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// 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.
// +build ignore
package main
// This program generates tables.go:
// go run maketables.go | gofmt > tables.go
// TODO: Emoji extensions?
// http://www.unicode.org/faq/emoji_dingbats.html
// http://www.unicode.org/Public/UNIDATA/EmojiSources.txt
import (
"bufio"
"fmt"
"log"
"net/http"
"sort"
"strings"
)
type entry struct {
jisCode, table int
}
func main() {
fmt.Printf("// generated by go run maketables.go; DO NOT EDIT\n\n")
fmt.Printf("// Package japanese provides Japanese encodings such as EUC-JP and Shift JIS.\n")
fmt.Printf(`package japanese // import "golang.org/x/text/encoding/japanese"` + "\n\n")
reverse := [65536]entry{}
for i := range reverse {
reverse[i].table = -1
}
tables := []struct {
url string
name string
}{
{"http://encoding.spec.whatwg.org/index-jis0208.txt", "0208"},
{"http://encoding.spec.whatwg.org/index-jis0212.txt", "0212"},
}
for i, table := range tables {
res, err := http.Get(table.url)
if err != nil {
log.Fatalf("%q: Get: %v", table.url, err)
}
defer res.Body.Close()
mapping := [65536]uint16{}
scanner := bufio.NewScanner(res.Body)
for scanner.Scan() {
s := strings.TrimSpace(scanner.Text())
if s == "" || s[0] == '#' {
continue
}
x, y := 0, uint16(0)
if _, err := fmt.Sscanf(s, "%d 0x%x", &x, &y); err != nil {
log.Fatalf("%q: could not parse %q", table.url, s)
}
if x < 0 || 120*94 <= x {
log.Fatalf("%q: JIS code %d is out of range", table.url, x)
}
mapping[x] = y
if reverse[y].table == -1 {
reverse[y] = entry{jisCode: x, table: i}
}
}
if err := scanner.Err(); err != nil {
log.Fatalf("%q: scanner error: %v", table.url, err)
}
fmt.Printf("// jis%sDecode is the decoding table from JIS %s code to Unicode.\n// It is defined at %s\n",
table.name, table.name, table.url)
fmt.Printf("var jis%sDecode = [...]uint16{\n", table.name)
for i, m := range mapping {
if m != 0 {
fmt.Printf("\t%d: 0x%04X,\n", i, m)
}
}
fmt.Printf("}\n\n")
}
// Any run of at least separation continuous zero entries in the reverse map will
// be a separate encode table.
const separation = 1024
intervals := []interval(nil)
low, high := -1, -1
for i, v := range reverse {
if v.table == -1 {
continue
}
if low < 0 {
low = i
} else if i-high >= separation {
if high >= 0 {
intervals = append(intervals, interval{low, high})
}
low = i
}
high = i + 1
}
if high >= 0 {
intervals = append(intervals, interval{low, high})
}
sort.Sort(byDecreasingLength(intervals))
fmt.Printf("const (\n")
fmt.Printf("\tjis0208 = 1\n")
fmt.Printf("\tjis0212 = 2\n")
fmt.Printf("\tcodeMask = 0x7f\n")
fmt.Printf("\tcodeShift = 7\n")
fmt.Printf("\ttableShift = 14\n")
fmt.Printf(")\n\n")
fmt.Printf("const numEncodeTables = %d\n\n", len(intervals))
fmt.Printf("// encodeX are the encoding tables from Unicode to JIS code,\n")
fmt.Printf("// sorted by decreasing length.\n")
for i, v := range intervals {
fmt.Printf("// encode%d: %5d entries for runes in [%5d, %5d).\n", i, v.len(), v.low, v.high)
}
fmt.Printf("//\n")
fmt.Printf("// The high two bits of the value record whether the JIS code comes from the\n")
fmt.Printf("// JIS0208 table (high bits == 1) or the JIS0212 table (high bits == 2).\n")
fmt.Printf("// The low 14 bits are two 7-bit unsigned integers j1 and j2 that form the\n")
fmt.Printf("// JIS code (94*j1 + j2) within that table.\n")
fmt.Printf("\n")
for i, v := range intervals {
fmt.Printf("const encode%dLow, encode%dHigh = %d, %d\n\n", i, i, v.low, v.high)
fmt.Printf("var encode%d = [...]uint16{\n", i)
for j := v.low; j < v.high; j++ {
x := reverse[j]
if x.table == -1 {
continue
}
fmt.Printf("\t%d - %d: jis%s<<14 | 0x%02X<<7 | 0x%02X,\n",
j, v.low, tables[x.table].name, x.jisCode/94, x.jisCode%94)
}
fmt.Printf("}\n\n")
}
}
// interval is a half-open interval [low, high).
type interval struct {
low, high int
}
func (i interval) len() int { return i.high - i.low }
// byDecreasingLength sorts intervals by decreasing length.
type byDecreasingLength []interval
func (b byDecreasingLength) Len() int { return len(b) }
func (b byDecreasingLength) Less(i, j int) bool { return b[i].len() > b[j].len() }
func (b byDecreasingLength) Swap(i, j int) { b[i], b[j] = b[j], b[i] }
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