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ulid.go
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ulid.go
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/*
* Copyright (c) 2019 OysterPack, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Package ulids provides support for generating and parsing ULIDs
package ulids
import (
"crypto/rand"
"errors"
"github.com/oklog/ulid"
"sync"
)
// MonotonicULIDGenerator returns a function that generates ULID(s) in strictly increasing order.
// - is safe for concurrent use.
// - panics if a ULID fails to be generated
func MonotonicULIDGenerator() func() ulid.ULID {
var m sync.Mutex
entropy := ulid.Monotonic(rand.Reader, 0)
return func() (uid ulid.ULID) {
m.Lock()
uid = ulid.MustNew(ulid.Now(), entropy)
m.Unlock()
return
}
}
// RandomULIDGenerator returns a function that generates a cryptographically random ULID
// - this is ~5x slower than MonotonicULIDGenerator functions
// - panics if a ULID fails to be generated
func RandomULIDGenerator() func() ulid.ULID {
return func() ulid.ULID {
return MustNew()
}
}
// MustNew generates a new crypto/rand based ULID.
// - panics if a ULID fails to be generated
func MustNew() ulid.ULID {
return ulid.MustNew(ulid.Now(), rand.Reader)
}
// Parse tries to parse the id into a ULID.
func Parse(id string) (ulid.ULID, error) {
ulidID, err := ulid.Parse(id)
if err != nil {
return ulidID, err
}
if IsZero(ulidID) {
return ulidID, errors.New("ID must not be zero")
}
return ulidID, nil
}
// IsZero returns true if the id is a zero value
func IsZero(id ulid.ULID) bool {
return ulid.ULID{} == id
}