rss-tools/vendor/golang.org/x/text/encoding/japanese/eucjp.go (view raw)
| 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 | package japanese |
| 6 | |
| 7 | import ( |
| 8 | "unicode/utf8" |
| 9 | |
| 10 | "golang.org/x/text/encoding" |
| 11 | "golang.org/x/text/encoding/internal" |
| 12 | "golang.org/x/text/encoding/internal/identifier" |
| 13 | "golang.org/x/text/transform" |
| 14 | ) |
| 15 | |
| 16 | // EUCJP is the EUC-JP encoding. |
| 17 | var EUCJP encoding.Encoding = &eucJP |
| 18 | |
| 19 | var eucJP = internal.Encoding{ |
| 20 | Encoding: &internal.SimpleEncoding{Decoder: eucJPDecoder{}, Encoder: eucJPEncoder{}}, |
| 21 | Name: "EUC-JP", |
| 22 | MIB: identifier.EUCPkdFmtJapanese, |
| 23 | } |
| 24 | |
| 25 | type eucJPDecoder struct{ transform.NopResetter } |
| 26 | |
| 27 | // See https://encoding.spec.whatwg.org/#euc-jp-decoder. |
| 28 | func (eucJPDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { |
| 29 | r, size := rune(0), 0 |
| 30 | loop: |
| 31 | for ; nSrc < len(src); nSrc += size { |
| 32 | switch c0 := src[nSrc]; { |
| 33 | case c0 < utf8.RuneSelf: |
| 34 | r, size = rune(c0), 1 |
| 35 | |
| 36 | case c0 == 0x8e: |
| 37 | if nSrc+1 >= len(src) { |
| 38 | if !atEOF { |
| 39 | err = transform.ErrShortSrc |
| 40 | break loop |
| 41 | } |
| 42 | r, size = utf8.RuneError, 1 |
| 43 | break |
| 44 | } |
| 45 | c1 := src[nSrc+1] |
| 46 | switch { |
| 47 | case c1 < 0xa1: |
| 48 | r, size = utf8.RuneError, 1 |
| 49 | case c1 > 0xdf: |
| 50 | r, size = utf8.RuneError, 2 |
| 51 | if c1 == 0xff { |
| 52 | size = 1 |
| 53 | } |
| 54 | default: |
| 55 | r, size = rune(c1)+(0xff61-0xa1), 2 |
| 56 | } |
| 57 | case c0 == 0x8f: |
| 58 | if nSrc+2 >= len(src) { |
| 59 | if !atEOF { |
| 60 | err = transform.ErrShortSrc |
| 61 | break loop |
| 62 | } |
| 63 | r, size = utf8.RuneError, 1 |
| 64 | if p := nSrc + 1; p < len(src) && 0xa1 <= src[p] && src[p] < 0xfe { |
| 65 | size = 2 |
| 66 | } |
| 67 | break |
| 68 | } |
| 69 | c1 := src[nSrc+1] |
| 70 | if c1 < 0xa1 || 0xfe < c1 { |
| 71 | r, size = utf8.RuneError, 1 |
| 72 | break |
| 73 | } |
| 74 | c2 := src[nSrc+2] |
| 75 | if c2 < 0xa1 || 0xfe < c2 { |
| 76 | r, size = utf8.RuneError, 2 |
| 77 | break |
| 78 | } |
| 79 | r, size = utf8.RuneError, 3 |
| 80 | if i := int(c1-0xa1)*94 + int(c2-0xa1); i < len(jis0212Decode) { |
| 81 | r = rune(jis0212Decode[i]) |
| 82 | if r == 0 { |
| 83 | r = utf8.RuneError |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | case 0xa1 <= c0 && c0 <= 0xfe: |
| 88 | if nSrc+1 >= len(src) { |
| 89 | if !atEOF { |
| 90 | err = transform.ErrShortSrc |
| 91 | break loop |
| 92 | } |
| 93 | r, size = utf8.RuneError, 1 |
| 94 | break |
| 95 | } |
| 96 | c1 := src[nSrc+1] |
| 97 | if c1 < 0xa1 || 0xfe < c1 { |
| 98 | r, size = utf8.RuneError, 1 |
| 99 | break |
| 100 | } |
| 101 | r, size = utf8.RuneError, 2 |
| 102 | if i := int(c0-0xa1)*94 + int(c1-0xa1); i < len(jis0208Decode) { |
| 103 | r = rune(jis0208Decode[i]) |
| 104 | if r == 0 { |
| 105 | r = utf8.RuneError |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | default: |
| 110 | r, size = utf8.RuneError, 1 |
| 111 | } |
| 112 | |
| 113 | if nDst+utf8.RuneLen(r) > len(dst) { |
| 114 | err = transform.ErrShortDst |
| 115 | break loop |
| 116 | } |
| 117 | nDst += utf8.EncodeRune(dst[nDst:], r) |
| 118 | } |
| 119 | return nDst, nSrc, err |
| 120 | } |
| 121 | |
| 122 | type eucJPEncoder struct{ transform.NopResetter } |
| 123 | |
| 124 | func (eucJPEncoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) { |
| 125 | r, size := rune(0), 0 |
| 126 | for ; nSrc < len(src); nSrc += size { |
| 127 | r = rune(src[nSrc]) |
| 128 | |
| 129 | // Decode a 1-byte rune. |
| 130 | if r < utf8.RuneSelf { |
| 131 | size = 1 |
| 132 | |
| 133 | } else { |
| 134 | // Decode a multi-byte rune. |
| 135 | r, size = utf8.DecodeRune(src[nSrc:]) |
| 136 | if size == 1 { |
| 137 | // All valid runes of size 1 (those below utf8.RuneSelf) were |
| 138 | // handled above. We have invalid UTF-8 or we haven't seen the |
| 139 | // full character yet. |
| 140 | if !atEOF && !utf8.FullRune(src[nSrc:]) { |
| 141 | err = transform.ErrShortSrc |
| 142 | break |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | // func init checks that the switch covers all tables. |
| 147 | switch { |
| 148 | case encode0Low <= r && r < encode0High: |
| 149 | if r = rune(encode0[r-encode0Low]); r != 0 { |
| 150 | goto write2or3 |
| 151 | } |
| 152 | case encode1Low <= r && r < encode1High: |
| 153 | if r = rune(encode1[r-encode1Low]); r != 0 { |
| 154 | goto write2or3 |
| 155 | } |
| 156 | case encode2Low <= r && r < encode2High: |
| 157 | if r = rune(encode2[r-encode2Low]); r != 0 { |
| 158 | goto write2or3 |
| 159 | } |
| 160 | case encode3Low <= r && r < encode3High: |
| 161 | if r = rune(encode3[r-encode3Low]); r != 0 { |
| 162 | goto write2or3 |
| 163 | } |
| 164 | case encode4Low <= r && r < encode4High: |
| 165 | if r = rune(encode4[r-encode4Low]); r != 0 { |
| 166 | goto write2or3 |
| 167 | } |
| 168 | case encode5Low <= r && r < encode5High: |
| 169 | if 0xff61 <= r && r < 0xffa0 { |
| 170 | goto write2 |
| 171 | } |
| 172 | if r = rune(encode5[r-encode5Low]); r != 0 { |
| 173 | goto write2or3 |
| 174 | } |
| 175 | } |
| 176 | err = internal.ErrASCIIReplacement |
| 177 | break |
| 178 | } |
| 179 | |
| 180 | if nDst >= len(dst) { |
| 181 | err = transform.ErrShortDst |
| 182 | break |
| 183 | } |
| 184 | dst[nDst] = uint8(r) |
| 185 | nDst++ |
| 186 | continue |
| 187 | |
| 188 | write2or3: |
| 189 | if r>>tableShift == jis0208 { |
| 190 | if nDst+2 > len(dst) { |
| 191 | err = transform.ErrShortDst |
| 192 | break |
| 193 | } |
| 194 | } else { |
| 195 | if nDst+3 > len(dst) { |
| 196 | err = transform.ErrShortDst |
| 197 | break |
| 198 | } |
| 199 | dst[nDst] = 0x8f |
| 200 | nDst++ |
| 201 | } |
| 202 | dst[nDst+0] = 0xa1 + uint8(r>>codeShift)&codeMask |
| 203 | dst[nDst+1] = 0xa1 + uint8(r)&codeMask |
| 204 | nDst += 2 |
| 205 | continue |
| 206 | |
| 207 | write2: |
| 208 | if nDst+2 > len(dst) { |
| 209 | err = transform.ErrShortDst |
| 210 | break |
| 211 | } |
| 212 | dst[nDst+0] = 0x8e |
| 213 | dst[nDst+1] = uint8(r - (0xff61 - 0xa1)) |
| 214 | nDst += 2 |
| 215 | continue |
| 216 | } |
| 217 | return nDst, nSrc, err |
| 218 | } |
| 219 | |
| 220 | func init() { |
| 221 | // Check that the hard-coded encode switch covers all tables. |
| 222 | if numEncodeTables != 6 { |
| 223 | panic("bad numEncodeTables") |
| 224 | } |
| 225 | } |