+++ /dev/null
-// Copyright (c) 2013-2016 The btcsuite developers
-// Copyright (c) 2015 The Decred developers
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-package chainhash
-
-import (
- "encoding/hex"
- "fmt"
-)
-
-// HashSize of array used to store hashes. See Hash.
-const HashSize = 32
-
-// MaxHashStringSize is the maximum length of a Hash hash string.
-const MaxHashStringSize = HashSize * 2
-
-// ErrHashStrSize describes an error that indicates the caller specified a hash
-// string that has too many characters.
-var ErrHashStrSize = fmt.Errorf("max hash string length is %v bytes", MaxHashStringSize)
-
-// Hash is used in several of the bitcoin messages and common structures. It
-// typically represents the double sha256 of data.
-type Hash [HashSize]byte
-
-// String returns the Hash as the hexadecimal string of the byte-reversed
-// hash.
-func (hash Hash) String() string {
- for i := 0; i < HashSize/2; i++ {
- hash[i], hash[HashSize-1-i] = hash[HashSize-1-i], hash[i]
- }
- return hex.EncodeToString(hash[:])
-}
-
-// CloneBytes returns a copy of the bytes which represent the hash as a byte
-// slice.
-//
-// NOTE: It is generally cheaper to just slice the hash directly thereby reusing
-// the same bytes rather than calling this method.
-func (hash *Hash) CloneBytes() []byte {
- newHash := make([]byte, HashSize)
- copy(newHash, hash[:])
-
- return newHash
-}
-
-// SetBytes sets the bytes which represent the hash. An error is returned if
-// the number of bytes passed in is not HashSize.
-func (hash *Hash) SetBytes(newHash []byte) error {
- nhlen := len(newHash)
- if nhlen != HashSize {
- return fmt.Errorf("invalid hash length of %v, want %v", nhlen,
- HashSize)
- }
- copy(hash[:], newHash)
-
- return nil
-}
-
-// IsEqual returns true if target is the same as hash.
-func (hash *Hash) IsEqual(target *Hash) bool {
- if hash == nil && target == nil {
- return true
- }
- if hash == nil || target == nil {
- return false
- }
- return *hash == *target
-}
-
-// NewHash returns a new Hash from a byte slice. An error is returned if
-// the number of bytes passed in is not HashSize.
-func NewHash(newHash []byte) (*Hash, error) {
- var sh Hash
- err := sh.SetBytes(newHash)
- if err != nil {
- return nil, err
- }
- return &sh, err
-}
-
-// NewHashFromStr creates a Hash from a hash string. The string should be
-// the hexadecimal string of a byte-reversed hash, but any missing characters
-// result in zero padding at the end of the Hash.
-func NewHashFromStr(hash string) (*Hash, error) {
- ret := new(Hash)
- err := Decode(ret, hash)
- if err != nil {
- return nil, err
- }
- return ret, nil
-}
-
-// Decode decodes the byte-reversed hexadecimal string encoding of a Hash to a
-// destination.
-func Decode(dst *Hash, src string) error {
- // Return error if hash string is too long.
- if len(src) > MaxHashStringSize {
- return ErrHashStrSize
- }
-
- // Hex decoder expects the hash to be a multiple of two. When not, pad
- // with a leading zero.
- var srcBytes []byte
- if len(src)%2 == 0 {
- srcBytes = []byte(src)
- } else {
- srcBytes = make([]byte, 1+len(src))
- srcBytes[0] = '0'
- copy(srcBytes[1:], src)
- }
-
- // Hex decode the source bytes to a temporary destination.
- var reversedHash Hash
- _, err := hex.Decode(reversedHash[HashSize-hex.DecodedLen(len(srcBytes)):], srcBytes)
- if err != nil {
- return err
- }
-
- // Reverse copy from the temporary hash to destination. Because the
- // temporary was zeroed, the written result will be correctly padded.
- for i, b := range reversedHash[:HashSize/2] {
- dst[i], dst[HashSize-1-i] = reversedHash[HashSize-1-i], b
- }
-
- return nil
-}
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