//
// Copyright 2011-2013 Ettus Research LLC
// Copyright 2018 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//

#include <uhd/types/time_spec.hpp>
#include <cmath>

using namespace uhd;

/***********************************************************************
 * Time spec constructors
 **********************************************************************/
#define time_spec_init(full, frac)               \
    {                                            \
        const int64_t _full = int64_t(full);     \
        const double _frac  = double(frac);      \
        const int _frac_int = int(_frac);        \
        _full_secs          = _full + _frac_int; \
        _frac_secs          = _frac - _frac_int; \
        if (_frac_secs < 0) {                    \
            _full_secs -= 1;                     \
            _frac_secs += 1;                     \
        }                                        \
    }

UHD_INLINE long long fast_llround(const double x)
{
    return (long long)(x + 0.5); // assumption of non-negativity
}

time_spec_t::time_spec_t(double secs)
{
    time_spec_init(0, secs);
}

time_spec_t::time_spec_t(int64_t full_secs, double frac_secs)
{
    time_spec_init(full_secs, frac_secs);
}

time_spec_t::time_spec_t(int64_t full_secs, long tick_count, double tick_rate)
{
    const double frac_secs = tick_count / tick_rate;
    time_spec_init(full_secs, frac_secs);
}

time_spec_t time_spec_t::from_ticks(long long ticks, double tick_rate)
{
    const long long rate_i      = (long long)(tick_rate);
    const double rate_f         = tick_rate - rate_i;
    const int64_t secs_full     = int64_t(ticks / rate_i);
    const long long ticks_error = ticks - (secs_full * rate_i);
    const double ticks_frac     = ticks_error - secs_full * rate_f;
    return time_spec_t(secs_full, ticks_frac / tick_rate);
}

/***********************************************************************
 * Time spec accessors
 **********************************************************************/
long time_spec_t::get_tick_count(double tick_rate) const
{
    return long(fast_llround(this->get_frac_secs() * tick_rate));
}

long long time_spec_t::to_ticks(double tick_rate) const
{
    const long long rate_i     = (long long)(tick_rate);
    const double rate_f        = tick_rate - rate_i;
    const long long ticks_full = this->get_full_secs() * rate_i;
    const double ticks_error   = this->get_full_secs() * rate_f;
    const double ticks_frac    = this->get_frac_secs() * tick_rate;
    return ticks_full + fast_llround(ticks_error + ticks_frac);
}

double time_spec_t::get_real_secs(void) const
{
    return this->get_full_secs() + this->get_frac_secs();
}

/***********************************************************************
 * Time spec math overloads
 **********************************************************************/
time_spec_t& time_spec_t::operator+=(const time_spec_t& rhs)
{
    time_spec_init(this->get_full_secs() + rhs.get_full_secs(),
        this->get_frac_secs() + rhs.get_frac_secs());
    return *this;
}

time_spec_t& time_spec_t::operator+=(double& rhs)
{
    double full_secs = std::trunc(rhs);
    time_spec_init(
        this->get_full_secs() + full_secs, this->get_frac_secs() + rhs - full_secs);
    return *this;
}

time_spec_t& time_spec_t::operator-=(const time_spec_t& rhs)
{
    time_spec_init(this->get_full_secs() - rhs.get_full_secs(),
        this->get_frac_secs() - rhs.get_frac_secs());
    return *this;
}

time_spec_t& time_spec_t::operator-=(double& rhs)
{
    double full_secs = std::trunc(rhs);
    time_spec_init(
        this->get_full_secs() - full_secs, this->get_frac_secs() - (rhs - full_secs));
    return *this;
}

bool uhd::operator==(const time_spec_t& lhs, const time_spec_t& rhs)
{
    return lhs.get_full_secs() == rhs.get_full_secs()
           and lhs.get_frac_secs() == rhs.get_frac_secs();
}

bool uhd::operator<(const time_spec_t& lhs, const time_spec_t& rhs)
{
    return ((lhs.get_full_secs() < rhs.get_full_secs())
            or ((lhs.get_full_secs() == rhs.get_full_secs())
                   and (lhs.get_frac_secs() < rhs.get_frac_secs())));
}
