timestamp.go

package main

import (
	"fmt"
	"log"
	"strconv"
	"time"
)

const hex = "0123456789abcdef"

func timestamp(mode int, now time.Time) []byte {
	out := []byte{}
	switch mode {
	case tsNone:
	case tsTAI64:
		out = timestampTAI64(now)
	case tsEpoch:
		out = timestampEpoch(now)
	case tsEpochMs:
		out = timestampEpochMs(now)
	case tsEpochUs:
		out = timestampEpochUs(now)
	case tsEpochNs:
		out = timestampEpochNs(now)
	case tsRFC3339:
		out = timestampRFC3339(now)
	case tsRFC3339Nano:
		out = timestampRFC3339Nano(now)
	default:
		log.Fatalf("ECANTHAPPEN: timestamps mode is %d\n", mode)
	}
	return out
}
func timestampEpoch(now time.Time) []byte {
	sec := now.Unix()
	return []byte(strconv.FormatInt(sec, 10))
}
func timestampEpochMs(now time.Time) []byte {
	sec := now.Unix()
	nano := now.Nanosecond()
	return []byte(fmt.Sprintf("%d%03d", sec, nano/1000000))
}
func timestampEpochUs(now time.Time) []byte {
	sec := now.Unix()
	nano := now.Nanosecond()
	return []byte(fmt.Sprintf("%d%06d", sec, nano/1000))
}
func timestampEpochNs(now time.Time) []byte {
	sec := now.Unix()
	nano := now.Nanosecond()
	return []byte(fmt.Sprintf("%d%09d", sec, nano))
}
func timestampRFC3339(now time.Time) []byte {
	return []byte(now.Format(time.RFC3339))
}
func timestampRFC3339Nano(now time.Time) []byte {
	return []byte(now.Format(time.RFC3339Nano))
}

func timestampTAI64(now time.Time) []byte {
	buf := make([]byte, 12)
	out := make([]byte, 25)
	sec := now.Unix()
	sec += 4611686018427387914
	nano := now.Nanosecond()

	buf[7] = byte(sec & 255)
	sec >>= 8
	buf[6] = byte(sec & 255)
	sec >>= 8
	buf[5] = byte(sec & 255)
	sec >>= 8
	buf[4] = byte(sec & 255)
	sec >>= 8
	buf[3] = byte(sec & 255)
	sec >>= 8
	buf[2] = byte(sec & 255)
	sec >>= 8
	buf[1] = byte(sec & 255)
	sec >>= 8
	buf[0] = byte(sec & 255)
	buf[11] = byte(nano & 255)
	nano >>= 8
	buf[10] = byte(nano & 255)
	nano >>= 8
	buf[9] = byte(nano & 255)
	nano >>= 8
	buf[8] = byte(nano & 255)

	out[0] = '@'

	for i := 0; i < 12; i++ {
		t := (buf[i] / 16) & 15
		out[i*2+1] = hex[t]
		t = (buf[i]) & 15
		out[i*2+2] = hex[t]
	}
	return out
}