distribution/vendor/github.com/stevvooe/resumable/resumable.go
Stephen J Day f01bcc8f62
vendor: update resumable dependency
Updates resumable hash implementation to Go 1.8 equivalent. This should
be a major speedup, since it includes a number of optimizations from Go
1.7.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2017-05-16 15:12:58 -07:00

51 lines
1.7 KiB
Go

// Package resumable registers resumable versions of hash functions. Resumable
// varieties of hash functions are available via the standard crypto package.
// Support can be checked by type assertion against the resumable.Hash
// interface.
//
// While one can use these sub-packages directly, it makes more sense to
// register them using side-effect imports:
//
// import _ "github.com/stevvooe/resumable/sha256"
//
// This will make the resumable hashes available to the application through
// the standard crypto package. For example, if a new sha256 is required, one
// should use the following:
//
// h := crypto.SHA256.New()
//
// Such a features allows one to control the inclusion of resumable hash
// support in a single file. Applications that require the resumable hash
// implementation can type switch to detect support, while other parts of the
// application can be completely oblivious to the presence of the alternative
// hash functions.
//
// Also note that the implementations available in this package are completely
// untouched from their Go counterparts in the standard library. Only an extra
// file is added to each package to implement the extra resumable hash
// functions.
package resumable
import (
"fmt"
"hash"
)
var (
// ErrBadState is returned if Restore fails post-unmarshaling validation.
ErrBadState = fmt.Errorf("bad hash state")
)
// Hash is the common interface implemented by all resumable hash functions.
type Hash interface {
hash.Hash
// Len returns the number of bytes written to the Hash so far.
Len() int64
// State returns a snapshot of the state of the Hash.
State() ([]byte, error)
// Restore resets the Hash to the given state.
Restore(state []byte) error
}