Moved ethutil => common

2015-03-16 11:27:38 +01:00
parent 0b8f66ed9e
commit b523441361
116 changed files with 610 additions and 604 deletions
--- a/common/.gitignore
+++ b/common/.gitignore
@ -0,0 +1,12 @@
+# See http://help.github.com/ignore-files/ for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile ~/.gitignore_global
+
+/tmp
+*/**/*un~
+*un~
+.DS_Store
+*/**/.DS_Store
+
--- a/common/.travis.yml
+++ b/common/.travis.yml
@ -0,0 +1,3 @@
+language: go
+go:
+  - 1.2
--- a/common/README.md
+++ b/common/README.md
@ -0,0 +1,139 @@
+# ethutil
+
+[![Build
+Status](https://travis-ci.org/ethereum/go-ethereum.png?branch=master)](https://travis-ci.org/ethereum/go-ethereum)
+
+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](http://wiki.ethereum.org/index.php/RLP)
+article.
+
+```go
+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](http://wiki.ethereum.org/index.php/Patricia_Tree).
+
+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`.
+
+```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.
+
+```go
+// ... 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.
+
+```go
+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.
+
+```go
+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
+
+```go
+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)
+
+```go
+val := ethutil.NewValue([]interface{}{1,"2",[]interface{}{3}})
+rlp := val.Encode()
+// Store the rlp data
+Store(rlp)
+```
--- a/common/big.go
+++ b/common/big.go
@ -0,0 +1,123 @@
+package common
+
+import "math/big"
+
+// Big pow
+//
+// Returns the power of two big integers
+func BigPow(a, b int) *big.Int {
+	c := new(big.Int)
+	c.Exp(big.NewInt(int64(a)), big.NewInt(int64(b)), big.NewInt(0))
+
+	return c
+}
+
+// Big
+//
+// Shortcut for new(big.Int).SetString(..., 0)
+func Big(num string) *big.Int {
+	n := new(big.Int)
+	n.SetString(num, 0)
+
+	return n
+}
+
+// BigD
+//
+// Shortcut for new(big.Int).SetBytes(...)
+func Bytes2Big(data []byte) *big.Int {
+	n := new(big.Int)
+	n.SetBytes(data)
+
+	return n
+}
+func BigD(data []byte) *big.Int { return Bytes2Big(data) }
+
+func String2Big(num string) *big.Int {
+	n := new(big.Int)
+	n.SetString(num, 0)
+	return n
+}
+
+func BitTest(num *big.Int, i int) bool {
+	return num.Bit(i) > 0
+}
+
+// To256
+//
+// "cast" the big int to a 256 big int (i.e., limit to)
+var tt256 = new(big.Int).Lsh(big.NewInt(1), 256)
+var tt256m1 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
+var tt255 = new(big.Int).Lsh(big.NewInt(1), 255)
+
+func U256(x *big.Int) *big.Int {
+	//if x.Cmp(Big0) < 0 {
+	//		return new(big.Int).Add(tt256, x)
+	//	}
+
+	x.And(x, tt256m1)
+
+	return x
+}
+
+func S256(x *big.Int) *big.Int {
+	if x.Cmp(tt255) < 0 {
+		return x
+	} else {
+		// We don't want to modify x, ever
+		return new(big.Int).Sub(x, tt256)
+	}
+}
+
+func FirstBitSet(v *big.Int) int {
+	for i := 0; i < v.BitLen(); i++ {
+		if v.Bit(i) > 0 {
+			return i
+		}
+	}
+
+	return v.BitLen()
+}
+
+// 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 BigToBytes(num *big.Int, base int) []byte {
+	ret := make([]byte, base/8)
+
+	if len(num.Bytes()) > base/8 {
+		return num.Bytes()
+	}
+
+	return append(ret[:len(ret)-len(num.Bytes())], num.Bytes()...)
+}
+
+// Big copy
+//
+// Creates a copy of the given big integer
+func BigCopy(src *big.Int) *big.Int {
+	return new(big.Int).Set(src)
+}
+
+// Big max
+//
+// Returns the maximum size big integer
+func BigMax(x, y *big.Int) *big.Int {
+	if x.Cmp(y) <= 0 {
+		return y
+	}
+
+	return x
+}
+
+// Big min
+//
+// Returns the minimum size big integer
+func BigMin(x, y *big.Int) *big.Int {
+	if x.Cmp(y) >= 0 {
+		return y
+	}
+
+	return x
+}
--- a/common/big_test.go
+++ b/common/big_test.go
@ -0,0 +1,73 @@
+package common
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestMisc(t *testing.T) {
+	a := Big("10")
+	b := Big("57896044618658097711785492504343953926634992332820282019728792003956564819968")
+	c := []byte{1, 2, 3, 4}
+	z := BitTest(a, 1)
+
+	if z != true {
+		t.Error("Expected true got", z)
+	}
+
+	U256(a)
+	S256(a)
+
+	U256(b)
+	S256(b)
+
+	BigD(c)
+}
+
+func TestBigMax(t *testing.T) {
+	a := Big("10")
+	b := Big("5")
+
+	max1 := BigMax(a, b)
+	if max1 != a {
+		t.Errorf("Expected %d got %d", a, max1)
+	}
+
+	max2 := BigMax(b, a)
+	if max2 != a {
+		t.Errorf("Expected %d got %d", a, max2)
+	}
+}
+
+func TestBigMin(t *testing.T) {
+	a := Big("10")
+	b := Big("5")
+
+	min1 := BigMin(a, b)
+	if min1 != b {
+		t.Errorf("Expected %d got %d", b, min1)
+	}
+
+	min2 := BigMin(b, a)
+	if min2 != b {
+		t.Errorf("Expected %d got %d", b, min2)
+	}
+}
+
+func TestBigCopy(t *testing.T) {
+	a := Big("10")
+	b := BigCopy(a)
+	c := Big("1000000000000")
+	y := BigToBytes(b, 16)
+	ybytes := []byte{0, 10}
+	z := BigToBytes(c, 16)
+	zbytes := []byte{232, 212, 165, 16, 0}
+
+	if bytes.Compare(y, ybytes) != 0 {
+		t.Error("Got", ybytes)
+	}
+
+	if bytes.Compare(z, zbytes) != 0 {
+		t.Error("Got", zbytes)
+	}
+}
--- a/common/bytes.go
+++ b/common/bytes.go
@ -0,0 +1,234 @@
+package common
+
+import (
+	"bytes"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"strings"
+)
+
+type Bytes []byte
+
+func (self Bytes) String() string {
+	return string(self)
+}
+
+func DeleteFromByteSlice(s [][]byte, hash []byte) [][]byte {
+	for i, h := range s {
+		if bytes.Compare(h, hash) == 0 {
+			return append(s[:i:i], s[i+1:]...)
+		}
+	}
+
+	return s
+}
+
+// Number to bytes
+//
+// Returns the number in bytes with the specified base
+func NumberToBytes(num interface{}, bits int) []byte {
+	buf := new(bytes.Buffer)
+	err := binary.Write(buf, binary.BigEndian, num)
+	if err != nil {
+		fmt.Println("NumberToBytes failed:", err)
+	}
+
+	return buf.Bytes()[buf.Len()-(bits/8):]
+}
+
+// Bytes to number
+//
+// Attempts to cast a byte slice to a unsigned integer
+func BytesToNumber(b []byte) uint64 {
+	var number uint64
+
+	// Make sure the buffer is 64bits
+	data := make([]byte, 8)
+	data = append(data[:len(b)], b...)
+
+	buf := bytes.NewReader(data)
+	err := binary.Read(buf, binary.BigEndian, &number)
+	if err != nil {
+		fmt.Println("BytesToNumber failed:", err)
+	}
+
+	return number
+}
+
+// Read variable int
+//
+// Read a variable length number in big endian byte order
+func ReadVarInt(buff []byte) (ret uint64) {
+	switch l := len(buff); {
+	case l > 4:
+		d := LeftPadBytes(buff, 8)
+		binary.Read(bytes.NewReader(d), binary.BigEndian, &ret)
+	case l > 2:
+		var num uint32
+		d := LeftPadBytes(buff, 4)
+		binary.Read(bytes.NewReader(d), binary.BigEndian, &num)
+		ret = uint64(num)
+	case l > 1:
+		var num uint16
+		d := LeftPadBytes(buff, 2)
+		binary.Read(bytes.NewReader(d), binary.BigEndian, &num)
+		ret = uint64(num)
+	default:
+		var num uint8
+		binary.Read(bytes.NewReader(buff), binary.BigEndian, &num)
+		ret = uint64(num)
+	}
+
+	return
+}
+
+// Binary length
+//
+// Returns the true binary length of the given number
+func BinaryLength(num int) int {
+	if num == 0 {
+		return 0
+	}
+
+	return 1 + BinaryLength(num>>8)
+}
+
+// Copy bytes
+//
+// Returns an exact copy of the provided bytes
+func CopyBytes(b []byte) (copiedBytes []byte) {
+	copiedBytes = make([]byte, len(b))
+	copy(copiedBytes, b)
+
+	return
+}
+
+func IsHex(str string) bool {
+	l := len(str)
+	return l >= 4 && l%2 == 0 && str[0:2] == "0x"
+}
+
+func Bytes2Hex(d []byte) string {
+	return hex.EncodeToString(d)
+}
+
+func Hex2Bytes(str string) []byte {
+	h, _ := hex.DecodeString(str)
+
+	return h
+}
+
+func StringToByteFunc(str string, cb func(str string) []byte) (ret []byte) {
+	if len(str) > 1 && str[0:2] == "0x" && !strings.Contains(str, "\n") {
+		ret = Hex2Bytes(str[2:])
+	} else {
+		ret = cb(str)
+	}
+
+	return
+}
+
+func FormatData(data string) []byte {
+	if len(data) == 0 {
+		return nil
+	}
+	// Simple stupid
+	d := new(big.Int)
+	if data[0:1] == "\"" && data[len(data)-1:] == "\"" {
+		return RightPadBytes([]byte(data[1:len(data)-1]), 32)
+	} else if len(data) > 1 && data[:2] == "0x" {
+		d.SetBytes(Hex2Bytes(data[2:]))
+	} else {
+		d.SetString(data, 0)
+	}
+
+	return BigToBytes(d, 256)
+}
+
+func ParseData(data ...interface{}) (ret []byte) {
+	for _, item := range data {
+		switch t := item.(type) {
+		case string:
+			var str []byte
+			if IsHex(t) {
+				str = Hex2Bytes(t[2:])
+			} else {
+				str = []byte(t)
+			}
+
+			ret = append(ret, RightPadBytes(str, 32)...)
+		case []byte:
+			ret = append(ret, LeftPadBytes(t, 32)...)
+		}
+	}
+
+	return
+}
+
+func RightPadBytes(slice []byte, l int) []byte {
+	if l < len(slice) {
+		return slice
+	}
+
+	padded := make([]byte, l)
+	copy(padded[0:len(slice)], slice)
+
+	return padded
+}
+
+func LeftPadBytes(slice []byte, l int) []byte {
+	if l < len(slice) {
+		return slice
+	}
+
+	padded := make([]byte, l)
+	copy(padded[l-len(slice):], slice)
+
+	return padded
+}
+
+func LeftPadString(str string, l int) string {
+	if l < len(str) {
+		return str
+	}
+
+	zeros := Bytes2Hex(make([]byte, (l-len(str))/2))
+
+	return zeros + str
+
+}
+
+func RightPadString(str string, l int) string {
+	if l < len(str) {
+		return str
+	}
+
+	zeros := Bytes2Hex(make([]byte, (l-len(str))/2))
+
+	return str + zeros
+
+}
+
+func Address(slice []byte) (addr []byte) {
+	if len(slice) < 20 {
+		addr = LeftPadBytes(slice, 20)
+	} else if len(slice) > 20 {
+		addr = slice[len(slice)-20:]
+	} else {
+		addr = slice
+	}
+
+	addr = CopyBytes(addr)
+
+	return
+}
+
+func ByteSliceToInterface(slice [][]byte) (ret []interface{}) {
+	for _, i := range slice {
+		ret = append(ret, i)
+	}
+
+	return
+}
--- a/common/bytes_test.go
+++ b/common/bytes_test.go
@ -0,0 +1,193 @@
+package common
+
+import (
+	checker "gopkg.in/check.v1"
+)
+
+type BytesSuite struct{}
+
+var _ = checker.Suite(&BytesSuite{})
+
+func (s *BytesSuite) TestByteString(c *checker.C) {
+	var data Bytes
+	data = []byte{102, 111, 111}
+	exp := "foo"
+	res := data.String()
+
+	c.Assert(res, checker.Equals, exp)
+}
+
+/*
+func (s *BytesSuite) TestDeleteFromByteSlice(c *checker.C) {
+	data := []byte{1, 2, 3, 4}
+	slice := []byte{1, 2, 3, 4}
+	exp := []byte{1, 4}
+	res := DeleteFromByteSlice(data, slice)
+
+	c.Assert(res, checker.DeepEquals, exp)
+}
+
+*/
+func (s *BytesSuite) TestNumberToBytes(c *checker.C) {
+	// data1 := int(1)
+	// res1 := NumberToBytes(data1, 16)
+	// c.Check(res1, checker.Panics)
+
+	var data2 float64 = 3.141592653
+	exp2 := []byte{0xe9, 0x38}
+	res2 := NumberToBytes(data2, 16)
+	c.Assert(res2, checker.DeepEquals, exp2)
+}
+
+func (s *BytesSuite) TestBytesToNumber(c *checker.C) {
+	datasmall := []byte{0xe9, 0x38, 0xe9, 0x38}
+	datalarge := []byte{0xe9, 0x38, 0xe9, 0x38, 0xe9, 0x38, 0xe9, 0x38}
+
+	var expsmall uint64 = 0xe938e938
+	var explarge uint64 = 0x0
+
+	ressmall := BytesToNumber(datasmall)
+	reslarge := BytesToNumber(datalarge)
+
+	c.Assert(ressmall, checker.Equals, expsmall)
+	c.Assert(reslarge, checker.Equals, explarge)
+
+}
+
+func (s *BytesSuite) TestReadVarInt(c *checker.C) {
+	data8 := []byte{1, 2, 3, 4, 5, 6, 7, 8}
+	data4 := []byte{1, 2, 3, 4}
+	data2 := []byte{1, 2}
+	data1 := []byte{1}
+
+	exp8 := uint64(72623859790382856)
+	exp4 := uint64(16909060)
+	exp2 := uint64(258)
+	exp1 := uint64(1)
+
+	res8 := ReadVarInt(data8)
+	res4 := ReadVarInt(data4)
+	res2 := ReadVarInt(data2)
+	res1 := ReadVarInt(data1)
+
+	c.Assert(res8, checker.Equals, exp8)
+	c.Assert(res4, checker.Equals, exp4)
+	c.Assert(res2, checker.Equals, exp2)
+	c.Assert(res1, checker.Equals, exp1)
+}
+
+func (s *BytesSuite) TestBinaryLength(c *checker.C) {
+	data1 := 0
+	data2 := 920987656789
+
+	exp1 := 0
+	exp2 := 5
+
+	res1 := BinaryLength(data1)
+	res2 := BinaryLength(data2)
+
+	c.Assert(res1, checker.Equals, exp1)
+	c.Assert(res2, checker.Equals, exp2)
+}
+
+func (s *BytesSuite) TestCopyBytes(c *checker.C) {
+	data1 := []byte{1, 2, 3, 4}
+	exp1 := []byte{1, 2, 3, 4}
+	res1 := CopyBytes(data1)
+	c.Assert(res1, checker.DeepEquals, exp1)
+}
+
+func (s *BytesSuite) TestIsHex(c *checker.C) {
+	data1 := "a9e67e"
+	exp1 := false
+	res1 := IsHex(data1)
+	c.Assert(res1, checker.DeepEquals, exp1)
+
+	data2 := "0xa9e67e00"
+	exp2 := true
+	res2 := IsHex(data2)
+	c.Assert(res2, checker.DeepEquals, exp2)
+
+}
+
+func (s *BytesSuite) TestParseDataString(c *checker.C) {
+	res1 := ParseData("hello", "world", "0x0106")
+	data := "68656c6c6f000000000000000000000000000000000000000000000000000000776f726c640000000000000000000000000000000000000000000000000000000106000000000000000000000000000000000000000000000000000000000000"
+	exp1 := Hex2Bytes(data)
+	c.Assert(res1, checker.DeepEquals, exp1)
+}
+
+func (s *BytesSuite) TestParseDataBytes(c *checker.C) {
+	data1 := []byte{232, 212, 165, 16, 0}
+	exp1 := []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 232, 212, 165, 16, 0}
+
+	res1 := ParseData(data1)
+	c.Assert(res1, checker.DeepEquals, exp1)
+
+}
+
+func (s *BytesSuite) TestLeftPadBytes(c *checker.C) {
+	val1 := []byte{1, 2, 3, 4}
+	exp1 := []byte{0, 0, 0, 0, 1, 2, 3, 4}
+
+	res1 := LeftPadBytes(val1, 8)
+	res2 := LeftPadBytes(val1, 2)
+
+	c.Assert(res1, checker.DeepEquals, exp1)
+	c.Assert(res2, checker.DeepEquals, val1)
+}
+
+func (s *BytesSuite) TestFormatData(c *checker.C) {
+	data1 := ""
+	data2 := "0xa9e67e00"
+	data3 := "a9e67e"
+	data4 := "\"a9e67e00\""
+
+	// exp1 := []byte{}
+	exp2 := []byte{00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 0xa9, 0xe6, 0x7e, 00}
+	exp3 := []byte{00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00}
+	exp4 := []byte{0x61, 0x39, 0x65, 0x36, 0x37, 0x65, 0x30, 0x30, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00, 00}
+
+	res1 := FormatData(data1)
+	res2 := FormatData(data2)
+	res3 := FormatData(data3)
+	res4 := FormatData(data4)
+
+	c.Assert(res1, checker.IsNil)
+	c.Assert(res2, checker.DeepEquals, exp2)
+	c.Assert(res3, checker.DeepEquals, exp3)
+	c.Assert(res4, checker.DeepEquals, exp4)
+}
+
+func (s *BytesSuite) TestRightPadBytes(c *checker.C) {
+	val := []byte{1, 2, 3, 4}
+	exp := []byte{1, 2, 3, 4, 0, 0, 0, 0}
+
+	resstd := RightPadBytes(val, 8)
+	resshrt := RightPadBytes(val, 2)
+
+	c.Assert(resstd, checker.DeepEquals, exp)
+	c.Assert(resshrt, checker.DeepEquals, val)
+}
+
+func (s *BytesSuite) TestLeftPadString(c *checker.C) {
+	val := "test"
+	exp := "\x30\x30\x30\x30" + val
+
+	resstd := LeftPadString(val, 8)
+	resshrt := LeftPadString(val, 2)
+
+	c.Assert(resstd, checker.Equals, exp)
+	c.Assert(resshrt, checker.Equals, val)
+}
+
+func (s *BytesSuite) TestRightPadString(c *checker.C) {
+	val := "test"
+	exp := val + "\x30\x30\x30\x30"
+
+	resstd := RightPadString(val, 8)
+	resshrt := RightPadString(val, 2)
+
+	c.Assert(resstd, checker.Equals, exp)
+	c.Assert(resshrt, checker.Equals, val)
+}
--- a/common/common.go
+++ b/common/common.go
@ -0,0 +1,165 @@
+package common
+
+import (
+	"fmt"
+	"math/big"
+	"os"
+	"os/user"
+	"path"
+	"path/filepath"
+	"runtime"
+	"time"
+
+	"github.com/kardianos/osext"
+)
+
+// 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 MakeName(name, version string) string {
+	return fmt.Sprintf("%s/v%s/%s/%s", name, version, runtime.GOOS, runtime.Version())
+}
+
+func DefaultAssetPath() string {
+	var assetPath string
+	pwd, _ := os.Getwd()
+	srcdir := path.Join(os.Getenv("GOPATH"), "src", "github.com", "ethereum", "go-ethereum", "cmd", "mist")
+
+	// If the current working directory is the go-ethereum dir
+	// assume a debug build and use the source directory as
+	// asset directory.
+	if pwd == srcdir {
+		assetPath = path.Join(pwd, "assets")
+	} else {
+		switch runtime.GOOS {
+		case "darwin":
+			// Get Binary Directory
+			exedir, _ := osext.ExecutableFolder()
+			assetPath = filepath.Join(exedir, "../Resources")
+		case "linux":
+			assetPath = "/usr/share/mist"
+		case "windows":
+			assetPath = "./assets"
+		default:
+			assetPath = "."
+		}
+	}
+
+	// Check if the assetPath exists. If not, try the source directory
+	// This happens when binary is run from outside cmd/mist directory
+	if _, err := os.Stat(assetPath); os.IsNotExist(err) {
+		assetPath = path.Join(srcdir, "assets")
+	}
+
+	return assetPath
+}
+
+func DefaultDataDir() string {
+	usr, _ := user.Current()
+	if runtime.GOOS == "darwin" {
+		return path.Join(usr.HomeDir, "Library/Ethereum")
+	} else if runtime.GOOS == "windows" {
+		return path.Join(usr.HomeDir, "AppData/Roaming/Ethereum")
+	} else {
+		return path.Join(usr.HomeDir, ".ethereum")
+	}
+}
+
+func FromHex(s string) []byte {
+	if len(s) > 1 {
+		if s[0:2] == "0x" {
+			s = s[2:]
+		}
+		if len(s)%2 == 1 {
+			s = "0" + s
+		}
+		return Hex2Bytes(s)
+	}
+	return nil
+}
+func IsWindows() bool {
+	return runtime.GOOS == "windows"
+}
+
+func WindonizePath(path string) string {
+	if string(path[0]) == "/" && IsWindows() {
+		path = path[1:]
+	}
+	return path
+}
+
+// The different number of units
+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)
+)
+
+//
+// Currency to string
+// Returns a string representing a human readable format
+func CurrencyToString(num *big.Int) string {
+	var (
+		fin   *big.Int = num
+		denom string   = "Wei"
+	)
+
+	switch {
+	case num.Cmp(Douglas) >= 0:
+		fin = new(big.Int).Div(num, Douglas)
+		denom = "Douglas"
+	case num.Cmp(Einstein) >= 0:
+		fin = new(big.Int).Div(num, Einstein)
+		denom = "Einstein"
+	case num.Cmp(Ether) >= 0:
+		fin = new(big.Int).Div(num, Ether)
+		denom = "Ether"
+	case num.Cmp(Finney) >= 0:
+		fin = new(big.Int).Div(num, Finney)
+		denom = "Finney"
+	case num.Cmp(Szabo) >= 0:
+		fin = new(big.Int).Div(num, Szabo)
+		denom = "Szabo"
+	case num.Cmp(Shannon) >= 0:
+		fin = new(big.Int).Div(num, Shannon)
+		denom = "Shannon"
+	case num.Cmp(Babbage) >= 0:
+		fin = new(big.Int).Div(num, Babbage)
+		denom = "Babbage"
+	case num.Cmp(Ada) >= 0:
+		fin = new(big.Int).Div(num, Ada)
+		denom = "Ada"
+	}
+
+	// TODO add comment clarifying expected behavior
+	if len(fin.String()) > 5 {
+		return fmt.Sprintf("%sE%d %s", fin.String()[0:5], len(fin.String())-5, denom)
+	}
+
+	return fmt.Sprintf("%v %s", fin, denom)
+}
+
+// Common big integers often used
+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)
+)
+
+func Bench(pre string, cb func()) {
+	start := time.Now()
+	cb()
+	fmt.Println(pre, ": took:", time.Since(start))
+}
--- a/common/common_test.go
+++ b/common/common_test.go
@ -0,0 +1,89 @@
+package common
+
+import (
+	"bytes"
+	"math/big"
+	"os"
+	"testing"
+
+	checker "gopkg.in/check.v1"
+)
+
+type CommonSuite struct{}
+
+var _ = checker.Suite(&CommonSuite{})
+
+func (s *CommonSuite) TestOS(c *checker.C) {
+	expwin := (os.PathSeparator == '\\' && os.PathListSeparator == ';')
+	res := IsWindows()
+
+	if !expwin {
+		c.Assert(res, checker.Equals, expwin, checker.Commentf("IsWindows is", res, "but path is", os.PathSeparator))
+	} else {
+		c.Assert(res, checker.Not(checker.Equals), expwin, checker.Commentf("IsWindows is", res, "but path is", os.PathSeparator))
+	}
+}
+
+func (s *CommonSuite) TestWindonziePath(c *checker.C) {
+	iswindowspath := os.PathSeparator == '\\'
+	path := "/opt/eth/test/file.ext"
+	res := WindonizePath(path)
+	ressep := string(res[0])
+
+	if !iswindowspath {
+		c.Assert(ressep, checker.Equals, "/")
+	} else {
+		c.Assert(ressep, checker.Not(checker.Equals), "/")
+	}
+}
+
+func (s *CommonSuite) TestCommon(c *checker.C) {
+	douglas := CurrencyToString(BigPow(10, 43))
+	einstein := CurrencyToString(BigPow(10, 22))
+	ether := CurrencyToString(BigPow(10, 19))
+	finney := CurrencyToString(BigPow(10, 16))
+	szabo := CurrencyToString(BigPow(10, 13))
+	shannon := CurrencyToString(BigPow(10, 10))
+	babbage := CurrencyToString(BigPow(10, 7))
+	ada := CurrencyToString(BigPow(10, 4))
+	wei := CurrencyToString(big.NewInt(10))
+
+	c.Assert(douglas, checker.Equals, "10 Douglas")
+	c.Assert(einstein, checker.Equals, "10 Einstein")
+	c.Assert(ether, checker.Equals, "10 Ether")
+	c.Assert(finney, checker.Equals, "10 Finney")
+	c.Assert(szabo, checker.Equals, "10 Szabo")
+	c.Assert(shannon, checker.Equals, "10 Shannon")
+	c.Assert(babbage, checker.Equals, "10 Babbage")
+	c.Assert(ada, checker.Equals, "10 Ada")
+	c.Assert(wei, checker.Equals, "10 Wei")
+}
+
+func (s *CommonSuite) TestLarge(c *checker.C) {
+	douglaslarge := CurrencyToString(BigPow(100000000, 43))
+	adalarge := CurrencyToString(BigPow(100000000, 4))
+	weilarge := CurrencyToString(big.NewInt(100000000))
+
+	c.Assert(douglaslarge, checker.Equals, "10000E298 Douglas")
+	c.Assert(adalarge, checker.Equals, "10000E7 Einstein")
+	c.Assert(weilarge, checker.Equals, "100 Babbage")
+}
+
+//fromHex
+func TestFromHex(t *testing.T) {
+	input := "0x01"
+	expected := []byte{1}
+	result := FromHex(input)
+	if bytes.Compare(expected, result) != 0 {
+		t.Errorf("Expected % x got % x", expected, result)
+	}
+}
+
+func TestFromHexOddLength(t *testing.T) {
+	input := "0x1"
+	expected := []byte{1}
+	result := FromHex(input)
+	if bytes.Compare(expected, result) != 0 {
+		t.Errorf("Expected % x got % x", expected, result)
+	}
+}
--- a/common/config.go
+++ b/common/config.go
@ -0,0 +1,67 @@
+package common
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/rakyll/globalconf"
+)
+
+// Config struct
+type ConfigManager struct {
+	ExecPath string
+	Debug    bool
+	Diff     bool
+	DiffType string
+	Paranoia bool
+	VmType   int
+
+	conf *globalconf.GlobalConf
+}
+
+// Read config
+//
+// Initialize Config from Config File
+func ReadConfig(ConfigFile string, Datadir string, EnvPrefix string) *ConfigManager {
+	if !FileExist(ConfigFile) {
+		// create ConfigFile if it does not exist, otherwise
+		// globalconf will panic when trying to persist flags.
+		fmt.Printf("config file '%s' doesn't exist, creating it\n", ConfigFile)
+		os.Create(ConfigFile)
+	}
+	g, err := globalconf.NewWithOptions(&globalconf.Options{
+		Filename:  ConfigFile,
+		EnvPrefix: EnvPrefix,
+	})
+	if err != nil {
+		fmt.Println(err)
+	} else {
+		g.ParseAll()
+	}
+	cfg := &ConfigManager{ExecPath: Datadir, Debug: true, conf: g, Paranoia: true}
+	return cfg
+}
+
+// provides persistence for flags
+func (c *ConfigManager) Save(key string, value interface{}) {
+	f := &flag.Flag{Name: key, Value: newConfValue(value)}
+	c.conf.Set("", f)
+}
+
+func (c *ConfigManager) Delete(key string) {
+	c.conf.Delete("", key)
+}
+
+// private type implementing flag.Value
+type confValue struct {
+	value string
+}
+
+// generic constructor to allow persising non-string values directly
+func newConfValue(value interface{}) *confValue {
+	return &confValue{fmt.Sprintf("%v", value)}
+}
+
+func (self confValue) String() string     { return self.value }
+func (self confValue) Set(s string) error { self.value = s; return nil }
--- a/common/db.go
+++ b/common/db.go
@ -0,0 +1,12 @@
+package common
+
+// Database interface
+type Database interface {
+	Put(key []byte, value []byte)
+	Get(key []byte) ([]byte, error)
+	//GetKeys() []*Key
+	Delete(key []byte) error
+	LastKnownTD() []byte
+	Close()
+	Print()
+}
--- a/common/list.go
+++ b/common/list.go
@ -0,0 +1,81 @@
+package common
+
+import (
+	"encoding/json"
+	"reflect"
+	"sync"
+)
+
+// 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)
+type List struct {
+	mut    sync.Mutex
+	val    interface{}
+	list   reflect.Value
+	Length int
+}
+
+// Initialise a new list. Panics if non-slice type is given.
+func NewList(t interface{}) *List {
+	list := reflect.ValueOf(t)
+	if list.Kind() != reflect.Slice {
+		panic("list container initialized with a non-slice type")
+	}
+
+	return &List{sync.Mutex{}, t, list, list.Len()}
+}
+
+func EmptyList() *List {
+	return NewList([]interface{}{})
+}
+
+// Get N element from the embedded slice. Returns nil if OOB.
+func (self *List) Get(i int) interface{} {
+	if self.list.Len() > i {
+		self.mut.Lock()
+		defer self.mut.Unlock()
+
+		i := self.list.Index(i).Interface()
+
+		return i
+	}
+
+	return nil
+}
+
+func (self *List) GetAsJson(i int) interface{} {
+	e := self.Get(i)
+
+	r, _ := json.Marshal(e)
+
+	return string(r)
+}
+
+// Appends value at the end of the slice. Panics when incompatible value
+// is given.
+func (self *List) Append(v interface{}) {
+	self.mut.Lock()
+	defer self.mut.Unlock()
+
+	self.list = reflect.Append(self.list, reflect.ValueOf(v))
+	self.Length = self.list.Len()
+}
+
+// Returns the underlying slice as interface.
+func (self *List) Interface() interface{} {
+	return self.list.Interface()
+}
+
+// For JavaScript <3
+func (self *List) ToJSON() string {
+	// make(T, 0) != nil
+	list := make([]interface{}, 0)
+	for i := 0; i < self.Length; i++ {
+		list = append(list, self.Get(i))
+	}
+
+	data, _ := json.Marshal(list)
+
+	return string(data)
+}
--- a/common/main_test.go
+++ b/common/main_test.go
@ -0,0 +1,9 @@
+package common
+
+import (
+	"testing"
+
+	checker "gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { checker.TestingT(t) }
--- a/common/math/dist.go
+++ b/common/math/dist.go
@ -0,0 +1,80 @@
+package math
+
+import (
+	"math/big"
+	"sort"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+type Summer interface {
+	Sum(i int) *big.Int
+	Len() int
+}
+
+func Sum(slice Summer) (sum *big.Int) {
+	sum = new(big.Int)
+
+	for i := 0; i < slice.Len(); i++ {
+		sum.Add(sum, slice.Sum(i))
+	}
+	return
+}
+
+type Vector struct {
+	Gas, Price *big.Int
+}
+
+type VectorsBy func(v1, v2 Vector) bool
+
+func (self VectorsBy) Sort(vectors []Vector) {
+	bs := vectorSorter{
+		vectors: vectors,
+		by:      self,
+	}
+	sort.Sort(bs)
+}
+
+type vectorSorter struct {
+	vectors []Vector
+	by      func(v1, v2 Vector) bool
+}
+
+func (v vectorSorter) Len() int           { return len(v.vectors) }
+func (v vectorSorter) Less(i, j int) bool { return v.by(v.vectors[i], v.vectors[j]) }
+func (v vectorSorter) Swap(i, j int)      { v.vectors[i], v.vectors[j] = v.vectors[j], v.vectors[i] }
+
+func PriceSort(v1, v2 Vector) bool { return v1.Price.Cmp(v2.Price) < 0 }
+func GasSort(v1, v2 Vector) bool   { return v1.Gas.Cmp(v2.Gas) < 0 }
+
+type vectorSummer struct {
+	vectors []Vector
+	by      func(v Vector) *big.Int
+}
+
+type VectorSum func(v Vector) *big.Int
+
+func (v VectorSum) Sum(vectors []Vector) *big.Int {
+	vs := vectorSummer{
+		vectors: vectors,
+		by:      v,
+	}
+	return Sum(vs)
+}
+
+func (v vectorSummer) Len() int           { return len(v.vectors) }
+func (v vectorSummer) Sum(i int) *big.Int { return v.by(v.vectors[i]) }
+
+func GasSum(v Vector) *big.Int { return v.Gas }
+
+var etherInWei = new(big.Rat).SetInt(common.String2Big("1000000000000000000"))
+
+func GasPrice(bp, gl, ep *big.Int) *big.Int {
+	BP := new(big.Rat).SetInt(bp)
+	GL := new(big.Rat).SetInt(gl)
+	EP := new(big.Rat).SetInt(ep)
+	GP := new(big.Rat).Quo(BP, GL)
+	GP = GP.Quo(GP, EP)
+
+	return GP.Mul(GP, etherInWei).Num()
+}
--- a/common/math/dist_test.go
+++ b/common/math/dist_test.go
@ -0,0 +1,66 @@
+package math
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+type summer struct {
+	numbers []*big.Int
+}
+
+func (s summer) Len() int { return len(s.numbers) }
+func (s summer) Sum(i int) *big.Int {
+	return s.numbers[i]
+}
+
+func TestSum(t *testing.T) {
+	summer := summer{numbers: []*big.Int{big.NewInt(1), big.NewInt(2), big.NewInt(3)}}
+	sum := Sum(summer)
+	if sum.Cmp(big.NewInt(6)) != 0 {
+		t.Errorf("not 6", sum)
+	}
+}
+
+func TestDist(t *testing.T) {
+	var vectors = []Vector{
+		Vector{big.NewInt(1000), big.NewInt(1234)},
+		Vector{big.NewInt(500), big.NewInt(10023)},
+		Vector{big.NewInt(1034), big.NewInt(1987)},
+		Vector{big.NewInt(1034), big.NewInt(1987)},
+		Vector{big.NewInt(8983), big.NewInt(1977)},
+		Vector{big.NewInt(98382), big.NewInt(1887)},
+		Vector{big.NewInt(12398), big.NewInt(1287)},
+		Vector{big.NewInt(12398), big.NewInt(1487)},
+		Vector{big.NewInt(12398), big.NewInt(1987)},
+		Vector{big.NewInt(12398), big.NewInt(128)},
+		Vector{big.NewInt(12398), big.NewInt(1987)},
+		Vector{big.NewInt(1398), big.NewInt(187)},
+		Vector{big.NewInt(12328), big.NewInt(1927)},
+		Vector{big.NewInt(12398), big.NewInt(1987)},
+		Vector{big.NewInt(22398), big.NewInt(1287)},
+		Vector{big.NewInt(1370), big.NewInt(1981)},
+		Vector{big.NewInt(12398), big.NewInt(1957)},
+		Vector{big.NewInt(42198), big.NewInt(1987)},
+	}
+
+	VectorsBy(GasSort).Sort(vectors)
+	fmt.Println(vectors)
+
+	BP := big.NewInt(15)
+	GL := big.NewInt(1000000)
+	EP := big.NewInt(100)
+	fmt.Println("BP", BP, "GL", GL, "EP", EP)
+	GP := GasPrice(BP, GL, EP)
+	fmt.Println("GP =", GP, "Wei per GU")
+
+	S := len(vectors) / 4
+	fmt.Println("L", len(vectors), "S", S)
+	for i := 1; i <= S*4; i += S {
+		fmt.Printf("T%d = %v\n", i, vectors[i])
+	}
+
+	g := VectorSum(GasSum).Sum(vectors)
+	fmt.Printf("G = ∑g* (%v)\n", g)
+}
--- a/common/natspec/natspec.go
+++ b/common/natspec/natspec.go
@ -0,0 +1,63 @@
+package natspec
+
+import (
+	"fmt"
+	"github.com/obscuren/otto"
+)
+
+type NatSpec struct {
+	jsvm *otto.Otto
+}
+
+// TODO: should initialise with abi and userdoc jsons
+func New() (self *NatSpec, err error) {
+
+	self = new(NatSpec)
+	self.jsvm = otto.New()
+
+	_, err = self.jsvm.Run(natspecJS)
+	if err != nil {
+		return
+	}
+	_, err = self.jsvm.Run("var natspec = require('natspec');")
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+func (self *NatSpec) Notice(transaction, abi, method, expression string) (string, error) {
+	var err error
+	if _, err = self.jsvm.Run("var transaction = " + transaction + ";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting transaction: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var abi = " + abi + ";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting abi: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var method = '" + method + "';"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting method: %v", err)
+	}
+
+	if _, err = self.jsvm.Run("var expression = \"" + expression + "\";"); err != nil {
+		return "", fmt.Errorf("natspec.js error setting expression: %v", err)
+	}
+
+	self.jsvm.Run("var call = {method: method,abi: abi,transaction: transaction};")
+	value, err := self.jsvm.Run("natspec.evaluateExpression(expression, call);")
+	if err != nil {
+		return "", fmt.Errorf("natspec.js error evaluating expression: %v", err)
+	}
+	evalError := "Natspec evaluation failed, wrong input params"
+	if value.String() == evalError {
+		return "", fmt.Errorf("natspec.js error evaluating expression: wrong input params in expression '%s'", expression)
+	}
+	if len(value.String()) == 0 {
+		return "", fmt.Errorf("natspec.js error evaluating expression")
+	}
+
+	return value.String(), nil
+
+}
--- a/common/natspec/natspec_js.go
+++ b/common/natspec/natspec_js.go
--- a/common/natspec/natspec_test.go
+++ b/common/natspec/natspec_test.go
@ -0,0 +1,97 @@
+package natspec
+
+import (
+	"testing"
+)
+
+func TestNotice(t *testing.T) {
+
+	tx := `
+	{
+    "jsonrpc": "2.0",
+    "method": "eth_call",
+    "params": [{
+        "to": "0x8521742d3f456bd237e312d6e30724960f72517a",
+        "data": "0xc6888fa1000000000000000000000000000000000000000000000000000000000000007a"
+    }],
+    "id": 6
+  }
+	`
+
+	abi := `
+	[{
+    "name": "multiply",
+    "constant": false,
+    "type": "function",
+    "inputs": [{
+      "name": "a",
+      "type": "uint256"
+    }],
+    "outputs": [{
+      "name": "d",
+      "type": "uint256"
+    }]
+  }]
+	`
+
+	desc := "Will multiply `a` by 7 and return `a * 7`."
+
+	method := "multiply"
+
+	ns, err := New()
+	if err != nil {
+		t.Errorf("NewNATSpec error %v", err)
+	}
+
+	notice, err := ns.Notice(tx, abi, method, desc)
+
+	if err != nil {
+		t.Errorf("expected no error got %v", err)
+	}
+
+	expected := "Will multiply 122 by 7 and return 854."
+	if notice != expected {
+		t.Errorf("incorrect notice. expected %v, got %v", expected, notice)
+	} else {
+		t.Logf("returned notice \"%v\"", notice)
+	}
+
+	notice, err = ns.Notice(tx, abi, method, "Will multiply 122 by \"7\" and return 854.")
+
+	expected = "natspec.js error setting expression: (anonymous): Line 1:41 Unexpected number"
+
+	if err == nil {
+		t.Errorf("expected error, got nothing (notice: '%v')", err, notice)
+	} else {
+		if err.Error() != expected {
+			t.Errorf("expected error '%s' got '%v' (notice: '%v')", expected, err, notice)
+		}
+	}
+
+	// https://github.com/ethereum/natspec.js/issues/1
+	badDesc := "Will multiply `e` by 7 and return `a * 7`."
+	notice, err = ns.Notice(tx, abi, method, badDesc)
+
+	expected = "natspec.js error evaluating expression: Error: Natspec evaluation failed, wrong input params"
+
+	if err == nil {
+		t.Errorf("expected error, got nothing (notice: '%v')", notice)
+	} else {
+		if err.Error() != expected {
+			t.Errorf("expected error '%s' got '%v' (notice: '%v')", expected, err, notice)
+		}
+	}
+
+	notice, err = ns.Notice(tx, abi, "missing_method", desc)
+
+	expected = "natspec.js error evaluating expression: Error: Natspec evaluation failed, method does not exist"
+
+	if err == nil {
+		t.Errorf("expected error, got nothing (notice: '%v')", notice)
+	} else {
+		if err.Error() != expected {
+			t.Errorf("expected error '%s' got '%v' (notice: '%v')", expected, err, notice)
+		}
+	}
+
+}
--- a/common/number/int.go
+++ b/common/number/int.go
@ -0,0 +1,181 @@
+package number
+
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+var tt256 = new(big.Int).Lsh(big.NewInt(1), 256)
+var tt256m1 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
+var tt255 = new(big.Int).Lsh(big.NewInt(1), 255)
+
+func limitUnsigned256(x *Number) *Number {
+	x.num.And(x.num, tt256m1)
+	return x
+}
+
+func limitSigned256(x *Number) *Number {
+	if x.num.Cmp(tt255) < 0 {
+		return x
+	} else {
+		x.num.Sub(x.num, tt256)
+		return x
+	}
+}
+
+// Number function
+type Initialiser func(n int64) *Number
+
+// A Number represents a generic integer with a bounding function limiter. Limit is called after each operations
+// to give "fake" bounded integers. New types of Number can be created through NewInitialiser returning a lambda
+// with the new Initialiser.
+type Number struct {
+	num   *big.Int
+	limit func(n *Number) *Number
+}
+
+// Returns a new initialiser for a new *Number without having to expose certain fields
+func NewInitialiser(limiter func(*Number) *Number) Initialiser {
+	return func(n int64) *Number {
+		return &Number{big.NewInt(n), limiter}
+	}
+}
+
+// Return a Number with a UNSIGNED limiter up to 256 bits
+func Uint256(n int64) *Number {
+	return &Number{big.NewInt(n), limitUnsigned256}
+}
+
+// Return a Number with a SIGNED limiter up to 256 bits
+func Int256(n int64) *Number {
+	return &Number{big.NewInt(n), limitSigned256}
+}
+
+// Returns a Number with a SIGNED unlimited size
+func Big(n int64) *Number {
+	return &Number{big.NewInt(n), func(x *Number) *Number { return x }}
+}
+
+// Sets i to sum of x+y
+func (i *Number) Add(x, y *Number) *Number {
+	i.num.Add(x.num, y.num)
+	return i.limit(i)
+}
+
+// Sets i to difference of x-y
+func (i *Number) Sub(x, y *Number) *Number {
+	i.num.Sub(x.num, y.num)
+	return i.limit(i)
+}
+
+// Sets i to product of x*y
+func (i *Number) Mul(x, y *Number) *Number {
+	i.num.Mul(x.num, y.num)
+	return i.limit(i)
+}
+
+// Sets i to the quotient prodject of x/y
+func (i *Number) Div(x, y *Number) *Number {
+	i.num.Div(x.num, y.num)
+	return i.limit(i)
+}
+
+// Sets i to x % y
+func (i *Number) Mod(x, y *Number) *Number {
+	i.num.Mod(x.num, y.num)
+	return i.limit(i)
+}
+
+// Sets i to x << s
+func (i *Number) Lsh(x *Number, s uint) *Number {
+	i.num.Lsh(x.num, s)
+	return i.limit(i)
+}
+
+// Sets i to x^y
+func (i *Number) Pow(x, y *Number) *Number {
+	i.num.Exp(x.num, y.num, big.NewInt(0))
+	return i.limit(i)
+}
+
+// Setters
+
+// Set x to i
+func (i *Number) Set(x *Number) *Number {
+	i.num.Set(x.num)
+	return i.limit(i)
+}
+
+// Set x bytes to i
+func (i *Number) SetBytes(x []byte) *Number {
+	i.num.SetBytes(x)
+	return i.limit(i)
+}
+
+// Cmp compares x and y and returns:
+//
+//     -1 if x <  y
+//     0 if x == y
+//     +1 if x >  y
+func (i *Number) Cmp(x *Number) int {
+	return i.num.Cmp(x.num)
+}
+
+// Getters
+
+// Returns the string representation of i
+func (i *Number) String() string {
+	return i.num.String()
+}
+
+// Returns the byte representation of i
+func (i *Number) Bytes() []byte {
+	return i.num.Bytes()
+}
+
+// Uint64 returns the Uint64 representation of x. If x cannot be represented in an int64, the result is undefined.
+func (i *Number) Uint64() uint64 {
+	return i.num.Uint64()
+}
+
+// Int64 returns the int64 representation of x. If x cannot be represented in an int64, the result is undefined.
+func (i *Number) Int64() int64 {
+	return i.num.Int64()
+}
+
+// Returns the signed version of i
+func (i *Number) Int256() *Number {
+	return Int(0).Set(i)
+}
+
+// Returns the unsigned version of i
+func (i *Number) Uint256() *Number {
+	return Uint(0).Set(i)
+}
+
+// Returns the index of the first bit that's set to 1
+func (i *Number) FirstBitSet() int {
+	for j := 0; j < i.num.BitLen(); j++ {
+		if i.num.Bit(j) > 0 {
+			return j
+		}
+	}
+
+	return i.num.BitLen()
+}
+
+// Variables
+
+var (
+	Zero       = Uint(0)
+	One        = Uint(1)
+	Two        = Uint(2)
+	MaxUint256 = Uint(0).SetBytes(common.Hex2Bytes("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"))
+
+	MinOne = Int(-1)
+
+	// "typedefs"
+	Uint = Uint256
+	Int  = Int256
+)
--- a/common/number/uint_test.go
+++ b/common/number/uint_test.go
@ -0,0 +1,92 @@
+package number
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+func TestSet(t *testing.T) {
+	a := Uint(0)
+	b := Uint(10)
+	a.Set(b)
+	if a.num.Cmp(b.num) != 0 {
+		t.Error("didn't compare", a, b)
+	}
+
+	c := Uint(0).SetBytes(common.Hex2Bytes("0a"))
+	if c.num.Cmp(big.NewInt(10)) != 0 {
+		t.Error("c set bytes failed.")
+	}
+}
+
+func TestInitialiser(t *testing.T) {
+	check := false
+	init := NewInitialiser(func(x *Number) *Number {
+		check = true
+		return x
+	})
+	a := init(0).Add(init(1), init(2))
+	if a.Cmp(init(3)) != 0 {
+		t.Error("expected 3. got", a)
+	}
+	if !check {
+		t.Error("expected limiter to be called")
+	}
+}
+
+func TestGet(t *testing.T) {
+	a := Uint(10)
+	if a.Uint64() != 10 {
+		t.Error("expected to get 10. got", a.Uint64())
+	}
+
+	a = Uint(10)
+	if a.Int64() != 10 {
+		t.Error("expected to get 10. got", a.Int64())
+	}
+}
+
+func TestCmp(t *testing.T) {
+	a := Uint(10)
+	b := Uint(10)
+	c := Uint(11)
+
+	if a.Cmp(b) != 0 {
+		t.Error("a b == 0 failed", a, b)
+	}
+
+	if a.Cmp(c) >= 0 {
+		t.Error("a c < 0 failed", a, c)
+	}
+
+	if c.Cmp(b) <= 0 {
+		t.Error("c b > 0 failed", c, b)
+	}
+}
+
+func TestMaxArith(t *testing.T) {
+	a := Uint(0).Add(MaxUint256, One)
+	if a.Cmp(Zero) != 0 {
+		t.Error("expected max256 + 1 = 0 got", a)
+	}
+
+	a = Uint(0).Sub(Uint(0), One)
+	if a.Cmp(MaxUint256) != 0 {
+		t.Error("expected 0 - 1 = max256 got", a)
+	}
+
+	a = Int(0).Sub(Int(0), One)
+	if a.Cmp(MinOne) != 0 {
+		t.Error("expected 0 - 1 = -1 got", a)
+	}
+}
+
+func TestConversion(t *testing.T) {
+	a := Int(-1)
+	b := a.Uint256()
+	if b.Cmp(MaxUint256) != 0 {
+		t.Error("expected -1 => unsigned to return max. got", b)
+	}
+}
--- a/common/package.go
+++ b/common/package.go
@ -0,0 +1,123 @@
+package common
+
+import (
+	"archive/zip"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"strings"
+)
+
+// Manifest object
+//
+// The manifest object holds all the relevant information supplied with the
+// the manifest specified in the package
+type Manifest struct {
+	Entry         string
+	Height, Width int
+}
+
+// External package
+//
+// External package contains the main html file and manifest
+type ExtPackage struct {
+	EntryHtml string
+	Manifest  *Manifest
+}
+
+// Read file
+//
+// Read a given compressed file and returns the read bytes.
+// Returns an error otherwise
+func ReadFile(f *zip.File) ([]byte, error) {
+	rc, err := f.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer rc.Close()
+
+	content, err := ioutil.ReadAll(rc)
+	if err != nil {
+		return nil, err
+	}
+
+	return content, nil
+}
+
+// Reads manifest
+//
+// Reads and returns a manifest object. Returns error otherwise
+func ReadManifest(m []byte) (*Manifest, error) {
+	var manifest Manifest
+
+	dec := json.NewDecoder(strings.NewReader(string(m)))
+	if err := dec.Decode(&manifest); err == io.EOF {
+	} else if err != nil {
+		return nil, err
+	}
+
+	return &manifest, nil
+}
+
+// Find file in archive
+//
+// Returns the index of the given file name if it exists. -1 if file not found
+func FindFileInArchive(fn string, files []*zip.File) (index int) {
+	index = -1
+	// Find the manifest first
+	for i, f := range files {
+		if f.Name == fn {
+			index = i
+		}
+	}
+
+	return
+}
+
+// Open package
+//
+// Opens a prepared ethereum package
+// Reads the manifest file and determines file contents and returns and
+// the external package.
+func OpenPackage(fn string) (*ExtPackage, error) {
+	r, err := zip.OpenReader(fn)
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+
+	manifestIndex := FindFileInArchive("manifest.json", r.File)
+
+	if manifestIndex < 0 {
+		return nil, fmt.Errorf("No manifest file found in archive")
+	}
+
+	f, err := ReadFile(r.File[manifestIndex])
+	if err != nil {
+		return nil, err
+	}
+
+	manifest, err := ReadManifest(f)
+	if err != nil {
+		return nil, err
+	}
+
+	if manifest.Entry == "" {
+		return nil, fmt.Errorf("Entry file specified but appears to be empty: %s", manifest.Entry)
+	}
+
+	entryIndex := FindFileInArchive(manifest.Entry, r.File)
+	if entryIndex < 0 {
+		return nil, fmt.Errorf("Entry file not found: '%s'", manifest.Entry)
+	}
+
+	f, err = ReadFile(r.File[entryIndex])
+	if err != nil {
+		return nil, err
+	}
+
+	extPackage := &ExtPackage{string(f), manifest}
+
+	return extPackage, nil
+}
--- a/common/path.go
+++ b/common/path.go
@ -0,0 +1,68 @@
+package common
+
+import (
+	"io/ioutil"
+	"os"
+	"os/user"
+	"path"
+	"strings"
+)
+
+func ExpandHomePath(p string) (path string) {
+	path = p
+
+	// Check in case of paths like "/something/~/something/"
+	if len(path) > 1 && path[:2] == "~/" {
+		usr, _ := user.Current()
+		dir := usr.HomeDir
+
+		path = strings.Replace(p, "~", dir, 1)
+	}
+
+	return
+}
+
+func FileExist(filePath string) bool {
+	_, err := os.Stat(filePath)
+	if err != nil && os.IsNotExist(err) {
+		return false
+	}
+
+	return true
+}
+
+func ReadAllFile(filePath string) (string, error) {
+	file, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+
+	data, err := ioutil.ReadAll(file)
+	if err != nil {
+		return "", err
+	}
+
+	return string(data), nil
+}
+
+func WriteFile(filePath string, content []byte) error {
+	fh, err := os.OpenFile(filePath, os.O_TRUNC|os.O_RDWR|os.O_CREATE, os.ModePerm)
+	if err != nil {
+		return err
+	}
+	defer fh.Close()
+
+	_, err = fh.Write(content)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func AbsolutePath(Datadir string, filename string) string {
+	if path.IsAbs(filename) {
+		return filename
+	}
+	return path.Join(Datadir, filename)
+}
--- a/common/path_test.go
+++ b/common/path_test.go
@ -0,0 +1,51 @@
+package common
+
+import (
+	// "os"
+	"testing"
+)
+
+func TestGoodFile(t *testing.T) {
+	goodpath := "~/goethereumtest.pass"
+	path := ExpandHomePath(goodpath)
+	contentstring := "3.14159265358979323846"
+
+	err := WriteFile(path, []byte(contentstring))
+	if err != nil {
+		t.Error("Could not write file")
+	}
+
+	if !FileExist(path) {
+		t.Error("File not found at", path)
+	}
+
+	v, err := ReadAllFile(path)
+	if err != nil {
+		t.Error("Could not read file", path)
+	}
+	if v != contentstring {
+		t.Error("Expected", contentstring, "Got", v)
+	}
+
+}
+
+func TestBadFile(t *testing.T) {
+	badpath := "/this/path/should/not/exist/goethereumtest.fail"
+	path := ExpandHomePath(badpath)
+	contentstring := "3.14159265358979323846"
+
+	err := WriteFile(path, []byte(contentstring))
+	if err == nil {
+		t.Error("Wrote file, but should not be able to", path)
+	}
+
+	if FileExist(path) {
+		t.Error("Found file, but should not be able to", path)
+	}
+
+	v, err := ReadAllFile(path)
+	if err == nil {
+		t.Error("Read file, but should not be able to", v)
+	}
+
+}
--- a/common/rlp.go
+++ b/common/rlp.go
@ -0,0 +1,276 @@
+package common
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"reflect"
+)
+
+type RlpEncode interface {
+	RlpEncode() []byte
+}
+
+type RlpEncodeDecode interface {
+	RlpEncode
+	RlpValue() []interface{}
+}
+
+type RlpEncodable interface {
+	RlpData() interface{}
+}
+
+func Rlp(encoder RlpEncode) []byte {
+	return encoder.RlpEncode()
+}
+
+type RlpEncoder struct {
+	rlpData []byte
+}
+
+func NewRlpEncoder() *RlpEncoder {
+	encoder := &RlpEncoder{}
+
+	return encoder
+}
+func (coder *RlpEncoder) EncodeData(rlpData interface{}) []byte {
+	return Encode(rlpData)
+}
+
+const (
+	RlpEmptyList = 0x80
+	RlpEmptyStr  = 0x40
+)
+
+const rlpEof = -1
+
+func Char(c []byte) int {
+	if len(c) > 0 {
+		return int(c[0])
+	}
+
+	return rlpEof
+}
+
+func DecodeWithReader(reader *bytes.Buffer) interface{} {
+	var slice []interface{}
+
+	// Read the next byte
+	char := Char(reader.Next(1))
+	switch {
+	case char <= 0x7f:
+		return char
+
+	case char <= 0xb7:
+		return reader.Next(int(char - 0x80))
+
+	case char <= 0xbf:
+		length := ReadVarInt(reader.Next(int(char - 0xb7)))
+
+		return reader.Next(int(length))
+
+	case char <= 0xf7:
+		length := int(char - 0xc0)
+		for i := 0; i < length; i++ {
+			obj := DecodeWithReader(reader)
+			slice = append(slice, obj)
+		}
+
+		return slice
+	case char <= 0xff:
+		length := ReadVarInt(reader.Next(int(char - 0xf7)))
+		for i := uint64(0); i < length; i++ {
+			obj := DecodeWithReader(reader)
+			slice = append(slice, obj)
+		}
+
+		return slice
+	default:
+		panic(fmt.Sprintf("byte not supported: %q", char))
+	}
+
+	return slice
+}
+
+var (
+	directRlp = big.NewInt(0x7f)
+	numberRlp = big.NewInt(0xb7)
+	zeroRlp   = big.NewInt(0x0)
+)
+
+func intlen(i int64) (length int) {
+	for i > 0 {
+		i = i >> 8
+		length++
+	}
+	return
+}
+
+func Encode(object interface{}) []byte {
+	var buff bytes.Buffer
+
+	if object != nil {
+		switch t := object.(type) {
+		case *Value:
+			buff.Write(Encode(t.Raw()))
+		case RlpEncodable:
+			buff.Write(Encode(t.RlpData()))
+		// Code dup :-/
+		case int:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case uint:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case int8:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case int16:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case int32:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case int64:
+			buff.Write(Encode(big.NewInt(t)))
+		case uint16:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case uint32:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case uint64:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case byte:
+			buff.Write(Encode(big.NewInt(int64(t))))
+		case *big.Int:
+			// Not sure how this is possible while we check for nil
+			if t == nil {
+				buff.WriteByte(0xc0)
+			} else {
+				buff.Write(Encode(t.Bytes()))
+			}
+		case Bytes:
+			buff.Write(Encode([]byte(t)))
+		case []byte:
+			if len(t) == 1 && t[0] <= 0x7f {
+				buff.Write(t)
+			} else if len(t) < 56 {
+				buff.WriteByte(byte(len(t) + 0x80))
+				buff.Write(t)
+			} else {
+				b := big.NewInt(int64(len(t)))
+				buff.WriteByte(byte(len(b.Bytes()) + 0xb7))
+				buff.Write(b.Bytes())
+				buff.Write(t)
+			}
+		case string:
+			buff.Write(Encode([]byte(t)))
+		case []interface{}:
+			// Inline function for writing the slice header
+			WriteSliceHeader := func(length int) {
+				if length < 56 {
+					buff.WriteByte(byte(length + 0xc0))
+				} else {
+					b := big.NewInt(int64(length))
+					buff.WriteByte(byte(len(b.Bytes()) + 0xf7))
+					buff.Write(b.Bytes())
+				}
+			}
+
+			var b bytes.Buffer
+			for _, val := range t {
+				b.Write(Encode(val))
+			}
+			WriteSliceHeader(len(b.Bytes()))
+			buff.Write(b.Bytes())
+		default:
+			// This is how it should have been from the start
+			// needs refactoring (@fjl)
+			v := reflect.ValueOf(t)
+			switch v.Kind() {
+			case reflect.Slice:
+				var b bytes.Buffer
+				for i := 0; i < v.Len(); i++ {
+					b.Write(Encode(v.Index(i).Interface()))
+				}
+
+				blen := b.Len()
+				if blen < 56 {
+					buff.WriteByte(byte(blen) + 0xc0)
+				} else {
+					ilen := byte(intlen(int64(blen)))
+					buff.WriteByte(ilen + 0xf7)
+					t := make([]byte, ilen)
+					for i := byte(0); i < ilen; i++ {
+						t[ilen-i-1] = byte(blen >> (i * 8))
+					}
+					buff.Write(t)
+				}
+				buff.ReadFrom(&b)
+			}
+		}
+	} else {
+		// Empty list for nil
+		buff.WriteByte(0xc0)
+	}
+
+	return buff.Bytes()
+}
+
+// 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 Decode(data []byte, pos uint64) (interface{}, uint64) {
+	var slice []interface{}
+	char := int(data[pos])
+	switch {
+	case char <= 0x7f:
+		return data[pos], pos + 1
+
+	case char <= 0xb7:
+		b := uint64(data[pos]) - 0x80
+
+		return data[pos+1 : pos+1+b], pos + 1 + b
+
+	case char <= 0xbf:
+		b := uint64(data[pos]) - 0xb7
+
+		b2 := ReadVarInt(data[pos+1 : pos+1+b])
+
+		return data[pos+1+b : pos+1+b+b2], pos + 1 + b + b2
+
+	case char <= 0xf7:
+		b := uint64(data[pos]) - 0xc0
+		prevPos := pos
+		pos++
+		for i := uint64(0); i < b; {
+			var obj interface{}
+
+			// Get the next item in the data list and append it
+			obj, prevPos = Decode(data, pos)
+			slice = append(slice, obj)
+
+			// Increment i by the amount bytes read in the previous
+			// read
+			i += (prevPos - pos)
+			pos = prevPos
+		}
+		return slice, pos
+
+	case char <= 0xff:
+		l := uint64(data[pos]) - 0xf7
+		b := ReadVarInt(data[pos+1 : pos+1+l])
+
+		pos = pos + l + 1
+
+		prevPos := b
+		for i := uint64(0); i < uint64(b); {
+			var obj interface{}
+
+			obj, prevPos = Decode(data, pos)
+			slice = append(slice, obj)
+
+			i += (prevPos - pos)
+			pos = prevPos
+		}
+		return slice, pos
+
+	default:
+		panic(fmt.Sprintf("byte not supported: %q", char))
+	}
+
+	return slice, 0
+}
--- a/common/rlp_test.go
+++ b/common/rlp_test.go
@ -0,0 +1,156 @@
+package common
+
+import (
+	"bytes"
+	"math/big"
+	"reflect"
+	"testing"
+)
+
+func TestNonInterfaceSlice(t *testing.T) {
+	vala := []string{"value1", "value2", "value3"}
+	valb := []interface{}{"value1", "value2", "value3"}
+	resa := Encode(vala)
+	resb := Encode(valb)
+	if !bytes.Equal(resa, resb) {
+		t.Errorf("expected []string & []interface{} to be equal")
+	}
+}
+
+func TestRlpValueEncoding(t *testing.T) {
+	val := EmptyValue()
+	val.AppendList().Append(1).Append(2).Append(3)
+	val.Append("4").AppendList().Append(5)
+
+	res := val.Encode()
+	exp := Encode([]interface{}{[]interface{}{1, 2, 3}, "4", []interface{}{5}})
+	if bytes.Compare(res, exp) != 0 {
+		t.Errorf("expected %q, got %q", res, exp)
+	}
+}
+
+func TestValueSlice(t *testing.T) {
+	val := []interface{}{
+		"value1",
+		"valeu2",
+		"value3",
+	}
+
+	value := NewValue(val)
+	splitVal := value.SliceFrom(1)
+
+	if splitVal.Len() != 2 {
+		t.Error("SliceFrom: Expected len", 2, "got", splitVal.Len())
+	}
+
+	splitVal = value.SliceTo(2)
+	if splitVal.Len() != 2 {
+		t.Error("SliceTo: Expected len", 2, "got", splitVal.Len())
+	}
+
+	splitVal = value.SliceFromTo(1, 3)
+	if splitVal.Len() != 2 {
+		t.Error("SliceFromTo: Expected len", 2, "got", splitVal.Len())
+	}
+}
+
+func TestLargeData(t *testing.T) {
+	data := make([]byte, 100000)
+	enc := Encode(data)
+	value := NewValue(enc)
+	value.Decode()
+
+	if value.Len() != len(data) {
+		t.Error("Expected data to be", len(data), "got", value.Len())
+	}
+}
+
+func TestValue(t *testing.T) {
+	value := NewValueFromBytes([]byte("\xcd\x83dog\x83god\x83cat\x01"))
+	if value.Get(0).Str() != "dog" {
+		t.Errorf("expected '%v', got '%v'", value.Get(0).Str(), "dog")
+	}
+
+	if value.Get(3).Uint() != 1 {
+		t.Errorf("expected '%v', got '%v'", value.Get(3).Uint(), 1)
+	}
+}
+
+func TestEncode(t *testing.T) {
+	strRes := "\x83dog"
+	bytes := Encode("dog")
+
+	str := string(bytes)
+	if str != strRes {
+		t.Errorf("Expected %q, got %q", strRes, str)
+	}
+
+	sliceRes := "\xcc\x83dog\x83god\x83cat"
+	strs := []interface{}{"dog", "god", "cat"}
+	bytes = Encode(strs)
+	slice := string(bytes)
+	if slice != sliceRes {
+		t.Error("Expected %q, got %q", sliceRes, slice)
+	}
+
+	intRes := "\x82\x04\x00"
+	bytes = Encode(1024)
+	if string(bytes) != intRes {
+		t.Errorf("Expected %q, got %q", intRes, bytes)
+	}
+}
+
+func TestDecode(t *testing.T) {
+	single := []byte("\x01")
+	b, _ := Decode(single, 0)
+
+	if b.(uint8) != 1 {
+		t.Errorf("Expected 1, got %q", b)
+	}
+
+	str := []byte("\x83dog")
+	b, _ = Decode(str, 0)
+	if bytes.Compare(b.([]byte), []byte("dog")) != 0 {
+		t.Errorf("Expected dog, got %q", b)
+	}
+
+	slice := []byte("\xcc\x83dog\x83god\x83cat")
+	res := []interface{}{"dog", "god", "cat"}
+	b, _ = Decode(slice, 0)
+	if reflect.DeepEqual(b, res) {
+		t.Errorf("Expected %q, got %q", res, b)
+	}
+}
+
+func TestEncodeDecodeBigInt(t *testing.T) {
+	bigInt := big.NewInt(1391787038)
+	encoded := Encode(bigInt)
+
+	value := NewValueFromBytes(encoded)
+	if value.BigInt().Cmp(bigInt) != 0 {
+		t.Errorf("Expected %v, got %v", bigInt, value.BigInt())
+	}
+}
+
+func TestEncodeDecodeBytes(t *testing.T) {
+	b := NewValue([]interface{}{[]byte{1, 2, 3, 4, 5}, byte(6)})
+	val := NewValueFromBytes(b.Encode())
+	if !b.Cmp(val) {
+		t.Errorf("Expected %v, got %v", val, b)
+	}
+}
+
+func TestEncodeZero(t *testing.T) {
+	b := NewValue(0).Encode()
+	exp := []byte{0xc0}
+	if bytes.Compare(b, exp) == 0 {
+		t.Error("Expected", exp, "got", b)
+	}
+}
+
+func BenchmarkEncodeDecode(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		bytes := Encode([]interface{}{"dog", "god", "cat"})
+		Decode(bytes, 0)
+	}
+}
--- a/common/size.go
+++ b/common/size.go
@ -0,0 +1,15 @@
+package common
+
+import "fmt"
+
+type StorageSize float64
+
+func (self StorageSize) String() string {
+	if self > 1000000 {
+		return fmt.Sprintf("%.2f mB", self/1000000)
+	} else if self > 1000 {
+		return fmt.Sprintf("%.2f kB", self/1000)
+	} else {
+		return fmt.Sprintf("%.2f B", self)
+	}
+}
--- a/common/size_test.go
+++ b/common/size_test.go
@ -0,0 +1,23 @@
+package common
+
+import (
+	checker "gopkg.in/check.v1"
+)
+
+type SizeSuite struct{}
+
+var _ = checker.Suite(&SizeSuite{})
+
+func (s *SizeSuite) TestStorageSizeString(c *checker.C) {
+	data1 := 2381273
+	data2 := 2192
+	data3 := 12
+
+	exp1 := "2.38 mB"
+	exp2 := "2.19 kB"
+	exp3 := "12.00 B"
+
+	c.Assert(StorageSize(data1).String(), checker.Equals, exp1)
+	c.Assert(StorageSize(data2).String(), checker.Equals, exp2)
+	c.Assert(StorageSize(data3).String(), checker.Equals, exp3)
+}
--- a/common/types.go
+++ b/common/types.go
@ -0,0 +1,6 @@
+package common
+
+type (
+	Hash    [32]byte
+	Address [20]byte
+)
--- a/common/value.go
+++ b/common/value.go
@ -0,0 +1,401 @@
+package common
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+	"reflect"
+	"strconv"
+)
+
+// 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
+type Value struct {
+	Val  interface{}
+	kind reflect.Value
+}
+
+func (val *Value) String() string {
+	return fmt.Sprintf("%x", val.Val)
+}
+
+func NewValue(val interface{}) *Value {
+	t := val
+	if v, ok := val.(*Value); ok {
+		t = v.Val
+	}
+
+	return &Value{Val: t}
+}
+
+func (val *Value) Type() reflect.Kind {
+	return reflect.TypeOf(val.Val).Kind()
+}
+
+func (val *Value) IsNil() bool {
+	return val.Val == nil
+}
+
+func (val *Value) Len() int {
+	//return val.kind.Len()
+	if data, ok := val.Val.([]interface{}); ok {
+		return len(data)
+	}
+
+	return len(val.Bytes())
+}
+
+func (val *Value) Raw() interface{} {
+	return val.Val
+}
+
+func (val *Value) Interface() interface{} {
+	return val.Val
+}
+
+func (val *Value) Uint() uint64 {
+	if Val, ok := val.Val.(uint8); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(uint16); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(uint32); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(uint64); ok {
+		return Val
+	} else if Val, ok := val.Val.(float32); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(float64); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(int); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.(uint); ok {
+		return uint64(Val)
+	} else if Val, ok := val.Val.([]byte); ok {
+		return new(big.Int).SetBytes(Val).Uint64()
+	} else if Val, ok := val.Val.(*big.Int); ok {
+		return Val.Uint64()
+	}
+
+	return 0
+}
+
+func (val *Value) Int() int64 {
+	if Val, ok := val.Val.(int8); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.(int16); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.(int32); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.(int64); ok {
+		return Val
+	} else if Val, ok := val.Val.(int); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.(float32); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.(float64); ok {
+		return int64(Val)
+	} else if Val, ok := val.Val.([]byte); ok {
+		return new(big.Int).SetBytes(Val).Int64()
+	} else if Val, ok := val.Val.(*big.Int); ok {
+		return Val.Int64()
+	} else if Val, ok := val.Val.(string); ok {
+		n, _ := strconv.Atoi(Val)
+		return int64(n)
+	}
+
+	return 0
+}
+
+func (val *Value) Byte() byte {
+	if Val, ok := val.Val.(byte); ok {
+		return Val
+	}
+
+	return 0x0
+}
+
+func (val *Value) BigInt() *big.Int {
+	if a, ok := val.Val.([]byte); ok {
+		b := new(big.Int).SetBytes(a)
+
+		return b
+	} else if a, ok := val.Val.(*big.Int); ok {
+		return a
+	} else if a, ok := val.Val.(string); ok {
+		return Big(a)
+	} else {
+		return big.NewInt(int64(val.Uint()))
+	}
+
+	return big.NewInt(0)
+}
+
+func (val *Value) Str() string {
+	if a, ok := val.Val.([]byte); ok {
+		return string(a)
+	} else if a, ok := val.Val.(string); ok {
+		return a
+	} else if a, ok := val.Val.(byte); ok {
+		return string(a)
+	}
+
+	return ""
+}
+
+func (val *Value) Bytes() []byte {
+	if a, ok := val.Val.([]byte); ok {
+		return a
+	} else if s, ok := val.Val.(byte); ok {
+		return []byte{s}
+	} else if s, ok := val.Val.(string); ok {
+		return []byte(s)
+	} else if s, ok := val.Val.(*big.Int); ok {
+		return s.Bytes()
+	} else {
+		return big.NewInt(val.Int()).Bytes()
+	}
+
+	return []byte{}
+}
+
+func (val *Value) Err() error {
+	if err, ok := val.Val.(error); ok {
+		return err
+	}
+
+	return nil
+}
+
+func (val *Value) Slice() []interface{} {
+	if d, ok := val.Val.([]interface{}); ok {
+		return d
+	}
+
+	return []interface{}{}
+}
+
+func (val *Value) SliceFrom(from int) *Value {
+	slice := val.Slice()
+
+	return NewValue(slice[from:])
+}
+
+func (val *Value) SliceTo(to int) *Value {
+	slice := val.Slice()
+
+	return NewValue(slice[:to])
+}
+
+func (val *Value) SliceFromTo(from, to int) *Value {
+	slice := val.Slice()
+
+	return NewValue(slice[from:to])
+}
+
+// TODO More type checking methods
+func (val *Value) IsSlice() bool {
+	return val.Type() == reflect.Slice
+}
+
+func (val *Value) IsStr() bool {
+	return val.Type() == reflect.String
+}
+
+func (self *Value) IsErr() bool {
+	_, ok := self.Val.(error)
+	return ok
+}
+
+// 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 (val *Value) IsList() bool {
+	_, ok := val.Val.([]interface{})
+
+	return ok
+}
+
+func (val *Value) IsEmpty() bool {
+	return val.Val == nil || ((val.IsSlice() || val.IsStr()) && val.Len() == 0)
+}
+
+// Threat the value as a slice
+func (val *Value) Get(idx int) *Value {
+	if d, ok := val.Val.([]interface{}); ok {
+		// Guard for oob
+		if len(d) <= idx {
+			return NewValue(nil)
+		}
+
+		if idx < 0 {
+			return NewValue(nil)
+		}
+
+		return NewValue(d[idx])
+	}
+
+	// If this wasn't a slice you probably shouldn't be using this function
+	return NewValue(nil)
+}
+
+func (self *Value) Copy() *Value {
+	switch val := self.Val.(type) {
+	case *big.Int:
+		return NewValue(new(big.Int).Set(val))
+	case []byte:
+		return NewValue(CopyBytes(val))
+	default:
+		return NewValue(self.Val)
+	}
+
+	return nil
+}
+
+func (val *Value) Cmp(o *Value) bool {
+	return reflect.DeepEqual(val.Val, o.Val)
+}
+
+func (self *Value) DeepCmp(o *Value) bool {
+	return bytes.Compare(self.Bytes(), o.Bytes()) == 0
+}
+
+func (val *Value) Encode() []byte {
+	return Encode(val.Val)
+}
+
+// Assume that the data we have is encoded
+func (self *Value) Decode() {
+	v, _ := Decode(self.Bytes(), 0)
+	self.Val = v
+	//self.Val = DecodeWithReader(bytes.NewBuffer(self.Bytes()))
+}
+
+func NewValueFromBytes(data []byte) *Value {
+	if len(data) != 0 {
+		value := NewValue(data)
+		value.Decode()
+
+		return value
+	}
+
+	return NewValue(nil)
+}
+
+// Value setters
+func NewSliceValue(s interface{}) *Value {
+	list := EmptyValue()
+
+	if s != nil {
+		if slice, ok := s.([]interface{}); ok {
+			for _, val := range slice {
+				list.Append(val)
+			}
+		} else if slice, ok := s.([]string); ok {
+			for _, val := range slice {
+				list.Append(val)
+			}
+		}
+	}
+
+	return list
+}
+
+func EmptyValue() *Value {
+	return NewValue([]interface{}{})
+}
+
+func (val *Value) AppendList() *Value {
+	list := EmptyValue()
+	val.Val = append(val.Slice(), list)
+
+	return list
+}
+
+func (val *Value) Append(v interface{}) *Value {
+	val.Val = append(val.Slice(), v)
+
+	return val
+}
+
+const (
+	valOpAdd = iota
+	valOpDiv
+	valOpMul
+	valOpPow
+	valOpSub
+)
+
+// Math stuff
+func (self *Value) doOp(op int, other interface{}) *Value {
+	left := self.BigInt()
+	right := NewValue(other).BigInt()
+
+	switch op {
+	case valOpAdd:
+		self.Val = left.Add(left, right)
+	case valOpDiv:
+		self.Val = left.Div(left, right)
+	case valOpMul:
+		self.Val = left.Mul(left, right)
+	case valOpPow:
+		self.Val = left.Exp(left, right, Big0)
+	case valOpSub:
+		self.Val = left.Sub(left, right)
+	}
+
+	return self
+}
+
+func (self *Value) Add(other interface{}) *Value {
+	return self.doOp(valOpAdd, other)
+}
+
+func (self *Value) Sub(other interface{}) *Value {
+	return self.doOp(valOpSub, other)
+}
+
+func (self *Value) Div(other interface{}) *Value {
+	return self.doOp(valOpDiv, other)
+}
+
+func (self *Value) Mul(other interface{}) *Value {
+	return self.doOp(valOpMul, other)
+}
+
+func (self *Value) Pow(other interface{}) *Value {
+	return self.doOp(valOpPow, other)
+}
+
+type ValueIterator struct {
+	value        *Value
+	currentValue *Value
+	idx          int
+}
+
+func (val *Value) NewIterator() *ValueIterator {
+	return &ValueIterator{value: val}
+}
+
+func (it *ValueIterator) Len() int {
+	return it.value.Len()
+}
+
+func (it *ValueIterator) Next() bool {
+	if it.idx >= it.value.Len() {
+		return false
+	}
+
+	it.currentValue = it.value.Get(it.idx)
+	it.idx++
+
+	return true
+}
+
+func (it *ValueIterator) Value() *Value {
+	return it.currentValue
+}
+
+func (it *ValueIterator) Idx() int {
+	return it.idx - 1
+}
--- a/common/value_test.go
+++ b/common/value_test.go
@ -0,0 +1,70 @@
+package common
+
+import (
+	"math/big"
+
+	checker "gopkg.in/check.v1"
+)
+
+type ValueSuite struct{}
+
+var _ = checker.Suite(&ValueSuite{})
+
+func (s *ValueSuite) TestValueCmp(c *checker.C) {
+	val1 := NewValue("hello")
+	val2 := NewValue("world")
+	c.Assert(val1.Cmp(val2), checker.Equals, false)
+
+	val3 := NewValue("hello")
+	val4 := NewValue("hello")
+	c.Assert(val3.Cmp(val4), checker.Equals, true)
+}
+
+func (s *ValueSuite) TestValueTypes(c *checker.C) {
+	str := NewValue("str")
+	num := NewValue(1)
+	inter := NewValue([]interface{}{1})
+	byt := NewValue([]byte{1, 2, 3, 4})
+	bigInt := NewValue(big.NewInt(10))
+
+	strExp := "str"
+	numExp := uint64(1)
+	interExp := []interface{}{1}
+	bytExp := []byte{1, 2, 3, 4}
+	bigExp := big.NewInt(10)
+
+	c.Assert(str.Str(), checker.Equals, strExp)
+	c.Assert(num.Uint(), checker.Equals, numExp)
+	c.Assert(NewValue(inter.Interface()).Cmp(NewValue(interExp)), checker.Equals, true)
+	c.Assert(byt.Bytes(), checker.DeepEquals, bytExp)
+	c.Assert(bigInt.BigInt(), checker.DeepEquals, bigExp)
+}
+
+func (s *ValueSuite) TestIterator(c *checker.C) {
+	value := NewValue([]interface{}{1, 2, 3})
+	iter := value.NewIterator()
+	values := []uint64{1, 2, 3}
+	i := 0
+	for iter.Next() {
+		c.Assert(values[i], checker.Equals, iter.Value().Uint())
+		i++
+	}
+}
+
+func (s *ValueSuite) TestMath(c *checker.C) {
+	data1 := NewValue(1)
+	data1.Add(1).Add(1)
+	exp1 := NewValue(3)
+	data2 := NewValue(2)
+	data2.Sub(1).Sub(1)
+	exp2 := NewValue(0)
+
+	c.Assert(data1.DeepCmp(exp1), checker.Equals, true)
+	c.Assert(data2.DeepCmp(exp2), checker.Equals, true)
+}
+
+func (s *ValueSuite) TestString(c *checker.C) {
+	data := "10"
+	exp := int64(10)
+	c.Assert(NewValue(data).Int(), checker.DeepEquals, exp)
+}