chainhash

README

chainhash

chainhash provides a generic hash type and associated functions that allows the specific hash algorithm to be abstracted.

Installation and updating

$ go get -u github.com/bitum-project/bitumd/chaincfg/chainhash

License

Package chainhash is licensed under the copyfree ISC License.

Documentation

Overview

Package chainhash provides abstracted hash functionality.

This package provides a generic hash type and associated functions that allows the specific hash algorithm to be abstracted.

Index

• Constants
• Variables
• func Decode(dst *Hash, src string) error
• func HashB(b []byte) []byte
• func HashFunc(b []byte) [blake256.Size]byte
• func PoWHashB(b []byte) []byte
• func XORBytes(b1 []byte, b2 []byte)
• type Hash
  • func HashH(b []byte) Hash
  • func NewHash(newHash []byte) (*Hash, error)
  • func NewHashFromStr(hash string) (*Hash, error)
  • func PoWHashH(b []byte) Hash
  • func (hash *Hash) CloneBytes() []byte
  • func (hash *Hash) IsEqual(target *Hash) bool
  • func (hash *Hash) SetBytes(newHash []byte) error
  • func (hash Hash) String() string

Constants

const HashBlockSize = blake256.BlockSize

HashBlockSize is the block size of the hash algorithm in bytes.

const HashSize = 32

HashSize of array used to store hashes. See Hash.

const MaxHashStringSize = HashSize * 2

MaxHashStringSize is the maximum length of a Hash hash string.

Variables

var ErrHashStrSize = fmt.Errorf("max hash string length is %v bytes", MaxHashStringSize)

ErrHashStrSize describes an error that indicates the caller specified a hash string that has too many characters.

var MagicBytes = []byte{
	0x3b, 0xe5, 0xd4, 0x9e, 0xca, 0x59, 0x81, 0x5b,
	0x7a, 0x5d, 0xa1, 0xbb, 0x65, 0x37, 0x6f, 0x5d,
	0x04, 0xf4, 0x3b, 0x90, 0x2a, 0x41, 0x3a, 0xe5,
	0x8f, 0x98, 0x87, 0x93, 0xf9, 0x41, 0x67, 0x35,
}

MagicBytes is the magic 256-bit random number used for Proof-of-Work in Bitum.

Functions

func Decode

func Decode(dst *Hash, src string) error

Decode decodes the byte-reversed hexadecimal string encoding of a Hash to a destination.

func HashB

func HashB(b []byte) []byte

HashB calculates hash(b) and returns the resulting bytes.

func HashFunc

func HashFunc(b []byte) [blake256.Size]byte

HashFunc calculates the hash of the supplied bytes. TODO(jcv) Should modify blake256 so it has the same interface as blake2 and sha256 so these function can look more like btcsuite. Then should try to get it to the upstream blake256 repo

func PoWHashB

func PoWHashB(b []byte) []byte

PoWHashB calculates (hash(hash(b) ^ MagicBytes) ^ MagicBytes) and returns the resulting bytes

func XORBytes

func XORBytes(b1 []byte, b2 []byte)

XORBytes modifies b1 by pefroming a bitwise XOR with respective elements in b2

Types

type Hash

type Hash [HashSize]byte

Hash is used in several of the messages and common structures. It is a generic type so that it can represent any fixed-size hash as specified by the HashSize.

func HashH

func HashH(b []byte) Hash

HashH calculates hash(b) and returns the resulting bytes as a Hash.

func NewHash

func NewHash(newHash []byte) (*Hash, error)

NewHash returns a new Hash from a byte slice. An error is returned if the number of bytes passed in is not HashSize.

func NewHashFromStr

func NewHashFromStr(hash string) (*Hash, error)

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 PoWHashH

func PoWHashH(b []byte) Hash

PoWHashH calculates (hash(hash(b) ^ MagicBytes) ^ MagicBytes) and returns the resulting bytes as a Hash.

func (*Hash) CloneBytes

func (hash *Hash) CloneBytes() []byte

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) IsEqual

func (hash *Hash) IsEqual(target *Hash) bool

IsEqual returns true if target is the same as hash.

func (*Hash) SetBytes

func (hash *Hash) SetBytes(newHash []byte) error

SetBytes sets the bytes which represent the hash. An error is returned if the number of bytes passed in is not HashSize.

func (Hash) String

func (hash Hash) String() string

String returns the Hash as the hexadecimal string of the byte-reversed hash.