(Go) High Resolution Timer / Sleeper for Windows

highres_windows.go

package main

import (
	"syscall"
	"unsafe"
	"time"
)

var (
	kernel32Dll                     = syscall.NewLazyDLL("kernel32.dll")
	winapiQueryPerformanceCounter   = kernel32Dll.NewProc("QueryPerformanceCounter")
	winapiQueryPerformanceFrequency = kernel32Dll.NewProc("QueryPerformanceFrequency")
	performanceFrequency            float64
)

// GetNanoTime get time in nanoseconds from native timer
func GetNanoTime() (int64, error) {
	var out int64
	if performanceFrequency == 0 {
		ret, _, err := winapiQueryPerformanceFrequency.Call(uintptr(unsafe.Pointer(&out)))
		if ret == 0 {
			return 0, err
		}
		performanceFrequency = float64(out)
	}
	ret, _, err := winapiQueryPerformanceCounter.Call(uintptr(unsafe.Pointer(&out)))
	if ret == 0 {
		return 0, err
	}
	return int64((float64(out) / performanceFrequency) * 1e9), nil
}

// Sleep via while lock and GetNanoTime
func SuperSleep(d time.Duration) {
	startTime, _ := GetNanoTime()
	getDuration := func() int64 {
		currentTime, _ := GetNanoTime()
		return currentTime - startTime
	}
	for {
		if getDuration() > int64(d.Nanoseconds()) {
			break
		}
	}
}