encoding/charmap/maketables.go - text - Git at Google

 // Copyright 2013 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 ignore
 // +build ignore

 package main

 import (
 	"bufio"
 	"fmt"
 	"log"
 	"net/http"
 	"sort"
 	"strings"
 	"unicode/utf8"

 	"golang.org/x/text/encoding"
 	"golang.org/x/text/internal/gen"
 )

 const ascii = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" +
 	"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" +
 	` !"#$%&'()*+,-./0123456789:;<=>?` +
 	`@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_` +
 	"`abcdefghijklmnopqrstuvwxyz{|}~\u007f"

 var encodings = []struct {
 	name        string
 	mib         string
 	comment     string
 	varName     string
 	replacement byte
 	mapping     string
 }{
 	{
 		"IBM Code Page 037",
 		"IBM037",
 		"",
 		"CodePage037",
 		0x3f,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM037-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 437",
 		"PC8CodePage437",
 		"",
 		"CodePage437",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM437-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 850",
 		"PC850Multilingual",
 		"",
 		"CodePage850",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM850-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 852",
 		"PCp852",
 		"",
 		"CodePage852",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM852-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 855",
 		"IBM855",
 		"",
 		"CodePage855",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM855-2.1.2.ucm",
 	},
 	{
 		"Windows Code Page 858", // PC latin1 with Euro
 		"IBM00858",
 		"",
 		"CodePage858",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/windows-858-2000.ucm",
 	},
 	{
 		"IBM Code Page 860",
 		"IBM860",
 		"",
 		"CodePage860",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM860-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 862",
 		"PC862LatinHebrew",
 		"",
 		"CodePage862",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM862-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 863",
 		"IBM863",
 		"",
 		"CodePage863",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM863-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 865",
 		"IBM865",
 		"",
 		"CodePage865",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM865-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 866",
 		"IBM866",
 		"",
 		"CodePage866",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-ibm866.txt",
 	},
 	{
 		"IBM Code Page 1047",
 		"IBM1047",
 		"",
 		"CodePage1047",
 		0x3f,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM1047-2.1.2.ucm",
 	},
 	{
 		"IBM Code Page 1140",
 		"IBM01140",
 		"",
 		"CodePage1140",
 		0x3f,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/ibm-1140_P100-1997.ucm",
 	},
 	{
 		"ISO 8859-1",
 		"ISOLatin1",
 		"",
 		"ISO8859_1",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/iso-8859_1-1998.ucm",
 	},
 	{
 		"ISO 8859-2",
 		"ISOLatin2",
 		"",
 		"ISO8859_2",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-2.txt",
 	},
 	{
 		"ISO 8859-3",
 		"ISOLatin3",
 		"",
 		"ISO8859_3",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-3.txt",
 	},
 	{
 		"ISO 8859-4",
 		"ISOLatin4",
 		"",
 		"ISO8859_4",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-4.txt",
 	},
 	{
 		"ISO 8859-5",
 		"ISOLatinCyrillic",
 		"",
 		"ISO8859_5",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-5.txt",
 	},
 	{
 		"ISO 8859-6",
 		"ISOLatinArabic",
 		"",
 		"ISO8859_6,ISO8859_6E,ISO8859_6I",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-6.txt",
 	},
 	{
 		"ISO 8859-7",
 		"ISOLatinGreek",
 		"",
 		"ISO8859_7",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-7.txt",
 	},
 	{
 		"ISO 8859-8",
 		"ISOLatinHebrew",
 		"",
 		"ISO8859_8,ISO8859_8E,ISO8859_8I",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-8.txt",
 	},
 	{
 		"ISO 8859-9",
 		"ISOLatin5",
 		"",
 		"ISO8859_9",
 		encoding.ASCIISub,
 		"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/iso-8859_9-1999.ucm",
 	},
 	{
 		"ISO 8859-10",
 		"ISOLatin6",
 		"",
 		"ISO8859_10",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-10.txt",
 	},
 	{
 		"ISO 8859-13",
 		"ISO885913",
 		"",
 		"ISO8859_13",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-13.txt",
 	},
 	{
 		"ISO 8859-14",
 		"ISO885914",
 		"",
 		"ISO8859_14",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-14.txt",
 	},
 	{
 		"ISO 8859-15",
 		"ISO885915",
 		"",
 		"ISO8859_15",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-15.txt",
 	},
 	{
 		"ISO 8859-16",
 		"ISO885916",
 		"",
 		"ISO8859_16",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-iso-8859-16.txt",
 	},
 	{
 		"KOI8-R",
 		"KOI8R",
 		"",
 		"KOI8R",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-koi8-r.txt",
 	},
 	{
 		"KOI8-U",
 		"KOI8U",
 		"",
 		"KOI8U",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-koi8-u.txt",
 	},
 	{
 		"Macintosh",
 		"Macintosh",
 		"",
 		"Macintosh",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-macintosh.txt",
 	},
 	{
 		"Macintosh Cyrillic",
 		"MacintoshCyrillic",
 		"",
 		"MacintoshCyrillic",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-x-mac-cyrillic.txt",
 	},
 	{
 		"Windows 874",
 		"Windows874",
 		"",
 		"Windows874",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-874.txt",
 	},
 	{
 		"Windows 1250",
 		"Windows1250",
 		"",
 		"Windows1250",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1250.txt",
 	},
 	{
 		"Windows 1251",
 		"Windows1251",
 		"",
 		"Windows1251",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1251.txt",
 	},
 	{
 		"Windows 1252",
 		"Windows1252",
 		"",
 		"Windows1252",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1252.txt",
 	},
 	{
 		"Windows 1253",
 		"Windows1253",
 		"",
 		"Windows1253",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1253.txt",
 	},
 	{
 		"Windows 1254",
 		"Windows1254",
 		"",
 		"Windows1254",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1254.txt",
 	},
 	{
 		"Windows 1255",
 		"Windows1255",
 		"",
 		"Windows1255",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1255.txt",
 	},
 	{
 		"Windows 1256",
 		"Windows1256",
 		"",
 		"Windows1256",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1256.txt",
 	},
 	{
 		"Windows 1257",
 		"Windows1257",
 		"",
 		"Windows1257",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1257.txt",
 	},
 	{
 		"Windows 1258",
 		"Windows1258",
 		"",
 		"Windows1258",
 		encoding.ASCIISub,
 		"http://encoding.spec.whatwg.org/index-windows-1258.txt",
 	},
 	{
 		"X-User-Defined",
 		"XUserDefined",
 		"It is defined at http://encoding.spec.whatwg.org/#x-user-defined",
 		"XUserDefined",
 		encoding.ASCIISub,
 		ascii +
 			"\uf780\uf781\uf782\uf783\uf784\uf785\uf786\uf787" +
 			"\uf788\uf789\uf78a\uf78b\uf78c\uf78d\uf78e\uf78f" +
 			"\uf790\uf791\uf792\uf793\uf794\uf795\uf796\uf797" +
 			"\uf798\uf799\uf79a\uf79b\uf79c\uf79d\uf79e\uf79f" +
 			"\uf7a0\uf7a1\uf7a2\uf7a3\uf7a4\uf7a5\uf7a6\uf7a7" +
 			"\uf7a8\uf7a9\uf7aa\uf7ab\uf7ac\uf7ad\uf7ae\uf7af" +
 			"\uf7b0\uf7b1\uf7b2\uf7b3\uf7b4\uf7b5\uf7b6\uf7b7" +
 			"\uf7b8\uf7b9\uf7ba\uf7bb\uf7bc\uf7bd\uf7be\uf7bf" +
 			"\uf7c0\uf7c1\uf7c2\uf7c3\uf7c4\uf7c5\uf7c6\uf7c7" +
 			"\uf7c8\uf7c9\uf7ca\uf7cb\uf7cc\uf7cd\uf7ce\uf7cf" +
 			"\uf7d0\uf7d1\uf7d2\uf7d3\uf7d4\uf7d5\uf7d6\uf7d7" +
 			"\uf7d8\uf7d9\uf7da\uf7db\uf7dc\uf7dd\uf7de\uf7df" +
 			"\uf7e0\uf7e1\uf7e2\uf7e3\uf7e4\uf7e5\uf7e6\uf7e7" +
 			"\uf7e8\uf7e9\uf7ea\uf7eb\uf7ec\uf7ed\uf7ee\uf7ef" +
 			"\uf7f0\uf7f1\uf7f2\uf7f3\uf7f4\uf7f5\uf7f6\uf7f7" +
 			"\uf7f8\uf7f9\uf7fa\uf7fb\uf7fc\uf7fd\uf7fe\uf7ff",
 	},
 }

 func getWHATWG(url string) string {
 	res, err := http.Get(url)
 	if err != nil {
 		log.Fatalf("%q: Get: %v", url, err)
 	}
 	defer res.Body.Close()

 	mapping := make([]rune, 128)
 	for i := range mapping {
 		mapping[i] = '\ufffd'
 	}

 	scanner := bufio.NewScanner(res.Body)
 	for scanner.Scan() {
 		s := strings.TrimSpace(scanner.Text())
 		if s == "" || s[0] == '#' {
 			continue
 		}
 		x, y := 0, 0
 		if _, err := fmt.Sscanf(s, "%d\t0x%x", &x, &y); err != nil {
 			log.Fatalf("could not parse %q", s)
 		}
 		if x < 0 || 128 <= x {
 			log.Fatalf("code %d is out of range", x)
 		}
 		if 0x80 <= y && y < 0xa0 {
 			// We diverge from the WHATWG spec by mapping control characters
 			// in the range [0x80, 0xa0) to U+FFFD.
 			continue
 		}
 		mapping[x] = rune(y)
 	}
 	return ascii + string(mapping)
 }

 func getUCM(url string) string {
 	res, err := http.Get(url)
 	if err != nil {
 		log.Fatalf("%q: Get: %v", url, err)
 	}
 	defer res.Body.Close()

 	mapping := make([]rune, 256)
 	for i := range mapping {
 		mapping[i] = '\ufffd'
 	}

 	charsFound := 0
 	scanner := bufio.NewScanner(res.Body)
 	for scanner.Scan() {
 		s := strings.TrimSpace(scanner.Text())
 		if s == "" || s[0] == '#' {
 			continue
 		}
 		var c byte
 		var r rune
 		if _, err := fmt.Sscanf(s, `<U%x> \x%x |0`, &r, &c); err != nil {
 			continue
 		}
 		mapping[c] = r
 		charsFound++
 	}

 	if charsFound < 200 {
 		log.Fatalf("%q: only %d characters found (wrong page format?)", url, charsFound)
 	}

 	return string(mapping)
 }

 func main() {
 	mibs := map[string]bool{}
 	all := []string{}

 	w := gen.NewCodeWriter()
 	defer w.WriteGoFile("tables.go", "charmap")

 	printf := func(s string, a ...interface{}) { fmt.Fprintf(w, s, a...) }

 	printf("import (\n")
 	printf("\t\"golang.org/x/text/encoding\"\n")
 	printf("\t\"golang.org/x/text/encoding/internal/identifier\"\n")
 	printf(")\n\n")
 	for _, e := range encodings {
 		varNames := strings.Split(e.varName, ",")
 		all = append(all, varNames...)
 		varName := varNames[0]
 		switch {
 		case strings.HasPrefix(e.mapping, "http://encoding.spec.whatwg.org/"):
 			e.mapping = getWHATWG(e.mapping)
 		case strings.HasPrefix(e.mapping, "http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/"):
 			e.mapping = getUCM(e.mapping)
 		}

 		asciiSuperset, low := strings.HasPrefix(e.mapping, ascii), 0x00
 		if asciiSuperset {
 			low = 0x80
 		}
 		lvn := 1
 		if strings.HasPrefix(varName, "ISO") || strings.HasPrefix(varName, "KOI") {
 			lvn = 3
 		}
 		lowerVarName := strings.ToLower(varName[:lvn]) + varName[lvn:]
 		printf("// %s is the %s encoding.\n", varName, e.name)
 		if e.comment != "" {
 			printf("//\n// %s\n", e.comment)
 		}
 		printf("var %s *Charmap = &%s\n\nvar %s = Charmap{\nname: %q,\n",
 			varName, lowerVarName, lowerVarName, e.name)
 		if mibs[e.mib] {
 			log.Fatalf("MIB type %q declared multiple times.", e.mib)
 		}
 		printf("mib: identifier.%s,\n", e.mib)
 		printf("asciiSuperset: %t,\n", asciiSuperset)
 		printf("low: 0x%02x,\n", low)
 		printf("replacement: 0x%02x,\n", e.replacement)

 		printf("decode: [256]utf8Enc{\n")
 		i, backMapping := 0, map[rune]byte{}
 		for _, c := range e.mapping {
 			if _, ok := backMapping[c]; !ok && c != utf8.RuneError {
 				backMapping[c] = byte(i)
 			}
 			var buf [8]byte
 			n := utf8.EncodeRune(buf[:], c)
 			if n > 3 {
 				panic(fmt.Sprintf("rune %q (%U) is too long", c, c))
 			}
 			printf("{%d,[3]byte{0x%02x,0x%02x,0x%02x}},", n, buf[0], buf[1], buf[2])
 			if i%2 == 1 {
 				printf("\n")
 			}
 			i++
 		}
 		printf("},\n")

 		printf("encode: [256]uint32{\n")
 		encode := make([]uint32, 0, 256)
 		for c, i := range backMapping {
 			encode = append(encode, uint32(i)<<24|uint32(c))
 		}
 		sort.Sort(byRune(encode))
 		for len(encode) < cap(encode) {
 			encode = append(encode, encode[len(encode)-1])
 		}
 		for i, enc := range encode {
 			printf("0x%08x,", enc)
 			if i%8 == 7 {
 				printf("\n")
 			}
 		}
 		printf("},\n}\n")

 		// Add an estimate of the size of a single Charmap{} struct value, which
 		// includes two 256 elem arrays of 4 bytes and some extra fields, which
 		// align to 3 uint64s on 64-bit architectures.
 		w.Size += 2*4*256 + 3*8
 	}
 	// TODO: add proper line breaking.
 	printf("var listAll = []encoding.Encoding{\n%s,\n}\n\n", strings.Join(all, ",\n"))
 }

 type byRune []uint32

 func (b byRune) Len() int           { return len(b) }
 func (b byRune) Less(i, j int) bool { return b[i]&0xffffff < b[j]&0xffffff }
 func (b byRune) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
	// Copyright 2013 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 ignore
	// +build ignore

	package main

	import (
	"bufio"
	"fmt"
	"log"
	"net/http"
	"sort"
	"strings"
	"unicode/utf8"

	"golang.org/x/text/encoding"
	"golang.org/x/text/internal/gen"
	)

	const ascii = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" +
	"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f" +
	` !"#$%&'()*+,-./0123456789:;<=>?` +
	`@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_` +
	"`abcdefghijklmnopqrstuvwxyz{\|}~\u007f"

	var encodings = []struct {
	name string
	mib string
	comment string
	varName string
	replacement byte
	mapping string
	}{
	{
	"IBM Code Page 037",
	"IBM037",
	"",
	"CodePage037",
	0x3f,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM037-2.1.2.ucm",
	},
	{
	"IBM Code Page 437",
	"PC8CodePage437",
	"",
	"CodePage437",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM437-2.1.2.ucm",
	},
	{
	"IBM Code Page 850",
	"PC850Multilingual",
	"",
	"CodePage850",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM850-2.1.2.ucm",
	},
	{
	"IBM Code Page 852",
	"PCp852",
	"",
	"CodePage852",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM852-2.1.2.ucm",
	},
	{
	"IBM Code Page 855",
	"IBM855",
	"",
	"CodePage855",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM855-2.1.2.ucm",
	},
	{
	"Windows Code Page 858", // PC latin1 with Euro
	"IBM00858",
	"",
	"CodePage858",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/windows-858-2000.ucm",
	},
	{
	"IBM Code Page 860",
	"IBM860",
	"",
	"CodePage860",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM860-2.1.2.ucm",
	},
	{
	"IBM Code Page 862",
	"PC862LatinHebrew",
	"",
	"CodePage862",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM862-2.1.2.ucm",
	},
	{
	"IBM Code Page 863",
	"IBM863",
	"",
	"CodePage863",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM863-2.1.2.ucm",
	},
	{
	"IBM Code Page 865",
	"IBM865",
	"",
	"CodePage865",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM865-2.1.2.ucm",
	},
	{
	"IBM Code Page 866",
	"IBM866",
	"",
	"CodePage866",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-ibm866.txt",
	},
	{
	"IBM Code Page 1047",
	"IBM1047",
	"",
	"CodePage1047",
	0x3f,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/glibc-IBM1047-2.1.2.ucm",
	},
	{
	"IBM Code Page 1140",
	"IBM01140",
	"",
	"CodePage1140",
	0x3f,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/ibm-1140_P100-1997.ucm",
	},
	{
	"ISO 8859-1",
	"ISOLatin1",
	"",
	"ISO8859_1",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/iso-8859_1-1998.ucm",
	},
	{
	"ISO 8859-2",
	"ISOLatin2",
	"",
	"ISO8859_2",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-2.txt",
	},
	{
	"ISO 8859-3",
	"ISOLatin3",
	"",
	"ISO8859_3",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-3.txt",
	},
	{
	"ISO 8859-4",
	"ISOLatin4",
	"",
	"ISO8859_4",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-4.txt",
	},
	{
	"ISO 8859-5",
	"ISOLatinCyrillic",
	"",
	"ISO8859_5",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-5.txt",
	},
	{
	"ISO 8859-6",
	"ISOLatinArabic",
	"",
	"ISO8859_6,ISO8859_6E,ISO8859_6I",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-6.txt",
	},
	{
	"ISO 8859-7",
	"ISOLatinGreek",
	"",
	"ISO8859_7",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-7.txt",
	},
	{
	"ISO 8859-8",
	"ISOLatinHebrew",
	"",
	"ISO8859_8,ISO8859_8E,ISO8859_8I",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-8.txt",
	},
	{
	"ISO 8859-9",
	"ISOLatin5",
	"",
	"ISO8859_9",
	encoding.ASCIISub,
	"http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/iso-8859_9-1999.ucm",
	},
	{
	"ISO 8859-10",
	"ISOLatin6",
	"",
	"ISO8859_10",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-10.txt",
	},
	{
	"ISO 8859-13",
	"ISO885913",
	"",
	"ISO8859_13",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-13.txt",
	},
	{
	"ISO 8859-14",
	"ISO885914",
	"",
	"ISO8859_14",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-14.txt",
	},
	{
	"ISO 8859-15",
	"ISO885915",
	"",
	"ISO8859_15",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-15.txt",
	},
	{
	"ISO 8859-16",
	"ISO885916",
	"",
	"ISO8859_16",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-iso-8859-16.txt",
	},
	{
	"KOI8-R",
	"KOI8R",
	"",
	"KOI8R",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-koi8-r.txt",
	},
	{
	"KOI8-U",
	"KOI8U",
	"",
	"KOI8U",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-koi8-u.txt",
	},
	{
	"Macintosh",
	"Macintosh",
	"",
	"Macintosh",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-macintosh.txt",
	},
	{
	"Macintosh Cyrillic",
	"MacintoshCyrillic",
	"",
	"MacintoshCyrillic",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-x-mac-cyrillic.txt",
	},
	{
	"Windows 874",
	"Windows874",
	"",
	"Windows874",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-874.txt",
	},
	{
	"Windows 1250",
	"Windows1250",
	"",
	"Windows1250",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1250.txt",
	},
	{
	"Windows 1251",
	"Windows1251",
	"",
	"Windows1251",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1251.txt",
	},
	{
	"Windows 1252",
	"Windows1252",
	"",
	"Windows1252",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1252.txt",
	},
	{
	"Windows 1253",
	"Windows1253",
	"",
	"Windows1253",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1253.txt",
	},
	{
	"Windows 1254",
	"Windows1254",
	"",
	"Windows1254",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1254.txt",
	},
	{
	"Windows 1255",
	"Windows1255",
	"",
	"Windows1255",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1255.txt",
	},
	{
	"Windows 1256",
	"Windows1256",
	"",
	"Windows1256",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1256.txt",
	},
	{
	"Windows 1257",
	"Windows1257",
	"",
	"Windows1257",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1257.txt",
	},
	{
	"Windows 1258",
	"Windows1258",
	"",
	"Windows1258",
	encoding.ASCIISub,
	"http://encoding.spec.whatwg.org/index-windows-1258.txt",
	},
	{
	"X-User-Defined",
	"XUserDefined",
	"It is defined at http://encoding.spec.whatwg.org/#x-user-defined",
	"XUserDefined",
	encoding.ASCIISub,
	ascii +
	"\uf780\uf781\uf782\uf783\uf784\uf785\uf786\uf787" +
	"\uf788\uf789\uf78a\uf78b\uf78c\uf78d\uf78e\uf78f" +
	"\uf790\uf791\uf792\uf793\uf794\uf795\uf796\uf797" +
	"\uf798\uf799\uf79a\uf79b\uf79c\uf79d\uf79e\uf79f" +
	"\uf7a0\uf7a1\uf7a2\uf7a3\uf7a4\uf7a5\uf7a6\uf7a7" +
	"\uf7a8\uf7a9\uf7aa\uf7ab\uf7ac\uf7ad\uf7ae\uf7af" +
	"\uf7b0\uf7b1\uf7b2\uf7b3\uf7b4\uf7b5\uf7b6\uf7b7" +
	"\uf7b8\uf7b9\uf7ba\uf7bb\uf7bc\uf7bd\uf7be\uf7bf" +
	"\uf7c0\uf7c1\uf7c2\uf7c3\uf7c4\uf7c5\uf7c6\uf7c7" +
	"\uf7c8\uf7c9\uf7ca\uf7cb\uf7cc\uf7cd\uf7ce\uf7cf" +
	"\uf7d0\uf7d1\uf7d2\uf7d3\uf7d4\uf7d5\uf7d6\uf7d7" +
	"\uf7d8\uf7d9\uf7da\uf7db\uf7dc\uf7dd\uf7de\uf7df" +
	"\uf7e0\uf7e1\uf7e2\uf7e3\uf7e4\uf7e5\uf7e6\uf7e7" +
	"\uf7e8\uf7e9\uf7ea\uf7eb\uf7ec\uf7ed\uf7ee\uf7ef" +
	"\uf7f0\uf7f1\uf7f2\uf7f3\uf7f4\uf7f5\uf7f6\uf7f7" +
	"\uf7f8\uf7f9\uf7fa\uf7fb\uf7fc\uf7fd\uf7fe\uf7ff",
	},
	}

	func getWHATWG(url string) string {
	res, err := http.Get(url)
	if err != nil {
	log.Fatalf("%q: Get: %v", url, err)
	}
	defer res.Body.Close()

	mapping := make([]rune, 128)
	for i := range mapping {
	mapping[i] = '\ufffd'
	}

	scanner := bufio.NewScanner(res.Body)
	for scanner.Scan() {
	s := strings.TrimSpace(scanner.Text())
	if s == "" \|\| s[0] == '#' {
	continue
	}
	x, y := 0, 0
	if _, err := fmt.Sscanf(s, "%d\t0x%x", &x, &y); err != nil {
	log.Fatalf("could not parse %q", s)
	}
	if x < 0 \|\| 128 <= x {
	log.Fatalf("code %d is out of range", x)
	}
	if 0x80 <= y && y < 0xa0 {
	// We diverge from the WHATWG spec by mapping control characters
	// in the range [0x80, 0xa0) to U+FFFD.
	continue
	}
	mapping[x] = rune(y)
	}
	return ascii + string(mapping)
	}

	func getUCM(url string) string {
	res, err := http.Get(url)
	if err != nil {
	log.Fatalf("%q: Get: %v", url, err)
	}
	defer res.Body.Close()

	mapping := make([]rune, 256)
	for i := range mapping {
	mapping[i] = '\ufffd'
	}

	charsFound := 0
	scanner := bufio.NewScanner(res.Body)
	for scanner.Scan() {
	s := strings.TrimSpace(scanner.Text())
	if s == "" \|\| s[0] == '#' {
	continue
	}
	var c byte
	var r rune
	if _, err := fmt.Sscanf(s, `<U%x> \x%x \|0`, &r, &c); err != nil {
	continue
	}
	mapping[c] = r
	charsFound++
	}

	if charsFound < 200 {
	log.Fatalf("%q: only %d characters found (wrong page format?)", url, charsFound)
	}

	return string(mapping)
	}

	func main() {
	mibs := map[string]bool{}
	all := []string{}

	w := gen.NewCodeWriter()
	defer w.WriteGoFile("tables.go", "charmap")

	printf := func(s string, a ...interface{}) { fmt.Fprintf(w, s, a...) }

	printf("import (\n")
	printf("\t\"golang.org/x/text/encoding\"\n")
	printf("\t\"golang.org/x/text/encoding/internal/identifier\"\n")
	printf(")\n\n")
	for _, e := range encodings {
	varNames := strings.Split(e.varName, ",")
	all = append(all, varNames...)
	varName := varNames[0]
	switch {
	case strings.HasPrefix(e.mapping, "http://encoding.spec.whatwg.org/"):
	e.mapping = getWHATWG(e.mapping)
	case strings.HasPrefix(e.mapping, "http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/"):
	e.mapping = getUCM(e.mapping)
	}

	asciiSuperset, low := strings.HasPrefix(e.mapping, ascii), 0x00
	if asciiSuperset {
	low = 0x80
	}
	lvn := 1
	if strings.HasPrefix(varName, "ISO") \|\| strings.HasPrefix(varName, "KOI") {
	lvn = 3
	}
	lowerVarName := strings.ToLower(varName[:lvn]) + varName[lvn:]
	printf("// %s is the %s encoding.\n", varName, e.name)
	if e.comment != "" {
	printf("//\n// %s\n", e.comment)
	}
	printf("var %s *Charmap = &%s\n\nvar %s = Charmap{\nname: %q,\n",
	varName, lowerVarName, lowerVarName, e.name)
	if mibs[e.mib] {
	log.Fatalf("MIB type %q declared multiple times.", e.mib)
	}
	printf("mib: identifier.%s,\n", e.mib)
	printf("asciiSuperset: %t,\n", asciiSuperset)
	printf("low: 0x%02x,\n", low)
	printf("replacement: 0x%02x,\n", e.replacement)

	printf("decode: [256]utf8Enc{\n")
	i, backMapping := 0, map[rune]byte{}
	for _, c := range e.mapping {
	if _, ok := backMapping[c]; !ok && c != utf8.RuneError {
	backMapping[c] = byte(i)
	}
	var buf [8]byte
	n := utf8.EncodeRune(buf[:], c)
	if n > 3 {
	panic(fmt.Sprintf("rune %q (%U) is too long", c, c))
	}
	printf("{%d,[3]byte{0x%02x,0x%02x,0x%02x}},", n, buf[0], buf[1], buf[2])
	if i%2 == 1 {
	printf("\n")
	}
	i++
	}
	printf("},\n")

	printf("encode: [256]uint32{\n")
	encode := make([]uint32, 0, 256)
	for c, i := range backMapping {
	encode = append(encode, uint32(i)<<24\|uint32(c))
	}
	sort.Sort(byRune(encode))
	for len(encode) < cap(encode) {
	encode = append(encode, encode[len(encode)-1])
	}
	for i, enc := range encode {
	printf("0x%08x,", enc)
	if i%8 == 7 {
	printf("\n")
	}
	}
	printf("},\n}\n")

	// Add an estimate of the size of a single Charmap{} struct value, which
	// includes two 256 elem arrays of 4 bytes and some extra fields, which
	// align to 3 uint64s on 64-bit architectures.
	w.Size += 24256 + 3*8
	}
	// TODO: add proper line breaking.
	printf("var listAll = []encoding.Encoding{\n%s,\n}\n\n", strings.Join(all, ",\n"))
	}

	type byRune []uint32

	func (b byRune) Len() int { return len(b) }
	func (b byRune) Less(i, j int) bool { return b[i]&0xffffff < b[j]&0xffffff }
	func (b byRune) Swap(i, j int) { b[i], b[j] = b[j], b[i] }