You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: swapper.go
    path of file: ./repos/under-the-hood/gosrc/reflect
    
    the code of the file until where you have to start completion: // Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package reflect

import (
	"internal/unsafeheader"
	"unsafe"
)

// Swapper returns a function that swaps the elements in the provided
// slice.
//
// Swapper panics if the provided interface is not a slice.
func Swapper(slice interface{}) func(i, j int) {
	v := 
    
func Swapper(slice interface{}) func(i, j int) {
	v := ValueOf(slice)
	if v.Kind() != Slice {
		panic(&ValueError{Method: "Swapper", Kind: v.Kind()})
	}
	// Fast path for slices of size 0 and 1. Nothing to swap.
	switch v.Len() {
	case 0:
		return func(i, j int) { panic("reflect: slice index out of range") }
	case 1:
		return func(i, j int) {
			if i != 0 || j != 0 {
				panic("reflect: slice index out of range")
			}
		}
	}

	typ := v.Type().Elem().(*rtype)
	size := typ.Size()
	hasPtr := typ.ptrdata != 0

	// Some common & small cases, without using memmove:
	if hasPtr {
		if size == ptrSize {
			ps := *(*[]unsafe.Pointer)(v.ptr)
			return func(i, j int) { ps[i], ps[j] = ps[j], ps[i] }
		}
		if typ.Kind() == String {
			ss := *(*[]string)(v.ptr)
			return func(i, j int) { ss[i], ss[j] = ss[j], ss[i] }
		}
	} else {
		switch size {
		case 8:
			is := *(*[]int64)(v.ptr)
			return func(i, j int) { is[i], is[j] = is[j], is[i] }
		case 4:
			is := *(*[]int32)(v.ptr)
			return func(i, j int) { is[i], is[j] = is[j], is[i] }
		case 2:
			is := *(*[]int16)(v.ptr)
			return func(i, j int) { is[i], is[j] = is[j], is[i] }
		case 1:
			is := *(*[]int8)(v.ptr)
			return func(i, j int) { is[i], is[j] = is[j], is[i] }
		}
	}

	s := (*unsafeheader.Slice)(v.ptr)
	tmp := unsafe_New(typ) // swap scratch space

	return func(i, j int) {
		if uint(i) >= uint(s.Len) || uint(j) >= uint(s.Len) {
			panic("reflect: slice index out of range")
		}
		val1 := arrayAt(s.Data, i, size, "i < s.Len")
		val2 := arrayAt(s.Data, j, size, "j < s.Len")
		typedmemmove(typ, tmp, val1)
		typedmemmove(typ, val1, val2)
		typedmemmove(typ, val2, tmp)
	}
}