forked from guregu/null
/
float.go
131 lines (116 loc) · 3.3 KB
/
float.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
package zero
import (
"database/sql"
"encoding/json"
"fmt"
"math"
"reflect"
"strconv"
"github.com/Nidal-Bakir/null/v7/internal"
)
// Float is a nullable float64. Zero input will be considered null.
// JSON marshals to zero if null.
// Considered null to SQL if zero.
type Float struct {
sql.NullFloat64
}
// NewFloat creates a new Float
func NewFloat(f float64, valid bool) Float {
return Float{
NullFloat64: sql.NullFloat64{
Float64: f,
Valid: valid,
},
}
}
// FloatFrom creates a new Float that will be null if zero.
func FloatFrom(f float64) Float {
return NewFloat(f, f != 0)
}
// FloatFromPtr creates a new Float that be null if f is nil.
func FloatFromPtr(f *float64) Float {
if f == nil {
return NewFloat(0, false)
}
return NewFloat(*f, true)
}
// ValueOrZero returns the inner value if valid, otherwise zero.
func (f Float) ValueOrZero() float64 {
if !f.Valid {
return 0
}
return f.Float64
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will be considered a null Float.
func (f *Float) UnmarshalJSON(data []byte) error {
err := internal.UnmarshalFloatJSON(data, &f.Float64, &f.Valid)
f.Valid = f.Float64 != 0
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Float if the input is blank or zero.
// It will return an error if the input is not a float, blank, or "null".
func (f *Float) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
f.Valid = false
return nil
}
var err error
f.Float64, err = strconv.ParseFloat(str, 64)
if err != nil {
return fmt.Errorf("zero: couldn't unmarshal text: %w", err)
}
f.Valid = f.Float64 != 0
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Float is null.
func (f Float) MarshalJSON() ([]byte, error) {
n := f.Float64
if !f.Valid {
n = 0
}
if math.IsInf(f.Float64, 0) || math.IsNaN(f.Float64) {
return nil, &json.UnsupportedValueError{
Value: reflect.ValueOf(f.Float64),
Str: strconv.FormatFloat(f.Float64, 'g', -1, 64),
}
}
return []byte(strconv.FormatFloat(n, 'f', -1, 64)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a zero if this Float is null.
func (f Float) MarshalText() ([]byte, error) {
n := f.Float64
if !f.Valid {
n = 0
}
return []byte(strconv.FormatFloat(n, 'f', -1, 64)), nil
}
// SetValid changes this Float's value and also sets it to be non-null.
func (f *Float) SetValid(v float64) {
f.Float64 = v
f.Valid = true
}
// Ptr returns a poFloater to this Float's value, or a nil poFloater if this Float is null.
func (f Float) Ptr() *float64 {
if !f.Valid {
return nil
}
return &f.Float64
}
// IsZero returns true for null or zero Floats, for future omitempty support (Go 1.4?)
func (f Float) IsZero() bool {
return !f.Valid || f.Float64 == 0
}
// Equal returns true if both floats have the same value or are both either null or zero.
// Warning: calculations using floating point numbers can result in different ways
// the numbers are stored in memory. Therefore, this function is not suitable to
// compare the result of a calculation. Use this method only to check if the value
// has changed in comparison to some previous value.
func (f Float) Equal(other Float) bool {
return f.ValueOrZero() == other.ValueOrZero()
}