You could apply time_durations in the maximum allowable increments (which is std::numeric_limits<long>::max()
) since the total_seconds
field is limited to long
(signed).
Note: I worded it as int32_t
below so that it will still work correctly if compiled on a 64-bit platform.
Here's a small demonstration:
#include "boost/date_time.hpp"
#include <iostream>
using namespace boost::gregorian;
using namespace boost::posix_time;
int main()
{
uint64_t offset = 113ul*365ul*24ul*60ul*60ul; // 113 years give or take some leap seconds/days etc.?
static const ptime time_t_epoch(date(1901,1,1));
static const uint32_t max_long = std::numeric_limits<int32_t>::max();
std::cout << "epoch: " << time_t_epoch << "\n";
ptime accum = time_t_epoch;
while (offset > max_long)
{
accum += seconds(max_long);
offset -= max_long;
std::cout << "accumulating: " << accum << "\n";
}
accum += seconds(offset);
std::cout << "final: " << accum << "\n";
}
Prints:
epoch: 1901-Jan-01 00:00:00
accumulating: 1969-Jan-19 03:14:07
final: 2013-Dec-04 00:00:00
See it Live on Coliru