vendor files

vendor/golang.org/x/text/width/common_test.go

@@ -0,0 +1,92 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package width
+
+// This code is shared between the main code generator and the test code.
+
+import (
+	"flag"
+	"log"
+	"strconv"
+	"strings"
+
+	"golang.org/x/text/internal/gen"
+	"golang.org/x/text/internal/ucd"
+)
+
+var (
+	outputFile = flag.String("out", "tables.go", "output file")
+)
+
+var typeMap = map[string]elem{
+	"A":  tagAmbiguous,
+	"N":  tagNeutral,
+	"Na": tagNarrow,
+	"W":  tagWide,
+	"F":  tagFullwidth,
+	"H":  tagHalfwidth,
+}
+
+// getWidthData calls f for every entry for which it is defined.
+//
+// f may be called multiple times for the same rune. The last call to f is the
+// correct value. f is not called for all runes. The default tag type is
+// Neutral.
+func getWidthData(f func(r rune, tag elem, alt rune)) {
+	// Set the default values for Unified Ideographs. In line with Annex 11,
+	// we encode full ranges instead of the defined runes in Unified_Ideograph.
+	for _, b := range []struct{ lo, hi rune }{
+		{0x4E00, 0x9FFF},   // the CJK Unified Ideographs block,
+		{0x3400, 0x4DBF},   // the CJK Unified Ideographs Externsion A block,
+		{0xF900, 0xFAFF},   // the CJK Compatibility Ideographs block,
+		{0x20000, 0x2FFFF}, // the Supplementary Ideographic Plane,
+		{0x30000, 0x3FFFF}, // the Tertiary Ideographic Plane,
+	} {
+		for r := b.lo; r <= b.hi; r++ {
+			f(r, tagWide, 0)
+		}
+	}
+
+	inverse := map[rune]rune{}
+	maps := map[string]bool{
+		"<wide>":   true,
+		"<narrow>": true,
+	}
+
+	// We cannot reuse package norm's decomposition, as we need an unexpanded
+	// decomposition. We make use of the opportunity to verify that the
+	// decomposition type is as expected.
+	ucd.Parse(gen.OpenUCDFile("UnicodeData.txt"), func(p *ucd.Parser) {
+		r := p.Rune(0)
+		s := strings.SplitN(p.String(ucd.DecompMapping), " ", 2)
+		if !maps[s[0]] {
+			return
+		}
+		x, err := strconv.ParseUint(s[1], 16, 32)
+		if err != nil {
+			log.Fatalf("Error parsing rune %q", s[1])
+		}
+		if inverse[r] != 0 || inverse[rune(x)] != 0 {
+			log.Fatalf("Circular dependency in mapping between %U and %U", r, x)
+		}
+		inverse[r] = rune(x)
+		inverse[rune(x)] = r
+	})
+
+	// <rune range>;<type>
+	ucd.Parse(gen.OpenUCDFile("EastAsianWidth.txt"), func(p *ucd.Parser) {
+		tag, ok := typeMap[p.String(1)]
+		if !ok {
+			log.Fatalf("Unknown width type %q", p.String(1))
+		}
+		r := p.Rune(0)
+		alt, ok := inverse[r]
+		if tag == tagFullwidth || tag == tagHalfwidth && r != wonSign {
+			tag |= tagNeedsFold
+			if !ok {
+				log.Fatalf("Narrow or wide rune %U has no decomposition", r)
+			}
+		}
+		f(r, tag, alt)
+	})
+}

vendor/golang.org/x/text/width/example_test.go

@@ -0,0 +1,52 @@
+// 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 width_test
+
+import (
+	"fmt"
+
+	"golang.org/x/text/width"
+)
+
+func ExampleTransformer_fold() {
+	s := "abｦ￦￮￥Ａ"
+	f := width.Fold.String(s)
+	fmt.Printf("%U: %s\n", []rune(s), s)
+	fmt.Printf("%U: %s\n", []rune(f), f)
+
+	// Output:
+	// [U+0061 U+0062 U+FF66 U+FFE6 U+FFEE U+FFE5 U+FF21]: abｦ￦￮￥Ａ
+	// [U+0061 U+0062 U+30F2 U+20A9 U+25CB U+00A5 U+0041]: abヲ₩○¥A
+}
+
+func ExampleTransformer_widen() {
+	s := "ab¥ｦ₩￮"
+	w := width.Widen.String(s)
+	fmt.Printf("%U: %s\n", []rune(s), s)
+	fmt.Printf("%U: %s\n", []rune(w), w)
+
+	// Output:
+	// [U+0061 U+0062 U+00A5 U+FF66 U+20A9 U+FFEE]: ab¥ｦ₩￮
+	// [U+FF41 U+FF42 U+FFE5 U+30F2 U+FFE6 U+25CB]: ａｂ￥ヲ￦○
+}
+
+func ExampleTransformer_narrow() {
+	s := "abヲ￦○￥Ａ"
+	n := width.Narrow.String(s)
+	fmt.Printf("%U: %s\n", []rune(s), s)
+	fmt.Printf("%U: %s\n", []rune(n), n)
+
+	// Ambiguous characters with a halfwidth equivalent get mapped as well.
+	s = "←"
+	n = width.Narrow.String(s)
+	fmt.Printf("%U: %s\n", []rune(s), s)
+	fmt.Printf("%U: %s\n", []rune(n), n)
+
+	// Output:
+	// [U+0061 U+0062 U+30F2 U+FFE6 U+25CB U+FFE5 U+FF21]: abヲ￦○￥Ａ
+	// [U+0061 U+0062 U+FF66 U+20A9 U+FFEE U+00A5 U+0041]: abｦ₩￮¥A
+	// [U+2190]: ←
+	// [U+FFE9]: ￩
+}

vendor/golang.org/x/text/width/gen.go

@@ -0,0 +1,115 @@
+// 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.
+
+// +build ignore
+
+// This program generates the trie for width operations. The generated table
+// includes width category information as well as the normalization mappings.
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"log"
+	"math"
+	"unicode/utf8"
+
+	"golang.org/x/text/internal/gen"
+	"golang.org/x/text/internal/triegen"
+)
+
+// See gen_common.go for flags.
+
+func main() {
+	gen.Init()
+	genTables()
+	genTests()
+	gen.Repackage("gen_trieval.go", "trieval.go", "width")
+	gen.Repackage("gen_common.go", "common_test.go", "width")
+}
+
+func genTables() {
+	t := triegen.NewTrie("width")
+	// fold and inverse mappings. See mapComment for a description of the format
+	// of each entry. Add dummy value to make an index of 0 mean no mapping.
+	inverse := [][4]byte{{}}
+	mapping := map[[4]byte]int{[4]byte{}: 0}
+
+	getWidthData(func(r rune, tag elem, alt rune) {
+		idx := 0
+		if alt != 0 {
+			var buf [4]byte
+			buf[0] = byte(utf8.EncodeRune(buf[1:], alt))
+			s := string(r)
+			buf[buf[0]] ^= s[len(s)-1]
+			var ok bool
+			if idx, ok = mapping[buf]; !ok {
+				idx = len(mapping)
+				if idx > math.MaxUint8 {
+					log.Fatalf("Index %d does not fit in a byte.", idx)
+				}
+				mapping[buf] = idx
+				inverse = append(inverse, buf)
+			}
+		}
+		t.Insert(r, uint64(tag|elem(idx)))
+	})
+
+	w := &bytes.Buffer{}
+	gen.WriteUnicodeVersion(w)
+
+	sz, err := t.Gen(w)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	sz += writeMappings(w, inverse)
+
+	fmt.Fprintf(w, "// Total table size %d bytes (%dKiB)\n", sz, sz/1024)
+
+	gen.WriteVersionedGoFile(*outputFile, "width", w.Bytes())
+}
+
+const inverseDataComment = `
+// inverseData contains 4-byte entries of the following format:
+//   <length> <modified UTF-8-encoded rune> <0 padding>
+// The last byte of the UTF-8-encoded rune is xor-ed with the last byte of the
+// UTF-8 encoding of the original rune. Mappings often have the following
+// pattern:
+//   Ａ -> A  (U+FF21 -> U+0041)
+//   Ｂ -> B  (U+FF22 -> U+0042)
+//   ...
+// By xor-ing the last byte the same entry can be shared by many mappings. This
+// reduces the total number of distinct entries by about two thirds.
+// The resulting entry for the aforementioned mappings is
+//   { 0x01, 0xE0, 0x00, 0x00 }
+// Using this entry to map U+FF21 (UTF-8 [EF BC A1]), we get
+//   E0 ^ A1 = 41.
+// Similarly, for U+FF22 (UTF-8 [EF BC A2]), we get
+//   E0 ^ A2 = 42.
+// Note that because of the xor-ing, the byte sequence stored in the entry is
+// not valid UTF-8.`
+
+func writeMappings(w io.Writer, data [][4]byte) int {
+	fmt.Fprintln(w, inverseDataComment)
+	fmt.Fprintf(w, "var inverseData = [%d][4]byte{\n", len(data))
+	for _, x := range data {
+		fmt.Fprintf(w, "{ 0x%02x, 0x%02x, 0x%02x, 0x%02x },\n", x[0], x[1], x[2], x[3])
+	}
+	fmt.Fprintln(w, "}")
+	return len(data) * 4
+}
+
+func genTests() {
+	w := &bytes.Buffer{}
+	fmt.Fprintf(w, "\nvar mapRunes = map[rune]struct{r rune; e elem}{\n")
+	getWidthData(func(r rune, tag elem, alt rune) {
+		if alt != 0 {
+			fmt.Fprintf(w, "\t0x%X: {0x%X, 0x%X},\n", r, alt, tag)
+		}
+	})
+	fmt.Fprintln(w, "}")
+	gen.WriteGoFile("runes_test.go", "width", w.Bytes())
+}

vendor/golang.org/x/text/width/gen_common.go

@@ -0,0 +1,96 @@
+// 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.
+
+// +build ignore
+
+package main
+
+// This code is shared between the main code generator and the test code.
+
+import (
+	"flag"
+	"log"
+	"strconv"
+	"strings"
+
+	"golang.org/x/text/internal/gen"
+	"golang.org/x/text/internal/ucd"
+)
+
+var (
+	outputFile = flag.String("out", "tables.go", "output file")
+)
+
+var typeMap = map[string]elem{
+	"A":  tagAmbiguous,
+	"N":  tagNeutral,
+	"Na": tagNarrow,
+	"W":  tagWide,
+	"F":  tagFullwidth,
+	"H":  tagHalfwidth,
+}
+
+// getWidthData calls f for every entry for which it is defined.
+//
+// f may be called multiple times for the same rune. The last call to f is the
+// correct value. f is not called for all runes. The default tag type is
+// Neutral.
+func getWidthData(f func(r rune, tag elem, alt rune)) {
+	// Set the default values for Unified Ideographs. In line with Annex 11,
+	// we encode full ranges instead of the defined runes in Unified_Ideograph.
+	for _, b := range []struct{ lo, hi rune }{
+		{0x4E00, 0x9FFF},   // the CJK Unified Ideographs block,
+		{0x3400, 0x4DBF},   // the CJK Unified Ideographs Externsion A block,
+		{0xF900, 0xFAFF},   // the CJK Compatibility Ideographs block,
+		{0x20000, 0x2FFFF}, // the Supplementary Ideographic Plane,
+		{0x30000, 0x3FFFF}, // the Tertiary Ideographic Plane,
+	} {
+		for r := b.lo; r <= b.hi; r++ {
+			f(r, tagWide, 0)
+		}
+	}
+
+	inverse := map[rune]rune{}
+	maps := map[string]bool{
+		"<wide>":   true,
+		"<narrow>": true,
+	}
+
+	// We cannot reuse package norm's decomposition, as we need an unexpanded
+	// decomposition. We make use of the opportunity to verify that the
+	// decomposition type is as expected.
+	ucd.Parse(gen.OpenUCDFile("UnicodeData.txt"), func(p *ucd.Parser) {
+		r := p.Rune(0)
+		s := strings.SplitN(p.String(ucd.DecompMapping), " ", 2)
+		if !maps[s[0]] {
+			return
+		}
+		x, err := strconv.ParseUint(s[1], 16, 32)
+		if err != nil {
+			log.Fatalf("Error parsing rune %q", s[1])
+		}
+		if inverse[r] != 0 || inverse[rune(x)] != 0 {
+			log.Fatalf("Circular dependency in mapping between %U and %U", r, x)
+		}
+		inverse[r] = rune(x)
+		inverse[rune(x)] = r
+	})
+
+	// <rune range>;<type>
+	ucd.Parse(gen.OpenUCDFile("EastAsianWidth.txt"), func(p *ucd.Parser) {
+		tag, ok := typeMap[p.String(1)]
+		if !ok {
+			log.Fatalf("Unknown width type %q", p.String(1))
+		}
+		r := p.Rune(0)
+		alt, ok := inverse[r]
+		if tag == tagFullwidth || tag == tagHalfwidth && r != wonSign {
+			tag |= tagNeedsFold
+			if !ok {
+				log.Fatalf("Narrow or wide rune %U has no decomposition", r)
+			}
+		}
+		f(r, tag, alt)
+	})
+}

vendor/golang.org/x/text/width/gen_trieval.go

@@ -0,0 +1,34 @@
+// 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.
+
+// +build ignore
+
+package main
+
+// elem is an entry of the width trie. The high byte is used to encode the type
+// of the rune. The low byte is used to store the index to a mapping entry in
+// the inverseData array.
+type elem uint16
+
+const (
+	tagNeutral elem = iota << typeShift
+	tagAmbiguous
+	tagWide
+	tagNarrow
+	tagFullwidth
+	tagHalfwidth
+)
+
+const (
+	numTypeBits = 3
+	typeShift   = 16 - numTypeBits
+
+	// tagNeedsFold is true for all fullwidth and halfwidth runes except for
+	// the Won sign U+20A9.
+	tagNeedsFold = 0x1000
+
+	// The Korean Won sign is halfwidth, but SHOULD NOT be mapped to a wide
+	// variant.
+	wonSign rune = 0x20A9
+)

vendor/golang.org/x/text/width/kind_string.go

@@ -0,0 +1,16 @@
+// Code generated by "stringer -type=Kind"; DO NOT EDIT.
+
+package width
+
+import "fmt"
+
+const _Kind_name = "NeutralEastAsianAmbiguousEastAsianWideEastAsianNarrowEastAsianFullwidthEastAsianHalfwidth"
+
+var _Kind_index = [...]uint8{0, 7, 25, 38, 53, 71, 89}
+
+func (i Kind) String() string {
+	if i < 0 || i >= Kind(len(_Kind_index)-1) {
+		return fmt.Sprintf("Kind(%d)", i)
+	}
+	return _Kind_name[_Kind_index[i]:_Kind_index[i+1]]
+}

vendor/golang.org/x/text/width/runes_test.go

@@ -0,0 +1,461 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package width
+
+var mapRunes = map[rune]struct {
+	r rune
+	e elem
+}{
+	0x20:   {0x3000, 0x6000},
+	0x21:   {0xFF01, 0x6000},
+	0x22:   {0xFF02, 0x6000},
+	0x23:   {0xFF03, 0x6000},
+	0x24:   {0xFF04, 0x6000},
+	0x25:   {0xFF05, 0x6000},
+	0x26:   {0xFF06, 0x6000},
+	0x27:   {0xFF07, 0x6000},
+	0x28:   {0xFF08, 0x6000},
+	0x29:   {0xFF09, 0x6000},
+	0x2A:   {0xFF0A, 0x6000},
+	0x2B:   {0xFF0B, 0x6000},
+	0x2C:   {0xFF0C, 0x6000},
+	0x2D:   {0xFF0D, 0x6000},
+	0x2E:   {0xFF0E, 0x6000},
+	0x2F:   {0xFF0F, 0x6000},
+	0x30:   {0xFF10, 0x6000},
+	0x31:   {0xFF11, 0x6000},
+	0x32:   {0xFF12, 0x6000},
+	0x33:   {0xFF13, 0x6000},
+	0x34:   {0xFF14, 0x6000},
+	0x35:   {0xFF15, 0x6000},
+	0x36:   {0xFF16, 0x6000},
+	0x37:   {0xFF17, 0x6000},
+	0x38:   {0xFF18, 0x6000},
+	0x39:   {0xFF19, 0x6000},
+	0x3A:   {0xFF1A, 0x6000},
+	0x3B:   {0xFF1B, 0x6000},
+	0x3C:   {0xFF1C, 0x6000},
+	0x3D:   {0xFF1D, 0x6000},
+	0x3E:   {0xFF1E, 0x6000},
+	0x3F:   {0xFF1F, 0x6000},
+	0x40:   {0xFF20, 0x6000},
+	0x41:   {0xFF21, 0x6000},
+	0x42:   {0xFF22, 0x6000},
+	0x43:   {0xFF23, 0x6000},
+	0x44:   {0xFF24, 0x6000},
+	0x45:   {0xFF25, 0x6000},
+	0x46:   {0xFF26, 0x6000},
+	0x47:   {0xFF27, 0x6000},
+	0x48:   {0xFF28, 0x6000},
+	0x49:   {0xFF29, 0x6000},
+	0x4A:   {0xFF2A, 0x6000},
+	0x4B:   {0xFF2B, 0x6000},
+	0x4C:   {0xFF2C, 0x6000},
+	0x4D:   {0xFF2D, 0x6000},
+	0x4E:   {0xFF2E, 0x6000},
+	0x4F:   {0xFF2F, 0x6000},
+	0x50:   {0xFF30, 0x6000},
+	0x51:   {0xFF31, 0x6000},
+	0x52:   {0xFF32, 0x6000},
+	0x53:   {0xFF33, 0x6000},
+	0x54:   {0xFF34, 0x6000},
+	0x55:   {0xFF35, 0x6000},
+	0x56:   {0xFF36, 0x6000},
+	0x57:   {0xFF37, 0x6000},
+	0x58:   {0xFF38, 0x6000},
+	0x59:   {0xFF39, 0x6000},
+	0x5A:   {0xFF3A, 0x6000},
+	0x5B:   {0xFF3B, 0x6000},
+	0x5C:   {0xFF3C, 0x6000},
+	0x5D:   {0xFF3D, 0x6000},
+	0x5E:   {0xFF3E, 0x6000},
+	0x5F:   {0xFF3F, 0x6000},
+	0x60:   {0xFF40, 0x6000},
+	0x61:   {0xFF41, 0x6000},
+	0x62:   {0xFF42, 0x6000},
+	0x63:   {0xFF43, 0x6000},
+	0x64:   {0xFF44, 0x6000},
+	0x65:   {0xFF45, 0x6000},
+	0x66:   {0xFF46, 0x6000},
+	0x67:   {0xFF47, 0x6000},
+	0x68:   {0xFF48, 0x6000},
+	0x69:   {0xFF49, 0x6000},
+	0x6A:   {0xFF4A, 0x6000},
+	0x6B:   {0xFF4B, 0x6000},
+	0x6C:   {0xFF4C, 0x6000},
+	0x6D:   {0xFF4D, 0x6000},
+	0x6E:   {0xFF4E, 0x6000},
+	0x6F:   {0xFF4F, 0x6000},
+	0x70:   {0xFF50, 0x6000},
+	0x71:   {0xFF51, 0x6000},
+	0x72:   {0xFF52, 0x6000},
+	0x73:   {0xFF53, 0x6000},
+	0x74:   {0xFF54, 0x6000},
+	0x75:   {0xFF55, 0x6000},
+	0x76:   {0xFF56, 0x6000},
+	0x77:   {0xFF57, 0x6000},
+	0x78:   {0xFF58, 0x6000},
+	0x79:   {0xFF59, 0x6000},
+	0x7A:   {0xFF5A, 0x6000},
+	0x7B:   {0xFF5B, 0x6000},
+	0x7C:   {0xFF5C, 0x6000},
+	0x7D:   {0xFF5D, 0x6000},
+	0x7E:   {0xFF5E, 0x6000},
+	0xA2:   {0xFFE0, 0x6000},
+	0xA3:   {0xFFE1, 0x6000},
+	0xA5:   {0xFFE5, 0x6000},
+	0xA6:   {0xFFE4, 0x6000},
+	0xAC:   {0xFFE2, 0x6000},
+	0xAF:   {0xFFE3, 0x6000},
+	0x20A9: {0xFFE6, 0xA000},
+	0x2190: {0xFFE9, 0x2000},
+	0x2191: {0xFFEA, 0x2000},
+	0x2192: {0xFFEB, 0x2000},
+	0x2193: {0xFFEC, 0x2000},
+	0x2502: {0xFFE8, 0x2000},
+	0x25A0: {0xFFED, 0x2000},
+	0x25CB: {0xFFEE, 0x2000},
+	0x2985: {0xFF5F, 0x6000},
+	0x2986: {0xFF60, 0x6000},
+	0x3000: {0x20, 0x9000},
+	0x3001: {0xFF64, 0x4000},
+	0x3002: {0xFF61, 0x4000},
+	0x300C: {0xFF62, 0x4000},
+	0x300D: {0xFF63, 0x4000},
+	0x3099: {0xFF9E, 0x4000},
+	0x309A: {0xFF9F, 0x4000},
+	0x30A1: {0xFF67, 0x4000},
+	0x30A2: {0xFF71, 0x4000},
+	0x30A3: {0xFF68, 0x4000},
+	0x30A4: {0xFF72, 0x4000},
+	0x30A5: {0xFF69, 0x4000},
+	0x30A6: {0xFF73, 0x4000},
+	0x30A7: {0xFF6A, 0x4000},
+	0x30A8: {0xFF74, 0x4000},
+	0x30A9: {0xFF6B, 0x4000},
+	0x30AA: {0xFF75, 0x4000},
+	0x30AB: {0xFF76, 0x4000},
+	0x30AD: {0xFF77, 0x4000},
+	0x30AF: {0xFF78, 0x4000},
+	0x30B1: {0xFF79, 0x4000},
+	0x30B3: {0xFF7A, 0x4000},
+	0x30B5: {0xFF7B, 0x4000},
+	0x30B7: {0xFF7C, 0x4000},
+	0x30B9: {0xFF7D, 0x4000},
+	0x30BB: {0xFF7E, 0x4000},
+	0x30BD: {0xFF7F, 0x4000},
+	0x30BF: {0xFF80, 0x4000},
+	0x30C1: {0xFF81, 0x4000},
+	0x30C3: {0xFF6F, 0x4000},
+	0x30C4: {0xFF82, 0x4000},
+	0x30C6: {0xFF83, 0x4000},
+	0x30C8: {0xFF84, 0x4000},
+	0x30CA: {0xFF85, 0x4000},
+	0x30CB: {0xFF86, 0x4000},
+	0x30CC: {0xFF87, 0x4000},
+	0x30CD: {0xFF88, 0x4000},
+	0x30CE: {0xFF89, 0x4000},
+	0x30CF: {0xFF8A, 0x4000},
+	0x30D2: {0xFF8B, 0x4000},
+	0x30D5: {0xFF8C, 0x4000},
+	0x30D8: {0xFF8D, 0x4000},
+	0x30DB: {0xFF8E, 0x4000},
+	0x30DE: {0xFF8F, 0x4000},
+	0x30DF: {0xFF90, 0x4000},
+	0x30E0: {0xFF91, 0x4000},
+	0x30E1: {0xFF92, 0x4000},
+	0x30E2: {0xFF93, 0x4000},
+	0x30E3: {0xFF6C, 0x4000},
+	0x30E4: {0xFF94, 0x4000},
+	0x30E5: {0xFF6D, 0x4000},
+	0x30E6: {0xFF95, 0x4000},
+	0x30E7: {0xFF6E, 0x4000},
+	0x30E8: {0xFF96, 0x4000},
+	0x30E9: {0xFF97, 0x4000},
+	0x30EA: {0xFF98, 0x4000},
+	0x30EB: {0xFF99, 0x4000},
+	0x30EC: {0xFF9A, 0x4000},
+	0x30ED: {0xFF9B, 0x4000},
+	0x30EF: {0xFF9C, 0x4000},
+	0x30F2: {0xFF66, 0x4000},
+	0x30F3: {0xFF9D, 0x4000},
+	0x30FB: {0xFF65, 0x4000},
+	0x30FC: {0xFF70, 0x4000},
+	0x3131: {0xFFA1, 0x4000},
+	0x3132: {0xFFA2, 0x4000},
+	0x3133: {0xFFA3, 0x4000},
+	0x3134: {0xFFA4, 0x4000},
+	0x3135: {0xFFA5, 0x4000},
+	0x3136: {0xFFA6, 0x4000},
+	0x3137: {0xFFA7, 0x4000},
+	0x3138: {0xFFA8, 0x4000},
+	0x3139: {0xFFA9, 0x4000},
+	0x313A: {0xFFAA, 0x4000},
+	0x313B: {0xFFAB, 0x4000},
+	0x313C: {0xFFAC, 0x4000},
+	0x313D: {0xFFAD, 0x4000},
+	0x313E: {0xFFAE, 0x4000},
+	0x313F: {0xFFAF, 0x4000},
+	0x3140: {0xFFB0, 0x4000},
+	0x3141: {0xFFB1, 0x4000},
+	0x3142: {0xFFB2, 0x4000},
+	0x3143: {0xFFB3, 0x4000},
+	0x3144: {0xFFB4, 0x4000},
+	0x3145: {0xFFB5, 0x4000},
+	0x3146: {0xFFB6, 0x4000},
+	0x3147: {0xFFB7, 0x4000},
+	0x3148: {0xFFB8, 0x4000},
+	0x3149: {0xFFB9, 0x4000},
+	0x314A: {0xFFBA, 0x4000},
+	0x314B: {0xFFBB, 0x4000},
+	0x314C: {0xFFBC, 0x4000},
+	0x314D: {0xFFBD, 0x4000},
+	0x314E: {0xFFBE, 0x4000},
+	0x314F: {0xFFC2, 0x4000},
+	0x3150: {0xFFC3, 0x4000},
+	0x3151: {0xFFC4, 0x4000},
+	0x3152: {0xFFC5, 0x4000},
+	0x3153: {0xFFC6, 0x4000},
+	0x3154: {0xFFC7, 0x4000},
+	0x3155: {0xFFCA, 0x4000},
+	0x3156: {0xFFCB, 0x4000},
+	0x3157: {0xFFCC, 0x4000},
+	0x3158: {0xFFCD, 0x4000},
+	0x3159: {0xFFCE, 0x4000},
+	0x315A: {0xFFCF, 0x4000},
+	0x315B: {0xFFD2, 0x4000},
+	0x315C: {0xFFD3, 0x4000},
+	0x315D: {0xFFD4, 0x4000},
+	0x315E: {0xFFD5, 0x4000},
+	0x315F: {0xFFD6, 0x4000},
+	0x3160: {0xFFD7, 0x4000},
+	0x3161: {0xFFDA, 0x4000},
+	0x3162: {0xFFDB, 0x4000},
+	0x3163: {0xFFDC, 0x4000},
+	0x3164: {0xFFA0, 0x4000},
+	0xFF01: {0x21, 0x9000},
+	0xFF02: {0x22, 0x9000},
+	0xFF03: {0x23, 0x9000},
+	0xFF04: {0x24, 0x9000},
+	0xFF05: {0x25, 0x9000},
+	0xFF06: {0x26, 0x9000},
+	0xFF07: {0x27, 0x9000},
+	0xFF08: {0x28, 0x9000},
+	0xFF09: {0x29, 0x9000},
+	0xFF0A: {0x2A, 0x9000},
+	0xFF0B: {0x2B, 0x9000},
+	0xFF0C: {0x2C, 0x9000},
+	0xFF0D: {0x2D, 0x9000},
+	0xFF0E: {0x2E, 0x9000},
+	0xFF0F: {0x2F, 0x9000},
+	0xFF10: {0x30, 0x9000},
+	0xFF11: {0x31, 0x9000},
+	0xFF12: {0x32, 0x9000},
+	0xFF13: {0x33, 0x9000},
+	0xFF14: {0x34, 0x9000},
+	0xFF15: {0x35, 0x9000},
+	0xFF16: {0x36, 0x9000},
+	0xFF17: {0x37, 0x9000},
+	0xFF18: {0x38, 0x9000},
+	0xFF19: {0x39, 0x9000},
+	0xFF1A: {0x3A, 0x9000},
+	0xFF1B: {0x3B, 0x9000},
+	0xFF1C: {0x3C, 0x9000},
+	0xFF1D: {0x3D, 0x9000},
+	0xFF1E: {0x3E, 0x9000},
+	0xFF1F: {0x3F, 0x9000},
+	0xFF20: {0x40, 0x9000},
+	0xFF21: {0x41, 0x9000},
+	0xFF22: {0x42, 0x9000},
+	0xFF23: {0x43, 0x9000},
+	0xFF24: {0x44, 0x9000},
+	0xFF25: {0x45, 0x9000},
+	0xFF26: {0x46, 0x9000},
+	0xFF27: {0x47, 0x9000},
+	0xFF28: {0x48, 0x9000},
+	0xFF29: {0x49, 0x9000},
+	0xFF2A: {0x4A, 0x9000},
+	0xFF2B: {0x4B, 0x9000},
+	0xFF2C: {0x4C, 0x9000},
+	0xFF2D: {0x4D, 0x9000},
+	0xFF2E: {0x4E, 0x9000},
+	0xFF2F: {0x4F, 0x9000},
+	0xFF30: {0x50, 0x9000},
+	0xFF31: {0x51, 0x9000},
+	0xFF32: {0x52, 0x9000},
+	0xFF33: {0x53, 0x9000},
+	0xFF34: {0x54, 0x9000},
+	0xFF35: {0x55, 0x9000},
+	0xFF36: {0x56, 0x9000},
+	0xFF37: {0x57, 0x9000},
+	0xFF38: {0x58, 0x9000},
+	0xFF39: {0x59, 0x9000},
+	0xFF3A: {0x5A, 0x9000},
+	0xFF3B: {0x5B, 0x9000},
+	0xFF3C: {0x5C, 0x9000},
+	0xFF3D: {0x5D, 0x9000},
+	0xFF3E: {0x5E, 0x9000},
+	0xFF3F: {0x5F, 0x9000},
+	0xFF40: {0x60, 0x9000},
+	0xFF41: {0x61, 0x9000},
+	0xFF42: {0x62, 0x9000},
+	0xFF43: {0x63, 0x9000},
+	0xFF44: {0x64, 0x9000},
+	0xFF45: {0x65, 0x9000},
+	0xFF46: {0x66, 0x9000},
+	0xFF47: {0x67, 0x9000},
+	0xFF48: {0x68, 0x9000},
+	0xFF49: {0x69, 0x9000},
+	0xFF4A: {0x6A, 0x9000},
+	0xFF4B: {0x6B, 0x9000},
+	0xFF4C: {0x6C, 0x9000},
+	0xFF4D: {0x6D, 0x9000},
+	0xFF4E: {0x6E, 0x9000},
+	0xFF4F: {0x6F, 0x9000},
+	0xFF50: {0x70, 0x9000},
+	0xFF51: {0x71, 0x9000},
+	0xFF52: {0x72, 0x9000},
+	0xFF53: {0x73, 0x9000},
+	0xFF54: {0x74, 0x9000},
+	0xFF55: {0x75, 0x9000},
+	0xFF56: {0x76, 0x9000},
+	0xFF57: {0x77, 0x9000},
+	0xFF58: {0x78, 0x9000},
+	0xFF59: {0x79, 0x9000},
+	0xFF5A: {0x7A, 0x9000},
+	0xFF5B: {0x7B, 0x9000},
+	0xFF5C: {0x7C, 0x9000},
+	0xFF5D: {0x7D, 0x9000},
+	0xFF5E: {0x7E, 0x9000},
+	0xFF5F: {0x2985, 0x9000},
+	0xFF60: {0x2986, 0x9000},
+	0xFF61: {0x3002, 0xB000},
+	0xFF62: {0x300C, 0xB000},
+	0xFF63: {0x300D, 0xB000},
+	0xFF64: {0x3001, 0xB000},
+	0xFF65: {0x30FB, 0xB000},
+	0xFF66: {0x30F2, 0xB000},
+	0xFF67: {0x30A1, 0xB000},
+	0xFF68: {0x30A3, 0xB000},
+	0xFF69: {0x30A5, 0xB000},
+	0xFF6A: {0x30A7, 0xB000},
+	0xFF6B: {0x30A9, 0xB000},
+	0xFF6C: {0x30E3, 0xB000},
+	0xFF6D: {0x30E5, 0xB000},
+	0xFF6E: {0x30E7, 0xB000},
+	0xFF6F: {0x30C3, 0xB000},
+	0xFF70: {0x30FC, 0xB000},
+	0xFF71: {0x30A2, 0xB000},
+	0xFF72: {0x30A4, 0xB000},
+	0xFF73: {0x30A6, 0xB000},
+	0xFF74: {0x30A8, 0xB000},
+	0xFF75: {0x30AA, 0xB000},
+	0xFF76: {0x30AB, 0xB000},
+	0xFF77: {0x30AD, 0xB000},
+	0xFF78: {0x30AF, 0xB000},
+	0xFF79: {0x30B1, 0xB000},
+	0xFF7A: {0x30B3, 0xB000},
+	0xFF7B: {0x30B5, 0xB000},
+	0xFF7C: {0x30B7, 0xB000},
+	0xFF7D: {0x30B9, 0xB000},
+	0xFF7E: {0x30BB, 0xB000},
+	0xFF7F: {0x30BD, 0xB000},
+	0xFF80: {0x30BF, 0xB000},
+	0xFF81: {0x30C1, 0xB000},
+	0xFF82: {0x30C4, 0xB000},
+	0xFF83: {0x30C6, 0xB000},
+	0xFF84: {0x30C8, 0xB000},
+	0xFF85: {0x30CA, 0xB000},
+	0xFF86: {0x30CB, 0xB000},
+	0xFF87: {0x30CC, 0xB000},
+	0xFF88: {0x30CD, 0xB000},
+	0xFF89: {0x30CE, 0xB000},
+	0xFF8A: {0x30CF, 0xB000},
+	0xFF8B: {0x30D2, 0xB000},
+	0xFF8C: {0x30D5, 0xB000},
+	0xFF8D: {0x30D8, 0xB000},
+	0xFF8E: {0x30DB, 0xB000},
+	0xFF8F: {0x30DE, 0xB000},
+	0xFF90: {0x30DF, 0xB000},
+	0xFF91: {0x30E0, 0xB000},
+	0xFF92: {0x30E1, 0xB000},
+	0xFF93: {0x30E2, 0xB000},
+	0xFF94: {0x30E4, 0xB000},
+	0xFF95: {0x30E6, 0xB000},
+	0xFF96: {0x30E8, 0xB000},
+	0xFF97: {0x30E9, 0xB000},
+	0xFF98: {0x30EA, 0xB000},
+	0xFF99: {0x30EB, 0xB000},
+	0xFF9A: {0x30EC, 0xB000},
+	0xFF9B: {0x30ED, 0xB000},
+	0xFF9C: {0x30EF, 0xB000},
+	0xFF9D: {0x30F3, 0xB000},
+	0xFF9E: {0x3099, 0xB000},
+	0xFF9F: {0x309A, 0xB000},
+	0xFFA0: {0x3164, 0xB000},
+	0xFFA1: {0x3131, 0xB000},
+	0xFFA2: {0x3132, 0xB000},
+	0xFFA3: {0x3133, 0xB000},
+	0xFFA4: {0x3134, 0xB000},
+	0xFFA5: {0x3135, 0xB000},
+	0xFFA6: {0x3136, 0xB000},
+	0xFFA7: {0x3137, 0xB000},
+	0xFFA8: {0x3138, 0xB000},
+	0xFFA9: {0x3139, 0xB000},
+	0xFFAA: {0x313A, 0xB000},
+	0xFFAB: {0x313B, 0xB000},
+	0xFFAC: {0x313C, 0xB000},
+	0xFFAD: {0x313D, 0xB000},
+	0xFFAE: {0x313E, 0xB000},
+	0xFFAF: {0x313F, 0xB000},
+	0xFFB0: {0x3140, 0xB000},
+	0xFFB1: {0x3141, 0xB000},
+	0xFFB2: {0x3142, 0xB000},
+	0xFFB3: {0x3143, 0xB000},
+	0xFFB4: {0x3144, 0xB000},
+	0xFFB5: {0x3145, 0xB000},
+	0xFFB6: {0x3146, 0xB000},
+	0xFFB7: {0x3147, 0xB000},
+	0xFFB8: {0x3148, 0xB000},
+	0xFFB9: {0x3149, 0xB000},
+	0xFFBA: {0x314A, 0xB000},
+	0xFFBB: {0x314B, 0xB000},
+	0xFFBC: {0x314C, 0xB000},
+	0xFFBD: {0x314D, 0xB000},
+	0xFFBE: {0x314E, 0xB000},
+	0xFFC2: {0x314F, 0xB000},
+	0xFFC3: {0x3150, 0xB000},
+	0xFFC4: {0x3151, 0xB000},
+	0xFFC5: {0x3152, 0xB000},
+	0xFFC6: {0x3153, 0xB000},
+	0xFFC7: {0x3154, 0xB000},
+	0xFFCA: {0x3155, 0xB000},
+	0xFFCB: {0x3156, 0xB000},
+	0xFFCC: {0x3157, 0xB000},
+	0xFFCD: {0x3158, 0xB000},
+	0xFFCE: {0x3159, 0xB000},
+	0xFFCF: {0x315A, 0xB000},
+	0xFFD2: {0x315B, 0xB000},
+	0xFFD3: {0x315C, 0xB000},
+	0xFFD4: {0x315D, 0xB000},
+	0xFFD5: {0x315E, 0xB000},
+	0xFFD6: {0x315F, 0xB000},
+	0xFFD7: {0x3160, 0xB000},
+	0xFFDA: {0x3161, 0xB000},
+	0xFFDB: {0x3162, 0xB000},
+	0xFFDC: {0x3163, 0xB000},
+	0xFFE0: {0xA2, 0x9000},
+	0xFFE1: {0xA3, 0x9000},
+	0xFFE2: {0xAC, 0x9000},
+	0xFFE3: {0xAF, 0x9000},
+	0xFFE4: {0xA6, 0x9000},
+	0xFFE5: {0xA5, 0x9000},
+	0xFFE6: {0x20A9, 0x9000},
+	0xFFE8: {0x2502, 0xB000},
+	0xFFE9: {0x2190, 0xB000},
+	0xFFEA: {0x2191, 0xB000},
+	0xFFEB: {0x2192, 0xB000},
+	0xFFEC: {0x2193, 0xB000},
+	0xFFED: {0x25A0, 0xB000},
+	0xFFEE: {0x25CB, 0xB000},
+}

vendor/golang.org/x/text/width/tables_test.go

@@ -0,0 +1,59 @@
+// 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 width
+
+import (
+	"testing"
+
+	"golang.org/x/text/internal/testtext"
+)
+
+const (
+	loSurrogate = 0xD800
+	hiSurrogate = 0xDFFF
+)
+
+func TestTables(t *testing.T) {
+	testtext.SkipIfNotLong(t)
+
+	runes := map[rune]Kind{}
+	getWidthData(func(r rune, tag elem, _ rune) {
+		runes[r] = tag.kind()
+	})
+	for r := rune(0); r < 0x10FFFF; r++ {
+		if loSurrogate <= r && r <= hiSurrogate {
+			continue
+		}
+		p := LookupRune(r)
+		if got, want := p.Kind(), runes[r]; got != want {
+			t.Errorf("Kind of %U was %s; want %s.", r, got, want)
+		}
+		want, mapped := foldRune(r)
+		if got := p.Folded(); (got == 0) == mapped || got != 0 && got != want {
+			t.Errorf("Folded(%U) = %U; want %U", r, got, want)
+		}
+		want, mapped = widenRune(r)
+		if got := p.Wide(); (got == 0) == mapped || got != 0 && got != want {
+			t.Errorf("Wide(%U) = %U; want %U", r, got, want)
+		}
+		want, mapped = narrowRune(r)
+		if got := p.Narrow(); (got == 0) == mapped || got != 0 && got != want {
+			t.Errorf("Narrow(%U) = %U; want %U", r, got, want)
+		}
+	}
+}
+
+// TestAmbiguous verifies that that ambiguous runes with a mapping always map to
+// a halfwidth rune.
+func TestAmbiguous(t *testing.T) {
+	for r, m := range mapRunes {
+		if m.e != tagAmbiguous {
+			continue
+		}
+		if k := mapRunes[m.r].e.kind(); k != EastAsianHalfwidth {
+			t.Errorf("Rune %U is ambiguous and maps to a rune of type %v", r, k)
+		}
+	}
+}

vendor/golang.org/x/text/width/transform.go

@@ -0,0 +1,239 @@
+// 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 width
+
+import (
+	"unicode/utf8"
+
+	"golang.org/x/text/transform"
+)
+
+type foldTransform struct {
+	transform.NopResetter
+}
+
+func (foldTransform) Span(src []byte, atEOF bool) (n int, err error) {
+	for n < len(src) {
+		if src[n] < utf8.RuneSelf {
+			// ASCII fast path.
+			for n++; n < len(src) && src[n] < utf8.RuneSelf; n++ {
+			}
+			continue
+		}
+		v, size := trie.lookup(src[n:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				err = transform.ErrShortSrc
+			} else {
+				n = len(src)
+			}
+			break
+		}
+		if elem(v)&tagNeedsFold != 0 {
+			err = transform.ErrEndOfSpan
+			break
+		}
+		n += size
+	}
+	return n, err
+}
+
+func (foldTransform) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	for nSrc < len(src) {
+		if src[nSrc] < utf8.RuneSelf {
+			// ASCII fast path.
+			start, end := nSrc, len(src)
+			if d := len(dst) - nDst; d < end-start {
+				end = nSrc + d
+			}
+			for nSrc++; nSrc < end && src[nSrc] < utf8.RuneSelf; nSrc++ {
+			}
+			n := copy(dst[nDst:], src[start:nSrc])
+			if nDst += n; nDst == len(dst) {
+				nSrc = start + n
+				if nSrc == len(src) {
+					return nDst, nSrc, nil
+				}
+				if src[nSrc] < utf8.RuneSelf {
+					return nDst, nSrc, transform.ErrShortDst
+				}
+			}
+			continue
+		}
+		v, size := trie.lookup(src[nSrc:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				return nDst, nSrc, transform.ErrShortSrc
+			}
+			size = 1 // gobble 1 byte
+		}
+		if elem(v)&tagNeedsFold == 0 {
+			if size != copy(dst[nDst:], src[nSrc:nSrc+size]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			nDst += size
+		} else {
+			data := inverseData[byte(v)]
+			if len(dst)-nDst < int(data[0]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			i := 1
+			for end := int(data[0]); i < end; i++ {
+				dst[nDst] = data[i]
+				nDst++
+			}
+			dst[nDst] = data[i] ^ src[nSrc+size-1]
+			nDst++
+		}
+		nSrc += size
+	}
+	return nDst, nSrc, nil
+}
+
+type narrowTransform struct {
+	transform.NopResetter
+}
+
+func (narrowTransform) Span(src []byte, atEOF bool) (n int, err error) {
+	for n < len(src) {
+		if src[n] < utf8.RuneSelf {
+			// ASCII fast path.
+			for n++; n < len(src) && src[n] < utf8.RuneSelf; n++ {
+			}
+			continue
+		}
+		v, size := trie.lookup(src[n:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				err = transform.ErrShortSrc
+			} else {
+				n = len(src)
+			}
+			break
+		}
+		if k := elem(v).kind(); byte(v) == 0 || k != EastAsianFullwidth && k != EastAsianWide && k != EastAsianAmbiguous {
+		} else {
+			err = transform.ErrEndOfSpan
+			break
+		}
+		n += size
+	}
+	return n, err
+}
+
+func (narrowTransform) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	for nSrc < len(src) {
+		if src[nSrc] < utf8.RuneSelf {
+			// ASCII fast path.
+			start, end := nSrc, len(src)
+			if d := len(dst) - nDst; d < end-start {
+				end = nSrc + d
+			}
+			for nSrc++; nSrc < end && src[nSrc] < utf8.RuneSelf; nSrc++ {
+			}
+			n := copy(dst[nDst:], src[start:nSrc])
+			if nDst += n; nDst == len(dst) {
+				nSrc = start + n
+				if nSrc == len(src) {
+					return nDst, nSrc, nil
+				}
+				if src[nSrc] < utf8.RuneSelf {
+					return nDst, nSrc, transform.ErrShortDst
+				}
+			}
+			continue
+		}
+		v, size := trie.lookup(src[nSrc:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				return nDst, nSrc, transform.ErrShortSrc
+			}
+			size = 1 // gobble 1 byte
+		}
+		if k := elem(v).kind(); byte(v) == 0 || k != EastAsianFullwidth && k != EastAsianWide && k != EastAsianAmbiguous {
+			if size != copy(dst[nDst:], src[nSrc:nSrc+size]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			nDst += size
+		} else {
+			data := inverseData[byte(v)]
+			if len(dst)-nDst < int(data[0]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			i := 1
+			for end := int(data[0]); i < end; i++ {
+				dst[nDst] = data[i]
+				nDst++
+			}
+			dst[nDst] = data[i] ^ src[nSrc+size-1]
+			nDst++
+		}
+		nSrc += size
+	}
+	return nDst, nSrc, nil
+}
+
+type wideTransform struct {
+	transform.NopResetter
+}
+
+func (wideTransform) Span(src []byte, atEOF bool) (n int, err error) {
+	for n < len(src) {
+		// TODO: Consider ASCII fast path. Special-casing ASCII handling can
+		// reduce the ns/op of BenchmarkWideASCII by about 30%. This is probably
+		// not enough to warrant the extra code and complexity.
+		v, size := trie.lookup(src[n:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				err = transform.ErrShortSrc
+			} else {
+				n = len(src)
+			}
+			break
+		}
+		if k := elem(v).kind(); byte(v) == 0 || k != EastAsianHalfwidth && k != EastAsianNarrow {
+		} else {
+			err = transform.ErrEndOfSpan
+			break
+		}
+		n += size
+	}
+	return n, err
+}
+
+func (wideTransform) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	for nSrc < len(src) {
+		// TODO: Consider ASCII fast path. Special-casing ASCII handling can
+		// reduce the ns/op of BenchmarkWideASCII by about 30%. This is probably
+		// not enough to warrant the extra code and complexity.
+		v, size := trie.lookup(src[nSrc:])
+		if size == 0 { // incomplete UTF-8 encoding
+			if !atEOF {
+				return nDst, nSrc, transform.ErrShortSrc
+			}
+			size = 1 // gobble 1 byte
+		}
+		if k := elem(v).kind(); byte(v) == 0 || k != EastAsianHalfwidth && k != EastAsianNarrow {
+			if size != copy(dst[nDst:], src[nSrc:nSrc+size]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			nDst += size
+		} else {
+			data := inverseData[byte(v)]
+			if len(dst)-nDst < int(data[0]) {
+				return nDst, nSrc, transform.ErrShortDst
+			}
+			i := 1
+			for end := int(data[0]); i < end; i++ {
+				dst[nDst] = data[i]
+				nDst++
+			}
+			dst[nDst] = data[i] ^ src[nSrc+size-1]
+			nDst++
+		}
+		nSrc += size
+	}
+	return nDst, nSrc, nil
+}

vendor/golang.org/x/text/width/transform_test.go

@@ -0,0 +1,701 @@
+// 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 width
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"golang.org/x/text/internal/testtext"
+	"golang.org/x/text/transform"
+)
+
+func foldRune(r rune) (folded rune, ok bool) {
+	alt, ok := mapRunes[r]
+	if ok && alt.e&tagNeedsFold != 0 {
+		return alt.r, true
+	}
+	return r, false
+}
+
+func widenRune(r rune) (wide rune, ok bool) {
+	alt, ok := mapRunes[r]
+	if k := alt.e.kind(); k == EastAsianHalfwidth || k == EastAsianNarrow {
+		return alt.r, true
+	}
+	return r, false
+}
+
+func narrowRune(r rune) (narrow rune, ok bool) {
+	alt, ok := mapRunes[r]
+	if k := alt.e.kind(); k == EastAsianFullwidth || k == EastAsianWide || k == EastAsianAmbiguous {
+		return alt.r, true
+	}
+	return r, false
+}
+
+func TestFoldSingleRunes(t *testing.T) {
+	for r := rune(0); r < 0x1FFFF; r++ {
+		if loSurrogate <= r && r <= hiSurrogate {
+			continue
+		}
+		x, _ := foldRune(r)
+		want := string(x)
+		got := Fold.String(string(r))
+		if got != want {
+			t.Errorf("Fold().String(%U) = %+q; want %+q", r, got, want)
+		}
+	}
+}
+
+type transformTest struct {
+	desc    string
+	src     string
+	nBuf    int
+	nDst    int
+	atEOF   bool
+	dst     string
+	nSrc    int
+	err     error
+	nSpan   int
+	errSpan error
+}
+
+func (tc *transformTest) doTest(t *testing.T, tr Transformer) {
+	testtext.Run(t, tc.desc, func(t *testing.T) {
+		b := make([]byte, tc.nBuf)
+		nDst, nSrc, err := tr.Transform(b, []byte(tc.src), tc.atEOF)
+		if got := string(b[:nDst]); got != tc.dst[:nDst] {
+			t.Errorf("dst was %+q; want %+q", got, tc.dst)
+		}
+		if nDst != tc.nDst {
+			t.Errorf("nDst was %d; want %d", nDst, tc.nDst)
+		}
+		if nSrc != tc.nSrc {
+			t.Errorf("nSrc was %d; want %d", nSrc, tc.nSrc)
+		}
+		if err != tc.err {
+			t.Errorf("error was %v; want %v", err, tc.err)
+		}
+		if got := tr.String(tc.src); got != tc.dst {
+			t.Errorf("String(%q) = %q; want %q", tc.src, got, tc.dst)
+		}
+		n, err := tr.Span([]byte(tc.src), tc.atEOF)
+		if n != tc.nSpan || err != tc.errSpan {
+			t.Errorf("Span: got %d, %v; want %d, %v", n, err, tc.nSpan, tc.errSpan)
+		}
+	})
+}
+
+func TestFold(t *testing.T) {
+	for _, tc := range []transformTest{{
+		desc:    "empty",
+		src:     "",
+		nBuf:    10,
+		dst:     "",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: nil,
+	}, {
+		desc:    "short source 1",
+		src:     "a\xc2",
+		nBuf:    10,
+		dst:     "a\xc2",
+		nDst:    1,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   1,
+		errSpan: transform.ErrShortSrc,
+	}, {
+		desc:    "short source 2",
+		src:     "a\xe0\x80",
+		nBuf:    10,
+		dst:     "a\xe0\x80",
+		nDst:    1,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   1,
+		errSpan: transform.ErrShortSrc,
+	}, {
+		desc:    "incomplete but terminated source 1",
+		src:     "a\xc2",
+		nBuf:    10,
+		dst:     "a\xc2",
+		nDst:    2,
+		nSrc:    2,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   2,
+		errSpan: nil,
+	}, {
+		desc:    "incomplete but terminated source 2",
+		src:     "a\xe0\x80",
+		nBuf:    10,
+		dst:     "a\xe0\x80",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   3,
+		errSpan: nil,
+	}, {
+		desc:    "exact fit dst",
+		src:     "a\uff01",
+		nBuf:    2,
+		dst:     "a!",
+		nDst:    2,
+		nSrc:    4,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   1,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "exact fit dst and src ascii",
+		src:     "ab",
+		nBuf:    2,
+		dst:     "ab",
+		nDst:    2,
+		nSrc:    2,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   2,
+		errSpan: nil,
+	}, {
+		desc:    "empty dst",
+		src:     "\u0300",
+		nBuf:    0,
+		dst:     "\u0300",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   2,
+		errSpan: nil,
+	}, {
+		desc:    "empty dst ascii",
+		src:     "a",
+		nBuf:    0,
+		dst:     "a",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   1,
+		errSpan: nil,
+	}, {
+		desc:    "short dst 1",
+		src:     "a\uffe0", // ￠
+		nBuf:    2,
+		dst:     "a\u00a2", // ¢
+		nDst:    1,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortDst,
+		nSpan:   1,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short dst 2",
+		src:     "不夠",
+		nBuf:    3,
+		dst:     "不夠",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   6,
+		errSpan: nil,
+	}, {
+		desc:    "short dst fast path",
+		src:     "fast",
+		nDst:    3,
+		dst:     "fast",
+		nBuf:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   4,
+		errSpan: nil,
+	}, {
+		desc:    "short dst larger buffer",
+		src:     "\uff21" + strings.Repeat("0", 127) + "B",
+		nBuf:    128,
+		dst:     "A" + strings.Repeat("0", 127) + "B",
+		nDst:    128,
+		nSrc:    130,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "fast path alternation",
+		src:     "fast路徑fast路徑",
+		nBuf:    20,
+		dst:     "fast路徑fast路徑",
+		nDst:    20,
+		nSrc:    20,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   20,
+		errSpan: nil,
+	}} {
+		tc.doTest(t, Fold)
+	}
+}
+
+func TestWidenSingleRunes(t *testing.T) {
+	for r := rune(0); r < 0x1FFFF; r++ {
+		if loSurrogate <= r && r <= hiSurrogate {
+			continue
+		}
+		alt, _ := widenRune(r)
+		want := string(alt)
+		got := Widen.String(string(r))
+		if got != want {
+			t.Errorf("Widen().String(%U) = %+q; want %+q", r, got, want)
+		}
+	}
+}
+
+func TestWiden(t *testing.T) {
+	for _, tc := range []transformTest{{
+		desc:    "empty",
+		src:     "",
+		nBuf:    10,
+		dst:     "",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: nil,
+	}, {
+		desc:    "short source 1",
+		src:     "a\xc2",
+		nBuf:    10,
+		dst:     "ａ\xc2",
+		nDst:    3,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short source 2",
+		src:     "a\xe0\x80",
+		nBuf:    10,
+		dst:     "ａ\xe0\x80",
+		nDst:    3,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "incomplete but terminated source 1",
+		src:     "a\xc2",
+		nBuf:    10,
+		dst:     "ａ\xc2",
+		nDst:    4,
+		nSrc:    2,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "incomplete but terminated source 2",
+		src:     "a\xe0\x80",
+		nBuf:    10,
+		dst:     "ａ\xe0\x80",
+		nDst:    5,
+		nSrc:    3,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short source 1 some span",
+		src:     "ａ\xc2",
+		nBuf:    10,
+		dst:     "ａ\xc2",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   3,
+		errSpan: transform.ErrShortSrc,
+	}, {
+		desc:    "short source 2 some span",
+		src:     "ａ\xe0\x80",
+		nBuf:    10,
+		dst:     "ａ\xe0\x80",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   3,
+		errSpan: transform.ErrShortSrc,
+	}, {
+		desc:    "incomplete but terminated source 1 some span",
+		src:     "ａ\xc2",
+		nBuf:    10,
+		dst:     "ａ\xc2",
+		nDst:    4,
+		nSrc:    4,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   4,
+		errSpan: nil,
+	}, {
+		desc:    "incomplete but terminated source 2 some span",
+		src:     "ａ\xe0\x80",
+		nBuf:    10,
+		dst:     "ａ\xe0\x80",
+		nDst:    5,
+		nSrc:    5,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   5,
+		errSpan: nil,
+	}, {
+		desc:    "exact fit dst",
+		src:     "a!",
+		nBuf:    6,
+		dst:     "ａ\uff01",
+		nDst:    6,
+		nSrc:    2,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "empty dst",
+		src:     "\u0300",
+		nBuf:    0,
+		dst:     "\u0300",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   2,
+		errSpan: nil,
+	}, {
+		desc:    "empty dst ascii",
+		src:     "a",
+		nBuf:    0,
+		dst:     "ａ",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short dst 1",
+		src:     "a\uffe0",
+		nBuf:    4,
+		dst:     "ａ\uffe0",
+		nDst:    3,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short dst 2",
+		src:     "不夠",
+		nBuf:    3,
+		dst:     "不夠",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   6,
+		errSpan: nil,
+	}, {
+		desc:    "short dst ascii",
+		src:     "ascii",
+		nBuf:    3,
+		dst:     "ａｓｃｉｉ", // U+ff41, ...
+		nDst:    3,
+		nSrc:    1,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "ambiguous",
+		src:     "\uffe9",
+		nBuf:    4,
+		dst:     "\u2190",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}} {
+		tc.doTest(t, Widen)
+	}
+}
+
+func TestNarrowSingleRunes(t *testing.T) {
+	for r := rune(0); r < 0x1FFFF; r++ {
+		if loSurrogate <= r && r <= hiSurrogate {
+			continue
+		}
+		alt, _ := narrowRune(r)
+		want := string(alt)
+		got := Narrow.String(string(r))
+		if got != want {
+			t.Errorf("Narrow().String(%U) = %+q; want %+q", r, got, want)
+		}
+	}
+}
+
+func TestNarrow(t *testing.T) {
+	for _, tc := range []transformTest{{
+		desc:    "empty",
+		src:     "",
+		nBuf:    10,
+		dst:     "",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: nil,
+	}, {
+		desc:    "short source 1",
+		src:     "a\xc2",
+		nBuf:    10,
+		dst:     "a\xc2",
+		nDst:    1,
+		nSrc:    1,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   1,
+		errSpan: transform.ErrShortSrc,
+	}, {
+		desc:    "short source 2",
+		src:     "ａ\xe0\x80",
+		nBuf:    10,
+		dst:     "a\xe0\x80",
+		nDst:    1,
+		nSrc:    3,
+		atEOF:   false,
+		err:     transform.ErrShortSrc,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "incomplete but terminated source 1",
+		src:     "ａ\xc2",
+		nBuf:    10,
+		dst:     "a\xc2",
+		nDst:    2,
+		nSrc:    4,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "incomplete but terminated source 2",
+		src:     "ａ\xe0\x80",
+		nBuf:    10,
+		dst:     "a\xe0\x80",
+		nDst:    3,
+		nSrc:    5,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "exact fit dst",
+		src:     "ａ\uff01",
+		nBuf:    2,
+		dst:     "a!",
+		nDst:    2,
+		nSrc:    6,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "exact fit dst some span",
+		src:     "a\uff01",
+		nBuf:    2,
+		dst:     "a!",
+		nDst:    2,
+		nSrc:    4,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   1,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "empty dst",
+		src:     "\u0300",
+		nBuf:    0,
+		dst:     "\u0300",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   2,
+		errSpan: nil,
+	}, {
+		desc:    "empty dst ascii",
+		src:     "a",
+		nBuf:    0,
+		dst:     "a",
+		nDst:    0,
+		nSrc:    0,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   1,
+		errSpan: nil,
+	}, {
+		desc:    "short dst 1",
+		src:     "ａ\uffe0", // ￠
+		nBuf:    2,
+		dst:     "a\u00a2", // ¢
+		nDst:    1,
+		nSrc:    3,
+		atEOF:   false,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short dst 2",
+		src:     "不夠",
+		nBuf:    3,
+		dst:     "不夠",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   6,
+		errSpan: nil,
+	}, {
+		// Create a narrow variant of ambiguous runes, if they exist.
+		desc:    "ambiguous",
+		src:     "\u2190",
+		nBuf:    4,
+		dst:     "\uffe9",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   false,
+		err:     nil,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "short dst fast path",
+		src:     "fast",
+		nBuf:    3,
+		dst:     "fast",
+		nDst:    3,
+		nSrc:    3,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   4,
+		errSpan: nil,
+	}, {
+		desc:    "short dst larger buffer",
+		src:     "\uff21" + strings.Repeat("0", 127) + "B",
+		nBuf:    128,
+		dst:     "A" + strings.Repeat("0", 127) + "B",
+		nDst:    128,
+		nSrc:    130,
+		atEOF:   true,
+		err:     transform.ErrShortDst,
+		nSpan:   0,
+		errSpan: transform.ErrEndOfSpan,
+	}, {
+		desc:    "fast path alternation",
+		src:     "fast路徑fast路徑",
+		nBuf:    20,
+		dst:     "fast路徑fast路徑",
+		nDst:    20,
+		nSrc:    20,
+		atEOF:   true,
+		err:     nil,
+		nSpan:   20,
+		errSpan: nil,
+	}} {
+		tc.doTest(t, Narrow)
+	}
+}
+
+func bench(b *testing.B, t Transformer, s string) {
+	dst := make([]byte, 1024)
+	src := []byte(s)
+	b.SetBytes(int64(len(src)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		t.Transform(dst, src, true)
+	}
+}
+
+func changingRunes(f func(r rune) (rune, bool)) string {
+	buf := &bytes.Buffer{}
+	for r := rune(0); r <= 0xFFFF; r++ {
+		if _, ok := foldRune(r); ok {
+			buf.WriteRune(r)
+		}
+	}
+	return buf.String()
+}
+
+func BenchmarkFoldASCII(b *testing.B) {
+	bench(b, Fold, testtext.ASCII)
+}
+
+func BenchmarkFoldCJK(b *testing.B) {
+	bench(b, Fold, testtext.CJK)
+}
+
+func BenchmarkFoldNonCanonical(b *testing.B) {
+	bench(b, Fold, changingRunes(foldRune))
+}
+
+func BenchmarkFoldOther(b *testing.B) {
+	bench(b, Fold, testtext.TwoByteUTF8+testtext.ThreeByteUTF8)
+}
+
+func BenchmarkWideASCII(b *testing.B) {
+	bench(b, Widen, testtext.ASCII)
+}
+
+func BenchmarkWideCJK(b *testing.B) {
+	bench(b, Widen, testtext.CJK)
+}
+
+func BenchmarkWideNonCanonical(b *testing.B) {
+	bench(b, Widen, changingRunes(widenRune))
+}
+
+func BenchmarkWideOther(b *testing.B) {
+	bench(b, Widen, testtext.TwoByteUTF8+testtext.ThreeByteUTF8)
+}
+
+func BenchmarkNarrowASCII(b *testing.B) {
+	bench(b, Narrow, testtext.ASCII)
+}
+
+func BenchmarkNarrowCJK(b *testing.B) {
+	bench(b, Narrow, testtext.CJK)
+}
+
+func BenchmarkNarrowNonCanonical(b *testing.B) {
+	bench(b, Narrow, changingRunes(narrowRune))
+}
+
+func BenchmarkNarrowOther(b *testing.B) {
+	bench(b, Narrow, testtext.TwoByteUTF8+testtext.ThreeByteUTF8)
+}

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

@@ -0,0 +1,30 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package width
+
+// elem is an entry of the width trie. The high byte is used to encode the type
+// of the rune. The low byte is used to store the index to a mapping entry in
+// the inverseData array.
+type elem uint16
+
+const (
+	tagNeutral elem = iota << typeShift
+	tagAmbiguous
+	tagWide
+	tagNarrow
+	tagFullwidth
+	tagHalfwidth
+)
+
+const (
+	numTypeBits = 3
+	typeShift   = 16 - numTypeBits
+
+	// tagNeedsFold is true for all fullwidth and halfwidth runes except for
+	// the Won sign U+20A9.
+	tagNeedsFold = 0x1000
+
+	// The Korean Won sign is halfwidth, but SHOULD NOT be mapped to a wide
+	// variant.
+	wonSign rune = 0x20A9
+)

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

@@ -0,0 +1,206 @@
+// 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.
+
+//go:generate stringer -type=Kind
+//go:generate go run gen.go gen_common.go gen_trieval.go
+
+// Package width provides functionality for handling different widths in text.
+//
+// Wide characters behave like ideographs; they tend to allow line breaks after
+// each character and remain upright in vertical text layout. Narrow characters
+// are kept together in words or runs that are rotated sideways in vertical text
+// layout.
+//
+// For more information, see http://unicode.org/reports/tr11/.
+package width // import "golang.org/x/text/width"
+
+import (
+	"unicode/utf8"
+
+	"golang.org/x/text/transform"
+)
+
+// TODO
+// 1) Reduce table size by compressing blocks.
+// 2) API proposition for computing display length
+//    (approximation, fixed pitch only).
+// 3) Implement display length.
+
+// Kind indicates the type of width property as defined in http://unicode.org/reports/tr11/.
+type Kind int
+
+const (
+	// Neutral characters do not occur in legacy East Asian character sets.
+	Neutral Kind = iota
+
+	// EastAsianAmbiguous characters that can be sometimes wide and sometimes
+	// narrow and require additional information not contained in the character
+	// code to further resolve their width.
+	EastAsianAmbiguous
+
+	// EastAsianWide characters are wide in its usual form. They occur only in
+	// the context of East Asian typography. These runes may have explicit
+	// halfwidth counterparts.
+	EastAsianWide
+
+	// EastAsianNarrow characters are narrow in its usual form. They often have
+	// fullwidth counterparts.
+	EastAsianNarrow
+
+	// Note: there exist Narrow runes that do not have fullwidth or wide
+	// counterparts, despite what the definition says (e.g. U+27E6).
+
+	// EastAsianFullwidth characters have a compatibility decompositions of type
+	// wide that map to a narrow counterpart.
+	EastAsianFullwidth
+
+	// EastAsianHalfwidth characters have a compatibility decomposition of type
+	// narrow that map to a wide or ambiguous counterpart, plus U+20A9 ₩ WON
+	// SIGN.
+	EastAsianHalfwidth
+
+	// Note: there exist runes that have a halfwidth counterparts but that are
+	// classified as Ambiguous, rather than wide (e.g. U+2190).
+)
+
+// TODO: the generated tries need to return size 1 for invalid runes for the
+// width to be computed correctly (each byte should render width 1)
+
+var trie = newWidthTrie(0)
+
+// Lookup reports the Properties of the first rune in b and the number of bytes
+// of its UTF-8 encoding.
+func Lookup(b []byte) (p Properties, size int) {
+	v, sz := trie.lookup(b)
+	return Properties{elem(v), b[sz-1]}, sz
+}
+
+// LookupString reports the Properties of the first rune in s and the number of
+// bytes of its UTF-8 encoding.
+func LookupString(s string) (p Properties, size int) {
+	v, sz := trie.lookupString(s)
+	return Properties{elem(v), s[sz-1]}, sz
+}
+
+// LookupRune reports the Properties of rune r.
+func LookupRune(r rune) Properties {
+	var buf [4]byte
+	n := utf8.EncodeRune(buf[:], r)
+	v, _ := trie.lookup(buf[:n])
+	last := byte(r)
+	if r >= utf8.RuneSelf {
+		last = 0x80 + byte(r&0x3f)
+	}
+	return Properties{elem(v), last}
+}
+
+// Properties provides access to width properties of a rune.
+type Properties struct {
+	elem elem
+	last byte
+}
+
+func (e elem) kind() Kind {
+	return Kind(e >> typeShift)
+}
+
+// Kind returns the Kind of a rune as defined in Unicode TR #11.
+// See http://unicode.org/reports/tr11/ for more details.
+func (p Properties) Kind() Kind {
+	return p.elem.kind()
+}
+
+// Folded returns the folded variant of a rune or 0 if the rune is canonical.
+func (p Properties) Folded() rune {
+	if p.elem&tagNeedsFold != 0 {
+		buf := inverseData[byte(p.elem)]
+		buf[buf[0]] ^= p.last
+		r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]])
+		return r
+	}
+	return 0
+}
+
+// Narrow returns the narrow variant of a rune or 0 if the rune is already
+// narrow or doesn't have a narrow variant.
+func (p Properties) Narrow() rune {
+	if k := p.elem.kind(); byte(p.elem) != 0 && (k == EastAsianFullwidth || k == EastAsianWide || k == EastAsianAmbiguous) {
+		buf := inverseData[byte(p.elem)]
+		buf[buf[0]] ^= p.last
+		r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]])
+		return r
+	}
+	return 0
+}
+
+// Wide returns the wide variant of a rune or 0 if the rune is already
+// wide or doesn't have a wide variant.
+func (p Properties) Wide() rune {
+	if k := p.elem.kind(); byte(p.elem) != 0 && (k == EastAsianHalfwidth || k == EastAsianNarrow) {
+		buf := inverseData[byte(p.elem)]
+		buf[buf[0]] ^= p.last
+		r, _ := utf8.DecodeRune(buf[1 : 1+buf[0]])
+		return r
+	}
+	return 0
+}
+
+// TODO for Properties:
+// - Add Fullwidth/Halfwidth or Inverted methods for computing variants
+// mapping.
+// - Add width information (including information on non-spacing runes).
+
+// Transformer implements the transform.Transformer interface.
+type Transformer struct {
+	t transform.SpanningTransformer
+}
+
+// Reset implements the transform.Transformer interface.
+func (t Transformer) Reset() { t.t.Reset() }
+
+// Transform implements the transform.Transformer interface.
+func (t Transformer) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	return t.t.Transform(dst, src, atEOF)
+}
+
+// Span implements the transform.SpanningTransformer interface.
+func (t Transformer) Span(src []byte, atEOF bool) (n int, err error) {
+	return t.t.Span(src, atEOF)
+}
+
+// Bytes returns a new byte slice with the result of applying t to b.
+func (t Transformer) Bytes(b []byte) []byte {
+	b, _, _ = transform.Bytes(t, b)
+	return b
+}
+
+// String returns a string with the result of applying t to s.
+func (t Transformer) String(s string) string {
+	s, _, _ = transform.String(t, s)
+	return s
+}
+
+var (
+	// Fold is a transform that maps all runes to their canonical width.
+	//
+	// Note that the NFKC and NFKD transforms in golang.org/x/text/unicode/norm
+	// provide a more generic folding mechanism.
+	Fold Transformer = Transformer{foldTransform{}}
+
+	// Widen is a transform that maps runes to their wide variant, if
+	// available.
+	Widen Transformer = Transformer{wideTransform{}}
+
+	// Narrow is a transform that maps runes to their narrow variant, if
+	// available.
+	Narrow Transformer = Transformer{narrowTransform{}}
+)
+
+// TODO: Consider the following options:
+// - Treat Ambiguous runes that have a halfwidth counterpart as wide, or some
+//   generalized variant of this.
+// - Consider a wide Won character to be the default width (or some generalized
+//   variant of this).
+// - Filter the set of characters that gets converted (the preferred approach is
+//   to allow applying filters to transforms).