aboutsummaryrefslogtreecommitdiffstats
path: root/ethutil/rlp.go
blob: 195ef0efbb50856396f867c6b02f1f855f1c23ed (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
package ethutil

import (
    "bytes"
    _ "encoding/binary"
    "fmt"
    _ "log"
    _ "math"
    "math/big"
)

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

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
)

func Char(c []byte) int {
    if len(c) > 0 {
        return int(c[0])
    }

    return 0
}

func DecodeWithReader(reader *bytes.Buffer) interface{} {
    var slice []interface{}

    // Read the next byte
    char := Char(reader.Next(1))
    switch {
    case char == 0:
        return nil
    case char <= 0x7f:
        return char

    case char <= 0xb7:
        return reader.Next(int(char - 0x80))

    case char <= 0xbf:
        buff := bytes.NewReader(reader.Next(int(char - 0xb8)))
        length := ReadVarint(buff)

        return reader.Next(int(length))

    case char <= 0xf7:
        length := int(char - 0xc0)
        for i := 0; i < length; i++ {
            obj := DecodeWithReader(reader)
            if obj != nil {
                slice = append(slice, obj)
            } else {
                break
            }
        }

        return slice

    }

    return slice
}

// 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(bytes.NewReader(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(bytes.NewReader(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
}

var (
    directRlp = big.NewInt(0x7f)
    numberRlp = big.NewInt(0xb7)
    zeroRlp   = big.NewInt(0x0)
)

func Encode(object interface{}) []byte {
    var buff bytes.Buffer

    if object != nil {
        switch t := object.(type) {
        case *Value:
            buff.Write(Encode(t.Raw()))
        // 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
            if t == nil {
                buff.WriteByte(0xc0)
            } else {
                buff.Write(Encode(t.Bytes()))
            }
        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())
        }
    } else {
        // Empty list for nil
        buff.WriteByte(0xc0)
    }

    return buff.Bytes()
}