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// Copyright (c) 2012, 2013 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a BSD-style license found in the LICENSE file.
package codec
// All non-std package dependencies live in this file,
// so porting to different environment is easy (just update functions).
import (
"errors"
"fmt"
"math"
"reflect"
)
var (
raisePanicAfterRecover = false
debugging = true
)
func panicValToErr(panicVal interface{}, err *error) {
switch xerr := panicVal.(type) {
case error:
*err = xerr
case string:
*err = errors.New(xerr)
default:
*err = fmt.Errorf("%v", panicVal)
}
if raisePanicAfterRecover {
panic(panicVal)
}
return
}
func hIsEmptyValue(v reflect.Value, deref, checkStruct bool) bool {
switch v.Kind() {
case reflect.Invalid:
return true
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
return v.Len() == 0
case reflect.Bool:
return !v.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return v.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return v.Uint() == 0
case reflect.Float32, reflect.Float64:
return v.Float() == 0
case reflect.Interface, reflect.Ptr:
if deref {
if v.IsNil() {
return true
}
return hIsEmptyValue(v.Elem(), deref, checkStruct)
} else {
return v.IsNil()
}
case reflect.Struct:
if !checkStruct {
return false
}
// return true if all fields are empty. else return false.
// we cannot use equality check, because some fields may be maps/slices/etc
// and consequently the structs are not comparable.
// return v.Interface() == reflect.Zero(v.Type()).Interface()
for i, n := 0, v.NumField(); i < n; i++ {
if !hIsEmptyValue(v.Field(i), deref, checkStruct) {
return false
}
}
return true
}
return false
}
func isEmptyValue(v reflect.Value) bool {
return hIsEmptyValue(v, derefForIsEmptyValue, checkStructForEmptyValue)
}
func debugf(format string, args ...interface{}) {
if debugging {
if len(format) == 0 || format[len(format)-1] != '\n' {
format = format + "\n"
}
fmt.Printf(format, args...)
}
}
func pruneSignExt(v []byte, pos bool) (n int) {
if len(v) < 2 {
} else if pos && v[0] == 0 {
for ; v[n] == 0 && n+1 < len(v) && (v[n+1]&(1<<7) == 0); n++ {
}
} else if !pos && v[0] == 0xff {
for ; v[n] == 0xff && n+1 < len(v) && (v[n+1]&(1<<7) != 0); n++ {
}
}
return
}
func implementsIntf(typ, iTyp reflect.Type) (success bool, indir int8) {
if typ == nil {
return
}
rt := typ
// The type might be a pointer and we need to keep
// dereferencing to the base type until we find an implementation.
for {
if rt.Implements(iTyp) {
return true, indir
}
if p := rt; p.Kind() == reflect.Ptr {
indir++
if indir >= math.MaxInt8 { // insane number of indirections
return false, 0
}
rt = p.Elem()
continue
}
break
}
// No luck yet, but if this is a base type (non-pointer), the pointer might satisfy.
if typ.Kind() != reflect.Ptr {
// Not a pointer, but does the pointer work?
if reflect.PtrTo(typ).Implements(iTyp) {
return true, -1
}
}
return false, 0
}
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