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shares.go
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shares.go
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package shares
import (
"encoding/binary"
"fmt"
"github.com/celestiaorg/celestia-app/pkg/appconsts"
"github.com/celestiaorg/nmt/namespace"
)
// Share contains the raw share data (including namespace ID).
type Share []byte
func NewShare(data []byte) (Share, error) {
if len(data) != appconsts.ShareSize {
return nil, fmt.Errorf("share data must be %d bytes, got %d", appconsts.ShareSize, len(data))
}
return Share(data), nil
}
func (s Share) NamespaceID() namespace.ID {
if len(s) < appconsts.NamespaceSize {
panic(fmt.Sprintf("share %s is too short to contain a namespace ID", s))
}
return namespace.ID(s[:appconsts.NamespaceSize])
}
func (s Share) InfoByte() (InfoByte, error) {
if len(s) < appconsts.NamespaceSize+appconsts.ShareInfoBytes {
return 0, fmt.Errorf("share %s is too short to contain an info byte", s)
}
// the info byte is the first byte after the namespace ID
unparsed := s[appconsts.NamespaceSize]
return ParseInfoByte(unparsed)
}
func (s Share) Version() (uint8, error) {
infoByte, err := s.InfoByte()
if err != nil {
return 0, err
}
return infoByte.Version(), nil
}
// IsSequenceStart returns true if this is the first share in a sequence.
func (s Share) IsSequenceStart() (bool, error) {
infoByte, err := s.InfoByte()
if err != nil {
return false, err
}
return infoByte.IsSequenceStart(), nil
}
// IsCompactShare returns true if this is a compact share.
func (s Share) IsCompactShare() bool {
return s.NamespaceID().Equal(appconsts.TxNamespaceID) || s.NamespaceID().Equal(appconsts.PayForBlobNamespaceID)
}
// SequenceLen returns the sequence length of this share and optionally an
// error. It returns 0, nil if this is a continuation share (i.e. doesn't
// contain a sequence length).
func (s Share) SequenceLen() (sequenceLen uint32, err error) {
isSequenceStart, err := s.IsSequenceStart()
if err != nil {
return 0, err
}
if !isSequenceStart {
return 0, nil
}
start := appconsts.NamespaceSize + appconsts.ShareInfoBytes
end := start + appconsts.SequenceLenBytes
if len(s) < end {
return 0, fmt.Errorf("share %s is too short to contain a sequence length", s)
}
return binary.BigEndian.Uint32(s[start:end]), nil
}
// IsPadding returns whether this share is padding or not.
func (s Share) IsPadding() (bool, error) {
isNamespacePadding, err := s.isNamespacePadding()
if err != nil {
return false, err
}
return isNamespacePadding || s.isTailPadding() || s.isReservedPadding(), nil
}
func (s Share) isNamespacePadding() (bool, error) {
isSequenceStart, err := s.IsSequenceStart()
if err != nil {
return false, err
}
sequenceLen, err := s.SequenceLen()
if err != nil {
return false, err
}
return isSequenceStart && sequenceLen == 0, nil
}
func (s Share) isTailPadding() bool {
return s.NamespaceID().Equal(appconsts.TailPaddingNamespaceID)
}
func (s Share) isReservedPadding() bool {
return s.NamespaceID().Equal(appconsts.ReservedPaddingNamespaceID)
}
func (s Share) ToBytes() []byte {
return []byte(s)
}
// RawData returns the raw share data. The raw share data does not contain the
// namespace ID, info byte, sequence length, or reserved bytes.
func (s Share) RawData() (rawData []byte, err error) {
if len(s) < s.rawDataStartIndex() {
return rawData, fmt.Errorf("share %s is too short to contain raw data", s)
}
return s[s.rawDataStartIndex():], nil
}
func (s Share) rawDataStartIndex() int {
isStart, err := s.IsSequenceStart()
if err != nil {
panic(err)
}
if isStart && s.IsCompactShare() {
return appconsts.NamespaceSize + appconsts.ShareInfoBytes + appconsts.SequenceLenBytes + appconsts.CompactShareReservedBytes
} else if isStart && !s.IsCompactShare() {
return appconsts.NamespaceSize + appconsts.ShareInfoBytes + appconsts.SequenceLenBytes
} else if !isStart && s.IsCompactShare() {
return appconsts.NamespaceSize + appconsts.ShareInfoBytes + appconsts.CompactShareReservedBytes
} else if !isStart && !s.IsCompactShare() {
return appconsts.NamespaceSize + appconsts.ShareInfoBytes
} else {
panic(fmt.Sprintf("unable to determine the rawDataStartIndex for share %s", s))
}
}
func ToBytes(shares []Share) (bytes [][]byte) {
bytes = make([][]byte, len(shares))
for i, share := range shares {
bytes[i] = []byte(share)
}
return bytes
}
func FromBytes(bytes [][]byte) (shares []Share) {
shares = make([]Share, len(bytes))
for i, b := range bytes {
shares[i] = Share(b)
}
return shares
}