plugeth/common
zelig 83ee39448e Registrar and contractInfo handling
* resolver -> common/registrar
  * global registrar name registry interface
  * add Call to resolver backend interface
  * the hashReg and UrlHing contracts now initialised from global registry
  * initialization of contracts uniform
  * improve errors and more econsistent method names
* common/registrar/ethreg: versioned registrar
* integrate new naming and registrar in natspec
* js console api: setGlobalRegistrar, setHashReg, setUrlHint
* js test TestContract uses mining - tests fixed all pass
* eth/backend: allow PoW test mode (small ethash DAG)
* console jsre refers to resolver.abi/addr,
* cmd/geth/contracts.go moved to common/registrar
2015-07-07 10:43:31 +02:00
..
compiler Registrar and contractInfo handling 2015-07-07 10:43:31 +02:00
docserver Registrar and contractInfo handling 2015-07-07 10:43:31 +02:00
math Moved ethutil => common 2015-03-16 11:27:38 +01:00
natspec Registrar and contractInfo handling 2015-07-07 10:43:31 +02:00
number Moved ethutil => common 2015-03-16 11:27:38 +01:00
registrar Registrar and contractInfo handling 2015-07-07 10:43:31 +02:00
.gitignore Moved ethutil => common 2015-03-16 11:27:38 +01:00
.travis.yml Moved ethutil => common 2015-03-16 11:27:38 +01:00
big_test.go Moved ethutil => common 2015-03-16 11:27:38 +01:00
big.go types: block json unmarshal method added 2015-06-03 22:39:17 +02:00
bytes_test.go common: delete BinaryLength 2015-04-22 12:31:19 +02:00
bytes.go common: delete BinaryLength 2015-04-22 12:31:19 +02:00
config.go Moved ethutil => common 2015-03-16 11:27:38 +01:00
db.go core, ethdb, trie: validate database errors 2015-06-21 16:59:15 +02:00
debug.go common: Added debug reporter 2015-04-15 16:39:44 +02:00
list.go Moved ethutil => common 2015-03-16 11:27:38 +01:00
main_test.go Moved ethutil => common 2015-03-16 11:27:38 +01:00
package.go Moved ethutil => common 2015-03-16 11:27:38 +01:00
path_test.go common: remove WriteFile and ReadAllFile (use ioutil instead) 2015-03-26 19:00:18 +00:00
path.go fixed windows ipc path issue 2015-06-12 09:32:37 +02:00
README.md Moved ethutil => common 2015-03-16 11:27:38 +01:00
rlp_test.go common: make Value encodable with package rlp 2015-03-20 14:00:26 +01:00
rlp.go common: drop accessors for Value.Val 2015-03-20 14:00:26 +01:00
size_test.go core, eth, miner: improved tx removal & fatal error on db sync err 2015-05-11 11:39:33 +02:00
size.go core, eth, miner: improved tx removal & fatal error on db sync err 2015-05-11 11:39:33 +02:00
test_utils.go Change keystore to version 3 2015-06-24 06:03:23 +02:00
types_template.go prep template for fixed size hashes 2015-03-18 14:15:58 +01:00
types_test.go Fixed VM & Tests w/ conversion 2015-03-17 13:24:25 +01:00
types.go core/state, core/vm: reworked storage get / set to use common.Hash 2015-06-17 11:24:40 +02:00
value_test.go common: drop accessors for Value.Val 2015-03-20 14:00:26 +01:00
value.go common: drop accessors for Value.Val 2015-03-20 14:00:26 +01:00

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)