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Diffstat (limited to 'vendor/github.com/google/uuid/time.go')
| -rw-r--r-- | vendor/github.com/google/uuid/time.go | 123 | 
1 files changed, 123 insertions, 0 deletions
diff --git a/vendor/github.com/google/uuid/time.go b/vendor/github.com/google/uuid/time.go new file mode 100644 index 0000000..e6ef06c --- /dev/null +++ b/vendor/github.com/google/uuid/time.go @@ -0,0 +1,123 @@ +// Copyright 2016 Google Inc.  All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package uuid + +import ( +	"encoding/binary" +	"sync" +	"time" +) + +// A Time represents a time as the number of 100's of nanoseconds since 15 Oct +// 1582. +type Time int64 + +const ( +	lillian    = 2299160          // Julian day of 15 Oct 1582 +	unix       = 2440587          // Julian day of 1 Jan 1970 +	epoch      = unix - lillian   // Days between epochs +	g1582      = epoch * 86400    // seconds between epochs +	g1582ns100 = g1582 * 10000000 // 100s of a nanoseconds between epochs +) + +var ( +	timeMu   sync.Mutex +	lasttime uint64 // last time we returned +	clockSeq uint16 // clock sequence for this run + +	timeNow = time.Now // for testing +) + +// UnixTime converts t the number of seconds and nanoseconds using the Unix +// epoch of 1 Jan 1970. +func (t Time) UnixTime() (sec, nsec int64) { +	sec = int64(t - g1582ns100) +	nsec = (sec % 10000000) * 100 +	sec /= 10000000 +	return sec, nsec +} + +// GetTime returns the current Time (100s of nanoseconds since 15 Oct 1582) and +// clock sequence as well as adjusting the clock sequence as needed.  An error +// is returned if the current time cannot be determined. +func GetTime() (Time, uint16, error) { +	defer timeMu.Unlock() +	timeMu.Lock() +	return getTime() +} + +func getTime() (Time, uint16, error) { +	t := timeNow() + +	// If we don't have a clock sequence already, set one. +	if clockSeq == 0 { +		setClockSequence(-1) +	} +	now := uint64(t.UnixNano()/100) + g1582ns100 + +	// If time has gone backwards with this clock sequence then we +	// increment the clock sequence +	if now <= lasttime { +		clockSeq = ((clockSeq + 1) & 0x3fff) | 0x8000 +	} +	lasttime = now +	return Time(now), clockSeq, nil +} + +// ClockSequence returns the current clock sequence, generating one if not +// already set.  The clock sequence is only used for Version 1 UUIDs. +// +// The uuid package does not use global static storage for the clock sequence or +// the last time a UUID was generated.  Unless SetClockSequence is used, a new +// random clock sequence is generated the first time a clock sequence is +// requested by ClockSequence, GetTime, or NewUUID.  (section 4.2.1.1) +func ClockSequence() int { +	defer timeMu.Unlock() +	timeMu.Lock() +	return clockSequence() +} + +func clockSequence() int { +	if clockSeq == 0 { +		setClockSequence(-1) +	} +	return int(clockSeq & 0x3fff) +} + +// SetClockSequence sets the clock sequence to the lower 14 bits of seq.  Setting to +// -1 causes a new sequence to be generated. +func SetClockSequence(seq int) { +	defer timeMu.Unlock() +	timeMu.Lock() +	setClockSequence(seq) +} + +func setClockSequence(seq int) { +	if seq == -1 { +		var b [2]byte +		randomBits(b[:]) // clock sequence +		seq = int(b[0])<<8 | int(b[1]) +	} +	oldSeq := clockSeq +	clockSeq = uint16(seq&0x3fff) | 0x8000 // Set our variant +	if oldSeq != clockSeq { +		lasttime = 0 +	} +} + +// Time returns the time in 100s of nanoseconds since 15 Oct 1582 encoded in +// uuid.  The time is only defined for version 1 and 2 UUIDs. +func (uuid UUID) Time() Time { +	time := int64(binary.BigEndian.Uint32(uuid[0:4])) +	time |= int64(binary.BigEndian.Uint16(uuid[4:6])) << 32 +	time |= int64(binary.BigEndian.Uint16(uuid[6:8])&0xfff) << 48 +	return Time(time) +} + +// ClockSequence returns the clock sequence encoded in uuid. +// The clock sequence is only well defined for version 1 and 2 UUIDs. +func (uuid UUID) ClockSequence() int { +	return int(binary.BigEndian.Uint16(uuid[8:10])) & 0x3fff +}  | 
