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
|
// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package math
import "strconv"
const (
// Integer limit values.
MaxInt8 = 1<<7 - 1
MinInt8 = -1 << 7
MaxInt16 = 1<<15 - 1
MinInt16 = -1 << 15
MaxInt32 = 1<<31 - 1
MinInt32 = -1 << 31
MaxInt64 = 1<<63 - 1
MinInt64 = -1 << 63
MaxUint8 = 1<<8 - 1
MaxUint16 = 1<<16 - 1
MaxUint32 = 1<<32 - 1
MaxUint64 = 1<<64 - 1
)
// ParseUint64 parses s as an integer in decimal or hexadecimal syntax.
// Leading zeros are accepted. The empty string parses as zero.
func ParseUint64(s string) (uint64, bool) {
if s == "" {
return 0, true
}
if len(s) >= 2 && (s[:2] == "0x" || s[:2] == "0X") {
v, err := strconv.ParseUint(s[2:], 16, 64)
return v, err == nil
}
v, err := strconv.ParseUint(s, 10, 64)
return v, err == nil
}
// MustParseUint64 parses s as an integer and panics if the string is invalid.
func MustParseUint64(s string) uint64 {
v, ok := ParseUint64(s)
if !ok {
panic("invalid unsigned 64 bit integer: " + s)
}
return v
}
// NOTE: The following methods need to be optimised using either bit checking or asm
// SafeSub returns subtraction result and whether overflow occurred.
func SafeSub(x, y uint64) (uint64, bool) {
return x - y, x < y
}
// SafeAdd returns the result and whether overflow occurred.
func SafeAdd(x, y uint64) (uint64, bool) {
return x + y, y > MaxUint64-x
}
// SafeMul returns multiplication result and whether overflow occurred.
func SafeMul(x, y uint64) (uint64, bool) {
if x == 0 || y == 0 {
return 0, false
}
return x * y, y > MaxUint64/x
}
|
