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util.go
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util.go
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package rel
import (
"math"
"reflect"
)
func indirect(rv reflect.Value) interface{} {
if rv.Kind() == reflect.Ptr {
if rv.IsNil() {
return nil
}
rv = rv.Elem()
}
return rv.Interface()
}
func must(err error) {
if err != nil {
panic(err)
}
}
type isZeroer interface {
IsZero() bool
}
// isZero shallowly check wether a field in struct is zero or not
func isZero(value interface{}) bool {
var (
zero bool
)
switch v := value.(type) {
case nil:
zero = true
case bool:
zero = v == false
case string:
zero = v == ""
case int:
zero = v == 0
case int8:
zero = v == 0
case int16:
zero = v == 0
case int32:
zero = v == 0
case int64:
zero = v == 0
case uint:
zero = v == 0
case uint8:
zero = v == 0
case uint16:
zero = v == 0
case uint32:
zero = v == 0
case uint64:
zero = v == 0
case uintptr:
zero = v == 0
case float32:
zero = v == 0
case float64:
zero = v == 0
case isZeroer:
zero = v.IsZero()
default:
zero = isDeepZero(reflect.ValueOf(value), 0)
}
return zero
}
// modified from https://golang.org/src/reflect/value.go?s=33807:33835#L1077
func isDeepZero(rv reflect.Value, depth int) bool {
if depth < 0 {
return true
}
switch rv.Kind() {
case reflect.Bool:
return !rv.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return rv.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return rv.Uint() == 0
case reflect.Float32, reflect.Float64:
return math.Float64bits(rv.Float()) == 0
case reflect.Complex64, reflect.Complex128:
c := rv.Complex()
return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
case reflect.Array:
for i := 0; i < rv.Len(); i++ {
if !isDeepZero(rv.Index(i), depth-1) {
return false
}
}
return true
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
return rv.IsNil()
case reflect.String:
return rv.Len() == 0
case reflect.Struct:
for i := 0; i < rv.NumField(); i++ {
if !isDeepZero(rv.Field(i), depth-1) {
return false
}
}
return true
default:
return true
}
}