--- /dev/null
+// 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.
+
+package japanese
+
+import (
+ "unicode/utf8"
+
+ "golang.org/x/text/encoding"
+ "golang.org/x/text/encoding/internal"
+ "golang.org/x/text/encoding/internal/identifier"
+ "golang.org/x/text/transform"
+)
+
+// ISO2022JP is the ISO-2022-JP encoding.
+var ISO2022JP encoding.Encoding = &iso2022JP
+
+var iso2022JP = internal.Encoding{
+ internal.FuncEncoding{iso2022JPNewDecoder, iso2022JPNewEncoder},
+ "ISO-2022-JP",
+ identifier.ISO2022JP,
+}
+
+func iso2022JPNewDecoder() transform.Transformer {
+ return new(iso2022JPDecoder)
+}
+
+func iso2022JPNewEncoder() transform.Transformer {
+ return new(iso2022JPEncoder)
+}
+
+const (
+ asciiState = iota
+ katakanaState
+ jis0208State
+ jis0212State
+)
+
+const asciiEsc = 0x1b
+
+type iso2022JPDecoder int
+
+func (d *iso2022JPDecoder) Reset() {
+ *d = asciiState
+}
+
+func (d *iso2022JPDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+ r, size := rune(0), 0
+ for ; nSrc < len(src); nSrc += size {
+ c0 := src[nSrc]
+ if c0 >= utf8.RuneSelf {
+ r, size = '\ufffd', 1
+ goto write
+ }
+
+ if c0 == asciiEsc {
+ if nSrc+2 >= len(src) {
+ if !atEOF {
+ return nDst, nSrc, transform.ErrShortSrc
+ }
+ // TODO: is it correct to only skip 1??
+ r, size = '\ufffd', 1
+ goto write
+ }
+ size = 3
+ c1 := src[nSrc+1]
+ c2 := src[nSrc+2]
+ switch {
+ case c1 == '$' && (c2 == '@' || c2 == 'B'): // 0x24 {0x40, 0x42}
+ *d = jis0208State
+ continue
+ case c1 == '$' && c2 == '(': // 0x24 0x28
+ if nSrc+3 >= len(src) {
+ if !atEOF {
+ return nDst, nSrc, transform.ErrShortSrc
+ }
+ r, size = '\ufffd', 1
+ goto write
+ }
+ size = 4
+ if src[nSrc+3] == 'D' {
+ *d = jis0212State
+ continue
+ }
+ case c1 == '(' && (c2 == 'B' || c2 == 'J'): // 0x28 {0x42, 0x4A}
+ *d = asciiState
+ continue
+ case c1 == '(' && c2 == 'I': // 0x28 0x49
+ *d = katakanaState
+ continue
+ }
+ r, size = '\ufffd', 1
+ goto write
+ }
+
+ switch *d {
+ case asciiState:
+ r, size = rune(c0), 1
+
+ case katakanaState:
+ if c0 < 0x21 || 0x60 <= c0 {
+ r, size = '\ufffd', 1
+ goto write
+ }
+ r, size = rune(c0)+(0xff61-0x21), 1
+
+ default:
+ if c0 == 0x0a {
+ *d = asciiState
+ r, size = rune(c0), 1
+ goto write
+ }
+ if nSrc+1 >= len(src) {
+ if !atEOF {
+ return nDst, nSrc, transform.ErrShortSrc
+ }
+ r, size = '\ufffd', 1
+ goto write
+ }
+ size = 2
+ c1 := src[nSrc+1]
+ i := int(c0-0x21)*94 + int(c1-0x21)
+ if *d == jis0208State && i < len(jis0208Decode) {
+ r = rune(jis0208Decode[i])
+ } else if *d == jis0212State && i < len(jis0212Decode) {
+ r = rune(jis0212Decode[i])
+ } else {
+ r = '\ufffd'
+ goto write
+ }
+ if r == 0 {
+ r = '\ufffd'
+ }
+ }
+
+ write:
+ if nDst+utf8.RuneLen(r) > len(dst) {
+ return nDst, nSrc, transform.ErrShortDst
+ }
+ nDst += utf8.EncodeRune(dst[nDst:], r)
+ }
+ return nDst, nSrc, err
+}
+
+type iso2022JPEncoder int
+
+func (e *iso2022JPEncoder) Reset() {
+ *e = asciiState
+}
+
+func (e *iso2022JPEncoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+ r, size := rune(0), 0
+ for ; nSrc < len(src); nSrc += size {
+ r = rune(src[nSrc])
+
+ // Decode a 1-byte rune.
+ if r < utf8.RuneSelf {
+ size = 1
+
+ } else {
+ // Decode a multi-byte rune.
+ r, size = utf8.DecodeRune(src[nSrc:])
+ if size == 1 {
+ // All valid runes of size 1 (those below utf8.RuneSelf) were
+ // handled above. We have invalid UTF-8 or we haven't seen the
+ // full character yet.
+ if !atEOF && !utf8.FullRune(src[nSrc:]) {
+ err = transform.ErrShortSrc
+ break
+ }
+ }
+
+ // func init checks that the switch covers all tables.
+ //
+ // http://encoding.spec.whatwg.org/#iso-2022-jp says that "the index jis0212
+ // is not used by the iso-2022-jp encoder due to lack of widespread support".
+ //
+ // TODO: do we have to special-case U+00A5 and U+203E, as per
+ // http://encoding.spec.whatwg.org/#iso-2022-jp
+ // Doing so would mean that "\u00a5" would not be preserved
+ // after an encode-decode round trip.
+ switch {
+ case encode0Low <= r && r < encode0High:
+ if r = rune(encode0[r-encode0Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ case encode1Low <= r && r < encode1High:
+ if r = rune(encode1[r-encode1Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ case encode2Low <= r && r < encode2High:
+ if r = rune(encode2[r-encode2Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ case encode3Low <= r && r < encode3High:
+ if r = rune(encode3[r-encode3Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ case encode4Low <= r && r < encode4High:
+ if r = rune(encode4[r-encode4Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ case encode5Low <= r && r < encode5High:
+ if 0xff61 <= r && r < 0xffa0 {
+ goto writeKatakana
+ }
+ if r = rune(encode5[r-encode5Low]); r>>tableShift == jis0208 {
+ goto writeJIS
+ }
+ }
+
+ // Switch back to ASCII state in case of error so that an ASCII
+ // replacement character can be written in the correct state.
+ if *e != asciiState {
+ if nDst+3 > len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ *e = asciiState
+ dst[nDst+0] = asciiEsc
+ dst[nDst+1] = '('
+ dst[nDst+2] = 'B'
+ nDst += 3
+ }
+ err = internal.ErrASCIIReplacement
+ break
+ }
+
+ if *e != asciiState {
+ if nDst+4 > len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ *e = asciiState
+ dst[nDst+0] = asciiEsc
+ dst[nDst+1] = '('
+ dst[nDst+2] = 'B'
+ nDst += 3
+ } else if nDst >= len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ dst[nDst] = uint8(r)
+ nDst++
+ continue
+
+ writeJIS:
+ if *e != jis0208State {
+ if nDst+5 > len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ *e = jis0208State
+ dst[nDst+0] = asciiEsc
+ dst[nDst+1] = '$'
+ dst[nDst+2] = 'B'
+ nDst += 3
+ } else if nDst+2 > len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ dst[nDst+0] = 0x21 + uint8(r>>codeShift)&codeMask
+ dst[nDst+1] = 0x21 + uint8(r)&codeMask
+ nDst += 2
+ continue
+
+ writeKatakana:
+ if *e != katakanaState {
+ if nDst+4 > len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ *e = katakanaState
+ dst[nDst+0] = asciiEsc
+ dst[nDst+1] = '('
+ dst[nDst+2] = 'I'
+ nDst += 3
+ } else if nDst >= len(dst) {
+ err = transform.ErrShortDst
+ break
+ }
+ dst[nDst] = uint8(r - (0xff61 - 0x21))
+ nDst++
+ continue
+ }
+ if atEOF && err == nil && *e != asciiState {
+ if nDst+3 > len(dst) {
+ err = transform.ErrShortDst
+ } else {
+ *e = asciiState
+ dst[nDst+0] = asciiEsc
+ dst[nDst+1] = '('
+ dst[nDst+2] = 'B'
+ nDst += 3
+ }
+ }
+ return nDst, nSrc, err
+}
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