NanoTime

Utilities for handling time periods at nanosecond resolution.

namespace NanoTime

Enums

enum Unit

Identify units for a scalar quantity of time.

Note

Ordered in increasing unit size, e.g. days > seconds

Values:

Nanoseconds
Microseconds
Milliseconds
Seconds
Minutes
Hours
Days
UnitMax = Days

Functions

const char *unitToString(Unit unit)

Get a string identifying the given time units, e.g. “ns”.

const char *unitToLongString(Unit unit)

Get a long string identifying the given time units, e.g. “seconds”.

template<uint64_t time, Unit unitsFrom, Unit unitsTo, typename R = std::ratio_divide<UnitTickRatio<unitsTo>, UnitTickRatio<unitsFrom>>>
constexpr uint64_t convert()

Function template to convert a constant time quantity from one unit to another.

Note

example: 

uint32_t micros = convert<50, Milliseconds, Microseconds>();

Template Parameters

  • time: The time to convert

  • unitsFrom: Units for time parameter

  • unitsTo: Units for return value

Return Value

  • TimeType: Converted time

template<typename TimeType>
TimeType convert(const TimeType &time, Unit unitsFrom, Unit unitsTo)

Function template to convert a time quantity from one unit to another.

Template Parameters

  • TimeType: Variable type to use for calculation

Parameters

  • time: The time to convert

  • unitsFrom: Units for time parameter

  • unitsTo: Units for return value

Return Value

  • TimeType: Converted time, returns TimeType(-1) if calculation overflowed

template<typename T>
Time<T> time(Unit unit, T value)

Helper function to create a Time and deduce the type.

template<Unit unitsFrom, Unit unitsTo, typename TimeType>
TimeType convert(const TimeType &time)

Function template to convert a time quantity from one unit to another.

Template Parameters

  • unitsFrom: Units for time parameter

  • unitsTo: Units for return value

  • TimeType: Variable type to use for calculation

Parameters

  • time: The time to convert

Return Value

  • TimeType: Converted time, returns TimeType(-1) if calculation overflowed

Variables

constexpr BasicRatio32 NanoTime::unitTicks[UnitMax+1]= { {1000000000, 1}, {1000000, 1}, {1000, 1}, {1, 1}, {1, 60}, {1, 60 * 60}, {1, 24 * 60 * 60}, }

List of clock ticks for each supported unit of time.

template<typename ClockDef, uint32_t frequency_, typename TickType_, TickType_ maxTicks_>
struct Clock
#include <NanoTime.h>

Class template representing a physical Clock with fixed timing characteristics.

Note

Physical clocks are implemented using this as a base. The provided frequency accounts for any prescaler setting in force. Fixing this at compile time helps to avoid expensive runtime calculations and permits static range checks.

See

Use TimeSource to work with a Clock in specific time units

Template Parameters

  • ClockDef: The actual Clock being constructed (so we can query its properties)

  • frequency_: Clock frequency in Hz

  • TickType_: Variable type representing the clock’s tick value

  • maxTicks_: Maximum count value for the clock

Subclassed by NanoTime::TimeSource< Clock, unit_, TimeType >

struct Frequency
#include <NanoTime.h>

Class to represent a frequency.

template<typename Clock_, typename T>
struct Ticks
#include <NanoTime.h>

Class to handle a tick value associated with a clock.

template<class Clock_, uint64_t ticks_>
struct TicksConst
#include <NanoTime.h>

Class template representing a fixed clock tick count.

Note

Includes compile-time range checking

Template Parameters

  • Source_:

  • ticks_:

template<typename T>
struct Time
#include <NanoTime.h>

Class to handle a simple time value with associated unit.

template<class Clock_, Unit unit_, uint64_t time_>
struct TimeConst
#include <NanoTime.h>

Class template to represent a fixed time value for a specific Clock.

Note

Includes compile-time range checking. Time is taken as reference for conversions.

Template Parameters

  • Clock_:

  • unit_:

  • time_:

template<class Clock_, Unit unit_, typename TimeType_>
struct TimeSource : public Clock_
#include <NanoTime.h>

Class template for accessing a Clock in specific time units.

Note

Includes compile-time range checking. Time is taken as reference for conversions.

Template Parameters

  • Clock_:

  • units_:

  • TimeType_: Limits range of calculations

struct TimeValue
#include <NanoTime.h>

A time time broken into its constituent elements.

Note

Useful for analysing and printing time values

template<Unit unit>
struct UnitTickRatio
#include <NanoTime.h>

Class template to define tick std::ratio type.

Note

This would be preferable: template <Unit unit> using UnitTickRatio = std::ratio<unitTicks[unit].num, unitTicks[unit].den>; But GCC 4.8 doesn’t like it (lvalue required as unary ‘&’ operand)

Template Parameters

  • unit:

Return Value

  • std::ratio: Ticks per second