// static
Time Time::FromExploded(bool is_local, const Exploded& exploded)
{
// 创建系统拆分时间结构, 代表本地时间或者UTC.
SYSTEMTIME st;
st.wYear = exploded.year;
st.wMonth = exploded.month;
st.wDayOfWeek = exploded.day_of_week;
st.wDay = exploded.day_of_month;
st.wHour = exploded.hour;
st.wMinute = exploded.minute;
st.wSecond = exploded.second;
st.wMilliseconds = exploded.millisecond;
// 转换到FILETIME.
FILETIME ft;
if(!SystemTimeToFileTime(&st, &ft))
{
NOTREACHED() << "Unable to convert time";
return Time(0);
}
// 确保是UTC.
if(is_local)
{
FILETIME utc_ft;
LocalFileTimeToFileTime(&ft, &utc_ft);
return Time(FileTimeToMicroseconds(utc_ft));
}
return Time(FileTimeToMicroseconds(ft));
}
// static
Time Time::Now()
{
if(initial_time == 0)
{
InitializeClock();
}
// 高精度计数器实现计时, 能够得到比10-15ms小的超时. 仅通过
// CurrentWallclockMicroseconds(), 无法得到细粒度的定时器.
//
// 使用时, 初始化时钟(initial_time)和计数器(initial_ctr). 通过
// 和初始时钟比较能得到消逝的时钟数, 然后就能得出时间差.
//
// 为避免误差, 计数器定期的和系统时钟同步.
while(true)
{
TimeTicks ticks = TimeTicks::Now();
// 计算自开始以来的时间计数.
TimeDelta elapsed = ticks - initial_ticks;
// 检查是否需要同步时钟.
if(elapsed.InMilliseconds() > kMaxMillisecondsToAvoidDrift)
{
InitializeClock();
continue;
}
return Time(elapsed + Time(initial_time));
}
}
// static
Time Time::FromFileTime(FILETIME ft)
{
return Time(FileTimeToMicroseconds(ft));
}
// static
Time Time::NowFromSystemTime()
{
// 强制同步.
InitializeClock();
return Time(initial_time);
}
void ManipulatorJointTrajectory::externalize(Externalizer& e, String format, Real version)
{
if (format=="") format = String("xml");
if (!formatSupported(format,version,e.ioType()))
throw std::invalid_argument(Exception(String("format ")+format+" "+base::realToString(version)+" unsupported"));
if (format == "txt") {
if (e.isInput()) {
array<Vector> qs;
array<Time> times;
bool first = true;
bool deltas = false;
while (e.moreInput()) {
String line(e.readLine());
if (line.empty()) break; // empty line or eof indicates end of list
while (line[0] == '#') line = e.readLine(); // skip comment lines
if (first) {
if (!( (line.substr(0,8) == "absolute") || (line.substr(0,8) == "relative")))
throw std::invalid_argument(Exception(String("joint waypoint text file must indicate 'absolute' or 'relative'")));
deltas = (line.substr(0,8) == String("relative"));
first = false;
}
else {
// count separating spaces to determine dof
Int spaces=0;
for(Int i=0; i<line.size(); i++)
if (line[i]==' ') {
spaces++;
while ( (i<line.size()-1) && (line[i]==' ')) i++;
}
if (line[0]==' ') spaces--; // don't count leading space(s)
std::istringstream iss(line);
iss.setf(std::ios_base::skipws | std::ios_base::dec);
const Int dof = spaces + 1 - 1; // don't count time at end as a dof
Vector q(dof);
for(Int i=0; i<dof; i++)
iss >> q[i];
Real t;
iss >> t;
qs.push_back(q);
times.push_back(Time(t));
}
}
if (first)
throw std::invalid_argument(Exception(String("joint waypoint text file contains no data.")));
if (qs.size() < 2)
throw std::invalid_argument(Exception(String("joint waypoint text file must contain at least 2 'waypoint' vectors")));
init(qs,times,deltas);
}
else { // output
Time ManipulatorJointTrajectory::time(Real s) const
{
Math::bound<Real>(s,0,1);
return Time( times[0].seconds() + ( (times[times.size()-1] - times[0]).seconds() * s ) );
}