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: idna9.0.0.go
    path of file: ./repos/go-gin-example/vendor/golang.org/x/net/idna
    
    the code of the file until where you have to start completion: // Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.

// 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.

// +build !go1.10

// Package
    
func validateAndMap(p *Profile, s string) (string, error) {
	var (
		err error
		b   []byte
		k   int
	)
	for i := 0; i < len(s); {
		v, sz := trie.lookupString(s[i:])
		start := i
		i += sz
		// Copy bytes not copied so far.
		switch p.simplify(info(v).category()) {
		case valid:
			continue
		case disallowed:
			if err == nil {
				r, _ := utf8.DecodeRuneInString(s[start:])
				err = runeError(r)
			}
			continue
		case mapped, deviation:
			b = append(b, s[k:start]...)
			b = info(v).appendMapping(b, s[start:i])
		case ignored:
			b = append(b, s[k:start]...)
			// drop the rune
		case unknown:
			b = append(b, s[k:start]...)
			b = append(b, "\ufffd"...)
		}
		k = i
	}
	if k == 0 {
		// No changes so far.
		s = norm.NFC.String(s)
	} else {
		b = append(b, s[k:]...)
		if norm.NFC.QuickSpan(b) != len(b) {
			b = norm.NFC.Bytes(b)
		}
		// TODO: the punycode converters require strings as input.
		s = string(b)
	}
	return s, err
}