terraform/vendor/github.com/influxdata/influxdb/models/time.go

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2016-03-20 20:55:48 +01:00
package models
// Helper time methods since parsing time can easily overflow and we only support a
// specific time range.
import (
"fmt"
"math"
"time"
)
var (
// MaxNanoTime is the maximum time that can be represented via int64 nanoseconds since the epoch.
MaxNanoTime = time.Unix(0, math.MaxInt64).UTC()
// MinNanoTime is the minumum time that can be represented via int64 nanoseconds since the epoch.
MinNanoTime = time.Unix(0, math.MinInt64).UTC()
// ErrTimeOutOfRange gets returned when time is out of the representable range using int64 nanoseconds since the epoch.
ErrTimeOutOfRange = fmt.Errorf("time outside range %s - %s", MinNanoTime, MaxNanoTime)
)
// SafeCalcTime safely calculates the time given. Will return error if the time is outside the
// supported range.
func SafeCalcTime(timestamp int64, precision string) (time.Time, error) {
mult := GetPrecisionMultiplier(precision)
if t, ok := safeSignedMult(timestamp, mult); ok {
return time.Unix(0, t).UTC(), nil
}
return time.Time{}, ErrTimeOutOfRange
}
// CheckTime checks that a time is within the safe range.
func CheckTime(t time.Time) error {
if t.Before(MinNanoTime) || t.After(MaxNanoTime) {
return ErrTimeOutOfRange
}
return nil
}
// Perform the multiplication and check to make sure it didn't overflow.
func safeSignedMult(a, b int64) (int64, bool) {
if a == 0 || b == 0 || a == 1 || b == 1 {
return a * b, true
}
if a == math.MinInt64 || b == math.MaxInt64 {
return 0, false
}
c := a * b
return c, c/b == a
}