common

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 Go to latest Published: Aug 30, 2018 License: AGPL-3.0 Imports: 20 Imported by: 0

README

common

Build Status

The common package contains the ethereum utility library.

Installation

As a subdirectory the main go-ethereum repository, you get it with go get github.com/ethereum/go-ethereum.

Usage

RLP (Recursive Linear Prefix) Encoding

RLP Encoding is an encoding scheme used by the Ethereum project. It encodes any native value or list to a string.

More in depth information about the encoding scheme see the Wiki article.

rlp := common.Encode("doge")
fmt.Printf("%q\n", rlp) // => "\0x83dog"

rlp = common.Encode([]interface{}{"dog", "cat"})
fmt.Printf("%q\n", rlp) // => "\0xc8\0x83dog\0x83cat"
decoded := common.Decode(rlp)
fmt.Println(decoded) // => ["dog" "cat"]

Patricia Trie

Patricie Tree is a merkle trie used by the Ethereum project.

More in depth information about the (modified) Patricia Trie can be found on the Wiki.

The patricia trie uses a db as backend and could be anything as long as it satisfies the Database interface found in common/db.go.

db := NewDatabase()

// db, root
trie := common.NewTrie(db, "")

trie.Put("puppy", "dog")
trie.Put("horse", "stallion")
trie.Put("do", "verb")
trie.Put("doge", "coin")

// Look up the key "do" in the trie
out := trie.Get("do")
fmt.Println(out) // => verb

trie.Delete("puppy")

The patricia trie, in combination with RLP, provides a robust, cryptographically authenticated data structure that can be used to store all (key, value) bindings.

// ... Create db/trie

// Note that RLP uses interface slices as list
value := common.Encode([]interface{}{"one", 2, "three", []interface{}{42}})
// Store the RLP encoded value of the list
trie.Put("mykey", value)

Value

Value is a Generic Value which is used in combination with RLP data or ([])interface{} structures. It may serve as a bridge between RLP data and actual real values and takes care of all the type checking and casting. Unlike Go's reflect.Value it does not panic if it's unable to cast to the requested value. It simple returns the base value of that type (e.g. Slice() returns []interface{}, Uint() return 0, etc).

Creating a new Value

NewEmptyValue() returns a new *Value with it's initial value set to a []interface{}

AppendList() appends a list to the current value.

Append(v) appends the value (v) to the current value/list.

val := common.NewEmptyValue().Append(1).Append("2")
val.AppendList().Append(3)
Retrieving values

Get(i) returns the i item in the list.

Uint() returns the value as an unsigned int64.

Slice() returns the value as a interface slice.

Str() returns the value as a string.

Bytes() returns the value as a byte slice.

Len() assumes current to be a slice and returns its length.

Byte() returns the value as a single byte.

val := common.NewValue([]interface{}{1,"2",[]interface{}{3}})
val.Get(0).Uint() // => 1
val.Get(1).Str()  // => "2"
s := val.Get(2)   // => Value([]interface{}{3})
s.Get(0).Uint()   // => 3

Decoding

Decoding streams of RLP data is simplified

val := common.NewValueFromBytes(rlpData)
val.Get(0).Uint()

Encoding

Encoding from Value to RLP is done with the Encode method. The underlying value can be anything RLP can encode (int, str, lists, bytes)

val := common.NewValue([]interface{}{1,"2",[]interface{}{3}})
rlp := val.Encode()
// Store the rlp data
Store(rlp)

Documentation

Overview

Package common contains various helper functions.

Index

Constants

View Source 
const (
	HashLength       = 32
	AddressLength    = 42
	PubkeyHashLength = 20
)

Variables

View Source 
var (
	// ErrChecksumMismatch describes an error where decoding failed due
	// to a bad checksum.
	ErrChecksumMismatch = errors.New("checksum mismatch")

	// ErrUnknownAddressType describes an error where an address can not
	// decoded as a specific address type due to the string encoding
	// begining with an identifier byte unknown to any standard or
	// registered (via chaincfg.Register) network.
	ErrUnknownAddressType = errors.New("unknown address type")

	// ErrAddressCollision describes an error where an address can not
	// be uniquely determined as either a pay-to-pubkey-hash or
	// pay-to-script-hash address since the leading identifier is used for
	// describing both address kinds, but for different networks.  Rather
	// than assuming or defaulting to one or the other, this error is
	// returned and the caller must decide how to decode the address.
	ErrAddressCollision = errors.New("address collision")

	// ErrUnsupportedWitnessVer describes an error where a segwit address being
	// decoded has an unsupported witness version.
	ErrUnsupportedWitnessVer = errors.New("unsupported witness version")

	// ErrUnsupportedWitnessProgLen describes an error where a segwit address
	// being decoded has an unsupported witness program length.
	ErrUnsupportedWitnessProgLen = errors.New("unsupported witness program length")
)
View Source 
var (
	Big1     = big.NewInt(1)
	Big2     = big.NewInt(2)
	Big3     = big.NewInt(3)
	Big0     = big.NewInt(0)
	BigTrue  = Big1
	BigFalse = Big0
	Big32    = big.NewInt(32)
	Big36    = big.NewInt(36)
	Big97    = big.NewInt(97)
	Big98    = big.NewInt(98)
	Big256   = big.NewInt(0xff)
	Big257   = big.NewInt(257)
	MaxBig   = String2Big("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
)

Common big integers often used

View Source 
var (
	Douglas  = BigPow(10, 42)
	Einstein = BigPow(10, 21)
	Ether    = BigPow(10, 18)
	Finney   = BigPow(10, 15)
	Szabo    = BigPow(10, 12)
	Shannon  = BigPow(10, 9)
	Babbage  = BigPow(10, 6)
	Ada      = BigPow(10, 3)
	Wei      = big.NewInt(1)
)

The different number of units

Functions

func AbsolutePath 

func AbsolutePath(Datadir string, filename string) string

func Big 

func Big(num string) *big.Int

Big

Shortcut for new(big.Int).SetString(..., 0)

func BigCopy 

func BigCopy(src *big.Int) *big.Int

Big copy

Creates a copy of the given big integer

func BigD 

func BigD(data []byte) *big.Int

func BigMax 

func BigMax(x, y *big.Int) *big.Int

Big max

Returns the maximum size big integer

func BigMin 

func BigMin(x, y *big.Int) *big.Int

Big min

Returns the minimum size big integer

func BigPow 

func BigPow(a, b int) *big.Int

Big pow

Returns the power of two big integers

func BigToBytes 

func BigToBytes(num *big.Int, base int) []byte

Big to bytes

Returns the bytes of a big integer with the size specified by **base** Attempts to pad the byte array with zeros.

func BitTest 

func BitTest(num *big.Int, i int) bool

func ByteSliceToInterface 

func ByteSliceToInterface(slice [][]byte) (ret []interface{})

func Bytes2Big 

func Bytes2Big(data []byte) *big.Int

func Bytes2Hex 

func Bytes2Hex(d []byte) string

func BytesToBig 

func BytesToBig(data []byte) *big.Int

Bytes2Big

func BytesToNumber 

func BytesToNumber(b []byte) uint64

Bytes to number

Attempts to cast a byte slice to a unsigned integer

func BytesToUnit64 

func BytesToUnit64(b []byte) uint64

func CopyBytes 

func CopyBytes(b []byte) (copiedBytes []byte)

Copy bytes

Returns an exact copy of the provided bytes

func CurrencyToString 

func CurrencyToString(num *big.Int) string

Currency to string Returns a string representing a human readable format

func EmptyHash 

func EmptyHash(h Hash) bool

func ExpandHomePath 

func ExpandHomePath(p string) (path string)

func FileExist 

func FileExist(filePath string) bool

func FirstBitSet 

func FirstBitSet(v *big.Int) int

func FormatData 

func FormatData(data string) []byte

func FromHex 

func FromHex(s string) []byte

func HasHexPrefix 

func HasHexPrefix(str string) bool

func Hex2Bytes 

func Hex2Bytes(str string) []byte

func Hex2BytesFixed 

func Hex2BytesFixed(str string, flen int) []byte

func HomeDir 

func HomeDir() string

func IsHex 

func IsHex(str string) bool

func LeftPadBytes 

func LeftPadBytes(slice []byte, l int) []byte

func LeftPadString 

func LeftPadString(str string, l int) string

func LoadJSON 

func LoadJSON(file string, val interface{}) error

LoadJSON reads the given file and unmarshals its content.

func MakeName 

func MakeName(name, version string) string

MakeName creates a node name that follows the ethereum convention for such names. It adds the operation system name and Go runtime version the name.

func NumberToBytes 

func NumberToBytes(num interface{}, bits int) []byte

Number to bytes

Returns the number in bytes with the specified base

func ParseData 

func ParseData(data ...interface{}) (ret []byte)

func PrintDepricationWarning 

func PrintDepricationWarning(str string)

PrintDepricationWarning prinst the given string in a box using fmt.Println.

func ReadVarInt 

func ReadVarInt(buff []byte) (ret uint64)

Read variable int

Read a variable length number in big endian byte order

func Report 

func Report(extra ...interface{})

Report gives off a warning requesting the user to submit an issue to the github tracker.

func RightPadBytes 

func RightPadBytes(slice []byte, l int) []byte

func RightPadString 

func RightPadString(str string, l int) string

func S256 

func S256(x *big.Int) *big.Int

func String2Big 

func String2Big(num string) *big.Int

func StringToByteFunc 

func StringToByteFunc(str string, cb func(str string) []byte) (ret []byte)

func ToAddress 

func ToAddress(slice []byte) (addr []byte)

func ToHex 

func ToHex(b []byte) string

func U256 

func U256(x *big.Int) *big.Int

func Unit64ToBytes 

func Unit64ToBytes(n uint64) []byte

Types

type Address 

type Address interface {
	// String returns the string encoding of the transaction output
	// destination.
	//
	// Please note that String differs subtly from EncodeAddress: String
	// will return the value as a string without any conversion, while
	// EncodeAddress may convert destination types (for example,
	// converting pubkeys to P2PKH addresses) before encoding as a
	// payment address string.
	String() string

	// EncodeAddress returns the string encoding of the payment address
	// associated with the Address value.  See the comment on String
	// for how this method differs from String.
	EncodeAddress() string

	// ScriptAddress returns the raw bytes of the address to be used
	// when inserting the address into a txout's script.
	ScriptAddress() []byte

	// IsForNet returns whether or not the address is associated with the
	// passed bytom network.
	IsForNet(*consensus.Params) bool
}

Address is an interface type for any type of destination a transaction output may spend to. This includes pay-to-pubkey (P2PK), pay-to-pubkey-hash (P2PKH), and pay-to-script-hash (P2SH). Address is designed to be generic enough that other kinds of addresses may be added in the future without changing the decoding and encoding API.

func DecodeAddress 

func DecodeAddress(addr string, param *consensus.Params) (Address, error)

DecodeAddress decodes the string encoding of an address and returns the Address if addr is a valid encoding for a known address type.

The bytom network the address is associated with is extracted if possible. When the address does not encode the network, such as in the case of a raw public key, the address will be associated with the passed defaultNet.

type AddressWitnessPubKeyHash 

type AddressWitnessPubKeyHash struct {
	// contains filtered or unexported fields
}

AddressWitnessPubKeyHash is an Address for a pay-to-witness-pubkey-hash (P2WPKH) output. See BIP 173 for further details regarding native segregated witness address encoding: https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki

func NewAddressWitnessPubKeyHash 

func NewAddressWitnessPubKeyHash(witnessProg []byte, param *consensus.Params) (*AddressWitnessPubKeyHash, error)

NewAddressWitnessPubKeyHash returns a new AddressWitnessPubKeyHash.

func (*AddressWitnessPubKeyHash) EncodeAddress 

func (a *AddressWitnessPubKeyHash) EncodeAddress() string

EncodeAddress returns the bech32 string encoding of an AddressWitnessPubKeyHash. Part of the Address interface.

func (*AddressWitnessPubKeyHash) Hash160 

func (a *AddressWitnessPubKeyHash) Hash160() *[20]byte

Hash160 returns the witness program of the AddressWitnessPubKeyHash as a byte array.

func (*AddressWitnessPubKeyHash) Hrp 

func (a *AddressWitnessPubKeyHash) Hrp() string

Hrp returns the human-readable part of the bech32 encoded AddressWitnessPubKeyHash.

func (*AddressWitnessPubKeyHash) IsForNet 

func (a *AddressWitnessPubKeyHash) IsForNet(param *consensus.Params) bool

IsForNet returns whether or not the AddressWitnessPubKeyHash is associated with the passed bitcoin network. Part of the Address interface.

func (*AddressWitnessPubKeyHash) ScriptAddress 

func (a *AddressWitnessPubKeyHash) ScriptAddress() []byte

ScriptAddress returns the witness program for this address. Part of the Address interface.

func (*AddressWitnessPubKeyHash) String 

func (a *AddressWitnessPubKeyHash) String() string

String returns a human-readable string for the AddressWitnessPubKeyHash. This is equivalent to calling EncodeAddress, but is provided so the type can be used as a fmt.Stringer. Part of the Address interface.

func (*AddressWitnessPubKeyHash) WitnessProgram 

func (a *AddressWitnessPubKeyHash) WitnessProgram() []byte

WitnessProgram returns the witness program of the AddressWitnessPubKeyHash.

func (*AddressWitnessPubKeyHash) WitnessVersion 

func (a *AddressWitnessPubKeyHash) WitnessVersion() byte

WitnessVersion returns the witness version of the AddressWitnessPubKeyHash.

type AddressWitnessScriptHash 

type AddressWitnessScriptHash struct {
	// contains filtered or unexported fields
}

AddressWitnessScriptHash is an Address for a pay-to-witness-script-hash (P2WSH) output. See BIP 173 for further details regarding native segregated witness address encoding: https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki

func NewAddressWitnessScriptHash 

func NewAddressWitnessScriptHash(witnessProg []byte, param *consensus.Params) (*AddressWitnessScriptHash, error)

NewAddressWitnessScriptHash returns a new AddressWitnessPubKeyHash.

func (*AddressWitnessScriptHash) EncodeAddress 

func (a *AddressWitnessScriptHash) EncodeAddress() string

EncodeAddress returns the bech32 string encoding of an AddressWitnessScriptHash. Part of the Address interface.

func (*AddressWitnessScriptHash) Hrp 

func (a *AddressWitnessScriptHash) Hrp() string

Hrp returns the human-readable part of the bech32 encoded AddressWitnessScriptHash.

func (*AddressWitnessScriptHash) IsForNet 

func (a *AddressWitnessScriptHash) IsForNet(param *consensus.Params) bool

IsForNet returns whether or not the AddressWitnessScriptHash is associated with the passed bytom network. Part of the Address interface.

func (*AddressWitnessScriptHash) ScriptAddress 

func (a *AddressWitnessScriptHash) ScriptAddress() []byte

ScriptAddress returns the witness program for this address. Part of the Address interface.

func (*AddressWitnessScriptHash) Sha256 

func (a *AddressWitnessScriptHash) Sha256() *[32]byte

Sha256 returns the witness program of the AddressWitnessPubKeyHash as a byte array.

func (*AddressWitnessScriptHash) String 

func (a *AddressWitnessScriptHash) String() string

String returns a human-readable string for the AddressWitnessScriptHash. This is equivalent to calling EncodeAddress, but is provided so the type can be used as a fmt.Stringer. Part of the Address interface.

func (*AddressWitnessScriptHash) WitnessProgram 

func (a *AddressWitnessScriptHash) WitnessProgram() []byte

WitnessProgram returns the witness program of the AddressWitnessScriptHash.

func (*AddressWitnessScriptHash) WitnessVersion 

func (a *AddressWitnessScriptHash) WitnessVersion() byte

WitnessVersion returns the witness version of the AddressWitnessScriptHash.

type Hash 

type Hash [HashLength]byte

func BigToHash 

func BigToHash(b *big.Int) Hash

func BytesToHash 

func BytesToHash(b []byte) Hash

func HexToHash 

func HexToHash(s string) Hash

func StringToHash 

func StringToHash(s string) Hash

func (Hash) Big 

func (h Hash) Big() *big.Int

func (Hash) Bytes 

func (h Hash) Bytes() []byte

func (Hash) Generate 

func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value

Generate implements testing/quick.Generator.

func (Hash) Hex 

func (h Hash) Hex() string

func (Hash) MarshalJSON 

func (h Hash) MarshalJSON() ([]byte, error)

Serialize given hash to JSON

func (*Hash) Set 

func (h *Hash) Set(other Hash)

Sets h to other

func (*Hash) SetBytes 

func (h *Hash) SetBytes(b []byte)

Sets the hash to the value of b. If b is larger than len(h) it will panic

func (*Hash) SetString 

func (h *Hash) SetString(s string)

Set string `s` to h. If s is larger than len(h) it will panic

func (Hash) Str 

func (h Hash) Str() string

Get the string representation of the underlying hash

func (*Hash) UnmarshalJSON 

func (h *Hash) UnmarshalJSON(input []byte) error

UnmarshalJSON parses a hash in its hex from to a hash.

type List 

type List struct {
	Length int
	// contains filtered or unexported fields
}

The list type is an anonymous slice handler which can be used for containing any slice type to use in an environment which does not support slice types (e.g., JavaScript, QML)

func EmptyList 

func EmptyList() *List

func NewList 

func NewList(t interface{}) *List

Initialise a new list. Panics if non-slice type is given.

func (*List) Append 

func (self *List) Append(v interface{})

Appends value at the end of the slice. Panics when incompatible value is given.

func (*List) Get 

func (self *List) Get(i int) interface{}

Get N element from the embedded slice. Returns nil if OOB.

func (*List) GetAsJson 

func (self *List) GetAsJson(i int) interface{}

func (*List) Interface 

func (self *List) Interface() interface{}

Returns the underlying slice as interface.

func (*List) ToJSON 

func (self *List) ToJSON() string

For JavaScript <3

type StorageSize 

type StorageSize float64

func (StorageSize) Int64 

func (self StorageSize) Int64() int64

func (StorageSize) String 

func (self StorageSize) String() string

type TimeSorter 

type TimeSorter []uint64

timeSorter implements sort.Interface to allow a slice of timestamps to be sorted.

func (TimeSorter) Len 

func (s TimeSorter) Len() int

Len returns the number of timestamps in the slice. It is part of the sort.Interface implementation.

func (TimeSorter) Less 

func (s TimeSorter) Less(i, j int) bool

Less returns whether the timstamp with index i should sort before the timestamp with index j. It is part of the sort.Interface implementation.

func (TimeSorter) Swap 

func (s TimeSorter) Swap(i, j int)

Swap swaps the timestamps at the passed indices. It is part of the sort.Interface implementation.

Source Files

View all Source files

Directories

Path Synopsis
Package bech32 provides a Go implementation of the bech32 format specified in BIP 173.
 Package bech32 provides a Go implementation of the bech32 format specified in BIP 173.

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