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package tmhash
import (
"crypto/sha256"
"hash"
)
const (
Size = sha256.Size
BlockSize = sha256.BlockSize
)
// New returns a new hash.Hash.
func New() hash.Hash {
return sha256.New()
}
// Sum returns the SHA256 of the bz.
func Sum(bz []byte) []byte {
h := sha256.Sum256(bz)
return h[:]
}
//-------------------------------------------------------------
const (
TruncatedSize = 20
)
type sha256trunc struct {
sha256 hash.Hash
}
func (h sha256trunc) Write(p []byte) (n int, err error) {
return h.sha256.Write(p)
}
func (h sha256trunc) Sum(b []byte) []byte {
shasum := h.sha256.Sum(b)
return shasum[:TruncatedSize]
}
func (h sha256trunc) Reset() {
h.sha256.Reset()
}
func (h sha256trunc) Size() int {
return TruncatedSize
}
func (h sha256trunc) BlockSize() int {
return h.sha256.BlockSize()
}
// NewTruncated returns a new hash.Hash.
func NewTruncated() hash.Hash {
return sha256trunc{
sha256: sha256.New(),
}
}
// SumTruncated returns the first 20 bytes of SHA256 of the bz.
func SumTruncated(bz []byte) []byte {
hash := sha256.Sum256(bz)
return hash[:TruncatedSize]
}