vendor files

vendor/golang.org/x/net/idna/example_test.go

@@ -0,0 +1,70 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+// Copyright 2017 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 idna_test
+
+import (
+	"fmt"
+
+	"golang.org/x/net/idna"
+)
+
+func ExampleProfile() {
+	// Raw Punycode has no restrictions and does no mappings.
+	fmt.Println(idna.ToASCII(""))
+	fmt.Println(idna.ToASCII("*.faß.com"))
+	fmt.Println(idna.Punycode.ToASCII("*.faß.com"))
+
+	// Rewrite IDN for lookup. This (currently) uses transitional mappings to
+	// find a balance between IDNA2003 and IDNA2008 compatibility.
+	fmt.Println(idna.Lookup.ToASCII(""))
+	fmt.Println(idna.Lookup.ToASCII("www.faß.com"))
+
+	// Convert an IDN to ASCII for registration purposes. This changes the
+	// encoding, but reports an error if the input was illformed.
+	fmt.Println(idna.Registration.ToASCII(""))
+	fmt.Println(idna.Registration.ToASCII("www.faß.com"))
+
+	// Output:
+	//  <nil>
+	// *.xn--fa-hia.com <nil>
+	// *.xn--fa-hia.com <nil>
+	//  <nil>
+	// www.fass.com <nil>
+	//  idna: invalid label ""
+	// www.xn--fa-hia.com <nil>
+}
+
+func ExampleNew() {
+	var p *idna.Profile
+
+	// Raw Punycode has no restrictions and does no mappings.
+	p = idna.New()
+	fmt.Println(p.ToASCII("*.faß.com"))
+
+	// Do mappings. Note that star is not allowed in a DNS lookup.
+	p = idna.New(
+		idna.MapForLookup(),
+		idna.Transitional(true)) // Map ß -> ss
+	fmt.Println(p.ToASCII("*.faß.com"))
+
+	// Lookup for registration. Also does not allow '*'.
+	p = idna.New(idna.ValidateForRegistration())
+	fmt.Println(p.ToUnicode("*.faß.com"))
+
+	// Set up a profile maps for lookup, but allows wild cards.
+	p = idna.New(
+		idna.MapForLookup(),
+		idna.Transitional(true),      // Map ß -> ss
+		idna.StrictDomainName(false)) // Set more permissive ASCII rules.
+	fmt.Println(p.ToASCII("*.faß.com"))
+
+	// Output:
+	// *.xn--fa-hia.com <nil>
+	// *.fass.com idna: disallowed rune U+002A
+	// *.faß.com idna: disallowed rune U+002A
+	// *.fass.com <nil>
+}

vendor/golang.org/x/net/idna/idna.go

@@ -0,0 +1,732 @@
+// 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.
+
+// Package idna implements IDNA2008 using the compatibility processing
+// defined by UTS (Unicode Technical Standard) #46, which defines a standard to
+// deal with the transition from IDNA2003.
+//
+// IDNA2008 (Internationalized Domain Names for Applications), is defined in RFC
+// 5890, RFC 5891, RFC 5892, RFC 5893 and RFC 5894.
+// UTS #46 is defined in http://www.unicode.org/reports/tr46.
+// See http://unicode.org/cldr/utility/idna.jsp for a visualization of the
+// differences between these two standards.
+package idna // import "golang.org/x/net/idna"
+
+import (
+	"fmt"
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/text/secure/bidirule"
+	"golang.org/x/text/unicode/bidi"
+	"golang.org/x/text/unicode/norm"
+)
+
+// NOTE: Unlike common practice in Go APIs, the functions will return a
+// sanitized domain name in case of errors. Browsers sometimes use a partially
+// evaluated string as lookup.
+// TODO: the current error handling is, in my opinion, the least opinionated.
+// Other strategies are also viable, though:
+// Option 1) Return an empty string in case of error, but allow the user to
+//    specify explicitly which errors to ignore.
+// Option 2) Return the partially evaluated string if it is itself a valid
+//    string, otherwise return the empty string in case of error.
+// Option 3) Option 1 and 2.
+// Option 4) Always return an empty string for now and implement Option 1 as
+//    needed, and document that the return string may not be empty in case of
+//    error in the future.
+// I think Option 1 is best, but it is quite opinionated.
+
+// ToASCII is a wrapper for Punycode.ToASCII.
+func ToASCII(s string) (string, error) {
+	return Punycode.process(s, true)
+}
+
+// ToUnicode is a wrapper for Punycode.ToUnicode.
+func ToUnicode(s string) (string, error) {
+	return Punycode.process(s, false)
+}
+
+// An Option configures a Profile at creation time.
+type Option func(*options)
+
+// Transitional sets a Profile to use the Transitional mapping as defined in UTS
+// #46. This will cause, for example, "ß" to be mapped to "ss". Using the
+// transitional mapping provides a compromise between IDNA2003 and IDNA2008
+// compatibility. It is used by most browsers when resolving domain names. This
+// option is only meaningful if combined with MapForLookup.
+func Transitional(transitional bool) Option {
+	return func(o *options) { o.transitional = true }
+}
+
+// VerifyDNSLength sets whether a Profile should fail if any of the IDN parts
+// are longer than allowed by the RFC.
+func VerifyDNSLength(verify bool) Option {
+	return func(o *options) { o.verifyDNSLength = verify }
+}
+
+// RemoveLeadingDots removes leading label separators. Leading runes that map to
+// dots, such as U+3002 IDEOGRAPHIC FULL STOP, are removed as well.
+//
+// This is the behavior suggested by the UTS #46 and is adopted by some
+// browsers.
+func RemoveLeadingDots(remove bool) Option {
+	return func(o *options) { o.removeLeadingDots = remove }
+}
+
+// ValidateLabels sets whether to check the mandatory label validation criteria
+// as defined in Section 5.4 of RFC 5891. This includes testing for correct use
+// of hyphens ('-'), normalization, validity of runes, and the context rules.
+func ValidateLabels(enable bool) Option {
+	return func(o *options) {
+		// Don't override existing mappings, but set one that at least checks
+		// normalization if it is not set.
+		if o.mapping == nil && enable {
+			o.mapping = normalize
+		}
+		o.trie = trie
+		o.validateLabels = enable
+		o.fromPuny = validateFromPunycode
+	}
+}
+
+// StrictDomainName limits the set of permissible ASCII characters to those
+// allowed in domain names as defined in RFC 1034 (A-Z, a-z, 0-9 and the
+// hyphen). This is set by default for MapForLookup and ValidateForRegistration.
+//
+// This option is useful, for instance, for browsers that allow characters
+// outside this range, for example a '_' (U+005F LOW LINE). See
+// http://www.rfc-editor.org/std/std3.txt for more details This option
+// corresponds to the UseSTD3ASCIIRules option in UTS #46.
+func StrictDomainName(use bool) Option {
+	return func(o *options) {
+		o.trie = trie
+		o.useSTD3Rules = use
+		o.fromPuny = validateFromPunycode
+	}
+}
+
+// NOTE: the following options pull in tables. The tables should not be linked
+// in as long as the options are not used.
+
+// BidiRule enables the Bidi rule as defined in RFC 5893. Any application
+// that relies on proper validation of labels should include this rule.
+func BidiRule() Option {
+	return func(o *options) { o.bidirule = bidirule.ValidString }
+}
+
+// ValidateForRegistration sets validation options to verify that a given IDN is
+// properly formatted for registration as defined by Section 4 of RFC 5891.
+func ValidateForRegistration() Option {
+	return func(o *options) {
+		o.mapping = validateRegistration
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+		VerifyDNSLength(true)(o)
+		BidiRule()(o)
+	}
+}
+
+// MapForLookup sets validation and mapping options such that a given IDN is
+// transformed for domain name lookup according to the requirements set out in
+// Section 5 of RFC 5891. The mappings follow the recommendations of RFC 5894,
+// RFC 5895 and UTS 46. It does not add the Bidi Rule. Use the BidiRule option
+// to add this check.
+//
+// The mappings include normalization and mapping case, width and other
+// compatibility mappings.
+func MapForLookup() Option {
+	return func(o *options) {
+		o.mapping = validateAndMap
+		StrictDomainName(true)(o)
+		ValidateLabels(true)(o)
+	}
+}
+
+type options struct {
+	transitional      bool
+	useSTD3Rules      bool
+	validateLabels    bool
+	verifyDNSLength   bool
+	removeLeadingDots bool
+
+	trie *idnaTrie
+
+	// fromPuny calls validation rules when converting A-labels to U-labels.
+	fromPuny func(p *Profile, s string) error
+
+	// mapping implements a validation and mapping step as defined in RFC 5895
+	// or UTS 46, tailored to, for example, domain registration or lookup.
+	mapping func(p *Profile, s string) (mapped string, isBidi bool, err error)
+
+	// bidirule, if specified, checks whether s conforms to the Bidi Rule
+	// defined in RFC 5893.
+	bidirule func(s string) bool
+}
+
+// A Profile defines the configuration of an IDNA mapper.
+type Profile struct {
+	options
+}
+
+func apply(o *options, opts []Option) {
+	for _, f := range opts {
+		f(o)
+	}
+}
+
+// New creates a new Profile.
+//
+// With no options, the returned Profile is the most permissive and equals the
+// Punycode Profile. Options can be passed to further restrict the Profile. The
+// MapForLookup and ValidateForRegistration options set a collection of options,
+// for lookup and registration purposes respectively, which can be tailored by
+// adding more fine-grained options, where later options override earlier
+// options.
+func New(o ...Option) *Profile {
+	p := &Profile{}
+	apply(&p.options, o)
+	return p
+}
+
+// ToASCII converts a domain or domain label to its ASCII form. For example,
+// ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and
+// ToASCII("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToASCII(s string) (string, error) {
+	return p.process(s, true)
+}
+
+// ToUnicode converts a domain or domain label to its Unicode form. For example,
+// ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and
+// ToUnicode("golang") is "golang". If an error is encountered it will return
+// an error and a (partially) processed result.
+func (p *Profile) ToUnicode(s string) (string, error) {
+	pp := *p
+	pp.transitional = false
+	return pp.process(s, false)
+}
+
+// String reports a string with a description of the profile for debugging
+// purposes. The string format may change with different versions.
+func (p *Profile) String() string {
+	s := ""
+	if p.transitional {
+		s = "Transitional"
+	} else {
+		s = "NonTransitional"
+	}
+	if p.useSTD3Rules {
+		s += ":UseSTD3Rules"
+	}
+	if p.validateLabels {
+		s += ":ValidateLabels"
+	}
+	if p.verifyDNSLength {
+		s += ":VerifyDNSLength"
+	}
+	return s
+}
+
+var (
+	// Punycode is a Profile that does raw punycode processing with a minimum
+	// of validation.
+	Punycode *Profile = punycode
+
+	// Lookup is the recommended profile for looking up domain names, according
+	// to Section 5 of RFC 5891. The exact configuration of this profile may
+	// change over time.
+	Lookup *Profile = lookup
+
+	// Display is the recommended profile for displaying domain names.
+	// The configuration of this profile may change over time.
+	Display *Profile = display
+
+	// Registration is the recommended profile for checking whether a given
+	// IDN is valid for registration, according to Section 4 of RFC 5891.
+	Registration *Profile = registration
+
+	punycode = &Profile{}
+	lookup   = &Profile{options{
+		transitional:   true,
+		useSTD3Rules:   true,
+		validateLabels: true,
+		trie:           trie,
+		fromPuny:       validateFromPunycode,
+		mapping:        validateAndMap,
+		bidirule:       bidirule.ValidString,
+	}}
+	display = &Profile{options{
+		useSTD3Rules:   true,
+		validateLabels: true,
+		trie:           trie,
+		fromPuny:       validateFromPunycode,
+		mapping:        validateAndMap,
+		bidirule:       bidirule.ValidString,
+	}}
+	registration = &Profile{options{
+		useSTD3Rules:    true,
+		validateLabels:  true,
+		verifyDNSLength: true,
+		trie:            trie,
+		fromPuny:        validateFromPunycode,
+		mapping:         validateRegistration,
+		bidirule:        bidirule.ValidString,
+	}}
+
+	// TODO: profiles
+	// Register: recommended for approving domain names: don't do any mappings
+	// but rather reject on invalid input. Bundle or block deviation characters.
+)
+
+type labelError struct{ label, code_ string }
+
+func (e labelError) code() string { return e.code_ }
+func (e labelError) Error() string {
+	return fmt.Sprintf("idna: invalid label %q", e.label)
+}
+
+type runeError rune
+
+func (e runeError) code() string { return "P1" }
+func (e runeError) Error() string {
+	return fmt.Sprintf("idna: disallowed rune %U", e)
+}
+
+// process implements the algorithm described in section 4 of UTS #46,
+// see http://www.unicode.org/reports/tr46.
+func (p *Profile) process(s string, toASCII bool) (string, error) {
+	var err error
+	var isBidi bool
+	if p.mapping != nil {
+		s, isBidi, err = p.mapping(p, s)
+	}
+	// Remove leading empty labels.
+	if p.removeLeadingDots {
+		for ; len(s) > 0 && s[0] == '.'; s = s[1:] {
+		}
+	}
+	// TODO: allow for a quick check of the tables data.
+	// It seems like we should only create this error on ToASCII, but the
+	// UTS 46 conformance tests suggests we should always check this.
+	if err == nil && p.verifyDNSLength && s == "" {
+		err = &labelError{s, "A4"}
+	}
+	labels := labelIter{orig: s}
+	for ; !labels.done(); labels.next() {
+		label := labels.label()
+		if label == "" {
+			// Empty labels are not okay. The label iterator skips the last
+			// label if it is empty.
+			if err == nil && p.verifyDNSLength {
+				err = &labelError{s, "A4"}
+			}
+			continue
+		}
+		if strings.HasPrefix(label, acePrefix) {
+			u, err2 := decode(label[len(acePrefix):])
+			if err2 != nil {
+				if err == nil {
+					err = err2
+				}
+				// Spec says keep the old label.
+				continue
+			}
+			isBidi = isBidi || bidirule.DirectionString(u) != bidi.LeftToRight
+			labels.set(u)
+			if err == nil && p.validateLabels {
+				err = p.fromPuny(p, u)
+			}
+			if err == nil {
+				// This should be called on NonTransitional, according to the
+				// spec, but that currently does not have any effect. Use the
+				// original profile to preserve options.
+				err = p.validateLabel(u)
+			}
+		} else if err == nil {
+			err = p.validateLabel(label)
+		}
+	}
+	if isBidi && p.bidirule != nil && err == nil {
+		for labels.reset(); !labels.done(); labels.next() {
+			if !p.bidirule(labels.label()) {
+				err = &labelError{s, "B"}
+				break
+			}
+		}
+	}
+	if toASCII {
+		for labels.reset(); !labels.done(); labels.next() {
+			label := labels.label()
+			if !ascii(label) {
+				a, err2 := encode(acePrefix, label)
+				if err == nil {
+					err = err2
+				}
+				label = a
+				labels.set(a)
+			}
+			n := len(label)
+			if p.verifyDNSLength && err == nil && (n == 0 || n > 63) {
+				err = &labelError{label, "A4"}
+			}
+		}
+	}
+	s = labels.result()
+	if toASCII && p.verifyDNSLength && err == nil {
+		// Compute the length of the domain name minus the root label and its dot.
+		n := len(s)
+		if n > 0 && s[n-1] == '.' {
+			n--
+		}
+		if len(s) < 1 || n > 253 {
+			err = &labelError{s, "A4"}
+		}
+	}
+	return s, err
+}
+
+func normalize(p *Profile, s string) (mapped string, isBidi bool, err error) {
+	// TODO: consider first doing a quick check to see if any of these checks
+	// need to be done. This will make it slower in the general case, but
+	// faster in the common case.
+	mapped = norm.NFC.String(s)
+	isBidi = bidirule.DirectionString(mapped) == bidi.RightToLeft
+	return mapped, isBidi, nil
+}
+
+func validateRegistration(p *Profile, s string) (idem string, bidi bool, err error) {
+	// TODO: filter need for normalization in loop below.
+	if !norm.NFC.IsNormalString(s) {
+		return s, false, &labelError{s, "V1"}
+	}
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			return s, bidi, runeError(utf8.RuneError)
+		}
+		bidi = bidi || info(v).isBidi(s[i:])
+		// Copy bytes not copied so far.
+		switch p.simplify(info(v).category()) {
+		// TODO: handle the NV8 defined in the Unicode idna data set to allow
+		// for strict conformance to IDNA2008.
+		case valid, deviation:
+		case disallowed, mapped, unknown, ignored:
+			r, _ := utf8.DecodeRuneInString(s[i:])
+			return s, bidi, runeError(r)
+		}
+		i += sz
+	}
+	return s, bidi, nil
+}
+
+func (c info) isBidi(s string) bool {
+	if !c.isMapped() {
+		return c&attributesMask == rtl
+	}
+	// TODO: also store bidi info for mapped data. This is possible, but a bit
+	// cumbersome and not for the common case.
+	p, _ := bidi.LookupString(s)
+	switch p.Class() {
+	case bidi.R, bidi.AL, bidi.AN:
+		return true
+	}
+	return false
+}
+
+func validateAndMap(p *Profile, s string) (vm string, bidi bool, err error) {
+	var (
+		b []byte
+		k int
+	)
+	// combinedInfoBits contains the or-ed bits of all runes. We use this
+	// to derive the mayNeedNorm bit later. This may trigger normalization
+	// overeagerly, but it will not do so in the common case. The end result
+	// is another 10% saving on BenchmarkProfile for the common case.
+	var combinedInfoBits info
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			b = append(b, s[k:i]...)
+			b = append(b, "\ufffd"...)
+			k = len(s)
+			if err == nil {
+				err = runeError(utf8.RuneError)
+			}
+			break
+		}
+		combinedInfoBits |= info(v)
+		bidi = bidi || info(v).isBidi(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.
+		if combinedInfoBits&mayNeedNorm != 0 {
+			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, bidi, err
+}
+
+// A labelIter allows iterating over domain name labels.
+type labelIter struct {
+	orig     string
+	slice    []string
+	curStart int
+	curEnd   int
+	i        int
+}
+
+func (l *labelIter) reset() {
+	l.curStart = 0
+	l.curEnd = 0
+	l.i = 0
+}
+
+func (l *labelIter) done() bool {
+	return l.curStart >= len(l.orig)
+}
+
+func (l *labelIter) result() string {
+	if l.slice != nil {
+		return strings.Join(l.slice, ".")
+	}
+	return l.orig
+}
+
+func (l *labelIter) label() string {
+	if l.slice != nil {
+		return l.slice[l.i]
+	}
+	p := strings.IndexByte(l.orig[l.curStart:], '.')
+	l.curEnd = l.curStart + p
+	if p == -1 {
+		l.curEnd = len(l.orig)
+	}
+	return l.orig[l.curStart:l.curEnd]
+}
+
+// next sets the value to the next label. It skips the last label if it is empty.
+func (l *labelIter) next() {
+	l.i++
+	if l.slice != nil {
+		if l.i >= len(l.slice) || l.i == len(l.slice)-1 && l.slice[l.i] == "" {
+			l.curStart = len(l.orig)
+		}
+	} else {
+		l.curStart = l.curEnd + 1
+		if l.curStart == len(l.orig)-1 && l.orig[l.curStart] == '.' {
+			l.curStart = len(l.orig)
+		}
+	}
+}
+
+func (l *labelIter) set(s string) {
+	if l.slice == nil {
+		l.slice = strings.Split(l.orig, ".")
+	}
+	l.slice[l.i] = s
+}
+
+// acePrefix is the ASCII Compatible Encoding prefix.
+const acePrefix = "xn--"
+
+func (p *Profile) simplify(cat category) category {
+	switch cat {
+	case disallowedSTD3Mapped:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = mapped
+		}
+	case disallowedSTD3Valid:
+		if p.useSTD3Rules {
+			cat = disallowed
+		} else {
+			cat = valid
+		}
+	case deviation:
+		if !p.transitional {
+			cat = valid
+		}
+	case validNV8, validXV8:
+		// TODO: handle V2008
+		cat = valid
+	}
+	return cat
+}
+
+func validateFromPunycode(p *Profile, s string) error {
+	if !norm.NFC.IsNormalString(s) {
+		return &labelError{s, "V1"}
+	}
+	// TODO: detect whether string may have to be normalized in the following
+	// loop.
+	for i := 0; i < len(s); {
+		v, sz := trie.lookupString(s[i:])
+		if sz == 0 {
+			return runeError(utf8.RuneError)
+		}
+		if c := p.simplify(info(v).category()); c != valid && c != deviation {
+			return &labelError{s, "V6"}
+		}
+		i += sz
+	}
+	return nil
+}
+
+const (
+	zwnj = "\u200c"
+	zwj  = "\u200d"
+)
+
+type joinState int8
+
+const (
+	stateStart joinState = iota
+	stateVirama
+	stateBefore
+	stateBeforeVirama
+	stateAfter
+	stateFAIL
+)
+
+var joinStates = [][numJoinTypes]joinState{
+	stateStart: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateVirama,
+	},
+	stateVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+	},
+	stateBefore: {
+		joiningL:   stateBefore,
+		joiningD:   stateBefore,
+		joiningT:   stateBefore,
+		joinZWNJ:   stateAfter,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateBeforeVirama,
+	},
+	stateBeforeVirama: {
+		joiningL: stateBefore,
+		joiningD: stateBefore,
+		joiningT: stateBefore,
+	},
+	stateAfter: {
+		joiningL:   stateFAIL,
+		joiningD:   stateBefore,
+		joiningT:   stateAfter,
+		joiningR:   stateStart,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateAfter, // no-op as we can't accept joiners here
+	},
+	stateFAIL: {
+		0:          stateFAIL,
+		joiningL:   stateFAIL,
+		joiningD:   stateFAIL,
+		joiningT:   stateFAIL,
+		joiningR:   stateFAIL,
+		joinZWNJ:   stateFAIL,
+		joinZWJ:    stateFAIL,
+		joinVirama: stateFAIL,
+	},
+}
+
+// validateLabel validates the criteria from Section 4.1. Item 1, 4, and 6 are
+// already implicitly satisfied by the overall implementation.
+func (p *Profile) validateLabel(s string) (err error) {
+	if s == "" {
+		if p.verifyDNSLength {
+			return &labelError{s, "A4"}
+		}
+		return nil
+	}
+	if !p.validateLabels {
+		return nil
+	}
+	trie := p.trie // p.validateLabels is only set if trie is set.
+	if len(s) > 4 && s[2] == '-' && s[3] == '-' {
+		return &labelError{s, "V2"}
+	}
+	if s[0] == '-' || s[len(s)-1] == '-' {
+		return &labelError{s, "V3"}
+	}
+	// TODO: merge the use of this in the trie.
+	v, sz := trie.lookupString(s)
+	x := info(v)
+	if x.isModifier() {
+		return &labelError{s, "V5"}
+	}
+	// Quickly return in the absence of zero-width (non) joiners.
+	if strings.Index(s, zwj) == -1 && strings.Index(s, zwnj) == -1 {
+		return nil
+	}
+	st := stateStart
+	for i := 0; ; {
+		jt := x.joinType()
+		if s[i:i+sz] == zwj {
+			jt = joinZWJ
+		} else if s[i:i+sz] == zwnj {
+			jt = joinZWNJ
+		}
+		st = joinStates[st][jt]
+		if x.isViramaModifier() {
+			st = joinStates[st][joinVirama]
+		}
+		if i += sz; i == len(s) {
+			break
+		}
+		v, sz = trie.lookupString(s[i:])
+		x = info(v)
+	}
+	if st == stateFAIL || st == stateAfter {
+		return &labelError{s, "C"}
+	}
+	return nil
+}
+
+func ascii(s string) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] >= utf8.RuneSelf {
+			return false
+		}
+	}
+	return true
+}

vendor/golang.org/x/net/idna/idna_test.go

@@ -0,0 +1,108 @@
+// Copyright 2012 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 idna
+
+import (
+	"testing"
+)
+
+var idnaTestCases = [...]struct {
+	ascii, unicode string
+}{
+	// Labels.
+	{"books", "books"},
+	{"xn--bcher-kva", "bücher"},
+
+	// Domains.
+	{"foo--xn--bar.org", "foo--xn--bar.org"},
+	{"golang.org", "golang.org"},
+	{"example.xn--p1ai", "example.рф"},
+	{"xn--czrw28b.tw", "商業.tw"},
+	{"www.xn--mller-kva.de", "www.müller.de"},
+}
+
+func TestIDNA(t *testing.T) {
+	for _, tc := range idnaTestCases {
+		if a, err := ToASCII(tc.unicode); err != nil {
+			t.Errorf("ToASCII(%q): %v", tc.unicode, err)
+		} else if a != tc.ascii {
+			t.Errorf("ToASCII(%q): got %q, want %q", tc.unicode, a, tc.ascii)
+		}
+
+		if u, err := ToUnicode(tc.ascii); err != nil {
+			t.Errorf("ToUnicode(%q): %v", tc.ascii, err)
+		} else if u != tc.unicode {
+			t.Errorf("ToUnicode(%q): got %q, want %q", tc.ascii, u, tc.unicode)
+		}
+	}
+}
+
+func TestIDNASeparators(t *testing.T) {
+	type subCase struct {
+		unicode   string
+		wantASCII string
+		wantErr   bool
+	}
+
+	testCases := []struct {
+		name     string
+		profile  *Profile
+		subCases []subCase
+	}{
+		{
+			name: "Punycode", profile: Punycode,
+			subCases: []subCase{
+				{"example\u3002jp", "xn--examplejp-ck3h", false},
+				{"東京\uFF0Ejp", "xn--jp-l92cn98g071o", false},
+				{"大阪\uFF61jp", "xn--jp-ku9cz72u463f", false},
+			},
+		},
+		{
+			name: "Lookup", profile: Lookup,
+			subCases: []subCase{
+				{"example\u3002jp", "example.jp", false},
+				{"東京\uFF0Ejp", "xn--1lqs71d.jp", false},
+				{"大阪\uFF61jp", "xn--pssu33l.jp", false},
+			},
+		},
+		{
+			name: "Display", profile: Display,
+			subCases: []subCase{
+				{"example\u3002jp", "example.jp", false},
+				{"東京\uFF0Ejp", "xn--1lqs71d.jp", false},
+				{"大阪\uFF61jp", "xn--pssu33l.jp", false},
+			},
+		},
+		{
+			name: "Registration", profile: Registration,
+			subCases: []subCase{
+				{"example\u3002jp", "", true},
+				{"東京\uFF0Ejp", "", true},
+				{"大阪\uFF61jp", "", true},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			for _, c := range tc.subCases {
+				gotA, err := tc.profile.ToASCII(c.unicode)
+				if c.wantErr {
+					if err == nil {
+						t.Errorf("ToASCII(%q): got no error, but an error expected", c.unicode)
+					}
+				} else {
+					if err != nil {
+						t.Errorf("ToASCII(%q): got err=%v, but no error expected", c.unicode, err)
+					} else if gotA != c.wantASCII {
+						t.Errorf("ToASCII(%q): got %q, want %q", c.unicode, gotA, c.wantASCII)
+					}
+				}
+			}
+		})
+	}
+}
+
+// TODO(nigeltao): test errors, once we've specified when ToASCII and ToUnicode
+// return errors.

vendor/golang.org/x/net/idna/punycode.go

@@ -0,0 +1,203 @@
+// 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.
+
+package idna
+
+// This file implements the Punycode algorithm from RFC 3492.
+
+import (
+	"math"
+	"strings"
+	"unicode/utf8"
+)
+
+// These parameter values are specified in section 5.
+//
+// All computation is done with int32s, so that overflow behavior is identical
+// regardless of whether int is 32-bit or 64-bit.
+const (
+	base        int32 = 36
+	damp        int32 = 700
+	initialBias int32 = 72
+	initialN    int32 = 128
+	skew        int32 = 38
+	tmax        int32 = 26
+	tmin        int32 = 1
+)
+
+func punyError(s string) error { return &labelError{s, "A3"} }
+
+// decode decodes a string as specified in section 6.2.
+func decode(encoded string) (string, error) {
+	if encoded == "" {
+		return "", nil
+	}
+	pos := 1 + strings.LastIndex(encoded, "-")
+	if pos == 1 {
+		return "", punyError(encoded)
+	}
+	if pos == len(encoded) {
+		return encoded[:len(encoded)-1], nil
+	}
+	output := make([]rune, 0, len(encoded))
+	if pos != 0 {
+		for _, r := range encoded[:pos-1] {
+			output = append(output, r)
+		}
+	}
+	i, n, bias := int32(0), initialN, initialBias
+	for pos < len(encoded) {
+		oldI, w := i, int32(1)
+		for k := base; ; k += base {
+			if pos == len(encoded) {
+				return "", punyError(encoded)
+			}
+			digit, ok := decodeDigit(encoded[pos])
+			if !ok {
+				return "", punyError(encoded)
+			}
+			pos++
+			i += digit * w
+			if i < 0 {
+				return "", punyError(encoded)
+			}
+			t := k - bias
+			if t < tmin {
+				t = tmin
+			} else if t > tmax {
+				t = tmax
+			}
+			if digit < t {
+				break
+			}
+			w *= base - t
+			if w >= math.MaxInt32/base {
+				return "", punyError(encoded)
+			}
+		}
+		x := int32(len(output) + 1)
+		bias = adapt(i-oldI, x, oldI == 0)
+		n += i / x
+		i %= x
+		if n > utf8.MaxRune || len(output) >= 1024 {
+			return "", punyError(encoded)
+		}
+		output = append(output, 0)
+		copy(output[i+1:], output[i:])
+		output[i] = n
+		i++
+	}
+	return string(output), nil
+}
+
+// encode encodes a string as specified in section 6.3 and prepends prefix to
+// the result.
+//
+// The "while h < length(input)" line in the specification becomes "for
+// remaining != 0" in the Go code, because len(s) in Go is in bytes, not runes.
+func encode(prefix, s string) (string, error) {
+	output := make([]byte, len(prefix), len(prefix)+1+2*len(s))
+	copy(output, prefix)
+	delta, n, bias := int32(0), initialN, initialBias
+	b, remaining := int32(0), int32(0)
+	for _, r := range s {
+		if r < 0x80 {
+			b++
+			output = append(output, byte(r))
+		} else {
+			remaining++
+		}
+	}
+	h := b
+	if b > 0 {
+		output = append(output, '-')
+	}
+	for remaining != 0 {
+		m := int32(0x7fffffff)
+		for _, r := range s {
+			if m > r && r >= n {
+				m = r
+			}
+		}
+		delta += (m - n) * (h + 1)
+		if delta < 0 {
+			return "", punyError(s)
+		}
+		n = m
+		for _, r := range s {
+			if r < n {
+				delta++
+				if delta < 0 {
+					return "", punyError(s)
+				}
+				continue
+			}
+			if r > n {
+				continue
+			}
+			q := delta
+			for k := base; ; k += base {
+				t := k - bias
+				if t < tmin {
+					t = tmin
+				} else if t > tmax {
+					t = tmax
+				}
+				if q < t {
+					break
+				}
+				output = append(output, encodeDigit(t+(q-t)%(base-t)))
+				q = (q - t) / (base - t)
+			}
+			output = append(output, encodeDigit(q))
+			bias = adapt(delta, h+1, h == b)
+			delta = 0
+			h++
+			remaining--
+		}
+		delta++
+		n++
+	}
+	return string(output), nil
+}
+
+func decodeDigit(x byte) (digit int32, ok bool) {
+	switch {
+	case '0' <= x && x <= '9':
+		return int32(x - ('0' - 26)), true
+	case 'A' <= x && x <= 'Z':
+		return int32(x - 'A'), true
+	case 'a' <= x && x <= 'z':
+		return int32(x - 'a'), true
+	}
+	return 0, false
+}
+
+func encodeDigit(digit int32) byte {
+	switch {
+	case 0 <= digit && digit < 26:
+		return byte(digit + 'a')
+	case 26 <= digit && digit < 36:
+		return byte(digit + ('0' - 26))
+	}
+	panic("idna: internal error in punycode encoding")
+}
+
+// adapt is the bias adaptation function specified in section 6.1.
+func adapt(delta, numPoints int32, firstTime bool) int32 {
+	if firstTime {
+		delta /= damp
+	} else {
+		delta /= 2
+	}
+	delta += delta / numPoints
+	k := int32(0)
+	for delta > ((base-tmin)*tmax)/2 {
+		delta /= base - tmin
+		k += base
+	}
+	return k + (base-tmin+1)*delta/(delta+skew)
+}

vendor/golang.org/x/net/idna/punycode_test.go

@@ -0,0 +1,198 @@
+// Copyright 2012 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 idna
+
+import (
+	"strings"
+	"testing"
+)
+
+var punycodeTestCases = [...]struct {
+	s, encoded string
+}{
+	{"", ""},
+	{"-", "--"},
+	{"-a", "-a-"},
+	{"-a-", "-a--"},
+	{"a", "a-"},
+	{"a-", "a--"},
+	{"a-b", "a-b-"},
+	{"books", "books-"},
+	{"bücher", "bcher-kva"},
+	{"Hello世界", "Hello-ck1hg65u"},
+	{"ü", "tda"},
+	{"üý", "tdac"},
+
+	// The test cases below come from RFC 3492 section 7.1 with Errata 3026.
+	{
+		// (A) Arabic (Egyptian).
+		"\u0644\u064A\u0647\u0645\u0627\u0628\u062A\u0643\u0644" +
+			"\u0645\u0648\u0634\u0639\u0631\u0628\u064A\u061F",
+		"egbpdaj6bu4bxfgehfvwxn",
+	},
+	{
+		// (B) Chinese (simplified).
+		"\u4ED6\u4EEC\u4E3A\u4EC0\u4E48\u4E0D\u8BF4\u4E2D\u6587",
+		"ihqwcrb4cv8a8dqg056pqjye",
+	},
+	{
+		// (C) Chinese (traditional).
+		"\u4ED6\u5011\u7232\u4EC0\u9EBD\u4E0D\u8AAA\u4E2D\u6587",
+		"ihqwctvzc91f659drss3x8bo0yb",
+	},
+	{
+		// (D) Czech.
+		"\u0050\u0072\u006F\u010D\u0070\u0072\u006F\u0073\u0074" +
+			"\u011B\u006E\u0065\u006D\u006C\u0075\u0076\u00ED\u010D" +
+			"\u0065\u0073\u006B\u0079",
+		"Proprostnemluvesky-uyb24dma41a",
+	},
+	{
+		// (E) Hebrew.
+		"\u05DC\u05DE\u05D4\u05D4\u05DD\u05E4\u05E9\u05D5\u05D8" +
+			"\u05DC\u05D0\u05DE\u05D3\u05D1\u05E8\u05D9\u05DD\u05E2" +
+			"\u05D1\u05E8\u05D9\u05EA",
+		"4dbcagdahymbxekheh6e0a7fei0b",
+	},
+	{
+		// (F) Hindi (Devanagari).
+		"\u092F\u0939\u0932\u094B\u0917\u0939\u093F\u0928\u094D" +
+			"\u0926\u0940\u0915\u094D\u092F\u094B\u0902\u0928\u0939" +
+			"\u0940\u0902\u092C\u094B\u0932\u0938\u0915\u0924\u0947" +
+			"\u0939\u0948\u0902",
+		"i1baa7eci9glrd9b2ae1bj0hfcgg6iyaf8o0a1dig0cd",
+	},
+	{
+		// (G) Japanese (kanji and hiragana).
+		"\u306A\u305C\u307F\u3093\u306A\u65E5\u672C\u8A9E\u3092" +
+			"\u8A71\u3057\u3066\u304F\u308C\u306A\u3044\u306E\u304B",
+		"n8jok5ay5dzabd5bym9f0cm5685rrjetr6pdxa",
+	},
+	{
+		// (H) Korean (Hangul syllables).
+		"\uC138\uACC4\uC758\uBAA8\uB4E0\uC0AC\uB78C\uB4E4\uC774" +
+			"\uD55C\uAD6D\uC5B4\uB97C\uC774\uD574\uD55C\uB2E4\uBA74" +
+			"\uC5BC\uB9C8\uB098\uC88B\uC744\uAE4C",
+		"989aomsvi5e83db1d2a355cv1e0vak1dwrv93d5xbh15a0dt30a5j" +
+			"psd879ccm6fea98c",
+	},
+	{
+		// (I) Russian (Cyrillic).
+		"\u043F\u043E\u0447\u0435\u043C\u0443\u0436\u0435\u043E" +
+			"\u043D\u0438\u043D\u0435\u0433\u043E\u0432\u043E\u0440" +
+			"\u044F\u0442\u043F\u043E\u0440\u0443\u0441\u0441\u043A" +
+			"\u0438",
+		"b1abfaaepdrnnbgefbadotcwatmq2g4l",
+	},
+	{
+		// (J) Spanish.
+		"\u0050\u006F\u0072\u0071\u0075\u00E9\u006E\u006F\u0070" +
+			"\u0075\u0065\u0064\u0065\u006E\u0073\u0069\u006D\u0070" +
+			"\u006C\u0065\u006D\u0065\u006E\u0074\u0065\u0068\u0061" +
+			"\u0062\u006C\u0061\u0072\u0065\u006E\u0045\u0073\u0070" +
+			"\u0061\u00F1\u006F\u006C",
+		"PorqunopuedensimplementehablarenEspaol-fmd56a",
+	},
+	{
+		// (K) Vietnamese.
+		"\u0054\u1EA1\u0069\u0073\u0061\u006F\u0068\u1ECD\u006B" +
+			"\u0068\u00F4\u006E\u0067\u0074\u0068\u1EC3\u0063\u0068" +
+			"\u1EC9\u006E\u00F3\u0069\u0074\u0069\u1EBF\u006E\u0067" +
+			"\u0056\u0069\u1EC7\u0074",
+		"TisaohkhngthchnitingVit-kjcr8268qyxafd2f1b9g",
+	},
+	{
+		// (L) 3<nen>B<gumi><kinpachi><sensei>.
+		"\u0033\u5E74\u0042\u7D44\u91D1\u516B\u5148\u751F",
+		"3B-ww4c5e180e575a65lsy2b",
+	},
+	{
+		// (M) <amuro><namie>-with-SUPER-MONKEYS.
+		"\u5B89\u5BA4\u5948\u7F8E\u6075\u002D\u0077\u0069\u0074" +
+			"\u0068\u002D\u0053\u0055\u0050\u0045\u0052\u002D\u004D" +
+			"\u004F\u004E\u004B\u0045\u0059\u0053",
+		"-with-SUPER-MONKEYS-pc58ag80a8qai00g7n9n",
+	},
+	{
+		// (N) Hello-Another-Way-<sorezore><no><basho>.
+		"\u0048\u0065\u006C\u006C\u006F\u002D\u0041\u006E\u006F" +
+			"\u0074\u0068\u0065\u0072\u002D\u0057\u0061\u0079\u002D" +
+			"\u305D\u308C\u305E\u308C\u306E\u5834\u6240",
+		"Hello-Another-Way--fc4qua05auwb3674vfr0b",
+	},
+	{
+		// (O) <hitotsu><yane><no><shita>2.
+		"\u3072\u3068\u3064\u5C4B\u6839\u306E\u4E0B\u0032",
+		"2-u9tlzr9756bt3uc0v",
+	},
+	{
+		// (P) Maji<de>Koi<suru>5<byou><mae>
+		"\u004D\u0061\u006A\u0069\u3067\u004B\u006F\u0069\u3059" +
+			"\u308B\u0035\u79D2\u524D",
+		"MajiKoi5-783gue6qz075azm5e",
+	},
+	{
+		// (Q) <pafii>de<runba>
+		"\u30D1\u30D5\u30A3\u30FC\u0064\u0065\u30EB\u30F3\u30D0",
+		"de-jg4avhby1noc0d",
+	},
+	{
+		// (R) <sono><supiido><de>
+		"\u305D\u306E\u30B9\u30D4\u30FC\u30C9\u3067",
+		"d9juau41awczczp",
+	},
+	{
+		// (S) -> $1.00 <-
+		"\u002D\u003E\u0020\u0024\u0031\u002E\u0030\u0030\u0020" +
+			"\u003C\u002D",
+		"-> $1.00 <--",
+	},
+}
+
+func TestPunycode(t *testing.T) {
+	for _, tc := range punycodeTestCases {
+		if got, err := decode(tc.encoded); err != nil {
+			t.Errorf("decode(%q): %v", tc.encoded, err)
+		} else if got != tc.s {
+			t.Errorf("decode(%q): got %q, want %q", tc.encoded, got, tc.s)
+		}
+
+		if got, err := encode("", tc.s); err != nil {
+			t.Errorf(`encode("", %q): %v`, tc.s, err)
+		} else if got != tc.encoded {
+			t.Errorf(`encode("", %q): got %q, want %q`, tc.s, got, tc.encoded)
+		}
+	}
+}
+
+var punycodeErrorTestCases = [...]string{
+	"decode -",            // A sole '-' is invalid.
+	"decode foo\x00bar",   // '\x00' is not in [0-9A-Za-z].
+	"decode foo#bar",      // '#' is not in [0-9A-Za-z].
+	"decode foo\u00A3bar", // '\u00A3' is not in [0-9A-Za-z].
+	"decode 9",            // "9a" decodes to codepoint \u00A3; "9" is truncated.
+	"decode 99999a",       // "99999a" decodes to codepoint \U0048A3C1, which is > \U0010FFFF.
+	"decode 9999999999a",  // "9999999999a" overflows the int32 calculation.
+
+	"encode " + strings.Repeat("x", 65536) + "\uff00", // int32 overflow.
+}
+
+func TestPunycodeErrors(t *testing.T) {
+	for _, tc := range punycodeErrorTestCases {
+		var err error
+		switch {
+		case strings.HasPrefix(tc, "decode "):
+			_, err = decode(tc[7:])
+		case strings.HasPrefix(tc, "encode "):
+			_, err = encode("", tc[7:])
+		}
+		if err == nil {
+			if len(tc) > 256 {
+				tc = tc[:100] + "..." + tc[len(tc)-100:]
+			}
+			t.Errorf("no error for %s", tc)
+		}
+	}
+}

vendor/golang.org/x/net/idna/trie.go

@@ -0,0 +1,72 @@
+// 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.
+
+package idna
+
+// appendMapping appends the mapping for the respective rune. isMapped must be
+// true. A mapping is a categorization of a rune as defined in UTS #46.
+func (c info) appendMapping(b []byte, s string) []byte {
+	index := int(c >> indexShift)
+	if c&xorBit == 0 {
+		s := mappings[index:]
+		return append(b, s[1:s[0]+1]...)
+	}
+	b = append(b, s...)
+	if c&inlineXOR == inlineXOR {
+		// TODO: support and handle two-byte inline masks
+		b[len(b)-1] ^= byte(index)
+	} else {
+		for p := len(b) - int(xorData[index]); p < len(b); p++ {
+			index++
+			b[p] ^= xorData[index]
+		}
+	}
+	return b
+}
+
+// Sparse block handling code.
+
+type valueRange struct {
+	value  uint16 // header: value:stride
+	lo, hi byte   // header: lo:n
+}
+
+type sparseBlocks struct {
+	values []valueRange
+	offset []uint16
+}
+
+var idnaSparse = sparseBlocks{
+	values: idnaSparseValues[:],
+	offset: idnaSparseOffset[:],
+}
+
+// Don't use newIdnaTrie to avoid unconditional linking in of the table.
+var trie = &idnaTrie{}
+
+// lookup determines the type of block n and looks up the value for b.
+// For n < t.cutoff, the block is a simple lookup table. Otherwise, the block
+// is a list of ranges with an accompanying value. Given a matching range r,
+// the value for b is by r.value + (b - r.lo) * stride.
+func (t *sparseBlocks) lookup(n uint32, b byte) uint16 {
+	offset := t.offset[n]
+	header := t.values[offset]
+	lo := offset + 1
+	hi := lo + uint16(header.lo)
+	for lo < hi {
+		m := lo + (hi-lo)/2
+		r := t.values[m]
+		if r.lo <= b && b <= r.hi {
+			return r.value + uint16(b-r.lo)*header.value
+		}
+		if b < r.lo {
+			hi = m
+		} else {
+			lo = m + 1
+		}
+	}
+	return 0
+}

vendor/golang.org/x/net/idna/trieval.go

@@ -0,0 +1,119 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package idna
+
+// This file contains definitions for interpreting the trie value of the idna
+// trie generated by "go run gen*.go". It is shared by both the generator
+// program and the resultant package. Sharing is achieved by the generator
+// copying gen_trieval.go to trieval.go and changing what's above this comment.
+
+// info holds information from the IDNA mapping table for a single rune. It is
+// the value returned by a trie lookup. In most cases, all information fits in
+// a 16-bit value. For mappings, this value may contain an index into a slice
+// with the mapped string. Such mappings can consist of the actual mapped value
+// or an XOR pattern to be applied to the bytes of the UTF8 encoding of the
+// input rune. This technique is used by the cases packages and reduces the
+// table size significantly.
+//
+// The per-rune values have the following format:
+//
+//   if mapped {
+//     if inlinedXOR {
+//       15..13 inline XOR marker
+//       12..11 unused
+//       10..3  inline XOR mask
+//     } else {
+//       15..3  index into xor or mapping table
+//     }
+//   } else {
+//       15..14 unused
+//       13     mayNeedNorm
+//       12..11 attributes
+//       10..8  joining type
+//        7..3  category type
+//   }
+//      2  use xor pattern
+//   1..0  mapped category
+//
+// See the definitions below for a more detailed description of the various
+// bits.
+type info uint16
+
+const (
+	catSmallMask = 0x3
+	catBigMask   = 0xF8
+	indexShift   = 3
+	xorBit       = 0x4    // interpret the index as an xor pattern
+	inlineXOR    = 0xE000 // These bits are set if the XOR pattern is inlined.
+
+	joinShift = 8
+	joinMask  = 0x07
+
+	// Attributes
+	attributesMask = 0x1800
+	viramaModifier = 0x1800
+	modifier       = 0x1000
+	rtl            = 0x0800
+
+	mayNeedNorm = 0x2000
+)
+
+// A category corresponds to a category defined in the IDNA mapping table.
+type category uint16
+
+const (
+	unknown              category = 0 // not currently defined in unicode.
+	mapped               category = 1
+	disallowedSTD3Mapped category = 2
+	deviation            category = 3
+)
+
+const (
+	valid               category = 0x08
+	validNV8            category = 0x18
+	validXV8            category = 0x28
+	disallowed          category = 0x40
+	disallowedSTD3Valid category = 0x80
+	ignored             category = 0xC0
+)
+
+// join types and additional rune information
+const (
+	joiningL = (iota + 1)
+	joiningD
+	joiningT
+	joiningR
+
+	//the following types are derived during processing
+	joinZWJ
+	joinZWNJ
+	joinVirama
+	numJoinTypes
+)
+
+func (c info) isMapped() bool {
+	return c&0x3 != 0
+}
+
+func (c info) category() category {
+	small := c & catSmallMask
+	if small != 0 {
+		return category(small)
+	}
+	return category(c & catBigMask)
+}
+
+func (c info) joinType() info {
+	if c.isMapped() {
+		return 0
+	}
+	return (c >> joinShift) & joinMask
+}
+
+func (c info) isModifier() bool {
+	return c&(modifier|catSmallMask) == modifier
+}
+
+func (c info) isViramaModifier() bool {
+	return c&(attributesMask|catSmallMask) == viramaModifier
+}