163 lines
3.5 KiB
Go
163 lines
3.5 KiB
Go
package checksum
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import (
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"crypto/sha256"
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"encoding/hex"
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"errors"
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"fmt"
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"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs"
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"git.frostfs.info/TrueCloudLab/tzhash/tz"
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)
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// Checksum represents checksum of some digital data.
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//
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// Checksum is mutually compatible with git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/refs.Checksum
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// message. See ReadFromV2 / WriteToV2 methods.
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//
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// Instances can be created using built-in var declaration.
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//
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// Note that direct typecast is not safe and may result in loss of compatibility:
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//
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// _ = Checksum(refs.Checksum{}) // not recommended
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type Checksum refs.Checksum
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// Type represents the enumeration
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// of checksum types.
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type Type refs.ChecksumType
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const (
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// Unknown is an undefined checksum type.
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Unknown Type = Type(refs.UnknownChecksum)
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// SHA256 is a SHA256 checksum type.
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SHA256 = Type(refs.SHA256)
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// TZ is a Tillich-Zémor checksum type.
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TZ = Type(refs.TillichZemor)
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)
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// ReadFromV2 reads Checksum from the refs.Checksum message. Checks if the
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// message conforms to FrostFS API V2 protocol.
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//
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// See also WriteToV2.
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func (c *Checksum) ReadFromV2(m refs.Checksum) error {
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if len(m.GetSum()) == 0 {
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return errors.New("missing value")
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}
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switch m.GetType() {
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default:
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return fmt.Errorf("unsupported type %v", m.GetType())
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case refs.SHA256, refs.TillichZemor:
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}
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*c = Checksum(m)
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return nil
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}
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// WriteToV2 writes Checksum to the refs.Checksum message.
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// The message must not be nil.
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//
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// See also ReadFromV2.
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func (c Checksum) WriteToV2(m *refs.Checksum) {
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*m = (refs.Checksum)(c)
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}
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// Type returns checksum type.
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//
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// Zero Checksum has Unknown checksum type.
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//
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// See also SetTillichZemor and SetSHA256.
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func (c Checksum) Type() Type {
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v2 := (refs.Checksum)(c)
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switch v2.GetType() {
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case refs.SHA256:
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return SHA256
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case refs.TillichZemor:
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return TZ
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default:
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return Unknown
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}
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}
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// Value returns checksum bytes. Return value
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// MUST NOT be mutated.
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//
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// Zero Checksum has nil sum.
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//
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// See also SetTillichZemor and SetSHA256.
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func (c Checksum) Value() []byte {
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v2 := (refs.Checksum)(c)
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return v2.GetSum()
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}
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// SetSHA256 sets checksum to SHA256 hash.
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//
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// See also Calculate.
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func (c *Checksum) SetSHA256(v [sha256.Size]byte) {
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v2 := (*refs.Checksum)(c)
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v2.SetType(refs.SHA256)
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v2.SetSum(v[:])
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}
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// Calculate calculates checksum and sets it
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// to the passed checksum. Checksum must not be nil.
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//
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// Does nothing if the passed type is not one of the:
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// - SHA256;
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// - TZ.
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//
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// Does not mutate the passed value.
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//
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// See also SetSHA256, SetTillichZemor.
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func Calculate(c *Checksum, t Type, v []byte) {
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switch t {
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case SHA256:
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c.SetSHA256(sha256.Sum256(v))
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case TZ:
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c.SetTillichZemor(tz.Sum(v))
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default:
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}
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}
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// SetTillichZemor sets checksum to Tillich-Zémor hash.
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//
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// See also Calculate.
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func (c *Checksum) SetTillichZemor(v [tz.Size]byte) {
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v2 := (*refs.Checksum)(c)
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v2.SetType(refs.TillichZemor)
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v2.SetSum(v[:])
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}
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// String implements fmt.Stringer.
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//
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// String is designed to be human-readable, and its format MAY differ between
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// SDK versions.
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func (c Checksum) String() string {
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v2 := (refs.Checksum)(c)
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return fmt.Sprintf("%s:%s", c.Type(), hex.EncodeToString(v2.GetSum()))
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}
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// String implements fmt.Stringer.
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//
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// String is designed to be human-readable, and its format MAY differ between
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// SDK versions.
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func (m Type) String() string {
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var m2 refs.ChecksumType
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switch m {
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default:
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m2 = refs.UnknownChecksum
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case TZ:
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m2 = refs.TillichZemor
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case SHA256:
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m2 = refs.SHA256
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}
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return m2.String()
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}
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