// 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] }