ref: f1a00b2069ede85feb487d29b9f690396e2402c6
dir: /tpl/collections/reflect_helpers.go/
// Copyright 2017 The Hugo Authors. All rights reserved.
//
// 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.
package collections
import (
"errors"
"fmt"
"reflect"
"time"
)
var (
zero reflect.Value
errorType = reflect.TypeOf((*error)(nil)).Elem()
timeType = reflect.TypeOf((*time.Time)(nil)).Elem()
)
func numberToFloat(v reflect.Value) (float64, error) {
switch kind := v.Kind(); {
case isFloat(kind):
return v.Float(), nil
case isInt(kind):
return float64(v.Int()), nil
case isUint(kind):
return float64(v.Uint()), nil
case kind == reflect.Interface:
return numberToFloat(v.Elem())
default:
return 0, fmt.Errorf("Invalid kind %s in numberToFloat", kind)
}
}
// There are potential overflows in this function, but the downconversion of
// int64 etc. into int8 etc. is coming from the synthetic unit tests for Union etc.
// TODO(bep) We should consider normalizing the slices to int64 etc.
func convertNumber(v reflect.Value, to reflect.Kind) (reflect.Value, error) {
var n reflect.Value
if isFloat(to) {
f, err := toFloat(v)
if err != nil {
return n, err
}
switch to {
case reflect.Float32:
n = reflect.ValueOf(float32(f))
default:
n = reflect.ValueOf(float64(f))
}
} else if isInt(to) {
i, err := toInt(v)
if err != nil {
return n, err
}
switch to {
case reflect.Int:
n = reflect.ValueOf(int(i))
case reflect.Int8:
n = reflect.ValueOf(int8(i))
case reflect.Int16:
n = reflect.ValueOf(int16(i))
case reflect.Int32:
n = reflect.ValueOf(int32(i))
case reflect.Int64:
n = reflect.ValueOf(int64(i))
}
} else if isUint(to) {
i, err := toUint(v)
if err != nil {
return n, err
}
switch to {
case reflect.Uint:
n = reflect.ValueOf(uint(i))
case reflect.Uint8:
n = reflect.ValueOf(uint8(i))
case reflect.Uint16:
n = reflect.ValueOf(uint16(i))
case reflect.Uint32:
n = reflect.ValueOf(uint32(i))
case reflect.Uint64:
n = reflect.ValueOf(uint64(i))
}
}
if !n.IsValid() {
return n, errors.New("invalid values")
}
return n, nil
}
func newSliceElement(items interface{}) interface{} {
tp := reflect.TypeOf(items)
if tp == nil {
return nil
}
switch tp.Kind() {
case reflect.Array, reflect.Slice:
tp = tp.Elem()
if tp.Kind() == reflect.Ptr {
tp = tp.Elem()
}
return reflect.New(tp).Interface()
}
return nil
}
func isNumber(kind reflect.Kind) bool {
return isInt(kind) || isUint(kind) || isFloat(kind)
}
func isInt(kind reflect.Kind) bool {
switch kind {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return true
default:
return false
}
}
func isUint(kind reflect.Kind) bool {
switch kind {
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return true
default:
return false
}
}
func isFloat(kind reflect.Kind) bool {
switch kind {
case reflect.Float32, reflect.Float64:
return true
default:
return false
}
}