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
5package japanese
6
7import (
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.
17var EUCJP encoding.Encoding = &eucJP
18
19var eucJP = internal.Encoding{
20	&internal.SimpleEncoding{eucJPDecoder{}, eucJPEncoder{}},
21	"EUC-JP",
22	identifier.EUCPkdFmtJapanese,
23}
24
25type eucJPDecoder struct{ transform.NopResetter }
26
27// See https://encoding.spec.whatwg.org/#euc-jp-decoder.
28func (eucJPDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
29	r, size := rune(0), 0
30loop:
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
122type eucJPEncoder struct{ transform.NopResetter }
123
124func (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
220func init() {
221	// Check that the hard-coded encode switch covers all tables.
222	if numEncodeTables != 6 {
223		panic("bad numEncodeTables")
224	}
225}
226