initial

refs/cid.go

@@ -0,0 +1,96 @@
+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
+}