpy ( (char *)value, pos->second.model, len);
    }
  else if  (strcmp (attr, "location") == 0) 
    {
      strncpy ( (char *)value, pos->second.location.c_str (), len);
    } 
  else if  (strcmp (attr, "nominal_temp") == 0) 
    {
      if  (pos->second.type != thermostat)
        return -1;                      // Must be thermostat
      memcpy (value, &pos->second.nominal_temp,
              min (len, sizeof (pos->second.nominal_temp)));
    } 
  else if  (strcmp (attr, "temperature") == 0) 
    {
      short temp = actual_temp (pos);
      memcpy (value, &temp, min (len, sizeof (temp)));
    }
  else if  (strcmp (attr, "MIN_TEMP") == 0) 
    {
      memcpy (value, &MIN_TEMP, min (len, sizeof (MIN_TEMP)));
    } 
  else if  (strcmp (attr, "MAX_TEMP") == 0) 
    {
      memcpy (value, &MAX_TEMP, min (len, sizeof (MAX_TEMP)));
    }
  else 
    {
      return -1;                          // No such attribute
    }
  return 0;                               // OK
}

// ICP_set () sets the the attributed specified by attr to the value
// specified by value for the device with ID id. Attempts to write a
// string longer than MAXSTR bytes (including the terminating NUL)
// result in silent truncation of the string.  Attempts to access a
// non-existent device or attribute return -1. Attempts to set a
// nominal temperature outside the legal range also return -1. A zero
// return value indicates success.

extern "C"
int
ICP_set (unsigned long id, const char * attr, const void * value)
{
  // Look for id in state map
  StateMap::iterator pos = dstate.find (id);
  if  (pos == dstate.end ())
    return -1;                          // No such device

  // Change either location or nominal temp, depending on attr.
  if (strcmp (attr, "location") == 0) 
    {
      pos->second.location.assign ((const char *)value, MAXSTR - 1);
    } 
  else if (strcmp (attr, "nominal_temp") == 0) 
    {
      if (pos->second.type != thermostat) 
        return -1;                      // Must be thermostat
      short temp;
      memcpy (&temp, value, sizeof (temp));
      if (temp < MIN_TEMP || temp > MAX_TEMP)
        return -1;
      pos->second.nominal_temp = temp;
    } 
  else
    {
      return -1;                          // No such attribute
    }
  return 0;                               // OK
}

#include <fstream>

class ICP_Persist 
{
public:
  ICP_Persist (const char *file);
  ~ICP_Persist ();
private:
  string m_filename;
};

// Read device state from a file and initialize the dstate map.

ICP_Persist::
ICP_Persist (const char *file)
  : m_filename (file)
{
  // Open input file, creating it if necessary.
  fstream db (m_filename.c_str (), ios::in|ios::out, 0666);
  if  (!db) 
    {
      cerr << "Error opening " << m_filename << endl;
      exit (1);
    }

  // Read device details, one attribute per line.
  DeviceState ds;
  unsigned long id;
  while  (db >> id) 
    {
      // Read device type and set model string accordingly.
      int dtype;
      db >> dtype;
      ds.type = dtype == thermometer
        ? thermometer : thermostat;
      ds.model = dtype == thermometer
        ? "Sens-A-Temp" : "Select-A-Temp";
      char loc[MAXSTR];
      db.get (loc[0]);                 // Skip newline
      db.getline (loc, sizeof (loc));   // Read location
      ds.location = loc;
      if  (ds.type == thermostat)
        db >> ds.nominal_temp;      // Read temperature
      dstate[id] = ds;                // Add entry to map
    }

  //db.close ();
  //if  (!db) {
  //    cerr << "Error closing " << m_filename << endl;
  //    exit (1);
  //}
}

// Write device state to the file.

ICP_Persist::
~ICP_Persist ()
{
  cout<<"~ICP_Persist"<<endl;///////////////////////
  // Open input file, truncating it.
  ofstream db (m_filename.c_str ());
  if  (!db) 
    {
      cerr << "Error opening " << m_filename << endl;
      exit (1);
    }

  // Write the state details for each device.
  StateMap::iterator i;
  for  (i = dstate.begin (); i != dstate.end (); i++) 
    {
      db << i->first << endl;
      db <<  (unsigned long) (i->second.type) << endl;
      db << i->second.location << endl;
      if  (i->second.type == thermostat)
        db << i->second.nominal_temp << endl;
    }
  if  (!db) 
    {
      cerr << "Error writing " << m_filename << endl;
      exit (1);
    }

  db.close ();
  if  (!db) 
    {
      cerr << "Error closing " << m_filename << endl;
      exit (1);
    }
}

// Instantiate a single global instance of the class.
static ICP_Persist mydb ("/tmp/CCS_DB");