1 files changed, 276 insertions, 0 deletions
diff --git a/common/rlp.go b/common/rlp.go
new file mode 100644
index 000000000..602f13202
--- /dev/null
+++ 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
+}