code-generator: use cases.Title instead of strings.Title

This pulls in language.Und for basic capitalisation.

Signed-off-by: Stephen Kitt <skitt@redhat.com>

staging/src/k8s.io/code-generator/cmd/client-gen/generators/fake/generator_fake_for_type.go

@@ -21,6 +21,8 @@ import (
 	"path"
 	"strings"
 
+	"golang.org/x/text/cases"
+	"golang.org/x/text/language"
 	"k8s.io/gengo/v2/generator"
 	"k8s.io/gengo/v2/namer"
 	"k8s.io/gengo/v2/types"
@@ -43,6 +45,8 @@ type genFakeForType struct {
 
 var _ generator.Generator = &genFakeForType{}
 
+var titler = cases.Title(language.Und)
+
 // Filter ignores all but one type because we're making a single file per type.
 func (g *genFakeForType) Filter(c *generator.Context, t *types.Type) bool { return t == g.typeToMatch }
 
@@ -299,9 +303,7 @@ func (g *genFakeForType) GenerateType(c *generator.Context, t *types.Type, w io.
 // TODO: Make the verbs in templates parametrized so the strings.Replace() is
 // not needed.
 func adjustTemplate(name, verbType, template string) string {
-	//nolint:staticcheck
+	return strings.ReplaceAll(template, " "+titler.String(verbType), " "+name)
-	// TODO: convert this to use golang.org/x/text/cases
-	return strings.ReplaceAll(template, " "+strings.Title(verbType), " "+name)
 }
 
 // template for the struct that implements the type's interface

staging/src/k8s.io/code-generator/cmd/client-gen/generators/generator_for_type.go

@@ -21,6 +21,8 @@ import (
 	"path"
 	"strings"
 
+	"golang.org/x/text/cases"
+	"golang.org/x/text/language"
 	"k8s.io/gengo/v2/generator"
 	"k8s.io/gengo/v2/namer"
 	"k8s.io/gengo/v2/types"
@@ -44,6 +46,8 @@ type genClientForType struct {
 
 var _ generator.Generator = &genClientForType{}
 
+var titler = cases.Title(language.Und)
+
 // Filter ignores all but one type because we're making a single file per type.
 func (g *genClientForType) Filter(c *generator.Context, t *types.Type) bool {
 	return t == g.typeToMatch
@@ -119,13 +123,9 @@ func (g *genClientForType) GenerateType(c *generator.Context, t *types.Type, w i
 		}
 		var updatedVerbtemplate string
 		if _, exists := subresourceDefaultVerbTemplates[e.VerbType]; e.IsSubresource() && exists {
-			//nolint:staticcheck
+			updatedVerbtemplate = e.VerbName + "(" + strings.TrimPrefix(subresourceDefaultVerbTemplates[e.VerbType], titler.String(e.VerbType)+"(")
-			// TODO: convert this to use golang.org/x/text/cases
-			updatedVerbtemplate = e.VerbName + "(" + strings.TrimPrefix(subresourceDefaultVerbTemplates[e.VerbType], strings.Title(e.VerbType)+"(")
 		} else {
-			//nolint:staticcheck
+			updatedVerbtemplate = e.VerbName + "(" + strings.TrimPrefix(defaultVerbTemplates[e.VerbType], titler.String(e.VerbType)+"(")
-			// TODO: convert this to use golang.org/x/text/cases
-			updatedVerbtemplate = e.VerbName + "(" + strings.TrimPrefix(defaultVerbTemplates[e.VerbType], strings.Title(e.VerbType)+"(")
 		}
 		extendedMethod := extendedInterfaceMethod{
 			template: updatedVerbtemplate,
@@ -348,9 +348,7 @@ func (g *genClientForType) GenerateType(c *generator.Context, t *types.Type, w i
 // TODO: Make the verbs in templates parametrized so the strings.Replace() is
 // not needed.
 func adjustTemplate(name, verbType, template string) string {
-	//nolint:staticcheck
+	return strings.ReplaceAll(template, " "+titler.String(verbType), " "+name)
-	// TODO: convert this to use golang.org/x/text/cases
-	return strings.ReplaceAll(template, " "+strings.Title(verbType), " "+name)
 }
 
 func generateInterface(defaultVerbTemplates map[string]string, tags util.Tags) string {

staging/src/k8s.io/code-generator/go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/google/go-cmp v0.6.0
 	github.com/google/gofuzz v1.2.0
 	github.com/spf13/pflag v1.0.5
+	golang.org/x/text v0.14.0
 	gopkg.in/yaml.v2 v2.4.0
 	k8s.io/apimachinery v0.0.0
 	k8s.io/gengo/v2 v2.0.0-20240228010128-51d4e06bde70

vendor/golang.org/x/text/cases/cases.go

@@ -0,0 +1,162 @@
+// Copyright 2014 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.
+
+//go:generate go run gen.go gen_trieval.go
+
+// Package cases provides general and language-specific case mappers.
+package cases // import "golang.org/x/text/cases"
+
+import (
+	"golang.org/x/text/language"
+	"golang.org/x/text/transform"
+)
+
+// References:
+// - Unicode Reference Manual Chapter 3.13, 4.2, and 5.18.
+// - https://www.unicode.org/reports/tr29/
+// - https://www.unicode.org/Public/6.3.0/ucd/CaseFolding.txt
+// - https://www.unicode.org/Public/6.3.0/ucd/SpecialCasing.txt
+// - https://www.unicode.org/Public/6.3.0/ucd/DerivedCoreProperties.txt
+// - https://www.unicode.org/Public/6.3.0/ucd/auxiliary/WordBreakProperty.txt
+// - https://www.unicode.org/Public/6.3.0/ucd/auxiliary/WordBreakTest.txt
+// - http://userguide.icu-project.org/transforms/casemappings
+
+// TODO:
+// - Case folding
+// - Wide and Narrow?
+// - Segmenter option for title casing.
+// - ASCII fast paths
+// - Encode Soft-Dotted property within trie somehow.
+
+// A Caser transforms given input to a certain case. It implements
+// transform.Transformer.
+//
+// A Caser may be stateful and should therefore not be shared between
+// goroutines.
+type Caser struct {
+	t transform.SpanningTransformer
+}
+
+// Bytes returns a new byte slice with the result of converting b to the case
+// form implemented by c.
+func (c Caser) Bytes(b []byte) []byte {
+	b, _, _ = transform.Bytes(c.t, b)
+	return b
+}
+
+// String returns a string with the result of transforming s to the case form
+// implemented by c.
+func (c Caser) String(s string) string {
+	s, _, _ = transform.String(c.t, s)
+	return s
+}
+
+// Reset resets the Caser to be reused for new input after a previous call to
+// Transform.
+func (c Caser) Reset() { c.t.Reset() }
+
+// Transform implements the transform.Transformer interface and transforms the
+// given input to the case form implemented by c.
+func (c Caser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	return c.t.Transform(dst, src, atEOF)
+}
+
+// Span implements the transform.SpanningTransformer interface.
+func (c Caser) Span(src []byte, atEOF bool) (n int, err error) {
+	return c.t.Span(src, atEOF)
+}
+
+// Upper returns a Caser for language-specific uppercasing.
+func Upper(t language.Tag, opts ...Option) Caser {
+	return Caser{makeUpper(t, getOpts(opts...))}
+}
+
+// Lower returns a Caser for language-specific lowercasing.
+func Lower(t language.Tag, opts ...Option) Caser {
+	return Caser{makeLower(t, getOpts(opts...))}
+}
+
+// Title returns a Caser for language-specific title casing. It uses an
+// approximation of the default Unicode Word Break algorithm.
+func Title(t language.Tag, opts ...Option) Caser {
+	return Caser{makeTitle(t, getOpts(opts...))}
+}
+
+// Fold returns a Caser that implements Unicode case folding. The returned Caser
+// is stateless and safe to use concurrently by multiple goroutines.
+//
+// Case folding does not normalize the input and may not preserve a normal form.
+// Use the collate or search package for more convenient and linguistically
+// sound comparisons. Use golang.org/x/text/secure/precis for string comparisons
+// where security aspects are a concern.
+func Fold(opts ...Option) Caser {
+	return Caser{makeFold(getOpts(opts...))}
+}
+
+// An Option is used to modify the behavior of a Caser.
+type Option func(o options) options
+
+// TODO: consider these options to take a boolean as well, like FinalSigma.
+// The advantage of using this approach is that other providers of a lower-case
+// algorithm could set different defaults by prefixing a user-provided slice
+// of options with their own. This is handy, for instance, for the precis
+// package which would override the default to not handle the Greek final sigma.
+
+var (
+	// NoLower disables the lowercasing of non-leading letters for a title
+	// caser.
+	NoLower Option = noLower
+
+	// Compact omits mappings in case folding for characters that would grow the
+	// input. (Unimplemented.)
+	Compact Option = compact
+)
+
+// TODO: option to preserve a normal form, if applicable?
+
+type options struct {
+	noLower bool
+	simple  bool
+
+	// TODO: segmenter, max ignorable, alternative versions, etc.
+
+	ignoreFinalSigma bool
+}
+
+func getOpts(o ...Option) (res options) {
+	for _, f := range o {
+		res = f(res)
+	}
+	return
+}
+
+func noLower(o options) options {
+	o.noLower = true
+	return o
+}
+
+func compact(o options) options {
+	o.simple = true
+	return o
+}
+
+// HandleFinalSigma specifies whether the special handling of Greek final sigma
+// should be enabled. Unicode prescribes handling the Greek final sigma for all
+// locales, but standards like IDNA and PRECIS override this default.
+func HandleFinalSigma(enable bool) Option {
+	if enable {
+		return handleFinalSigma
+	}
+	return ignoreFinalSigma
+}
+
+func ignoreFinalSigma(o options) options {
+	o.ignoreFinalSigma = true
+	return o
+}
+
+func handleFinalSigma(o options) options {
+	o.ignoreFinalSigma = false
+	return o
+}

vendor/golang.org/x/text/cases/context.go

@@ -0,0 +1,376 @@
+// Copyright 2014 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 cases
+
+import "golang.org/x/text/transform"
+
+// A context is used for iterating over source bytes, fetching case info and
+// writing to a destination buffer.
+//
+// Casing operations may need more than one rune of context to decide how a rune
+// should be cased. Casing implementations should call checkpoint on context
+// whenever it is known to be safe to return the runes processed so far.
+//
+// It is recommended for implementations to not allow for more than 30 case
+// ignorables as lookahead (analogous to the limit in norm) and to use state if
+// unbounded lookahead is needed for cased runes.
+type context struct {
+	dst, src []byte
+	atEOF    bool
+
+	pDst int // pDst points past the last written rune in dst.
+	pSrc int // pSrc points to the start of the currently scanned rune.
+
+	// checkpoints safe to return in Transform, where nDst <= pDst and nSrc <= pSrc.
+	nDst, nSrc int
+	err        error
+
+	sz   int  // size of current rune
+	info info // case information of currently scanned rune
+
+	// State preserved across calls to Transform.
+	isMidWord bool // false if next cased letter needs to be title-cased.
+}
+
+func (c *context) Reset() {
+	c.isMidWord = false
+}
+
+// ret returns the return values for the Transform method. It checks whether
+// there were insufficient bytes in src to complete and introduces an error
+// accordingly, if necessary.
+func (c *context) ret() (nDst, nSrc int, err error) {
+	if c.err != nil || c.nSrc == len(c.src) {
+		return c.nDst, c.nSrc, c.err
+	}
+	// This point is only reached by mappers if there was no short destination
+	// buffer. This means that the source buffer was exhausted and that c.sz was
+	// set to 0 by next.
+	if c.atEOF && c.pSrc == len(c.src) {
+		return c.pDst, c.pSrc, nil
+	}
+	return c.nDst, c.nSrc, transform.ErrShortSrc
+}
+
+// retSpan returns the return values for the Span method. It checks whether
+// there were insufficient bytes in src to complete and introduces an error
+// accordingly, if necessary.
+func (c *context) retSpan() (n int, err error) {
+	_, nSrc, err := c.ret()
+	return nSrc, err
+}
+
+// checkpoint sets the return value buffer points for Transform to the current
+// positions.
+func (c *context) checkpoint() {
+	if c.err == nil {
+		c.nDst, c.nSrc = c.pDst, c.pSrc+c.sz
+	}
+}
+
+// unreadRune causes the last rune read by next to be reread on the next
+// invocation of next. Only one unreadRune may be called after a call to next.
+func (c *context) unreadRune() {
+	c.sz = 0
+}
+
+func (c *context) next() bool {
+	c.pSrc += c.sz
+	if c.pSrc == len(c.src) || c.err != nil {
+		c.info, c.sz = 0, 0
+		return false
+	}
+	v, sz := trie.lookup(c.src[c.pSrc:])
+	c.info, c.sz = info(v), sz
+	if c.sz == 0 {
+		if c.atEOF {
+			// A zero size means we have an incomplete rune. If we are atEOF,
+			// this means it is an illegal rune, which we will consume one
+			// byte at a time.
+			c.sz = 1
+		} else {
+			c.err = transform.ErrShortSrc
+			return false
+		}
+	}
+	return true
+}
+
+// writeBytes adds bytes to dst.
+func (c *context) writeBytes(b []byte) bool {
+	if len(c.dst)-c.pDst < len(b) {
+		c.err = transform.ErrShortDst
+		return false
+	}
+	// This loop is faster than using copy.
+	for _, ch := range b {
+		c.dst[c.pDst] = ch
+		c.pDst++
+	}
+	return true
+}
+
+// writeString writes the given string to dst.
+func (c *context) writeString(s string) bool {
+	if len(c.dst)-c.pDst < len(s) {
+		c.err = transform.ErrShortDst
+		return false
+	}
+	// This loop is faster than using copy.
+	for i := 0; i < len(s); i++ {
+		c.dst[c.pDst] = s[i]
+		c.pDst++
+	}
+	return true
+}
+
+// copy writes the current rune to dst.
+func (c *context) copy() bool {
+	return c.writeBytes(c.src[c.pSrc : c.pSrc+c.sz])
+}
+
+// copyXOR copies the current rune to dst and modifies it by applying the XOR
+// pattern of the case info. It is the responsibility of the caller to ensure
+// that this is a rune with a XOR pattern defined.
+func (c *context) copyXOR() bool {
+	if !c.copy() {
+		return false
+	}
+	if c.info&xorIndexBit == 0 {
+		// Fast path for 6-bit XOR pattern, which covers most cases.
+		c.dst[c.pDst-1] ^= byte(c.info >> xorShift)
+	} else {
+		// Interpret XOR bits as an index.
+		// TODO: test performance for unrolling this loop. Verify that we have
+		// at least two bytes and at most three.
+		idx := c.info >> xorShift
+		for p := c.pDst - 1; ; p-- {
+			c.dst[p] ^= xorData[idx]
+			idx--
+			if xorData[idx] == 0 {
+				break
+			}
+		}
+	}
+	return true
+}
+
+// hasPrefix returns true if src[pSrc:] starts with the given string.
+func (c *context) hasPrefix(s string) bool {
+	b := c.src[c.pSrc:]
+	if len(b) < len(s) {
+		return false
+	}
+	for i, c := range b[:len(s)] {
+		if c != s[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// caseType returns an info with only the case bits, normalized to either
+// cLower, cUpper, cTitle or cUncased.
+func (c *context) caseType() info {
+	cm := c.info & 0x7
+	if cm < 4 {
+		return cm
+	}
+	if cm >= cXORCase {
+		// xor the last bit of the rune with the case type bits.
+		b := c.src[c.pSrc+c.sz-1]
+		return info(b&1) ^ cm&0x3
+	}
+	if cm == cIgnorableCased {
+		return cLower
+	}
+	return cUncased
+}
+
+// lower writes the lowercase version of the current rune to dst.
+func lower(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cLower {
+		return c.copy()
+	}
+	if c.info&exceptionBit == 0 {
+		return c.copyXOR()
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	offset := 2 + e[0]&lengthMask // size of header + fold string
+	if nLower := (e[1] >> lengthBits) & lengthMask; nLower != noChange {
+		return c.writeString(e[offset : offset+nLower])
+	}
+	return c.copy()
+}
+
+func isLower(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cLower {
+		return true
+	}
+	if c.info&exceptionBit == 0 {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	if nLower := (e[1] >> lengthBits) & lengthMask; nLower != noChange {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	return true
+}
+
+// upper writes the uppercase version of the current rune to dst.
+func upper(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cUpper {
+		return c.copy()
+	}
+	if c.info&exceptionBit == 0 {
+		return c.copyXOR()
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	offset := 2 + e[0]&lengthMask // size of header + fold string
+	// Get length of first special case mapping.
+	n := (e[1] >> lengthBits) & lengthMask
+	if ct == cTitle {
+		// The first special case mapping is for lower. Set n to the second.
+		if n == noChange {
+			n = 0
+		}
+		n, e = e[1]&lengthMask, e[n:]
+	}
+	if n != noChange {
+		return c.writeString(e[offset : offset+n])
+	}
+	return c.copy()
+}
+
+// isUpper writes the isUppercase version of the current rune to dst.
+func isUpper(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cUpper {
+		return true
+	}
+	if c.info&exceptionBit == 0 {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	// Get length of first special case mapping.
+	n := (e[1] >> lengthBits) & lengthMask
+	if ct == cTitle {
+		n = e[1] & lengthMask
+	}
+	if n != noChange {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	return true
+}
+
+// title writes the title case version of the current rune to dst.
+func title(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cTitle {
+		return c.copy()
+	}
+	if c.info&exceptionBit == 0 {
+		if ct == cLower {
+			return c.copyXOR()
+		}
+		return c.copy()
+	}
+	// Get the exception data.
+	e := exceptions[c.info>>exceptionShift:]
+	offset := 2 + e[0]&lengthMask // size of header + fold string
+
+	nFirst := (e[1] >> lengthBits) & lengthMask
+	if nTitle := e[1] & lengthMask; nTitle != noChange {
+		if nFirst != noChange {
+			e = e[nFirst:]
+		}
+		return c.writeString(e[offset : offset+nTitle])
+	}
+	if ct == cLower && nFirst != noChange {
+		// Use the uppercase version instead.
+		return c.writeString(e[offset : offset+nFirst])
+	}
+	// Already in correct case.
+	return c.copy()
+}
+
+// isTitle reports whether the current rune is in title case.
+func isTitle(c *context) bool {
+	ct := c.caseType()
+	if c.info&hasMappingMask == 0 || ct == cTitle {
+		return true
+	}
+	if c.info&exceptionBit == 0 {
+		if ct == cLower {
+			c.err = transform.ErrEndOfSpan
+			return false
+		}
+		return true
+	}
+	// Get the exception data.
+	e := exceptions[c.info>>exceptionShift:]
+	if nTitle := e[1] & lengthMask; nTitle != noChange {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	nFirst := (e[1] >> lengthBits) & lengthMask
+	if ct == cLower && nFirst != noChange {
+		c.err = transform.ErrEndOfSpan
+		return false
+	}
+	return true
+}
+
+// foldFull writes the foldFull version of the current rune to dst.
+func foldFull(c *context) bool {
+	if c.info&hasMappingMask == 0 {
+		return c.copy()
+	}
+	ct := c.caseType()
+	if c.info&exceptionBit == 0 {
+		if ct != cLower || c.info&inverseFoldBit != 0 {
+			return c.copyXOR()
+		}
+		return c.copy()
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	n := e[0] & lengthMask
+	if n == 0 {
+		if ct == cLower {
+			return c.copy()
+		}
+		n = (e[1] >> lengthBits) & lengthMask
+	}
+	return c.writeString(e[2 : 2+n])
+}
+
+// isFoldFull reports whether the current run is mapped to foldFull
+func isFoldFull(c *context) bool {
+	if c.info&hasMappingMask == 0 {
+		return true
+	}
+	ct := c.caseType()
+	if c.info&exceptionBit == 0 {
+		if ct != cLower || c.info&inverseFoldBit != 0 {
+			c.err = transform.ErrEndOfSpan
+			return false
+		}
+		return true
+	}
+	e := exceptions[c.info>>exceptionShift:]
+	n := e[0] & lengthMask
+	if n == 0 && ct == cLower {
+		return true
+	}
+	c.err = transform.ErrEndOfSpan
+	return false
+}

vendor/golang.org/x/text/cases/fold.go

@@ -0,0 +1,34 @@
+// 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 cases
+
+import "golang.org/x/text/transform"
+
+type caseFolder struct{ transform.NopResetter }
+
+// caseFolder implements the Transformer interface for doing case folding.
+func (t *caseFolder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	c := context{dst: dst, src: src, atEOF: atEOF}
+	for c.next() {
+		foldFull(&c)
+		c.checkpoint()
+	}
+	return c.ret()
+}
+
+func (t *caseFolder) Span(src []byte, atEOF bool) (n int, err error) {
+	c := context{src: src, atEOF: atEOF}
+	for c.next() && isFoldFull(&c) {
+		c.checkpoint()
+	}
+	return c.retSpan()
+}
+
+func makeFold(o options) transform.SpanningTransformer {
+	// TODO: Special case folding, through option Language, Special/Turkic, or
+	// both.
+	// TODO: Implement Compact options.
+	return &caseFolder{}
+}

vendor/golang.org/x/text/cases/icu.go

@@ -0,0 +1,61 @@
+// 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.
+
+//go:build icu
+
+package cases
+
+// Ideally these functions would be defined in a test file, but go test doesn't
+// allow CGO in tests. The build tag should ensure either way that these
+// functions will not end up in the package.
+
+// TODO: Ensure that the correct ICU version is set.
+
+/*
+#cgo LDFLAGS: -licui18n.57 -licuuc.57
+#include <stdlib.h>
+#include <unicode/ustring.h>
+#include <unicode/utypes.h>
+#include <unicode/localpointer.h>
+#include <unicode/ucasemap.h>
+*/
+import "C"
+
+import "unsafe"
+
+func doICU(tag, caser, input string) string {
+	err := C.UErrorCode(0)
+	loc := C.CString(tag)
+	cm := C.ucasemap_open(loc, C.uint32_t(0), &err)
+
+	buf := make([]byte, len(input)*4)
+	dst := (*C.char)(unsafe.Pointer(&buf[0]))
+	src := C.CString(input)
+
+	cn := C.int32_t(0)
+
+	switch caser {
+	case "fold":
+		cn = C.ucasemap_utf8FoldCase(cm,
+			dst, C.int32_t(len(buf)),
+			src, C.int32_t(len(input)),
+			&err)
+	case "lower":
+		cn = C.ucasemap_utf8ToLower(cm,
+			dst, C.int32_t(len(buf)),
+			src, C.int32_t(len(input)),
+			&err)
+	case "upper":
+		cn = C.ucasemap_utf8ToUpper(cm,
+			dst, C.int32_t(len(buf)),
+			src, C.int32_t(len(input)),
+			&err)
+	case "title":
+		cn = C.ucasemap_utf8ToTitle(cm,
+			dst, C.int32_t(len(buf)),
+			src, C.int32_t(len(input)),
+			&err)
+	}
+	return string(buf[:cn])
+}

vendor/golang.org/x/text/cases/info.go

@@ -0,0 +1,82 @@
+// Copyright 2015 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 cases
+
+func (c info) cccVal() info {
+	if c&exceptionBit != 0 {
+		return info(exceptions[c>>exceptionShift]) & cccMask
+	}
+	return c & cccMask
+}
+
+func (c info) cccType() info {
+	ccc := c.cccVal()
+	if ccc <= cccZero {
+		return cccZero
+	}
+	return ccc
+}
+
+// TODO: Implement full Unicode breaking algorithm:
+// 1) Implement breaking in separate package.
+// 2) Use the breaker here.
+// 3) Compare table size and performance of using the more generic breaker.
+//
+// Note that we can extend the current algorithm to be much more accurate. This
+// only makes sense, though, if the performance and/or space penalty of using
+// the generic breaker is big. Extra data will only be needed for non-cased
+// runes, which means there are sufficient bits left in the caseType.
+// ICU prohibits breaking in such cases as well.
+
+// For the purpose of title casing we use an approximation of the Unicode Word
+// Breaking algorithm defined in Annex #29:
+// https://www.unicode.org/reports/tr29/#Default_Grapheme_Cluster_Table.
+//
+// For our approximation, we group the Word Break types into the following
+// categories, with associated rules:
+//
+// 1) Letter:
+//    ALetter, Hebrew_Letter, Numeric, ExtendNumLet, Extend, Format_FE, ZWJ.
+//    Rule: Never break between consecutive runes of this category.
+//
+// 2) Mid:
+//    MidLetter, MidNumLet, Single_Quote.
+//    (Cf. case-ignorable: MidLetter, MidNumLet, Single_Quote or cat is Mn,
+//    Me, Cf, Lm or Sk).
+//    Rule: Don't break between Letter and Mid, but break between two Mids.
+//
+// 3) Break:
+//    Any other category: NewLine, MidNum, CR, LF, Double_Quote, Katakana, and
+//    Other.
+//    These categories should always result in a break between two cased letters.
+//    Rule: Always break.
+//
+// Note 1: the Katakana and MidNum categories can, in esoteric cases, result in
+// preventing a break between two cased letters. For now we will ignore this
+// (e.g. [ALetter] [ExtendNumLet] [Katakana] [ExtendNumLet] [ALetter] and
+// [ALetter] [Numeric] [MidNum] [Numeric] [ALetter].)
+//
+// Note 2: the rule for Mid is very approximate, but works in most cases. To
+// improve, we could store the categories in the trie value and use a FA to
+// manage breaks. See TODO comment above.
+//
+// Note 3: according to the spec, it is possible for the Extend category to
+// introduce breaks between other categories grouped in Letter. However, this
+// is undesirable for our purposes. ICU prevents breaks in such cases as well.
+
+// isBreak returns whether this rune should introduce a break.
+func (c info) isBreak() bool {
+	return c.cccVal() == cccBreak
+}
+
+// isLetter returns whether the rune is of break type ALetter, Hebrew_Letter,
+// Numeric, ExtendNumLet, or Extend.
+func (c info) isLetter() bool {
+	ccc := c.cccVal()
+	if ccc == cccZero {
+		return !c.isCaseIgnorable()
+	}
+	return ccc != cccBreak
+}

vendor/golang.org/x/text/cases/map.go

@@ -0,0 +1,816 @@
+// Copyright 2014 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 cases
+
+// This file contains the definitions of case mappings for all supported
+// languages. The rules for the language-specific tailorings were taken and
+// modified from the CLDR transform definitions in common/transforms.
+
+import (
+	"strings"
+	"unicode"
+	"unicode/utf8"
+
+	"golang.org/x/text/internal"
+	"golang.org/x/text/language"
+	"golang.org/x/text/transform"
+	"golang.org/x/text/unicode/norm"
+)
+
+// A mapFunc takes a context set to the current rune and writes the mapped
+// version to the same context. It may advance the context to the next rune. It
+// returns whether a checkpoint is possible: whether the pDst bytes written to
+// dst so far won't need changing as we see more source bytes.
+type mapFunc func(*context) bool
+
+// A spanFunc takes a context set to the current rune and returns whether this
+// rune would be altered when written to the output. It may advance the context
+// to the next rune. It returns whether a checkpoint is possible.
+type spanFunc func(*context) bool
+
+// maxIgnorable defines the maximum number of ignorables to consider for
+// lookahead operations.
+const maxIgnorable = 30
+
+// supported lists the language tags for which we have tailorings.
+const supported = "und af az el lt nl tr"
+
+func init() {
+	tags := []language.Tag{}
+	for _, s := range strings.Split(supported, " ") {
+		tags = append(tags, language.MustParse(s))
+	}
+	matcher = internal.NewInheritanceMatcher(tags)
+	Supported = language.NewCoverage(tags)
+}
+
+var (
+	matcher *internal.InheritanceMatcher
+
+	Supported language.Coverage
+
+	// We keep the following lists separate, instead of having a single per-
+	// language struct, to give the compiler a chance to remove unused code.
+
+	// Some uppercase mappers are stateless, so we can precompute the
+	// Transformers and save a bit on runtime allocations.
+	upperFunc = []struct {
+		upper mapFunc
+		span  spanFunc
+	}{
+		{nil, nil},                  // und
+		{nil, nil},                  // af
+		{aztrUpper(upper), isUpper}, // az
+		{elUpper, noSpan},           // el
+		{ltUpper(upper), noSpan},    // lt
+		{nil, nil},                  // nl
+		{aztrUpper(upper), isUpper}, // tr
+	}
+
+	undUpper            transform.SpanningTransformer = &undUpperCaser{}
+	undLower            transform.SpanningTransformer = &undLowerCaser{}
+	undLowerIgnoreSigma transform.SpanningTransformer = &undLowerIgnoreSigmaCaser{}
+
+	lowerFunc = []mapFunc{
+		nil,       // und
+		nil,       // af
+		aztrLower, // az
+		nil,       // el
+		ltLower,   // lt
+		nil,       // nl
+		aztrLower, // tr
+	}
+
+	titleInfos = []struct {
+		title     mapFunc
+		lower     mapFunc
+		titleSpan spanFunc
+		rewrite   func(*context)
+	}{
+		{title, lower, isTitle, nil},                // und
+		{title, lower, isTitle, afnlRewrite},        // af
+		{aztrUpper(title), aztrLower, isTitle, nil}, // az
+		{title, lower, isTitle, nil},                // el
+		{ltUpper(title), ltLower, noSpan, nil},      // lt
+		{nlTitle, lower, nlTitleSpan, afnlRewrite},  // nl
+		{aztrUpper(title), aztrLower, isTitle, nil}, // tr
+	}
+)
+
+func makeUpper(t language.Tag, o options) transform.SpanningTransformer {
+	_, i, _ := matcher.Match(t)
+	f := upperFunc[i].upper
+	if f == nil {
+		return undUpper
+	}
+	return &simpleCaser{f: f, span: upperFunc[i].span}
+}
+
+func makeLower(t language.Tag, o options) transform.SpanningTransformer {
+	_, i, _ := matcher.Match(t)
+	f := lowerFunc[i]
+	if f == nil {
+		if o.ignoreFinalSigma {
+			return undLowerIgnoreSigma
+		}
+		return undLower
+	}
+	if o.ignoreFinalSigma {
+		return &simpleCaser{f: f, span: isLower}
+	}
+	return &lowerCaser{
+		first:   f,
+		midWord: finalSigma(f),
+	}
+}
+
+func makeTitle(t language.Tag, o options) transform.SpanningTransformer {
+	_, i, _ := matcher.Match(t)
+	x := &titleInfos[i]
+	lower := x.lower
+	if o.noLower {
+		lower = (*context).copy
+	} else if !o.ignoreFinalSigma {
+		lower = finalSigma(lower)
+	}
+	return &titleCaser{
+		title:     x.title,
+		lower:     lower,
+		titleSpan: x.titleSpan,
+		rewrite:   x.rewrite,
+	}
+}
+
+func noSpan(c *context) bool {
+	c.err = transform.ErrEndOfSpan
+	return false
+}
+
+// TODO: consider a similar special case for the fast majority lower case. This
+// is a bit more involved so will require some more precise benchmarking to
+// justify it.
+
+type undUpperCaser struct{ transform.NopResetter }
+
+// undUpperCaser implements the Transformer interface for doing an upper case
+// mapping for the root locale (und). It eliminates the need for an allocation
+// as it prevents escaping by not using function pointers.
+func (t undUpperCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	c := context{dst: dst, src: src, atEOF: atEOF}
+	for c.next() {
+		upper(&c)
+		c.checkpoint()
+	}
+	return c.ret()
+}
+
+func (t undUpperCaser) Span(src []byte, atEOF bool) (n int, err error) {
+	c := context{src: src, atEOF: atEOF}
+	for c.next() && isUpper(&c) {
+		c.checkpoint()
+	}
+	return c.retSpan()
+}
+
+// undLowerIgnoreSigmaCaser implements the Transformer interface for doing
+// a lower case mapping for the root locale (und) ignoring final sigma
+// handling. This casing algorithm is used in some performance-critical packages
+// like secure/precis and x/net/http/idna, which warrants its special-casing.
+type undLowerIgnoreSigmaCaser struct{ transform.NopResetter }
+
+func (t undLowerIgnoreSigmaCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	c := context{dst: dst, src: src, atEOF: atEOF}
+	for c.next() && lower(&c) {
+		c.checkpoint()
+	}
+	return c.ret()
+
+}
+
+// Span implements a generic lower-casing. This is possible as isLower works
+// for all lowercasing variants. All lowercase variants only vary in how they
+// transform a non-lowercase letter. They will never change an already lowercase
+// letter. In addition, there is no state.
+func (t undLowerIgnoreSigmaCaser) Span(src []byte, atEOF bool) (n int, err error) {
+	c := context{src: src, atEOF: atEOF}
+	for c.next() && isLower(&c) {
+		c.checkpoint()
+	}
+	return c.retSpan()
+}
+
+type simpleCaser struct {
+	context
+	f    mapFunc
+	span spanFunc
+}
+
+// simpleCaser implements the Transformer interface for doing a case operation
+// on a rune-by-rune basis.
+func (t *simpleCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	c := context{dst: dst, src: src, atEOF: atEOF}
+	for c.next() && t.f(&c) {
+		c.checkpoint()
+	}
+	return c.ret()
+}
+
+func (t *simpleCaser) Span(src []byte, atEOF bool) (n int, err error) {
+	c := context{src: src, atEOF: atEOF}
+	for c.next() && t.span(&c) {
+		c.checkpoint()
+	}
+	return c.retSpan()
+}
+
+// undLowerCaser implements the Transformer interface for doing a lower case
+// mapping for the root locale (und) ignoring final sigma handling. This casing
+// algorithm is used in some performance-critical packages like secure/precis
+// and x/net/http/idna, which warrants its special-casing.
+type undLowerCaser struct{ transform.NopResetter }
+
+func (t undLowerCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	c := context{dst: dst, src: src, atEOF: atEOF}
+
+	for isInterWord := true; c.next(); {
+		if isInterWord {
+			if c.info.isCased() {
+				if !lower(&c) {
+					break
+				}
+				isInterWord = false
+			} else if !c.copy() {
+				break
+			}
+		} else {
+			if c.info.isNotCasedAndNotCaseIgnorable() {
+				if !c.copy() {
+					break
+				}
+				isInterWord = true
+			} else if !c.hasPrefix("Σ") {
+				if !lower(&c) {
+					break
+				}
+			} else if !finalSigmaBody(&c) {
+				break
+			}
+		}
+		c.checkpoint()
+	}
+	return c.ret()
+}
+
+func (t undLowerCaser) Span(src []byte, atEOF bool) (n int, err error) {
+	c := context{src: src, atEOF: atEOF}
+	for c.next() && isLower(&c) {
+		c.checkpoint()
+	}
+	return c.retSpan()
+}
+
+// lowerCaser implements the Transformer interface. The default Unicode lower
+// casing requires different treatment for the first and subsequent characters
+// of a word, most notably to handle the Greek final Sigma.
+type lowerCaser struct {
+	undLowerIgnoreSigmaCaser
+
+	context
+
+	first, midWord mapFunc
+}
+
+func (t *lowerCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	t.context = context{dst: dst, src: src, atEOF: atEOF}
+	c := &t.context
+
+	for isInterWord := true; c.next(); {
+		if isInterWord {
+			if c.info.isCased() {
+				if !t.first(c) {
+					break
+				}
+				isInterWord = false
+			} else if !c.copy() {
+				break
+			}
+		} else {
+			if c.info.isNotCasedAndNotCaseIgnorable() {
+				if !c.copy() {
+					break
+				}
+				isInterWord = true
+			} else if !t.midWord(c) {
+				break
+			}
+		}
+		c.checkpoint()
+	}
+	return c.ret()
+}
+
+// titleCaser implements the Transformer interface. Title casing algorithms
+// distinguish between the first letter of a word and subsequent letters of the
+// same word. It uses state to avoid requiring a potentially infinite lookahead.
+type titleCaser struct {
+	context
+
+	// rune mappings used by the actual casing algorithms.
+	title     mapFunc
+	lower     mapFunc
+	titleSpan spanFunc
+
+	rewrite func(*context)
+}
+
+// Transform implements the standard Unicode title case algorithm as defined in
+// Chapter 3 of The Unicode Standard:
+// toTitlecase(X): Find the word boundaries in X according to Unicode Standard
+// Annex #29, "Unicode Text Segmentation." For each word boundary, find the
+// first cased character F following the word boundary. If F exists, map F to
+// Titlecase_Mapping(F); then map all characters C between F and the following
+// word boundary to Lowercase_Mapping(C).
+func (t *titleCaser) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	t.context = context{dst: dst, src: src, atEOF: atEOF, isMidWord: t.isMidWord}
+	c := &t.context
+
+	if !c.next() {
+		return c.ret()
+	}
+
+	for {
+		p := c.info
+		if t.rewrite != nil {
+			t.rewrite(c)
+		}
+
+		wasMid := p.isMid()
+		// Break out of this loop on failure to ensure we do not modify the
+		// state incorrectly.
+		if p.isCased() {
+			if !c.isMidWord {
+				if !t.title(c) {
+					break
+				}
+				c.isMidWord = true
+			} else if !t.lower(c) {
+				break
+			}
+		} else if !c.copy() {
+			break
+		} else if p.isBreak() {
+			c.isMidWord = false
+		}
+
+		// As we save the state of the transformer, it is safe to call
+		// checkpoint after any successful write.
+		if !(c.isMidWord && wasMid) {
+			c.checkpoint()
+		}
+
+		if !c.next() {
+			break
+		}
+		if wasMid && c.info.isMid() {
+			c.isMidWord = false
+		}
+	}
+	return c.ret()
+}
+
+func (t *titleCaser) Span(src []byte, atEOF bool) (n int, err error) {
+	t.context = context{src: src, atEOF: atEOF, isMidWord: t.isMidWord}
+	c := &t.context
+
+	if !c.next() {
+		return c.retSpan()
+	}
+
+	for {
+		p := c.info
+		if t.rewrite != nil {
+			t.rewrite(c)
+		}
+
+		wasMid := p.isMid()
+		// Break out of this loop on failure to ensure we do not modify the
+		// state incorrectly.
+		if p.isCased() {
+			if !c.isMidWord {
+				if !t.titleSpan(c) {
+					break
+				}
+				c.isMidWord = true
+			} else if !isLower(c) {
+				break
+			}
+		} else if p.isBreak() {
+			c.isMidWord = false
+		}
+		// As we save the state of the transformer, it is safe to call
+		// checkpoint after any successful write.
+		if !(c.isMidWord && wasMid) {
+			c.checkpoint()
+		}
+
+		if !c.next() {
+			break
+		}
+		if wasMid && c.info.isMid() {
+			c.isMidWord = false
+		}
+	}
+	return c.retSpan()
+}
+
+// finalSigma adds Greek final Sigma handing to another casing function. It
+// determines whether a lowercased sigma should be σ or ς, by looking ahead for
+// case-ignorables and a cased letters.
+func finalSigma(f mapFunc) mapFunc {
+	return func(c *context) bool {
+		if !c.hasPrefix("Σ") {
+			return f(c)
+		}
+		return finalSigmaBody(c)
+	}
+}
+
+func finalSigmaBody(c *context) bool {
+	// Current rune must be ∑.
+
+	// ::NFD();
+	// # 03A3; 03C2; 03A3; 03A3; Final_Sigma; # GREEK CAPITAL LETTER SIGMA
+	// Σ } [:case-ignorable:]* [:cased:] → σ;
+	// [:cased:] [:case-ignorable:]* { Σ → ς;
+	// ::Any-Lower;
+	// ::NFC();
+
+	p := c.pDst
+	c.writeString("ς")
+
+	// TODO: we should do this here, but right now this will never have an
+	// effect as this is called when the prefix is Sigma, whereas Dutch and
+	// Afrikaans only test for an apostrophe.
+	//
+	// if t.rewrite != nil {
+	// 	t.rewrite(c)
+	// }
+
+	// We need to do one more iteration after maxIgnorable, as a cased
+	// letter is not an ignorable and may modify the result.
+	wasMid := false
+	for i := 0; i < maxIgnorable+1; i++ {
+		if !c.next() {
+			return false
+		}
+		if !c.info.isCaseIgnorable() {
+			// All Midword runes are also case ignorable, so we are
+			// guaranteed to have a letter or word break here. As we are
+			// unreading the run, there is no need to unset c.isMidWord;
+			// the title caser will handle this.
+			if c.info.isCased() {
+				// p+1 is guaranteed to be in bounds: if writing ς was
+				// successful, p+1 will contain the second byte of ς. If not,
+				// this function will have returned after c.next returned false.
+				c.dst[p+1]++ // ς → σ
+			}
+			c.unreadRune()
+			return true
+		}
+		// A case ignorable may also introduce a word break, so we may need
+		// to continue searching even after detecting a break.
+		isMid := c.info.isMid()
+		if (wasMid && isMid) || c.info.isBreak() {
+			c.isMidWord = false
+		}
+		wasMid = isMid
+		c.copy()
+	}
+	return true
+}
+
+// finalSigmaSpan would be the same as isLower.
+
+// elUpper implements Greek upper casing, which entails removing a predefined
+// set of non-blocked modifiers. Note that these accents should not be removed
+// for title casing!
+// Example: "Οδός" -> "ΟΔΟΣ".
+func elUpper(c *context) bool {
+	// From CLDR:
+	// [:Greek:] [^[:ccc=Not_Reordered:][:ccc=Above:]]*? { [\u0313\u0314\u0301\u0300\u0306\u0342\u0308\u0304] → ;
+	// [:Greek:] [^[:ccc=Not_Reordered:][:ccc=Iota_Subscript:]]*? { \u0345 → ;
+
+	r, _ := utf8.DecodeRune(c.src[c.pSrc:])
+	oldPDst := c.pDst
+	if !upper(c) {
+		return false
+	}
+	if !unicode.Is(unicode.Greek, r) {
+		return true
+	}
+	i := 0
+	// Take the properties of the uppercased rune that is already written to the
+	// destination. This saves us the trouble of having to uppercase the
+	// decomposed rune again.
+	if b := norm.NFD.Properties(c.dst[oldPDst:]).Decomposition(); b != nil {
+		// Restore the destination position and process the decomposed rune.
+		r, sz := utf8.DecodeRune(b)
+		if r <= 0xFF { // See A.6.1
+			return true
+		}
+		c.pDst = oldPDst
+		// Insert the first rune and ignore the modifiers. See A.6.2.
+		c.writeBytes(b[:sz])
+		i = len(b[sz:]) / 2 // Greek modifiers are always of length 2.
+	}
+
+	for ; i < maxIgnorable && c.next(); i++ {
+		switch r, _ := utf8.DecodeRune(c.src[c.pSrc:]); r {
+		// Above and Iota Subscript
+		case 0x0300, // U+0300 COMBINING GRAVE ACCENT
+			0x0301, // U+0301 COMBINING ACUTE ACCENT
+			0x0304, // U+0304 COMBINING MACRON
+			0x0306, // U+0306 COMBINING BREVE
+			0x0308, // U+0308 COMBINING DIAERESIS
+			0x0313, // U+0313 COMBINING COMMA ABOVE
+			0x0314, // U+0314 COMBINING REVERSED COMMA ABOVE
+			0x0342, // U+0342 COMBINING GREEK PERISPOMENI
+			0x0345: // U+0345 COMBINING GREEK YPOGEGRAMMENI
+			// No-op. Gobble the modifier.
+
+		default:
+			switch v, _ := trie.lookup(c.src[c.pSrc:]); info(v).cccType() {
+			case cccZero:
+				c.unreadRune()
+				return true
+
+			// We don't need to test for IotaSubscript as the only rune that
+			// qualifies (U+0345) was already excluded in the switch statement
+			// above. See A.4.
+
+			case cccAbove:
+				return c.copy()
+			default:
+				// Some other modifier. We're still allowed to gobble Greek
+				// modifiers after this.
+				c.copy()
+			}
+		}
+	}
+	return i == maxIgnorable
+}
+
+// TODO: implement elUpperSpan (low-priority: complex and infrequent).
+
+func ltLower(c *context) bool {
+	// From CLDR:
+	// # Introduce an explicit dot above when lowercasing capital I's and J's
+	// # whenever there are more accents above.
+	// # (of the accents used in Lithuanian: grave, acute, tilde above, and ogonek)
+	// # 0049; 0069 0307; 0049; 0049; lt More_Above; # LATIN CAPITAL LETTER I
+	// # 004A; 006A 0307; 004A; 004A; lt More_Above; # LATIN CAPITAL LETTER J
+	// # 012E; 012F 0307; 012E; 012E; lt More_Above; # LATIN CAPITAL LETTER I WITH OGONEK
+	// # 00CC; 0069 0307 0300; 00CC; 00CC; lt; # LATIN CAPITAL LETTER I WITH GRAVE
+	// # 00CD; 0069 0307 0301; 00CD; 00CD; lt; # LATIN CAPITAL LETTER I WITH ACUTE
+	// # 0128; 0069 0307 0303; 0128; 0128; lt; # LATIN CAPITAL LETTER I WITH TILDE
+	// ::NFD();
+	// I } [^[:ccc=Not_Reordered:][:ccc=Above:]]* [:ccc=Above:] → i \u0307;
+	// J } [^[:ccc=Not_Reordered:][:ccc=Above:]]* [:ccc=Above:] → j \u0307;
+	// I \u0328 (Į) } [^[:ccc=Not_Reordered:][:ccc=Above:]]* [:ccc=Above:] → i \u0328 \u0307;
+	// I \u0300 (Ì) → i \u0307 \u0300;
+	// I \u0301 (Í) → i \u0307 \u0301;
+	// I \u0303 (Ĩ) → i \u0307 \u0303;
+	// ::Any-Lower();
+	// ::NFC();
+
+	i := 0
+	if r := c.src[c.pSrc]; r < utf8.RuneSelf {
+		lower(c)
+		if r != 'I' && r != 'J' {
+			return true
+		}
+	} else {
+		p := norm.NFD.Properties(c.src[c.pSrc:])
+		if d := p.Decomposition(); len(d) >= 3 && (d[0] == 'I' || d[0] == 'J') {
+			// UTF-8 optimization: the decomposition will only have an above
+			// modifier if the last rune of the decomposition is in [U+300-U+311].
+			// In all other cases, a decomposition starting with I is always
+			// an I followed by modifiers that are not cased themselves. See A.2.
+			if d[1] == 0xCC && d[2] <= 0x91 { // A.2.4.
+				if !c.writeBytes(d[:1]) {
+					return false
+				}
+				c.dst[c.pDst-1] += 'a' - 'A' // lower
+
+				// Assumption: modifier never changes on lowercase. See A.1.
+				// Assumption: all modifiers added have CCC = Above. See A.2.3.
+				return c.writeString("\u0307") && c.writeBytes(d[1:])
+			}
+			// In all other cases the additional modifiers will have a CCC
+			// that is less than 230 (Above). We will insert the U+0307, if
+			// needed, after these modifiers so that a string in FCD form
+			// will remain so. See A.2.2.
+			lower(c)
+			i = 1
+		} else {
+			return lower(c)
+		}
+	}
+
+	for ; i < maxIgnorable && c.next(); i++ {
+		switch c.info.cccType() {
+		case cccZero:
+			c.unreadRune()
+			return true
+		case cccAbove:
+			return c.writeString("\u0307") && c.copy() // See A.1.
+		default:
+			c.copy() // See A.1.
+		}
+	}
+	return i == maxIgnorable
+}
+
+// ltLowerSpan would be the same as isLower.
+
+func ltUpper(f mapFunc) mapFunc {
+	return func(c *context) bool {
+		// Unicode:
+		// 0307; 0307; ; ; lt After_Soft_Dotted; # COMBINING DOT ABOVE
+		//
+		// From CLDR:
+		// # Remove \u0307 following soft-dotteds (i, j, and the like), with possible
+		// # intervening non-230 marks.
+		// ::NFD();
+		// [:Soft_Dotted:] [^[:ccc=Not_Reordered:][:ccc=Above:]]* { \u0307 → ;
+		// ::Any-Upper();
+		// ::NFC();
+
+		// TODO: See A.5. A soft-dotted rune never has an exception. This would
+		// allow us to overload the exception bit and encode this property in
+		// info. Need to measure performance impact of this.
+		r, _ := utf8.DecodeRune(c.src[c.pSrc:])
+		oldPDst := c.pDst
+		if !f(c) {
+			return false
+		}
+		if !unicode.Is(unicode.Soft_Dotted, r) {
+			return true
+		}
+
+		// We don't need to do an NFD normalization, as a soft-dotted rune never
+		// contains U+0307. See A.3.
+
+		i := 0
+		for ; i < maxIgnorable && c.next(); i++ {
+			switch c.info.cccType() {
+			case cccZero:
+				c.unreadRune()
+				return true
+			case cccAbove:
+				if c.hasPrefix("\u0307") {
+					// We don't do a full NFC, but rather combine runes for
+					// some of the common cases. (Returning NFC or
+					// preserving normal form is neither a requirement nor
+					// a possibility anyway).
+					if !c.next() {
+						return false
+					}
+					if c.dst[oldPDst] == 'I' && c.pDst == oldPDst+1 && c.src[c.pSrc] == 0xcc {
+						s := ""
+						switch c.src[c.pSrc+1] {
+						case 0x80: // U+0300 COMBINING GRAVE ACCENT
+							s = "\u00cc" // U+00CC LATIN CAPITAL LETTER I WITH GRAVE
+						case 0x81: // U+0301 COMBINING ACUTE ACCENT
+							s = "\u00cd" // U+00CD LATIN CAPITAL LETTER I WITH ACUTE
+						case 0x83: // U+0303 COMBINING TILDE
+							s = "\u0128" // U+0128 LATIN CAPITAL LETTER I WITH TILDE
+						case 0x88: // U+0308 COMBINING DIAERESIS
+							s = "\u00cf" // U+00CF LATIN CAPITAL LETTER I WITH DIAERESIS
+						default:
+						}
+						if s != "" {
+							c.pDst = oldPDst
+							return c.writeString(s)
+						}
+					}
+				}
+				return c.copy()
+			default:
+				c.copy()
+			}
+		}
+		return i == maxIgnorable
+	}
+}
+
+// TODO: implement ltUpperSpan (low priority: complex and infrequent).
+
+func aztrUpper(f mapFunc) mapFunc {
+	return func(c *context) bool {
+		// i→İ;
+		if c.src[c.pSrc] == 'i' {
+			return c.writeString("İ")
+		}
+		return f(c)
+	}
+}
+
+func aztrLower(c *context) (done bool) {
+	// From CLDR:
+	// # I and i-dotless; I-dot and i are case pairs in Turkish and Azeri
+	// # 0130; 0069; 0130; 0130; tr; # LATIN CAPITAL LETTER I WITH DOT ABOVE
+	// İ→i;
+	// # When lowercasing, remove dot_above in the sequence I + dot_above, which will turn into i.
+	// # This matches the behavior of the canonically equivalent I-dot_above
+	// # 0307; ; 0307; 0307; tr After_I; # COMBINING DOT ABOVE
+	// # When lowercasing, unless an I is before a dot_above, it turns into a dotless i.
+	// # 0049; 0131; 0049; 0049; tr Not_Before_Dot; # LATIN CAPITAL LETTER I
+	// I([^[:ccc=Not_Reordered:][:ccc=Above:]]*)\u0307 → i$1 ;
+	// I→ı ;
+	// ::Any-Lower();
+	if c.hasPrefix("\u0130") { // İ
+		return c.writeString("i")
+	}
+	if c.src[c.pSrc] != 'I' {
+		return lower(c)
+	}
+
+	// We ignore the lower-case I for now, but insert it later when we know
+	// which form we need.
+	start := c.pSrc + c.sz
+
+	i := 0
+Loop:
+	// We check for up to n ignorables before \u0307. As \u0307 is an
+	// ignorable as well, n is maxIgnorable-1.
+	for ; i < maxIgnorable && c.next(); i++ {
+		switch c.info.cccType() {
+		case cccAbove:
+			if c.hasPrefix("\u0307") {
+				return c.writeString("i") && c.writeBytes(c.src[start:c.pSrc]) // ignore U+0307
+			}
+			done = true
+			break Loop
+		case cccZero:
+			c.unreadRune()
+			done = true
+			break Loop
+		default:
+			// We'll write this rune after we know which starter to use.
+		}
+	}
+	if i == maxIgnorable {
+		done = true
+	}
+	return c.writeString("ı") && c.writeBytes(c.src[start:c.pSrc+c.sz]) && done
+}
+
+// aztrLowerSpan would be the same as isLower.
+
+func nlTitle(c *context) bool {
+	// From CLDR:
+	// # Special titlecasing for Dutch initial "ij".
+	// ::Any-Title();
+	// # Fix up Ij at the beginning of a "word" (per Any-Title, notUAX #29)
+	// [:^WB=ALetter:] [:WB=Extend:]* [[:WB=MidLetter:][:WB=MidNumLet:]]? { Ij } → IJ ;
+	if c.src[c.pSrc] != 'I' && c.src[c.pSrc] != 'i' {
+		return title(c)
+	}
+
+	if !c.writeString("I") || !c.next() {
+		return false
+	}
+	if c.src[c.pSrc] == 'j' || c.src[c.pSrc] == 'J' {
+		return c.writeString("J")
+	}
+	c.unreadRune()
+	return true
+}
+
+func nlTitleSpan(c *context) bool {
+	// From CLDR:
+	// # Special titlecasing for Dutch initial "ij".
+	// ::Any-Title();
+	// # Fix up Ij at the beginning of a "word" (per Any-Title, notUAX #29)
+	// [:^WB=ALetter:] [:WB=Extend:]* [[:WB=MidLetter:][:WB=MidNumLet:]]? { Ij } → IJ ;
+	if c.src[c.pSrc] != 'I' {
+		return isTitle(c)
+	}
+	if !c.next() || c.src[c.pSrc] == 'j' {
+		return false
+	}
+	if c.src[c.pSrc] != 'J' {
+		c.unreadRune()
+	}
+	return true
+}
+
+// Not part of CLDR, but see https://unicode.org/cldr/trac/ticket/7078.
+func afnlRewrite(c *context) {
+	if c.hasPrefix("'") || c.hasPrefix("’") {
+		c.isMidWord = true
+	}
+}

vendor/golang.org/x/text/cases/trieval.go

@@ -0,0 +1,217 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package cases
+
+// This file contains definitions for interpreting the trie value of the case
+// 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 case information for a single rune. It is the value returned
+// by a trie lookup. Most mapping information can be stored in a single 16-bit
+// value. If not, for example when a rune is mapped to multiple runes, the value
+// stores some basic case data and an index into an array with additional data.
+//
+// The per-rune values have the following format:
+//
+//	if (exception) {
+//	  15..4  unsigned exception index
+//	} else {
+//	  15..8  XOR pattern or index to XOR pattern for case mapping
+//	         Only 13..8 are used for XOR patterns.
+//	      7  inverseFold (fold to upper, not to lower)
+//	      6  index: interpret the XOR pattern as an index
+//	         or isMid if case mode is cIgnorableUncased.
+//	   5..4  CCC: zero (normal or break), above or other
+//	}
+//	   3  exception: interpret this value as an exception index
+//	      (TODO: is this bit necessary? Probably implied from case mode.)
+//	2..0  case mode
+//
+// For the non-exceptional cases, a rune must be either uncased, lowercase or
+// uppercase. If the rune is cased, the XOR pattern maps either a lowercase
+// rune to uppercase or an uppercase rune to lowercase (applied to the 10
+// least-significant bits of the rune).
+//
+// See the definitions below for a more detailed description of the various
+// bits.
+type info uint16
+
+const (
+	casedMask      = 0x0003
+	fullCasedMask  = 0x0007
+	ignorableMask  = 0x0006
+	ignorableValue = 0x0004
+
+	inverseFoldBit = 1 << 7
+	isMidBit       = 1 << 6
+
+	exceptionBit     = 1 << 3
+	exceptionShift   = 4
+	numExceptionBits = 12
+
+	xorIndexBit = 1 << 6
+	xorShift    = 8
+
+	// There is no mapping if all xor bits and the exception bit are zero.
+	hasMappingMask = 0xff80 | exceptionBit
+)
+
+// The case mode bits encodes the case type of a rune. This includes uncased,
+// title, upper and lower case and case ignorable. (For a definition of these
+// terms see Chapter 3 of The Unicode Standard Core Specification.) In some rare
+// cases, a rune can be both cased and case-ignorable. This is encoded by
+// cIgnorableCased. A rune of this type is always lower case. Some runes are
+// cased while not having a mapping.
+//
+// A common pattern for scripts in the Unicode standard is for upper and lower
+// case runes to alternate for increasing rune values (e.g. the accented Latin
+// ranges starting from U+0100 and U+1E00 among others and some Cyrillic
+// characters). We use this property by defining a cXORCase mode, where the case
+// mode (always upper or lower case) is derived from the rune value. As the XOR
+// pattern for case mappings is often identical for successive runes, using
+// cXORCase can result in large series of identical trie values. This, in turn,
+// allows us to better compress the trie blocks.
+const (
+	cUncased          info = iota // 000
+	cTitle                        // 001
+	cLower                        // 010
+	cUpper                        // 011
+	cIgnorableUncased             // 100
+	cIgnorableCased               // 101 // lower case if mappings exist
+	cXORCase                      // 11x // case is cLower | ((rune&1) ^ x)
+
+	maxCaseMode = cUpper
+)
+
+func (c info) isCased() bool {
+	return c&casedMask != 0
+}
+
+func (c info) isCaseIgnorable() bool {
+	return c&ignorableMask == ignorableValue
+}
+
+func (c info) isNotCasedAndNotCaseIgnorable() bool {
+	return c&fullCasedMask == 0
+}
+
+func (c info) isCaseIgnorableAndNotCased() bool {
+	return c&fullCasedMask == cIgnorableUncased
+}
+
+func (c info) isMid() bool {
+	return c&(fullCasedMask|isMidBit) == isMidBit|cIgnorableUncased
+}
+
+// The case mapping implementation will need to know about various Canonical
+// Combining Class (CCC) values. We encode two of these in the trie value:
+// cccZero (0) and cccAbove (230). If the value is cccOther, it means that
+// CCC(r) > 0, but not 230. A value of cccBreak means that CCC(r) == 0 and that
+// the rune also has the break category Break (see below).
+const (
+	cccBreak info = iota << 4
+	cccZero
+	cccAbove
+	cccOther
+
+	cccMask = cccBreak | cccZero | cccAbove | cccOther
+)
+
+const (
+	starter       = 0
+	above         = 230
+	iotaSubscript = 240
+)
+
+// The exceptions slice holds data that does not fit in a normal info entry.
+// The entry is pointed to by the exception index in an entry. It has the
+// following format:
+//
+// Header:
+//
+//	byte 0:
+//	 7..6  unused
+//	 5..4  CCC type (same bits as entry)
+//	    3  unused
+//	 2..0  length of fold
+//
+//	byte 1:
+//	  7..6  unused
+//	  5..3  length of 1st mapping of case type
+//	  2..0  length of 2nd mapping of case type
+//
+//	  case     1st    2nd
+//	  lower -> upper, title
+//	  upper -> lower, title
+//	  title -> lower, upper
+//
+// Lengths with the value 0x7 indicate no value and implies no change.
+// A length of 0 indicates a mapping to zero-length string.
+//
+// Body bytes:
+//
+//	case folding bytes
+//	lowercase mapping bytes
+//	uppercase mapping bytes
+//	titlecase mapping bytes
+//	closure mapping bytes (for NFKC_Casefold). (TODO)
+//
+// Fallbacks:
+//
+//	missing fold  -> lower
+//	missing title -> upper
+//	all missing   -> original rune
+//
+// exceptions starts with a dummy byte to enforce that there is no zero index
+// value.
+const (
+	lengthMask = 0x07
+	lengthBits = 3
+	noChange   = 0
+)
+
+// References to generated trie.
+
+var trie = newCaseTrie(0)
+
+var sparse = sparseBlocks{
+	values:  sparseValues[:],
+	offsets: sparseOffsets[:],
+}
+
+// Sparse block lookup code.
+
+// valueRange is an entry in a sparse block.
+type valueRange struct {
+	value  uint16
+	lo, hi byte
+}
+
+type sparseBlocks struct {
+	values  []valueRange
+	offsets []uint16
+}
+
+// lookup returns the value from values block n for byte b using binary search.
+func (s *sparseBlocks) lookup(n uint32, b byte) uint16 {
+	lo := s.offsets[n]
+	hi := s.offsets[n+1]
+	for lo < hi {
+		m := lo + (hi-lo)/2
+		r := s.values[m]
+		if r.lo <= b && b <= r.hi {
+			return r.value
+		}
+		if b < r.lo {
+			hi = m
+		} else {
+			lo = m + 1
+		}
+	}
+	return 0
+}
+
+// lastRuneForTesting is the last rune used for testing. Everything after this
+// is boring.
+const lastRuneForTesting = rune(0x1FFFF)

vendor/modules.txt

@@ -955,6 +955,7 @@ golang.org/x/sys/windows/svc/mgr
 golang.org/x/term
 # golang.org/x/text v0.14.0
 ## explicit; go 1.18
+golang.org/x/text/cases
 golang.org/x/text/encoding
 golang.org/x/text/encoding/charmap
 golang.org/x/text/encoding/htmlindex