-
Notifications
You must be signed in to change notification settings - Fork 660
/
id.go
149 lines (118 loc) · 3.62 KB
/
id.go
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
// Copyright (C) 2019-2021, Ava Labs, Inc. All rights reserved.
// See the file LICENSE for licensing terms.
package ids
import (
"bytes"
"encoding/hex"
"errors"
"fmt"
"sort"
"github.com/ava-labs/avalanchego/utils"
"github.com/ava-labs/avalanchego/utils/formatting"
"github.com/ava-labs/avalanchego/utils/hashing"
"github.com/ava-labs/avalanchego/utils/wrappers"
)
const (
// The encoding used to convert IDs from bytes to string and vice versa
defaultEncoding = formatting.CB58
nullStr = "null"
)
var (
// Empty is a useful all zero value
Empty = ID{}
errMissingQuotes = errors.New("first and last characters should be quotes")
)
// ID wraps a 32 byte hash used as an identifier
type ID [32]byte
// ToID attempt to convert a byte slice into an id
func ToID(bytes []byte) (ID, error) {
return hashing.ToHash256(bytes)
}
// FromString is the inverse of ID.String()
func FromString(idStr string) (ID, error) {
bytes, err := formatting.Decode(defaultEncoding, idStr)
if err != nil {
return ID{}, err
}
return ToID(bytes)
}
func (id ID) MarshalJSON() ([]byte, error) {
str, err := formatting.EncodeWithChecksum(defaultEncoding, id[:])
if err != nil {
return nil, err
}
return []byte("\"" + str + "\""), nil
}
func (id *ID) UnmarshalJSON(b []byte) error {
str := string(b)
if str == nullStr { // If "null", do nothing
return nil
} else if len(str) < 2 {
return errMissingQuotes
}
lastIndex := len(str) - 1
if str[0] != '"' || str[lastIndex] != '"' {
return errMissingQuotes
}
// Parse CB58 formatted string to bytes
bytes, err := formatting.Decode(defaultEncoding, str[1:lastIndex])
if err != nil {
return fmt.Errorf("couldn't decode ID to bytes: %w", err)
}
*id, err = ToID(bytes)
return err
}
func (id *ID) UnmarshalText(text []byte) error {
return id.UnmarshalJSON(text)
}
// Prefix this id to create a more selective id. This can be used to store
// multiple values under the same key. For example:
// prefix1(id) -> confidence
// prefix2(id) -> vertex
// This will return a new id and not modify the original id.
func (id ID) Prefix(prefixes ...uint64) ID {
packer := wrappers.Packer{
Bytes: make([]byte, len(prefixes)*wrappers.LongLen+hashing.HashLen),
}
for _, prefix := range prefixes {
packer.PackLong(prefix)
}
packer.PackFixedBytes(id[:])
return hashing.ComputeHash256Array(packer.Bytes)
}
// Bit returns the bit value at the ith index of the byte array. Returns 0 or 1
func (id ID) Bit(i uint) int {
byteIndex := i / BitsPerByte
bitIndex := i % BitsPerByte
b := id[byteIndex]
// b = [7, 6, 5, 4, 3, 2, 1, 0]
b >>= bitIndex
// b = [0, ..., bitIndex + 1, bitIndex]
// 1 = [0, 0, 0, 0, 0, 0, 0, 1]
b &= 1
// b = [0, 0, 0, 0, 0, 0, 0, bitIndex]
return int(b)
}
// Hex returns a hex encoded string of this id.
func (id ID) Hex() string { return hex.EncodeToString(id[:]) }
func (id ID) String() string {
// We assume that the maximum size of a byte slice that
// can be stringified is at least the length of an ID
s, _ := formatting.EncodeWithChecksum(defaultEncoding, id[:])
return s
}
func (id ID) MarshalText() ([]byte, error) {
return []byte(id.String()), nil
}
type sortIDData []ID
func (ids sortIDData) Less(i, j int) bool {
return bytes.Compare(
ids[i][:],
ids[j][:]) == -1
}
func (ids sortIDData) Len() int { return len(ids) }
func (ids sortIDData) Swap(i, j int) { ids[j], ids[i] = ids[i], ids[j] }
// SortIDs sorts the ids lexicographically
func SortIDs(ids []ID) { sort.Sort(sortIDData(ids)) }
// IsSortedAndUniqueIDs returns true if the ids are sorted and unique
func IsSortedAndUniqueIDs(ids []ID) bool { return utils.IsSortedAndUnique(sortIDData(ids)) }