/
bitwise.go
150 lines (140 loc) · 2.44 KB
/
bitwise.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
150
package vm
import "bytes"
func opInvert(vm *virtualMachine) error {
err := vm.applyCost(1)
if err != nil {
return err
}
top, err := vm.top()
if err != nil {
return err
}
err = vm.applyCost(int64(len(top)))
if err != nil {
return err
}
// Could rewrite top in place but maybe it's a shared data
// structure?
newTop := make([]byte, 0, len(top))
for _, b := range top {
newTop = append(newTop, ^b)
}
vm.dataStack[len(vm.dataStack)-1] = newTop
return nil
}
func opAnd(vm *virtualMachine) error {
err := vm.applyCost(1)
if err != nil {
return err
}
b, err := vm.pop(true)
if err != nil {
return err
}
a, err := vm.pop(true)
if err != nil {
return err
}
min, max := len(a), len(b)
if min > max {
min, max = max, min
}
err = vm.applyCost(int64(min))
if err != nil {
return err
}
res := make([]byte, 0, min)
for i := 0; i < min; i++ {
res = append(res, a[i]&b[i])
}
return vm.push(res, true)
}
func opOr(vm *virtualMachine) error {
return doOr(vm, false)
}
func opXor(vm *virtualMachine) error {
return doOr(vm, true)
}
func doOr(vm *virtualMachine, xor bool) error {
err := vm.applyCost(1)
if err != nil {
return err
}
b, err := vm.pop(true)
if err != nil {
return err
}
a, err := vm.pop(true)
if err != nil {
return err
}
min, max := len(a), len(b)
if min > max {
min, max = max, min
}
err = vm.applyCost(int64(max))
if err != nil {
return err
}
res := make([]byte, 0, max)
for i := 0; i < max; i++ {
var aByte, bByte, resByte byte
if i >= len(a) {
aByte = 0
} else {
aByte = a[i]
}
if i >= len(b) {
bByte = 0
} else {
bByte = b[i]
}
if xor {
resByte = aByte ^ bByte
} else {
resByte = aByte | bByte
}
res = append(res, resByte)
}
return vm.push(res, true)
}
func opEqual(vm *virtualMachine) error {
res, err := doEqual(vm)
if err != nil {
return err
}
return vm.pushBool(res, true)
}
func opEqualVerify(vm *virtualMachine) error {
res, err := doEqual(vm)
if err != nil {
return err
}
if res {
return nil
}
return ErrVerifyFailed
}
func doEqual(vm *virtualMachine) (bool, error) {
err := vm.applyCost(1)
if err != nil {
return false, err
}
b, err := vm.pop(true)
if err != nil {
return false, err
}
a, err := vm.pop(true)
if err != nil {
return false, err
}
min, max := len(a), len(b)
if min > max {
min, max = max, min
}
err = vm.applyCost(int64(min))
if err != nil {
return false, err
}
return bytes.Equal(a, b), nil
}