frostfs-api-go-pogpp/refs/cid.go

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2019-11-18 13:34:06 +00:00
package refs
import (
"bytes"
"crypto/sha256"
"github.com/mr-tron/base58"
"github.com/pkg/errors"
)
// CIDForBytes creates CID for passed bytes.
func CIDForBytes(data []byte) CID { return sha256.Sum256(data) }
// CIDFromBytes parses CID from passed bytes.
func CIDFromBytes(data []byte) (cid CID, err error) {
if ln := len(data); ln != CIDSize {
return CID{}, errors.Wrapf(ErrWrongDataSize, "expect=%d, actual=%d", CIDSize, ln)
}
copy(cid[:], data)
return
}
// CIDFromString parses CID from string representation of CID.
func CIDFromString(c string) (CID, error) {
var cid CID
decoded, err := base58.Decode(c)
if err != nil {
return cid, err
}
return CIDFromBytes(decoded)
}
// Size returns size of CID (CIDSize).
func (c CID) Size() int { return CIDSize }
// Parse tries to parse CID from string representation.
func (c *CID) Parse(cid string) error {
var err error
if *c, err = CIDFromString(cid); err != nil {
return err
}
return nil
}
// Empty checks that current CID is empty.
func (c CID) Empty() bool { return bytes.Equal(c.Bytes(), emptyCID) }
// Equal checks that current CID is equal to passed CID.
func (c CID) Equal(cid CID) bool { return bytes.Equal(c.Bytes(), cid.Bytes()) }
// Marshal returns CID bytes representation.
func (c CID) Marshal() ([]byte, error) { return c.Bytes(), nil }
// MarshalBinary returns CID bytes representation.
func (c CID) MarshalBinary() ([]byte, error) { return c.Bytes(), nil }
// MarshalTo marshal CID to bytes representation into passed bytes.
func (c *CID) MarshalTo(data []byte) (int, error) { return copy(data, c.Bytes()), nil }
// ProtoMessage method to satisfy proto.Message interface.
func (c CID) ProtoMessage() {}
// String returns string representation of CID.
func (c CID) String() string { return base58.Encode(c[:]) }
// Reset resets current CID to zero value.
func (c *CID) Reset() { *c = CID{} }
// Bytes returns CID bytes representation.
func (c CID) Bytes() []byte {
buf := make([]byte, CIDSize)
copy(buf, c[:])
return buf
}
// UnmarshalBinary tries to parse bytes representation of CID.
func (c *CID) UnmarshalBinary(data []byte) error { return c.Unmarshal(data) }
// Unmarshal tries to parse bytes representation of CID.
func (c *CID) Unmarshal(data []byte) error {
if ln := len(data); ln != CIDSize {
return errors.Wrapf(ErrWrongDataSize, "expect=%d, actual=%d", CIDSize, ln)
}
copy((*c)[:], data)
return nil
}
// Verify validates that current CID is generated for passed bytes data.
func (c CID) Verify(data []byte) error {
if id := CIDForBytes(data); !bytes.Equal(c[:], id[:]) {
return errors.New("wrong hash for data")
}
return nil
}