58 lines
1.7 KiB
Go
58 lines
1.7 KiB
Go
|
// Copyright (c) 2015 The Decred developers
|
||
|
|
// Copyright (c) 2016-2017 The btcsuite developers
|
||
|
|
// Use of this source code is governed by an ISC
|
||
|
|
// license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
package chainhash
|
||
|
|
|
||
|
|
import (
|
||
|
|
"crypto/sha256"
|
||
|
|
"io"
|
||
|
|
)
|
||
|
|
|
||
|
|
// HashB calculates hash(b) and returns the resulting bytes.
|
||
|
|
func HashB(b []byte) []byte {
|
||
|
|
hash := sha256.Sum256(b)
|
||
|
|
return hash[:]
|
||
|
|
}
|
||
|
|
|
||
|
|
// HashH calculates hash(b) and returns the resulting bytes as a Hash.
|
||
|
|
func HashH(b []byte) Hash {
|
||
|
|
return Hash(sha256.Sum256(b))
|
||
|
|
}
|
||
|
|
|
||
|
|
// DoubleHashB calculates hash(hash(b)) and returns the resulting bytes.
|
||
|
|
func DoubleHashB(b []byte) []byte {
|
||
|
|
first := sha256.Sum256(b)
|
||
|
|
second := sha256.Sum256(first[:])
|
||
|
|
return second[:]
|
||
|
|
}
|
||
|
|
|
||
|
|
// DoubleHashH calculates hash(hash(b)) and returns the resulting bytes as a
|
||
|
|
// Hash.
|
||
|
|
func DoubleHashH(b []byte) Hash {
|
||
|
|
first := sha256.Sum256(b)
|
||
|
|
return Hash(sha256.Sum256(first[:]))
|
||
|
|
}
|
||
|
|
|
||
|
|
// DoubleHashRaw calculates hash(hash(w)) where w is the resulting bytes from
|
||
|
|
// the given serialize function and returns the resulting bytes as a Hash.
|
||
|
|
func DoubleHashRaw(serialize func(w io.Writer) error) Hash {
|
||
|
|
// Encode the transaction into the hash. Ignore the error returns
|
||
|
|
// since the only way the encode could fail is being out of memory
|
||
|
|
// or due to nil pointers, both of which would cause a run-time panic.
|
||
|
|
h := sha256.New()
|
||
|
|
_ = serialize(h)
|
||
|
|
|
||
|
|
// This buf is here because Sum() will append the result to the passed
|
||
|
|
// in byte slice. Pre-allocating here saves an allocation on the second
|
||
|
|
// hash as we can reuse it. This allocation also does not escape to the
|
||
|
|
// heap, saving an allocation.
|
||
|
|
buf := make([]byte, 0, HashSize)
|
||
|
|
first := h.Sum(buf)
|
||
|
|
h.Reset()
|
||
|
|
h.Write(first)
|
||
|
|
res := h.Sum(buf)
|
||
|
|
return *(*Hash)(res)
|
||
|
|
}
|