Golang Value.SetFloat方法代碼示例

func newInfo(val float64) Info {
	now := timeutil.Now()

	v := roachpb.Value{Timestamp: hlc.Timestamp{WallTime: now.UnixNano()}}
	v.SetFloat(val)

	return Info{
		Value:     v,
		OrigStamp: now.UnixNano(),
		TTLStamp:  now.Add(time.Millisecond).UnixNano(),
	}
}

// MarshalColumnValue returns a Go primitive value equivalent of val, of the
// type expected by col. If val's type is incompatible with col, or if
// col's type is not yet implemented, an error is returned.
func MarshalColumnValue(col ColumnDescriptor, val parser.Datum) (roachpb.Value, error) {
	var r roachpb.Value

	if val == parser.DNull {
		return r, nil
	}

	switch col.Type.Kind {
	case ColumnType_BOOL:
		if v, ok := val.(*parser.DBool); ok {
			r.SetBool(bool(*v))
			return r, nil
		}
	case ColumnType_INT:
		if v, ok := val.(*parser.DInt); ok {
			r.SetInt(int64(*v))
			return r, nil
		}
	case ColumnType_FLOAT:
		if v, ok := val.(*parser.DFloat); ok {
			r.SetFloat(float64(*v))
			return r, nil
		}
	case ColumnType_DECIMAL:
		if v, ok := val.(*parser.DDecimal); ok {
			err := r.SetDecimal(&v.Dec)
			return r, err
		}
	case ColumnType_STRING:
		if v, ok := val.(*parser.DString); ok {
			r.SetString(string(*v))
			return r, nil
		}
	case ColumnType_BYTES:
		if v, ok := val.(*parser.DBytes); ok {
			r.SetString(string(*v))
			return r, nil
		}
		if v, ok := val.(*parser.DString); ok {
			r.SetString(string(*v))
			return r, nil
		}
	case ColumnType_DATE:
		if v, ok := val.(*parser.DDate); ok {
			r.SetInt(int64(*v))
			return r, nil
		}
	case ColumnType_TIMESTAMP:
		if v, ok := val.(*parser.DTimestamp); ok {
			r.SetTime(v.Time)
			return r, nil
		}
	case ColumnType_TIMESTAMPTZ:
		if v, ok := val.(*parser.DTimestampTZ); ok {
			r.SetTime(v.Time)
			return r, nil
		}
	case ColumnType_INTERVAL:
		if v, ok := val.(*parser.DInterval); ok {
			err := r.SetDuration(v.Duration)
			return r, err
		}
	default:
		return r, errors.Errorf("unsupported column type: %s", col.Type.Kind)
	}
	return r, fmt.Errorf("value type %s doesn't match type %s of column %q",
		val.ResolvedType(), col.Type.Kind, col.Name)
}

// marshalValue returns a roachpb.Value initialized from the source
// interface{}, returning an error if the types are not compatible.
func marshalValue(v interface{}) (roachpb.Value, error) {
	var r roachpb.Value

	// Handle a few common types via a type switch.
	switch t := v.(type) {
	case *roachpb.Value:
		return *t, nil

	case nil:
		return r, nil

	case bool:
		r.SetBool(t)
		return r, nil

	case string:
		r.SetBytes([]byte(t))
		return r, nil

	case []byte:
		r.SetBytes(t)
		return r, nil

	case inf.Dec:
		err := r.SetDecimal(&t)
		return r, err

	case roachpb.Key:
		r.SetBytes([]byte(t))
		return r, nil

	case time.Time:
		r.SetTime(t)
		return r, nil

	case duration.Duration:
		err := r.SetDuration(t)
		return r, err

	case proto.Message:
		err := r.SetProto(t)
		return r, err

	case roachpb.Value:
		panic("unexpected type roachpb.Value (use *roachpb.Value)")
	}

	// Handle all of the Go primitive types besides struct and pointers. This
	// switch also handles types based on a primitive type (e.g. "type MyInt
	// int").
	switch v := reflect.ValueOf(v); v.Kind() {
	case reflect.Bool:
		r.SetBool(v.Bool())
		return r, nil

	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		r.SetInt(v.Int())
		return r, nil

	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		r.SetInt(int64(v.Uint()))
		return r, nil

	case reflect.Float32, reflect.Float64:
		r.SetFloat(v.Float())
		return r, nil

	case reflect.String:
		r.SetBytes([]byte(v.String()))
		return r, nil
	}

	return r, fmt.Errorf("unable to marshal %T: %v", v, v)
}