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
|
package ethutil
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 BigD(data []byte) *big.Int {
n := new(big.Int)
n.SetBytes(data)
return n
}
// To256
//
// "cast" the big int to a 256 big int (i.e., limit to)
var tt256 = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
func To256(x *big.Int) *big.Int {
x.And(x, tt256)
if x.Cmp(new(big.Int)) < 0 {
x.SetInt64(0)
}
return x
}
// 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
}
|
