97 lines
3.4 KiB
Go
97 lines
3.4 KiB
Go
// Copyright (c) 2012 The gocql Authors. All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// The uuid package can be used to generate and parse universally unique
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// identifiers, a standardized format in the form of a 128 bit number.
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//
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// http://tools.ietf.org/html/rfc4122
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// Package uuid provides functions to create time-based UUIDs.
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package uuid // import "github.com/influxdata/influxdb/uuid"
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import (
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"sync/atomic"
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"time"
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)
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// UUID - unique identifier type representing a 128 bit number
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type UUID [16]byte
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var timeBase = time.Date(1582, time.October, 15, 0, 0, 0, 0, time.UTC).Unix()
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var hardwareAddr []byte
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var clockSeq uint32
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// TimeUUID generates a new time based UUID (version 1) using the current
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// time as the timestamp.
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func TimeUUID() UUID {
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return FromTime(time.Now())
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}
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// FromTime generates a new time based UUID (version 1) as described in
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// RFC 4122. This UUID contains the MAC address of the node that generated
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// the UUID, the given timestamp and a sequence number.
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func FromTime(aTime time.Time) UUID {
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var u UUID
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utcTime := aTime.In(time.UTC)
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t := uint64(utcTime.Unix()-timeBase)*10000000 + uint64(utcTime.Nanosecond()/100)
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u[0], u[1], u[2], u[3] = byte(t>>24), byte(t>>16), byte(t>>8), byte(t)
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u[4], u[5] = byte(t>>40), byte(t>>32)
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u[6], u[7] = byte(t>>56)&0x0F, byte(t>>48)
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clock := atomic.AddUint32(&clockSeq, 1)
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u[8] = byte(clock >> 8)
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u[9] = byte(clock)
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copy(u[10:], hardwareAddr)
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u[6] |= 0x10 // set version to 1 (time based uuid)
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u[8] &= 0x3F // clear variant
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u[8] |= 0x80 // set to IETF variant
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return u
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}
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// String returns the UUID in it's canonical form, a 32 digit hexadecimal
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// number in the form of xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
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func (u UUID) String() string {
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var offsets = [...]int{0, 2, 4, 6, 9, 11, 14, 16, 19, 21, 24, 26, 28, 30, 32, 34}
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const hexString = "0123456789abcdef"
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r := make([]byte, 36)
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for i, b := range u {
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r[offsets[i]] = hexString[b>>4]
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r[offsets[i]+1] = hexString[b&0xF]
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}
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r[8] = '-'
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r[13] = '-'
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r[18] = '-'
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r[23] = '-'
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return string(r)
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}
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