common

package
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 Go to latest Published: Oct 2, 2015 License: GPL-3.0 Imports: 21 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 (
	RlpEmptyList = 0x80
	RlpEmptyStr  = 0x40
)

Variables

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)
	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 added in v0.9.39 

func Big(num string) *big.Int

Big

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

func BigCopy added in v0.9.39 

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

Big copy

Creates a copy of the given big integer

func BigD added in v0.9.39 

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

func BigMax added in v0.9.39 

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

Big max

Returns the maximum size big integer

func BigMin added in v0.9.39 

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

Big min

Returns the minimum size big integer

func BigPow added in v0.9.39 

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

Big pow

Returns the power of two big integers

func BigToBytes added in v0.9.39 

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 added in v0.9.39 

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

func ByteSliceToInterface added in v0.9.39 

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

func Bytes2Big added in v0.9.39 

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

func Bytes2Hex 

func Bytes2Hex(d []byte) string

func BytesToBig added in v0.9.39 

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

Bytes2Big

func BytesToNumber added in v0.9.39 

func BytesToNumber(b []byte) uint64

Bytes to number

Attempts to cast a byte slice to a unsigned integer

func Char added in v0.9.39 

func Char(c []byte) int

func CopyBytes 

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

Copy bytes

Returns an exact copy of the provided bytes

func CurrencyToString added in v0.9.39 

func CurrencyToString(num *big.Int) string

Currency to string Returns a string representing a human readable format

func Decode added in v0.9.39 

func Decode(data []byte, pos uint64) (interface{}, uint64)

TODO Use a bytes.Buffer instead of a raw byte slice. Cleaner code, and use draining instead of seeking the next bytes to read

func DecodeWithReader added in v0.9.39 

func DecodeWithReader(reader *bytes.Buffer) interface{}

func DefaultAssetPath added in v0.9.39 

func DefaultAssetPath() string

func DefaultDataDir added in v0.9.39 

func DefaultDataDir() string

func DefaultIpcPath added in v0.9.39 

func DefaultIpcPath() string

func DeleteFromByteSlice added in v0.9.39 

func DeleteFromByteSlice(s [][]byte, hash []byte) [][]byte

func EmptyHash added in v0.9.39 

func EmptyHash(h Hash) bool

func Encode added in v0.9.39 

func Encode(object interface{}) []byte

func ExpandHomePath added in v0.9.39 

func ExpandHomePath(p string) (path string)

func FileExist 

func FileExist(filePath string) bool

func FindFileInArchive added in v0.9.39 

func FindFileInArchive(fn string, files []*zip.File) (index int)

Find file in archive

Returns the index of the given file name if it exists. -1 if file not found

func FirstBitSet added in v0.9.39 

func FirstBitSet(v *big.Int) int

func FormatData added in v0.9.39 

func FormatData(data string) []byte

func FromHex 

func FromHex(s string) []byte

func HasHexPrefix added in v0.9.39 

func HasHexPrefix(str string) bool

func Hex2Bytes 

func Hex2Bytes(str string) []byte

func Hex2BytesFixed 

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

func IsHex added in v0.9.39 

func IsHex(str string) bool

func LeftPadBytes 

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

func LeftPadString added in v0.9.39 

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 added in v0.9.39 

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

Number to bytes

Returns the number in bytes with the specified base

func PP added in v0.9.39 

func PP(value []byte) string

PP Pretty Prints a byte slice in the following format: 

hex(value[:4])...(hex[len(value)-4:])

func ParseData added in v0.9.39 

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

func ReadFile added in v0.9.39 

func ReadFile(f *zip.File) ([]byte, error)

Read file

Read a given compressed file and returns the read bytes. Returns an error otherwise

func ReadVarInt added in v0.9.39 

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{})

func RightPadBytes 

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

func RightPadString added in v0.9.39 

func RightPadString(str string, l int) string

func Rlp added in v0.9.39 

func Rlp(encoder RlpEncode) []byte

func S256 added in v0.9.39 

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

func String2Big added in v0.9.39 

func String2Big(num string) *big.Int

func StringToByteFunc added in v0.9.39 

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

func ToAddress added in v0.9.39 

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

func ToHex 

func ToHex(b []byte) string

func U256 added in v0.9.39 

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

Types

type Address 

type Address [addressLength]byte

func BigToAddress 

func BigToAddress(b *big.Int) Address

func BytesToAddress 

func BytesToAddress(b []byte) Address

///////// Address

func HexToAddress 

func HexToAddress(s string) Address

func StringToAddress added in v0.9.39 

func StringToAddress(s string) Address

func (Address) Big 

func (a Address) Big() *big.Int

func (Address) Bytes 

func (a Address) Bytes() []byte

func (Address) Hash 

func (a Address) Hash() Hash

func (Address) Hex 

func (a Address) Hex() string

func (*Address) Set added in v0.9.39 

func (a *Address) Set(other Address)

Sets a to other

func (*Address) SetBytes 

func (a *Address) SetBytes(b []byte)

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

func (*Address) SetString added in v0.9.39 

func (a *Address) SetString(s string)

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

func (Address) Str added in v0.9.39 

func (a Address) Str() string

Get the string representation of the underlying address

type Bytes added in v0.9.39 

type Bytes []byte

func (Bytes) String added in v0.9.39 

func (self Bytes) String() string

type ExtPackage added in v0.9.39 

type ExtPackage struct {
	EntryHtml string
	Manifest  *Manifest
}

External package

External package contains the main html file and manifest

func OpenPackage added in v0.9.39 

func OpenPackage(fn string) (*ExtPackage, error)

Open package

Opens a prepared ethereum package Reads the manifest file and determines file contents and returns and the external package.

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 added in v0.9.39 

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) Set added in v0.9.39 

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 added in v0.9.39 

func (h *Hash) SetString(s string)

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

func (Hash) Str added in v0.9.39 

func (h Hash) Str() string

Get the string representation of the underlying hash

type List added in v0.9.39 

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 added in v0.9.39 

func EmptyList() *List

func NewList added in v0.9.39 

func NewList(t interface{}) *List

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

func (*List) Append added in v0.9.39 

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

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

func (*List) Get added in v0.9.39 

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

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

func (*List) GetAsJson added in v0.9.39 

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

func (*List) Interface added in v0.9.39 

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

Returns the underlying slice as interface.

func (*List) ToJSON added in v0.9.39 

func (self *List) ToJSON() string

For JavaScript <3

type Manifest added in v0.9.39 

type Manifest struct {
	Entry         string
	Height, Width int
}

Manifest object

The manifest object holds all the relevant information supplied with the the manifest specified in the package

func ReadManifest added in v0.9.39 

func ReadManifest(m []byte) (*Manifest, error)

Reads manifest

Reads and returns a manifest object. Returns error otherwise

type RlpEncodable added in v0.9.39 

type RlpEncodable interface {
	RlpData() interface{}
}

type RlpEncode added in v0.9.39 

type RlpEncode interface {
	RlpEncode() []byte
}

type RlpEncodeDecode added in v0.9.39 

type RlpEncodeDecode interface {
	RlpEncode
	RlpValue() []interface{}
}

type RlpEncoder added in v0.9.39 

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

func NewRlpEncoder added in v0.9.39 

func NewRlpEncoder() *RlpEncoder

func (*RlpEncoder) EncodeData added in v0.9.39 

func (coder *RlpEncoder) EncodeData(rlpData interface{}) []byte

type StorageSize 

type StorageSize float64

func (StorageSize) Int64 added in v0.9.39 

func (self StorageSize) Int64() int64

func (StorageSize) String 

func (self StorageSize) String() string

type Value added in v0.9.39 

type Value struct{ Val interface{} }

Value can hold values of certain basic types and provides ways to convert between types without bothering to check whether the conversion is actually meaningful.

It currently supports the following types:

  • int{,8,16,32,64}
  • uint{,8,16,32,64}
  • *big.Int
  • []byte, string
  • []interface{}

Value is useful whenever you feel that Go's types limit your ability to express yourself. In these situations, use Value and forget about this strong typing nonsense.

func EmptyValue added in v0.9.39 

func EmptyValue() *Value

func NewSliceValue added in v0.9.39 

func NewSliceValue(s interface{}) *Value

Value setters

func NewValue added in v0.9.39 

func NewValue(val interface{}) *Value

func NewValueFromBytes added in v0.9.39 

func NewValueFromBytes(data []byte) *Value

NewValueFromBytes decodes RLP data. The contained value will be nil if data contains invalid RLP.

func (*Value) Add added in v0.9.39 

func (self *Value) Add(other interface{}) *Value

func (*Value) Append added in v0.9.39 

func (val *Value) Append(v interface{}) *Value

func (*Value) AppendList added in v0.9.39 

func (val *Value) AppendList() *Value

func (*Value) BigInt added in v0.9.39 

func (val *Value) BigInt() *big.Int

func (*Value) Byte added in v0.9.39 

func (val *Value) Byte() byte

func (*Value) Bytes added in v0.9.39 

func (val *Value) Bytes() []byte

func (*Value) Cmp added in v0.9.39 

func (val *Value) Cmp(o *Value) bool

func (*Value) Copy added in v0.9.39 

func (self *Value) Copy() *Value

func (*Value) DecodeRLP added in v0.9.39 

func (self *Value) DecodeRLP(s *rlp.Stream) error

func (*Value) DeepCmp added in v0.9.39 

func (self *Value) DeepCmp(o *Value) bool

func (*Value) Div added in v0.9.39 

func (self *Value) Div(other interface{}) *Value

func (*Value) EncodeRLP added in v0.9.39 

func (self *Value) EncodeRLP(w io.Writer) error

func (*Value) Err added in v0.9.39 

func (val *Value) Err() error

func (*Value) Get added in v0.9.39 

func (val *Value) Get(idx int) *Value

Threat the value as a slice

func (*Value) Int added in v0.9.39 

func (val *Value) Int() int64

func (*Value) IsEmpty added in v0.9.39 

func (val *Value) IsEmpty() bool

func (*Value) IsErr added in v0.9.39 

func (self *Value) IsErr() bool

func (*Value) IsList added in v0.9.39 

func (val *Value) IsList() bool

Special list checking function. Something is considered a list if it's of type []interface{}. The list is usually used in conjunction with rlp decoded streams.

func (*Value) IsNil added in v0.9.39 

func (val *Value) IsNil() bool

func (*Value) IsSlice added in v0.9.39 

func (val *Value) IsSlice() bool

TODO More type checking methods

func (*Value) IsStr added in v0.9.39 

func (val *Value) IsStr() bool

func (*Value) Len added in v0.9.39 

func (val *Value) Len() int

func (*Value) Mul added in v0.9.39 

func (self *Value) Mul(other interface{}) *Value

func (*Value) NewIterator added in v0.9.39 

func (val *Value) NewIterator() *ValueIterator

func (*Value) Pow added in v0.9.39 

func (self *Value) Pow(other interface{}) *Value

func (*Value) Slice added in v0.9.39 

func (val *Value) Slice() []interface{}

func (*Value) SliceFrom added in v0.9.39 

func (val *Value) SliceFrom(from int) *Value

func (*Value) SliceFromTo added in v0.9.39 

func (val *Value) SliceFromTo(from, to int) *Value

func (*Value) SliceTo added in v0.9.39 

func (val *Value) SliceTo(to int) *Value

func (*Value) Str added in v0.9.39 

func (val *Value) Str() string

func (*Value) String added in v0.9.39 

func (val *Value) String() string

func (*Value) Sub added in v0.9.39 

func (self *Value) Sub(other interface{}) *Value

func (*Value) Type added in v0.9.39 

func (val *Value) Type() reflect.Kind

func (*Value) Uint added in v0.9.39 

func (val *Value) Uint() uint64

type ValueIterator added in v0.9.39 

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

func (*ValueIterator) Idx added in v0.9.39 

func (it *ValueIterator) Idx() int

func (*ValueIterator) Len added in v0.9.39 

func (it *ValueIterator) Len() int

func (*ValueIterator) Next added in v0.9.39 

func (it *ValueIterator) Next() bool

func (*ValueIterator) Value added in v0.9.39 

func (it *ValueIterator) Value() *Value

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