add uuid generator

pkg/uuid/internal_generator.go

@@ -0,0 +1,100 @@
+package uuid
+
+import (
+	"sync/atomic"
+	"time"
+
+	"github.com/mayswind/lab/pkg/settings"
+)
+
+const (
+	INTERNAL_UUID_UNIX_TIME_BITS = 32
+	INTERNAL_UUID_UNIX_TIME_MASK = (1 << INTERNAL_UUID_UNIX_TIME_BITS) - 1
+
+	INTERNAL_UUID_TYPE_BITS = 4
+	INTERNAL_UUID_TYPE_MASK = (1 << INTERNAL_UUID_TYPE_BITS) - 1
+
+	INTERNAL_UUID_SERVER_ID_BITS = 8
+	INTERNAL_UUID_SERVER_ID_MASK = (1 << INTERNAL_UUID_SERVER_ID_BITS) - 1
+
+	INTERNAL_UUID_SEQ_ID_BITS = 19
+	INTERNAL_UUID_SEQ_ID_MASK = (1 << INTERNAL_UUID_SEQ_ID_BITS) - 1
+
+	SEQ_NUMBER_ID_BITS = 32
+	SEQ_NUMBER_ID_MASK = (1 << SEQ_NUMBER_ID_BITS) - 1
+)
+
+type InternalUuidInfo struct {
+	UnixTime     uint32
+	UuidType     uint8
+	UuidServerId uint8
+	SequentialId uint32
+}
+
+type InternalUuidGenerator struct {
+	uuidServerId   uint8
+	uuidSeqNumbers [1 << INTERNAL_UUID_TYPE_BITS]uint64
+}
+
+func NewInternalUuidGenerator(config *settings.Config) (*InternalUuidGenerator, error) {
+	generator := &InternalUuidGenerator{
+		uuidServerId: config.UuidServerId,
+	}
+
+	return generator, nil
+}
+
+func (u *InternalUuidGenerator) GenerateUuid(idType UuidType) int64 {
+	// 63bits = unixTime(32bits) + uuidType(4bits) + uuidServerId(8bits) + sequentialNumber(19bits)
+
+	var unixTime uint64
+	var newSeqId uint64
+	uuidType := uint8(idType)
+
+	for {
+		unixTime = uint64(time.Now().Unix())
+		newSeqId = atomic.AddUint64(&u.uuidSeqNumbers[uuidType], 1)
+
+		if newSeqId>>SEQ_NUMBER_ID_BITS == unixTime {
+			break
+		}
+
+		currentSeqId := newSeqId
+		newSeqId = unixTime << SEQ_NUMBER_ID_BITS
+
+		if atomic.CompareAndSwapUint64(&u.uuidSeqNumbers[uuidType], currentSeqId, newSeqId) {
+			break
+		}
+	}
+
+	seqId := newSeqId & SEQ_NUMBER_ID_MASK
+
+	unixTimePart := (int64(unixTime) & INTERNAL_UUID_UNIX_TIME_MASK) << (INTERNAL_UUID_TYPE_BITS + INTERNAL_UUID_SERVER_ID_BITS + INTERNAL_UUID_SEQ_ID_BITS)
+	uuidTypePart := (int64(uuidType) & INTERNAL_UUID_TYPE_MASK) << (INTERNAL_UUID_SERVER_ID_BITS + INTERNAL_UUID_SEQ_ID_BITS)
+	uuidServerIdPart := (int64(u.uuidServerId) & INTERNAL_UUID_SERVER_ID_MASK) << INTERNAL_UUID_SEQ_ID_BITS
+	seqIdPart := int64(seqId) & INTERNAL_UUID_SEQ_ID_MASK
+
+	uuid := unixTimePart | uuidTypePart | uuidServerIdPart | seqIdPart
+
+	return uuid
+}
+
+func (u *InternalUuidGenerator) ParseUuidInfo(uuid int64) *InternalUuidInfo {
+	seqId := uint32(uuid & INTERNAL_UUID_SEQ_ID_MASK)
+	uuid = uuid >> INTERNAL_UUID_SEQ_ID_BITS
+
+	uuidServerId := uint8(uuid & INTERNAL_UUID_SERVER_ID_MASK)
+	uuid = uuid >> INTERNAL_UUID_SERVER_ID_BITS
+
+	uuidType := uint8(uuid & INTERNAL_UUID_TYPE_MASK)
+	uuid = uuid >> INTERNAL_UUID_TYPE_BITS
+
+	unixTime := uint32(uuid & INTERNAL_UUID_UNIX_TIME_MASK)
+
+	return &InternalUuidInfo{
+		UnixTime:     unixTime,
+		UuidType:     uuidType,
+		UuidServerId: uuidServerId,
+		SequentialId: seqId,
+	}
+}