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Miloslav Trmač 069edc3adf Add (podman {image,manifest} push --sign-by-sigstore=param-file.yaml)
(podman push) and (podman manifest push) now support --sign-by-sigstore=param-file,
using the containers-sigstore-signing-params.yaml(5) file format.

That notably adds support for Fulcio and Rekor signing.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>
2023-01-27 16:47:32 +01:00

56 lines
1.5 KiB
Go

package ksuid
import (
"encoding/binary"
"errors"
"math"
)
// Sequence is a KSUID generator which produces a sequence of ordered KSUIDs
// from a seed.
//
// Up to 65536 KSUIDs can be generated by for a single seed.
//
// A typical usage of a Sequence looks like this:
//
// seq := ksuid.Sequence{
// Seed: ksuid.New(),
// }
// id, err := seq.Next()
//
// Sequence values are not safe to use concurrently from multiple goroutines.
type Sequence struct {
// The seed is used as base for the KSUID generator, all generated KSUIDs
// share the same leading 18 bytes of the seed.
Seed KSUID
count uint32 // uint32 for overflow, only 2 bytes are used
}
// Next produces the next KSUID in the sequence, or returns an error if the
// sequence has been exhausted.
func (seq *Sequence) Next() (KSUID, error) {
id := seq.Seed // copy
count := seq.count
if count > math.MaxUint16 {
return Nil, errors.New("too many IDs were generated")
}
seq.count++
return withSequenceNumber(id, uint16(count)), nil
}
// Bounds returns the inclusive min and max bounds of the KSUIDs that may be
// generated by the sequence. If all ids have been generated already then the
// returned min value is equal to the max.
func (seq *Sequence) Bounds() (min KSUID, max KSUID) {
count := seq.count
if count > math.MaxUint16 {
count = math.MaxUint16
}
return withSequenceNumber(seq.Seed, uint16(count)), withSequenceNumber(seq.Seed, math.MaxUint16)
}
func withSequenceNumber(id KSUID, n uint16) KSUID {
binary.BigEndian.PutUint16(id[len(id)-2:], n)
return id
}