boost-react-native-bundle
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Boost library as in https://sourceforge.net/projects/boost/files/boost/1.57.0/
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<!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
"../../../tools/boostbook/dtd/boostbook.dtd">
<!-- Copyright (c) 2001-2005 CrystalClear Software, Inc.
Subject to the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
-->
<section id="date_time.examples.meeting_planner">
<title>Teleconference Scheduler (partial listing)</title>
<para>
The Teleconference Scheduler is a Qt based example (found in the examples/qt directory). Partial listings of <link linkend="meeting_planner_hpp">meeting_planner.hpp</link> and <link linkend="planner_form_cpp">planner_form.cpp</link> are provided to illustrate techniques for using the local_date_time and tz_database objects.
</para>
<anchor id="planner_form_cpp" />
<para>
The planner_form class is derived from a QDialog. This listing illustrates the initialization of a tz_database object and using it to populate combo boxes with region lists. Only the init function is listed here for the sake of brevity.
</para>
<programlisting>
<![CDATA[
void planner_form::init() {
try{
tz_db.load_from_file("../../data/date_time_zonespec.csv");
}catch(boost::local_time::data_not_accessible dna) {
std::cerr << "Error with time zone data file: " << dna.what() << std::endl;
exit(EXIT_FAILURE);
}catch(boost::local_time::bad_field_count bfc) {
std::cerr << "Error with time zone data file: " << bfc.what() << std::endl;
exit(EXIT_FAILURE);
}
// populate combo boxes with region names
typedef std::vector<std::string> vect;
vect regions = tz_db.region_list();
vect::const_iterator itr = regions.begin();
while(itr != regions.end()) {
comboBox1->insertItem(*itr);
comboBox2->insertItem(*itr);
comboBox3->insertItem(*itr);
++itr;
}
comboBox1->insertItem("<Select Region>", 0);
comboBox2->insertItem("<Select Region>", 0);
comboBox3->insertItem("<Select Region>", 0);
// set up dateEdit
dateEdit2->setSeparator("-");
this->reset();
}
]]>
</programlisting>
<anchor id="meeting_planner_hpp" />
<para>
This class coordinates local times across multiple time zones. It accomplishes this by iterating across a collection of time zones and verifying that the target time falls within a set period (a workday).
</para>
<programlisting>
<![CDATA[
/* The heart of the meeting_planner is the synchronization of different
* time zones to a single point in time.
* The class takes a vector of regions and a date. The default time
* range is 9am to 5pm but can be changed.
* The resulting time specs are returned as a vector of strings
*/
using namespace boost;
using namespace local_time;
using namespace posix_time;
//! Coordinates meeting times accounting for time zone differences
class meeting_planner {
public:
typedef std::vector<shared_ptr<time_zone_base> > vector_type;
// a multimap is used so time_zones can be sorted according to utc_offset
typedef std::multimap<posix_time::time_duration, shared_ptr<time_zone_base> > zone_map_type;
typedef std::vector<std::string> result_type;
meeting_planner(const gregorian::date& d, const vector_type& v)
: l_time(posix_time::not_a_date_time, shared_ptr<time_zone_base>()),
workday(ptime(d,hours(9)), time_duration(8,0,0,1))
{
vector_type::const_iterator iter = v.begin();
while(iter != v.end()) {
time_duration offset(0,0,0);
if(*iter == NULL) {
offset = hours(0);
}
else{
// null pointers may wind up in the vector
// TODO: this should be fixed in tz_database
offset = (*iter)->base_utc_offset();
}
zones.insert(zone_map_type::value_type(offset, *iter));
++iter;
}
// set l_time to noon UTC
l_time = local_date_time(posix_time::ptime(d, posix_time::hours(12)),
shared_ptr<time_zone_base>());
}
//! Changes range of valid meeting times (ie. The hours in a workday) times are inclusive
void change_range(const time_duration& start, const time_duration& end)
{
ptime pt(l_time.date(), start);
// add one unit to make the give times inclusive
workday = time_period(pt, (end - start) + time_duration::unit());
}
//! strings returned in the form of "yyyy-Mon-dd: hh:mm Zzz [repeat]"
result_type coordinate_time() const
{
using namespace posix_time;
result_type result;
bool flag = true;
std::stringstream ss;
ss.str("");
// set the output format for local_date_time to only give
// time_of_day & zone offset
typedef boost::date_time::time_facet<local_date_time, char> ldt_facet;
ldt_facet* timefacet = new ldt_facet("%H:%M (%q)");
std::locale loc(std::locale::classic(), timefacet);
ss.imbue(loc);
// backup a full day and start iterating from there
// I went overkill because I've got no decent
// algorithm to set a starting point (yet)
local_date_time tmp = l_time - gregorian::days(1);
zone_map_type::const_iterator iter;
for(int i = 0; i < 48; ++i) {
iter = zones.begin();
flag = true;
tmp += posix_time::hours(1);
while(iter != zones.end() && flag) {
if(!workday.contains(tmp.local_time_in(iter->second).local_time())) {
flag = false;
}
++iter;
}
if(flag) {
iter = zones.begin();
ss << tmp.date() << ':';
while(iter != zones.end()) {
ss << ' ' << tmp.local_time_in(iter->second);
++iter;
if(iter != zones.end()) {
ss << ',';
}
}
result.push_back(ss.str());
ss.str("");
}
}
if(result.empty()) {
result.push_back("Scheduling within the time period given is not possible for these time zones.");
}
return result;
}
private:
zone_map_type zones;
local_date_time l_time;
time_period workday;
};
]]>
</programlisting>
</section>