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dex/vendor/golang.org/x/text/encoding/japanese/eucjp.go
2020-01-31 10:32:00 +01:00

226 lines
4.8 KiB
Go

// 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"
)
// EUCJP is the EUC-JP encoding.
var EUCJP encoding.Encoding = &eucJP
var eucJP = internal.Encoding{
&internal.SimpleEncoding{eucJPDecoder{}, eucJPEncoder{}},
"EUC-JP",
identifier.EUCPkdFmtJapanese,
}
type eucJPDecoder struct{ transform.NopResetter }
// See https://encoding.spec.whatwg.org/#euc-jp-decoder.
func (eucJPDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
r, size := rune(0), 0
loop:
for ; nSrc < len(src); nSrc += size {
switch c0 := src[nSrc]; {
case c0 < utf8.RuneSelf:
r, size = rune(c0), 1
case c0 == 0x8e:
if nSrc+1 >= len(src) {
if !atEOF {
err = transform.ErrShortSrc
break loop
}
r, size = utf8.RuneError, 1
break
}
c1 := src[nSrc+1]
switch {
case c1 < 0xa1:
r, size = utf8.RuneError, 1
case c1 > 0xdf:
r, size = utf8.RuneError, 2
if c1 == 0xff {
size = 1
}
default:
r, size = rune(c1)+(0xff61-0xa1), 2
}
case c0 == 0x8f:
if nSrc+2 >= len(src) {
if !atEOF {
err = transform.ErrShortSrc
break loop
}
r, size = utf8.RuneError, 1
if p := nSrc + 1; p < len(src) && 0xa1 <= src[p] && src[p] < 0xfe {
size = 2
}
break
}
c1 := src[nSrc+1]
if c1 < 0xa1 || 0xfe < c1 {
r, size = utf8.RuneError, 1
break
}
c2 := src[nSrc+2]
if c2 < 0xa1 || 0xfe < c2 {
r, size = utf8.RuneError, 2
break
}
r, size = utf8.RuneError, 3
if i := int(c1-0xa1)*94 + int(c2-0xa1); i < len(jis0212Decode) {
r = rune(jis0212Decode[i])
if r == 0 {
r = utf8.RuneError
}
}
case 0xa1 <= c0 && c0 <= 0xfe:
if nSrc+1 >= len(src) {
if !atEOF {
err = transform.ErrShortSrc
break loop
}
r, size = utf8.RuneError, 1
break
}
c1 := src[nSrc+1]
if c1 < 0xa1 || 0xfe < c1 {
r, size = utf8.RuneError, 1
break
}
r, size = utf8.RuneError, 2
if i := int(c0-0xa1)*94 + int(c1-0xa1); i < len(jis0208Decode) {
r = rune(jis0208Decode[i])
if r == 0 {
r = utf8.RuneError
}
}
default:
r, size = utf8.RuneError, 1
}
if nDst+utf8.RuneLen(r) > len(dst) {
err = transform.ErrShortDst
break loop
}
nDst += utf8.EncodeRune(dst[nDst:], r)
}
return nDst, nSrc, err
}
type eucJPEncoder struct{ transform.NopResetter }
func (eucJPEncoder) 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.
switch {
case encode0Low <= r && r < encode0High:
if r = rune(encode0[r-encode0Low]); r != 0 {
goto write2or3
}
case encode1Low <= r && r < encode1High:
if r = rune(encode1[r-encode1Low]); r != 0 {
goto write2or3
}
case encode2Low <= r && r < encode2High:
if r = rune(encode2[r-encode2Low]); r != 0 {
goto write2or3
}
case encode3Low <= r && r < encode3High:
if r = rune(encode3[r-encode3Low]); r != 0 {
goto write2or3
}
case encode4Low <= r && r < encode4High:
if r = rune(encode4[r-encode4Low]); r != 0 {
goto write2or3
}
case encode5Low <= r && r < encode5High:
if 0xff61 <= r && r < 0xffa0 {
goto write2
}
if r = rune(encode5[r-encode5Low]); r != 0 {
goto write2or3
}
}
err = internal.ErrASCIIReplacement
break
}
if nDst >= len(dst) {
err = transform.ErrShortDst
break
}
dst[nDst] = uint8(r)
nDst++
continue
write2or3:
if r>>tableShift == jis0208 {
if nDst+2 > len(dst) {
err = transform.ErrShortDst
break
}
} else {
if nDst+3 > len(dst) {
err = transform.ErrShortDst
break
}
dst[nDst] = 0x8f
nDst++
}
dst[nDst+0] = 0xa1 + uint8(r>>codeShift)&codeMask
dst[nDst+1] = 0xa1 + uint8(r)&codeMask
nDst += 2
continue
write2:
if nDst+2 > len(dst) {
err = transform.ErrShortDst
break
}
dst[nDst+0] = 0x8e
dst[nDst+1] = uint8(r - (0xff61 - 0xa1))
nDst += 2
continue
}
return nDst, nSrc, err
}
func init() {
// Check that the hard-coded encode switch covers all tables.
if numEncodeTables != 6 {
panic("bad numEncodeTables")
}
}