1// Copyright 2013 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5// +build ignore
6
7package main
8
9// This program generates tables.go:
10//	go run maketables.go | gofmt > tables.go
11
12import (
13	"bufio"
14	"fmt"
15	"log"
16	"net/http"
17	"sort"
18	"strings"
19)
20
21func main() {
22	fmt.Printf("// generated by go run maketables.go; DO NOT EDIT\n\n")
23	fmt.Printf("// Package simplifiedchinese provides Simplified Chinese encodings such as GBK.\n")
24	fmt.Printf(`package simplifiedchinese // import "golang.org/x/text/encoding/simplifiedchinese"` + "\n\n")
25
26	printGB18030()
27	printGBK()
28}
29
30func printGB18030() {
31	res, err := http.Get("http://encoding.spec.whatwg.org/index-gb18030.txt")
32	if err != nil {
33		log.Fatalf("Get: %v", err)
34	}
35	defer res.Body.Close()
36
37	fmt.Printf("// gb18030 is the table from http://encoding.spec.whatwg.org/index-gb18030.txt\n")
38	fmt.Printf("var gb18030 = [...][2]uint16{\n")
39	scanner := bufio.NewScanner(res.Body)
40	for scanner.Scan() {
41		s := strings.TrimSpace(scanner.Text())
42		if s == "" || s[0] == '#' {
43			continue
44		}
45		x, y := uint32(0), uint32(0)
46		if _, err := fmt.Sscanf(s, "%d 0x%x", &x, &y); err != nil {
47			log.Fatalf("could not parse %q", s)
48		}
49		if x < 0x10000 && y < 0x10000 {
50			fmt.Printf("\t{0x%04x, 0x%04x},\n", x, y)
51		}
52	}
53	fmt.Printf("}\n\n")
54}
55
56func printGBK() {
57	res, err := http.Get("http://encoding.spec.whatwg.org/index-gbk.txt")
58	if err != nil {
59		log.Fatalf("Get: %v", err)
60	}
61	defer res.Body.Close()
62
63	mapping := [65536]uint16{}
64	reverse := [65536]uint16{}
65
66	scanner := bufio.NewScanner(res.Body)
67	for scanner.Scan() {
68		s := strings.TrimSpace(scanner.Text())
69		if s == "" || s[0] == '#' {
70			continue
71		}
72		x, y := uint16(0), uint16(0)
73		if _, err := fmt.Sscanf(s, "%d 0x%x", &x, &y); err != nil {
74			log.Fatalf("could not parse %q", s)
75		}
76		if x < 0 || 126*190 <= x {
77			log.Fatalf("GBK code %d is out of range", x)
78		}
79		mapping[x] = y
80		if reverse[y] == 0 {
81			c0, c1 := x/190, x%190
82			if c1 >= 0x3f {
83				c1++
84			}
85			reverse[y] = (0x81+c0)<<8 | (0x40 + c1)
86		}
87	}
88	if err := scanner.Err(); err != nil {
89		log.Fatalf("scanner error: %v", err)
90	}
91
92	fmt.Printf("// decode is the decoding table from GBK code to Unicode.\n")
93	fmt.Printf("// It is defined at http://encoding.spec.whatwg.org/index-gbk.txt\n")
94	fmt.Printf("var decode = [...]uint16{\n")
95	for i, v := range mapping {
96		if v != 0 {
97			fmt.Printf("\t%d: 0x%04X,\n", i, v)
98		}
99	}
100	fmt.Printf("}\n\n")
101
102	// Any run of at least separation continuous zero entries in the reverse map will
103	// be a separate encode table.
104	const separation = 1024
105
106	intervals := []interval(nil)
107	low, high := -1, -1
108	for i, v := range reverse {
109		if v == 0 {
110			continue
111		}
112		if low < 0 {
113			low = i
114		} else if i-high >= separation {
115			if high >= 0 {
116				intervals = append(intervals, interval{low, high})
117			}
118			low = i
119		}
120		high = i + 1
121	}
122	if high >= 0 {
123		intervals = append(intervals, interval{low, high})
124	}
125	sort.Sort(byDecreasingLength(intervals))
126
127	fmt.Printf("const numEncodeTables = %d\n\n", len(intervals))
128	fmt.Printf("// encodeX are the encoding tables from Unicode to GBK code,\n")
129	fmt.Printf("// sorted by decreasing length.\n")
130	for i, v := range intervals {
131		fmt.Printf("// encode%d: %5d entries for runes in [%5d, %5d).\n", i, v.len(), v.low, v.high)
132	}
133	fmt.Printf("\n")
134
135	for i, v := range intervals {
136		fmt.Printf("const encode%dLow, encode%dHigh = %d, %d\n\n", i, i, v.low, v.high)
137		fmt.Printf("var encode%d = [...]uint16{\n", i)
138		for j := v.low; j < v.high; j++ {
139			x := reverse[j]
140			if x == 0 {
141				continue
142			}
143			fmt.Printf("\t%d-%d: 0x%04X,\n", j, v.low, x)
144		}
145		fmt.Printf("}\n\n")
146	}
147}
148
149// interval is a half-open interval [low, high).
150type interval struct {
151	low, high int
152}
153
154func (i interval) len() int { return i.high - i.low }
155
156// byDecreasingLength sorts intervals by decreasing length.
157type byDecreasingLength []interval
158
159func (b byDecreasingLength) Len() int           { return len(b) }
160func (b byDecreasingLength) Less(i, j int) bool { return b[i].len() > b[j].len() }
161func (b byDecreasingLength) Swap(i, j int)      { b[i], b[j] = b[j], b[i] }
162