118 lines
2.9 KiB
Go
118 lines
2.9 KiB
Go
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package null
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import (
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"database/sql"
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"encoding/json"
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"fmt"
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"reflect"
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"strconv"
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)
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// Float64 is a nullable float64.
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// It does not consider zero values to be null.
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// It will decode to null, not zero, if null.
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type Float64 struct {
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sql.NullFloat64
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}
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// NewFloat64 creates a new Float64
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func NewFloat64(f float64, valid bool) Float64 {
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return Float64{
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NullFloat64: sql.NullFloat64{
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Float64: f,
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Valid: valid,
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},
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}
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}
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// Float64From creates a new Float64 that will always be valid.
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func Float64From(f float64) Float64 {
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return NewFloat64(f, true)
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}
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// Float64FromPtr creates a new Float64 that be null if f is nil.
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func Float64FromPtr(f *float64) Float64 {
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if f == nil {
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return NewFloat64(0, false)
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}
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return NewFloat64(*f, true)
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}
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// UnmarshalJSON implements json.Unmarshaler.
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// It supports number and null input.
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// 0 will not be considered a null Float64.
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// It also supports unmarshalling a sql.NullFloat64.
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func (f *Float64) UnmarshalJSON(data []byte) error {
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var err error
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var v interface{}
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if err = json.Unmarshal(data, &v); err != nil {
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return err
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}
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switch x := v.(type) {
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case float64:
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f.Float64 = float64(x)
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case map[string]interface{}:
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err = json.Unmarshal(data, &f.NullFloat64)
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case nil:
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f.Valid = false
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return nil
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default:
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err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Float64", reflect.TypeOf(v).Name())
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}
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f.Valid = err == nil
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return err
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}
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// UnmarshalText implements encoding.TextUnmarshaler.
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// It will unmarshal to a null Float64 if the input is a blank or not an integer.
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// It will return an error if the input is not an integer, blank, or "null".
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func (f *Float64) UnmarshalText(text []byte) error {
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str := string(text)
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if str == "" || str == "null" {
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f.Valid = false
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return nil
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}
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var err error
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f.Float64, err = strconv.ParseFloat(string(text), 64)
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f.Valid = err == nil
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return err
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}
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// MarshalJSON implements json.Marshaler.
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// It will encode null if this Float64 is null.
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func (f Float64) MarshalJSON() ([]byte, error) {
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if !f.Valid {
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return []byte("null"), nil
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}
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return []byte(strconv.FormatFloat(f.Float64, 'f', -1, 64)), nil
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}
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// MarshalText implements encoding.TextMarshaler.
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// It will encode a blank string if this Float64 is null.
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func (f Float64) MarshalText() ([]byte, error) {
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if !f.Valid {
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return []byte{}, nil
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}
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return []byte(strconv.FormatFloat(f.Float64, 'f', -1, 64)), nil
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}
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// SetValid changes this Float64's value and also sets it to be non-null.
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func (f *Float64) SetValid(n float64) {
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f.Float64 = n
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f.Valid = true
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}
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// Ptr returns a pointer to this Float64's value, or a nil pointer if this Float64 is null.
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func (f Float64) Ptr() *float64 {
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if !f.Valid {
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return nil
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}
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return &f.Float64
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}
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// IsZero returns true for invalid Float64s, for future omitempty support (Go 1.4?)
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// A non-null Float64 with a 0 value will not be considered zero.
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func (f Float64) IsZero() bool {
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return !f.Valid
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}
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