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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build ignore
package main
import (
"encoding/xml"
"fmt"
"io"
"log"
"sort"
"strconv"
"strings"
"golang.org/x/text/encoding/internal/identifier"
"golang.org/x/text/internal/gen"
)
type registry struct {
XMLName xml.Name `xml:"registry"`
Updated string `xml:"updated"`
Registry []struct {
ID string `xml:"id,attr"`
Record []struct {
Name string `xml:"name"`
Xref []struct {
Type string `xml:"type,attr"`
Data string `xml:"data,attr"`
} `xml:"xref"`
Desc struct {
Data string `xml:",innerxml"`
} `xml:"description,"`
MIB string `xml:"value"`
Alias []string `xml:"alias"`
MIME string `xml:"preferred_alias"`
} `xml:"record"`
} `xml:"registry"`
}
func main() {
r := gen.OpenIANAFile("assignments/character-sets/character-sets.xml")
reg := ®istry{}
if err := xml.NewDecoder(r).Decode(®); err != nil && err != io.EOF {
log.Fatalf("Error decoding charset registry: %v", err)
}
if len(reg.Registry) == 0 || reg.Registry[0].ID != "character-sets-1" {
log.Fatalf("Unexpected ID %s", reg.Registry[0].ID)
}
x := &indexInfo{}
for _, rec := range reg.Registry[0].Record {
mib := identifier.MIB(parseInt(rec.MIB))
x.addEntry(mib, rec.Name)
for _, a := range rec.Alias {
a = strings.Split(a, " ")[0] // strip comments.
x.addAlias(a, mib)
// MIB name aliases are prefixed with a "cs" (character set) in the
// registry to identify them as display names and to ensure that
// the name starts with a lowercase letter in case it is used as
// an identifier. We remove it to be left with a nice clean name.
if strings.HasPrefix(a, "cs") {
x.setName(2, a[2:])
}
}
if rec.MIME != "" {
x.addAlias(rec.MIME, mib)
x.setName(1, rec.MIME)
}
}
w := gen.NewCodeWriter()
fmt.Fprintln(w, `import "golang.org/x/text/encoding/internal/identifier"`)
writeIndex(w, x)
w.WriteGoFile("tables.go", "ianaindex")
}
type alias struct {
name string
mib identifier.MIB
}
type indexInfo struct {
// compacted index from code to MIB
codeToMIB []identifier.MIB
alias []alias
names [][3]string
}
func (ii *indexInfo) Len() int {
return len(ii.codeToMIB)
}
func (ii *indexInfo) Less(a, b int) bool {
return ii.codeToMIB[a] < ii.codeToMIB[b]
}
func (ii *indexInfo) Swap(a, b int) {
ii.codeToMIB[a], ii.codeToMIB[b] = ii.codeToMIB[b], ii.codeToMIB[a]
// Co-sort the names.
ii.names[a], ii.names[b] = ii.names[b], ii.names[a]
}
func (ii *indexInfo) setName(i int, name string) {
ii.names[len(ii.names)-1][i] = name
}
func (ii *indexInfo) addEntry(mib identifier.MIB, name string) {
ii.names = append(ii.names, [3]string{name, name, name})
ii.addAlias(name, mib)
ii.codeToMIB = append(ii.codeToMIB, mib)
}
func (ii *indexInfo) addAlias(name string, mib identifier.MIB) {
// Don't add duplicates for the same mib. Adding duplicate aliases for
// different MIBs will cause the compiler to barf on an invalid map: great!.
for i := len(ii.alias) - 1; i >= 0 && ii.alias[i].mib == mib; i-- {
if ii.alias[i].name == name {
return
}
}
ii.alias = append(ii.alias, alias{name, mib})
lower := strings.ToLower(name)
if lower != name {
ii.addAlias(lower, mib)
}
}
const maxMIMENameLen = '0' - 1 // officially 40, but we leave some buffer.
func writeIndex(w *gen.CodeWriter, x *indexInfo) {
sort.Stable(x)
// Write constants.
fmt.Fprintln(w, "const (")
for i, m := range x.codeToMIB {
if i == 0 {
fmt.Fprintf(w, "enc%d = iota\n", m)
} else {
fmt.Fprintf(w, "enc%d\n", m)
}
}
fmt.Fprintln(w, "numIANA")
fmt.Fprintln(w, ")")
w.WriteVar("ianaToMIB", x.codeToMIB)
var ianaNames, mibNames []string
for _, names := range x.names {
n := names[0]
if names[0] != names[1] {
// MIME names are mostly identical to IANA names. We share the
// tables by setting the first byte of the string to an index into
// the string itself (< maxMIMENameLen) to the IANA name. The MIME
// name immediately follows the index.
x := len(names[1]) + 1
if x > maxMIMENameLen {
log.Fatalf("MIME name length (%d) > %d", x, maxMIMENameLen)
}
n = string(x) + names[1] + names[0]
}
ianaNames = append(ianaNames, n)
mibNames = append(mibNames, names[2])
}
w.WriteVar("ianaNames", ianaNames)
w.WriteVar("mibNames", mibNames)
w.WriteComment(`
TODO: Instead of using a map, we could use binary search strings doing
on-the fly lower-casing per character. This allows to always avoid
allocation and will be considerably more compact.`)
fmt.Fprintln(w, "var ianaAliases = map[string]int{")
for _, a := range x.alias {
fmt.Fprintf(w, "%q: enc%d,\n", a.name, a.mib)
}
fmt.Fprintln(w, "}")
}
func parseInt(s string) int {
x, err := strconv.ParseInt(s, 10, 64)
if err != nil {
log.Fatalf("Could not parse integer: %v", err)
}
return int(x)
}
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