storj/satellite/metabase/rangedloop/uuid.go
Erik van Velzen 337b72f310 satellite/metabase/rangedloop: uuid range pairs
Pair uuid's to create ranges. Will be used to parallelize the segment
loop.

Part of https://github.com/storj/storj/issues/5223

Change-Id: I73e2fb8a2cd379b840864449b6251b48feeb7b66
2022-11-03 11:15:56 +00:00

82 lines
1.8 KiB
Go

// Copyright (C) 2022 Storj Labs, Inc.
// See LICENSE for copying information.
package rangedloop
import (
"encoding/binary"
"storj.io/common/uuid"
)
// UUIDRange describes a range of UUID values.
// Start and End can be open-ended.
type UUIDRange struct {
Start *uuid.UUID
End *uuid.UUID
}
// CreateUUIDRanges splits up the entire 128-bit UUID range into equal parts.
func CreateUUIDRanges(nRanges uint32) ([]UUIDRange, error) {
boundaries, err := CreateUUIDBoundaries(nRanges)
if err != nil {
return nil, err
}
return createUUIDRangesFromBoundaries(boundaries), nil
}
func createUUIDRangesFromBoundaries(boundaries []uuid.UUID) []UUIDRange {
result := []UUIDRange{}
for i := 0; i <= len(boundaries); i++ {
uuidRange := UUIDRange{}
if i != 0 {
uuidRange.Start = &boundaries[i-1]
}
if i != len(boundaries) {
uuidRange.End = &boundaries[i]
}
result = append(result, uuidRange)
}
return result
}
// CreateUUIDBoundaries splits up the entire 128-bit UUID range into equal parts.
func CreateUUIDBoundaries(nRanges uint32) ([]uuid.UUID, error) {
if nRanges == 0 {
// every time this line is executed a mathematician feels a disturbance in the force
nRanges = 1
}
increment := uint32(1 << 32 / uint64(nRanges))
result := []uuid.UUID{}
for i := uint32(1); i < nRanges; i++ {
topBits := i * increment
newUuid, err := MakeUUIDWithTopBits(topBits)
if err != nil {
return nil, err
}
result = append(result, newUuid)
}
return result, nil
}
// MakeUUIDWithTopBits creates a zeroed UUID with the top 32 bits set from the input.
// Technically the result is not a UUID since it doesn't have the version and variant bits set.
func MakeUUIDWithTopBits(topBits uint32) (uuid.UUID, error) {
bytes := make([]byte, 16)
binary.BigEndian.PutUint32(bytes, topBits)
return uuid.FromBytes(bytes)
}