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
|
/**
* Copyright 2014 Paul Querna
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
/* Portions of this file are on Go stdlib's strconv/iota.go */
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package v1
import (
"io"
)
const (
digits = "0123456789abcdefghijklmnopqrstuvwxyz"
digits01 = "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789"
digits10 = "0000000000111111111122222222223333333333444444444455555555556666666666777777777788888888889999999999"
)
var shifts = [len(digits) + 1]uint{
1 << 1: 1,
1 << 2: 2,
1 << 3: 3,
1 << 4: 4,
1 << 5: 5,
}
var smallNumbers = [][]byte{
[]byte("0"),
[]byte("1"),
[]byte("2"),
[]byte("3"),
[]byte("4"),
[]byte("5"),
[]byte("6"),
[]byte("7"),
[]byte("8"),
[]byte("9"),
[]byte("10"),
}
type FormatBitsWriter interface {
io.Writer
io.ByteWriter
}
type FormatBitsScratch struct{}
//
// DEPRECIATED: `scratch` is no longer used, FormatBits2 is available.
//
// FormatBits computes the string representation of u in the given base.
// If neg is set, u is treated as negative int64 value. If append_ is
// set, the string is appended to dst and the resulting byte slice is
// returned as the first result value; otherwise the string is returned
// as the second result value.
//
func FormatBits(scratch *FormatBitsScratch, dst FormatBitsWriter, u uint64, base int, neg bool) {
FormatBits2(dst, u, base, neg)
}
// FormatBits2 computes the string representation of u in the given base.
// If neg is set, u is treated as negative int64 value. If append_ is
// set, the string is appended to dst and the resulting byte slice is
// returned as the first result value; otherwise the string is returned
// as the second result value.
//
func FormatBits2(dst FormatBitsWriter, u uint64, base int, neg bool) {
if base < 2 || base > len(digits) {
panic("strconv: illegal AppendInt/FormatInt base")
}
// fast path for small common numbers
if u <= 10 {
if neg {
dst.WriteByte('-')
}
dst.Write(smallNumbers[u])
return
}
// 2 <= base && base <= len(digits)
var a = makeSlice(65)
// var a [64 + 1]byte // +1 for sign of 64bit value in base 2
i := len(a)
if neg {
u = -u
}
// convert bits
if base == 10 {
// common case: use constants for / and % because
// the compiler can optimize it into a multiply+shift,
// and unroll loop
for u >= 100 {
i -= 2
q := u / 100
j := uintptr(u - q*100)
a[i+1] = digits01[j]
a[i+0] = digits10[j]
u = q
}
if u >= 10 {
i--
q := u / 10
a[i] = digits[uintptr(u-q*10)]
u = q
}
} else if s := shifts[base]; s > 0 {
// base is power of 2: use shifts and masks instead of / and %
b := uint64(base)
m := uintptr(b) - 1 // == 1<<s - 1
for u >= b {
i--
a[i] = digits[uintptr(u)&m]
u >>= s
}
} else {
// general case
b := uint64(base)
for u >= b {
i--
a[i] = digits[uintptr(u%b)]
u /= b
}
}
// u < base
i--
a[i] = digits[uintptr(u)]
// add sign, if any
if neg {
i--
a[i] = '-'
}
dst.Write(a[i:])
Pool(a)
return
}
|
