MaysWind
126 lines
3.4 KiB
Go
126 lines
3.4 KiB
Go
package uuid
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import (
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"sync/atomic"
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"time"
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"github.com/mayswind/ezbookkeeping/pkg/settings"
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)
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// Length and mask of all information in uuid
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const (
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internalUuidUnixTimeBits = 32
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internalUuidUnixTimeMask = (1 << internalUuidUnixTimeBits) - 1
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internalUuidTypeBits = 4
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internalUuidTypeMask = (1 << internalUuidTypeBits) - 1
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internalUuidServerIdBits = 8
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internalUuidServerIdMask = (1 << internalUuidServerIdBits) - 1
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internalUuidSeqIdBits = 19
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internalUuidSeqIdMask = (1 << internalUuidSeqIdBits) - 1
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seqNumberIdBits = 32
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seqNumberIdMask = (1 << seqNumberIdBits) - 1
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)
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// InternalUuidInfo represents a struct which has all information in uuid
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type InternalUuidInfo struct {
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UnixTime uint32
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UuidType uint8
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UuidServerId uint8
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SequentialId uint32
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}
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// InternalUuidGenerator represents internal bundled uuid generator
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type InternalUuidGenerator struct {
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uuidSeqNumbers [1 << internalUuidTypeBits]uint64
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uuidServerId uint8
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}
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// NewInternalUuidGenerator returns a new internal uuid generator
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func NewInternalUuidGenerator(config *settings.Config) (*InternalUuidGenerator, error) {
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generator := &InternalUuidGenerator{
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uuidServerId: config.UuidServerId,
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}
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return generator, nil
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}
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// GenerateUuid generates a new uuid
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func (u *InternalUuidGenerator) GenerateUuid(idType UuidType) int64 {
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uuids := u.GenerateUuids(idType, 1)
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return uuids[0]
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}
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// GenerateUuids generates new uuids
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func (u *InternalUuidGenerator) GenerateUuids(idType UuidType, count uint8) []int64 {
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// 63bits = unixTime(32bits) + uuidType(4bits) + uuidServerId(8bits) + sequentialNumber(19bits)
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uuids := make([]int64, count)
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if count < 1 {
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return uuids
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}
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var unixTime uint64
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var newFirstSeqId uint64
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var newLastSeqId uint64
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uuidType := uint8(idType)
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for {
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unixTime = uint64(time.Now().Unix())
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newLastSeqId = atomic.AddUint64(&u.uuidSeqNumbers[uuidType], uint64(count))
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if newLastSeqId>>seqNumberIdBits == unixTime {
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newFirstSeqId = newLastSeqId - uint64(count-1)
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break
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}
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currentSeqId := newLastSeqId
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newFirstSeqId = unixTime << seqNumberIdBits
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newLastSeqId = newFirstSeqId + uint64(count-1)
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if atomic.CompareAndSwapUint64(&u.uuidSeqNumbers[uuidType], currentSeqId, newLastSeqId) {
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break
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}
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}
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for i := 0; i < int(count); i++ {
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seqId := (newFirstSeqId + uint64(i)) & seqNumberIdMask
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uuids[i] = u.assembleUuid(unixTime, uuidType, seqId)
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}
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return uuids
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}
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func (u *InternalUuidGenerator) parseInternalUuidInfo(uuid int64) *InternalUuidInfo {
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seqId := uint32(uuid & internalUuidSeqIdMask)
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uuid = uuid >> internalUuidSeqIdBits
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uuidServerId := uint8(uuid & internalUuidServerIdMask)
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uuid = uuid >> internalUuidServerIdBits
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uuidType := uint8(uuid & internalUuidTypeMask)
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uuid = uuid >> internalUuidTypeBits
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unixTime := uint32(uuid & internalUuidUnixTimeMask)
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return &InternalUuidInfo{
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UnixTime: unixTime,
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UuidType: uuidType,
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UuidServerId: uuidServerId,
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SequentialId: seqId,
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}
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}
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func (u *InternalUuidGenerator) assembleUuid(unixTime uint64, uuidType uint8, seqId uint64) int64 {
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unixTimePart := (int64(unixTime) & internalUuidUnixTimeMask) << (internalUuidTypeBits + internalUuidServerIdBits + internalUuidSeqIdBits)
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uuidTypePart := (int64(uuidType) & internalUuidTypeMask) << (internalUuidServerIdBits + internalUuidSeqIdBits)
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uuidServerIdPart := (int64(u.uuidServerId) & internalUuidServerIdMask) << internalUuidSeqIdBits
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seqIdPart := int64(seqId) & internalUuidSeqIdMask
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return unixTimePart | uuidTypePart | uuidServerIdPart | seqIdPart
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}
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