125 lines
2.2 KiB
Go
125 lines
2.2 KiB
Go
package mahonia
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import (
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"unicode/utf8"
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)
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// converters for ISO-2022-JP encoding
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const esc = 27
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func init() {
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type jpEncoding int
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const (
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ascii jpEncoding = iota
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jisX0201Roman
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jisX0208
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)
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RegisterCharset(&Charset{
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Name: "ISO-2022-JP",
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NewDecoder: func() Decoder {
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encoding := ascii
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return func(p []byte) (c rune, size int, status Status) {
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if len(p) == 0 {
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return 0, 0, NO_ROOM
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}
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b := p[0]
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if b == esc {
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if len(p) < 3 {
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return 0, 0, NO_ROOM
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}
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switch p[1] {
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case '(':
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switch p[2] {
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case 'B':
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encoding = ascii
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return 0, 3, STATE_ONLY
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case 'J':
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encoding = jisX0201Roman
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return 0, 3, STATE_ONLY
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}
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case '$':
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switch p[2] {
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case '@', 'B':
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encoding = jisX0208
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return 0, 3, STATE_ONLY
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}
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}
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}
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switch encoding {
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case ascii:
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if b > 127 {
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return utf8.RuneError, 1, INVALID_CHAR
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}
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return rune(b), 1, SUCCESS
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case jisX0201Roman:
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if b > 127 {
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return utf8.RuneError, 1, INVALID_CHAR
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}
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switch b {
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case '\\':
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return 0xA5, 1, SUCCESS
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case '~':
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return 0x203E, 1, SUCCESS
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}
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return rune(b), 1, SUCCESS
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case jisX0208:
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return jis0208Table.DecodeLow(p)
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}
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panic("unreachable")
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}
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},
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NewEncoder: func() Encoder {
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jis0208Table.Reverse()
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encoding := ascii
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return func(p []byte, c rune) (size int, status Status) {
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if len(p) == 0 {
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return 0, NO_ROOM
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}
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if c < 128 {
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if encoding != ascii {
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if len(p) < 4 {
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return 0, NO_ROOM
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}
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p[0], p[1], p[2] = esc, '(', 'B'
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p[3] = byte(c)
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encoding = ascii
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return 4, SUCCESS
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}
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p[0] = byte(c)
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return 1, SUCCESS
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}
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if c > 65535 {
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return 0, INVALID_CHAR
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}
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jis := jis0208Table.FromUnicode[c]
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if jis == [2]byte{0, 0} && c != rune(jis0208Table.Data[0][0]) {
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return 0, INVALID_CHAR
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}
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if encoding != jisX0208 {
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if len(p) < 3 {
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return 0, NO_ROOM
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}
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p[0], p[1], p[2] = esc, '$', 'B'
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encoding = jisX0208
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return 3, STATE_ONLY
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}
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p[0] = jis[0] + 0x21
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p[1] = jis[1] + 0x21
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return 2, SUCCESS
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}
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},
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})
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}
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