ethutil

package
v0.5.22 Latest Latest
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 Go to latest Published: Jul 23, 2014 License: MIT Imports: 22 Imported by: 0

README

ethutil

Build Status

The ethutil package contains the ethereum utility library.

Installation

go get github.com/ethereum/ethutil-go

Usage

RLP (Recursive Linear Prefix) Encoding

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

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

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

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

Patricia Trie

Patricie Tree is a merkle trie utilized 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 ethutil/db.go.

db := NewDatabase()

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

Documentation

Index

Constants

View Source 
const (
	RlpEmptyList = 0x80
	RlpEmptyStr  = 0x40
)

Variables

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

View Source 
var (
	Big1   = big.NewInt(1)
	Big2   = big.NewInt(2)
	Big0   = big.NewInt(0)
	Big32  = big.NewInt(32)
	Big256 = big.NewInt(0xff)
)

Common big integers often used

View Source 
var BigFalse *big.Int = big.NewInt(0)

False

View Source 
var BigInt0 *big.Int = big.NewInt(0)
View Source 
var BigTrue *big.Int = big.NewInt(1)

True

Functions

func Address 

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

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

BigD

Shortcut for new(big.Int).SetBytes(...)

func BigMax 

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

Big max

Returns the maximum 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 BinaryLength 

func BinaryLength(num int) int

Binary length

Returns the true binary length of the given number

func Bytes2Hex 

func Bytes2Hex(d []byte) string

func BytesToNumber 

func BytesToNumber(b []byte) uint64

Bytes to number

Attempts to cast a byte slice to a unsigned integer

func Char 

func Char(c []byte) int

func Compile 

func Compile(script string, silent bool) (ret []byte, err error)

General compile function

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 Decode 

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 

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

func Encode 

func Encode(object interface{}) []byte

func ExpandHomePath 

func ExpandHomePath(p string) (path string)

func FindFileInArchive 

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 FormatData 

func FormatData(data string) []byte

func Hex2Bytes 

func Hex2Bytes(str string) []byte

func IsHex 

func IsHex(str string) bool

func IsWindows 

func IsWindows() bool

func LeftPadBytes 

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

func NumberToBytes 

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

Number to bytes

Returns the number in bytes with the specified base

func RandomUint64 

func RandomUint64() (uint64, error)

RandomUint64 returns a cryptographically random uint64 value.

func ReadFile 

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 

func ReadVarint(reader *bytes.Reader) (ret uint64)

Read variable int

Read a variable length number in big endian byte order

func RightPadBytes 

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

func StringToByteFunc 

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

func WindonizePath 

func WindonizePath(path string) string

Types

type ConfigManager 

type ConfigManager struct {
	Db Database

	ExecPath string
	Debug    bool
	Diff     bool
	DiffType string
	Paranoia bool
	// contains filtered or unexported fields
}

Config struct 

var Config *ConfigManager

func ReadConfig 

func ReadConfig(ConfigFile string, Datadir string, EnvPrefix string) *ConfigManager

Read config

Initialize Config from Config File

func (*ConfigManager) Delete 

func (c *ConfigManager) Delete(key string)

func (*ConfigManager) Save 

func (c *ConfigManager) Save(key string, value interface{})

provides persistence for flags

type Database 

type Database interface {
	Put(key []byte, value []byte)
	Get(key []byte) ([]byte, error)
	//GetKeys() []*Key
	Delete(key []byte) error
	LastKnownTD() []byte
	Close()
	Print()
}

Database interface

type ExtPackage 

type ExtPackage struct {
	EntryHtml string
	Manifest  *Manifest
}

External package

External package contains the main html file and manifest

func OpenPackage 

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 Manifest 

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 

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

Reads manifest

Reads and returns a manifest object. Returns error otherwise

type React 

type React struct {
	Resource interface{}
	Event    string
}

Basic reactor resource

type ReactorEngine 

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

The reactor basic engine. Acts as bridge between the events and the subscribers/posters

func NewReactorEngine 

func NewReactorEngine() *ReactorEngine

func (*ReactorEngine) Post 

func (reactor *ReactorEngine) Post(event string, resource interface{})

func (*ReactorEngine) Subscribe 

func (reactor *ReactorEngine) Subscribe(event string, ch chan React)

Subscribe a channel to the specified event

func (*ReactorEngine) Unsubscribe 

func (reactor *ReactorEngine) Unsubscribe(event string, ch chan React)

type ReactorEvent 

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

func (*ReactorEvent) Add 

func (e *ReactorEvent) Add(ch chan React)

Add a subscriber to this event

func (*ReactorEvent) Post 

func (e *ReactorEvent) Post(react React)

Post the specified reactor resource on the channels currently subscribed

func (*ReactorEvent) Remove 

func (e *ReactorEvent) Remove(ch chan React)

Remove a subscriber

type RlpEncodable 

type RlpEncodable interface {
	RlpEncode() []byte
	RlpValue() []interface{}
}

type RlpEncoder 

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

func NewRlpEncoder 

func NewRlpEncoder() *RlpEncoder

func (*RlpEncoder) EncodeData 

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

type Value 

type Value struct {
	Val interface{}
	// contains filtered or unexported fields
}

Data values are returned by the rlp decoder. The data values represents one item within the rlp data structure. It's responsible for all the casting It always returns something valid

func EmptyValue 

func EmptyValue() *Value

func NewSliceValue 

func NewSliceValue(s interface{}) *Value

Value setters

func NewValue 

func NewValue(val interface{}) *Value

func NewValueFromBytes 

func NewValueFromBytes(data []byte) *Value

func (*Value) Append 

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

func (*Value) AppendList 

func (val *Value) AppendList() *Value

func (*Value) BigInt 

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

func (*Value) Byte 

func (val *Value) Byte() byte

func (*Value) Bytes 

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

func (*Value) Cmp 

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

func (*Value) Copy 

func (self *Value) Copy() *Value

func (*Value) Decode 

func (self *Value) Decode()

Assume that the data we have is encoded

func (*Value) Encode 

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

func (*Value) Get 

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

Threat the value as a slice

func (*Value) Interface 

func (val *Value) Interface() interface{}

func (*Value) IsEmpty 

func (val *Value) IsEmpty() bool

func (*Value) IsList 

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 

func (val *Value) IsNil() bool

func (*Value) IsSlice 

func (val *Value) IsSlice() bool

TODO More type checking methods

func (*Value) IsStr 

func (val *Value) IsStr() bool

func (*Value) Len 

func (val *Value) Len() int

func (*Value) NewIterator 

func (val *Value) NewIterator() *ValueIterator

func (*Value) Raw 

func (val *Value) Raw() interface{}

func (*Value) Slice 

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

func (*Value) SliceFrom 

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

func (*Value) SliceFromTo 

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

func (*Value) SliceTo 

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

func (*Value) Str 

func (val *Value) Str() string

func (*Value) String 

func (val *Value) String() string

func (*Value) Type 

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

func (*Value) Uint 

func (val *Value) Uint() uint64

type ValueIterator 

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

func (*ValueIterator) Idx 

func (it *ValueIterator) Idx() int

func (*ValueIterator) Next 

func (it *ValueIterator) Next() bool

func (*ValueIterator) Value 

func (it *ValueIterator) Value() *Value

Source Files

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