prysm-pulse/shared/htrutils/hashers.go
Paul Nelson c1c3b75867
Move generic HashTreeRoot funcs to //shared (#6167)
* Functions that are to be moved to //shared/htrutils captured in separate file.

* Move files into new //shared/htutils package

hash_function.go renamed to hashers.go

* Refactor to reference moved methods in new package

- Added import for htrutils to state and stateutil packages
- Update references to imported funcs (append "htrutils.")
- Updated funcs in htrutils to be exported where necessary

* Add tests
2020-06-18 10:15:13 +08:00

53 lines
1.3 KiB
Go

// Package htrutils defines HashTreeRoot utility functions.
package htrutils
import "encoding/binary"
// HashFn is the generic hash function signature.
type HashFn func(input []byte) [32]byte
// Hasher describes an interface through which we can
// perform hash operations on byte arrays,indices,etc.
type Hasher interface {
Hash(a []byte) [32]byte
Combi(a [32]byte, b [32]byte) [32]byte
MixIn(a [32]byte, i uint64) [32]byte
}
// HasherFunc defines a structure to hold a hash function and can be used for multiple rounds of
// hashing.
type HasherFunc struct {
b [64]byte
hashFunc HashFn
}
// NewHasherFunc is the constructor for the object
// that fulfills the Hasher interface.
func NewHasherFunc(h HashFn) *HasherFunc {
return &HasherFunc{
b: [64]byte{},
hashFunc: h,
}
}
// Hash utilizes the provided hash function for
// the object.
func (h *HasherFunc) Hash(a []byte) [32]byte {
return h.hashFunc(a)
}
// Combi appends the two inputs and hashes them.
func (h *HasherFunc) Combi(a [32]byte, b [32]byte) [32]byte {
copy(h.b[:32], a[:])
copy(h.b[32:], b[:])
return h.Hash(h.b[:])
}
// MixIn works like Combi, but using an integer as the second input.
func (h *HasherFunc) MixIn(a [32]byte, i uint64) [32]byte {
copy(h.b[:32], a[:])
copy(h.b[32:], make([]byte, 32, 32))
binary.LittleEndian.PutUint64(h.b[32:], i)
return h.Hash(h.b[:])
}