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 korean
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// All is a list of all defined encodings in this package.
17var All = []encoding.Encoding{EUCKR}
18
19// EUCKR is the EUC-KR encoding, also known as Code Page 949.
20var EUCKR encoding.Encoding = &eucKR
21
22var eucKR = internal.Encoding{
23	&internal.SimpleEncoding{eucKRDecoder{}, eucKREncoder{}},
24	"EUC-KR",
25	identifier.EUCKR,
26}
27
28type eucKRDecoder struct{ transform.NopResetter }
29
30func (eucKRDecoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
31	r, size := rune(0), 0
32loop:
33	for ; nSrc < len(src); nSrc += size {
34		switch c0 := src[nSrc]; {
35		case c0 < utf8.RuneSelf:
36			r, size = rune(c0), 1
37
38		case 0x81 <= c0 && c0 < 0xff:
39			if nSrc+1 >= len(src) {
40				if !atEOF {
41					err = transform.ErrShortSrc
42					break loop
43				}
44				r, size = utf8.RuneError, 1
45				break
46			}
47			c1 := src[nSrc+1]
48			size = 2
49			if c0 < 0xc7 {
50				r = 178 * rune(c0-0x81)
51				switch {
52				case 0x41 <= c1 && c1 < 0x5b:
53					r += rune(c1) - (0x41 - 0*26)
54				case 0x61 <= c1 && c1 < 0x7b:
55					r += rune(c1) - (0x61 - 1*26)
56				case 0x81 <= c1 && c1 < 0xff:
57					r += rune(c1) - (0x81 - 2*26)
58				default:
59					goto decError
60				}
61			} else if 0xa1 <= c1 && c1 < 0xff {
62				r = 178*(0xc7-0x81) + rune(c0-0xc7)*94 + rune(c1-0xa1)
63			} else {
64				goto decError
65			}
66			if int(r) < len(decode) {
67				r = rune(decode[r])
68				if r != 0 {
69					break
70				}
71			}
72		decError:
73			r = utf8.RuneError
74			if c1 < utf8.RuneSelf {
75				size = 1
76			}
77
78		default:
79			r, size = utf8.RuneError, 1
80			break
81		}
82
83		if nDst+utf8.RuneLen(r) > len(dst) {
84			err = transform.ErrShortDst
85			break
86		}
87		nDst += utf8.EncodeRune(dst[nDst:], r)
88	}
89	return nDst, nSrc, err
90}
91
92type eucKREncoder struct{ transform.NopResetter }
93
94func (eucKREncoder) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
95	r, size := rune(0), 0
96	for ; nSrc < len(src); nSrc += size {
97		r = rune(src[nSrc])
98
99		// Decode a 1-byte rune.
100		if r < utf8.RuneSelf {
101			size = 1
102
103			if nDst >= len(dst) {
104				err = transform.ErrShortDst
105				break
106			}
107			dst[nDst] = uint8(r)
108			nDst++
109			continue
110
111		} else {
112			// Decode a multi-byte rune.
113			r, size = utf8.DecodeRune(src[nSrc:])
114			if size == 1 {
115				// All valid runes of size 1 (those below utf8.RuneSelf) were
116				// handled above. We have invalid UTF-8 or we haven't seen the
117				// full character yet.
118				if !atEOF && !utf8.FullRune(src[nSrc:]) {
119					err = transform.ErrShortSrc
120					break
121				}
122			}
123
124			// func init checks that the switch covers all tables.
125			switch {
126			case encode0Low <= r && r < encode0High:
127				if r = rune(encode0[r-encode0Low]); r != 0 {
128					goto write2
129				}
130			case encode1Low <= r && r < encode1High:
131				if r = rune(encode1[r-encode1Low]); r != 0 {
132					goto write2
133				}
134			case encode2Low <= r && r < encode2High:
135				if r = rune(encode2[r-encode2Low]); r != 0 {
136					goto write2
137				}
138			case encode3Low <= r && r < encode3High:
139				if r = rune(encode3[r-encode3Low]); r != 0 {
140					goto write2
141				}
142			case encode4Low <= r && r < encode4High:
143				if r = rune(encode4[r-encode4Low]); r != 0 {
144					goto write2
145				}
146			case encode5Low <= r && r < encode5High:
147				if r = rune(encode5[r-encode5Low]); r != 0 {
148					goto write2
149				}
150			case encode6Low <= r && r < encode6High:
151				if r = rune(encode6[r-encode6Low]); r != 0 {
152					goto write2
153				}
154			}
155			err = internal.ErrASCIIReplacement
156			break
157		}
158
159	write2:
160		if nDst+2 > len(dst) {
161			err = transform.ErrShortDst
162			break
163		}
164		dst[nDst+0] = uint8(r >> 8)
165		dst[nDst+1] = uint8(r)
166		nDst += 2
167		continue
168	}
169	return nDst, nSrc, err
170}
171
172func init() {
173	// Check that the hard-coded encode switch covers all tables.
174	if numEncodeTables != 7 {
175		panic("bad numEncodeTables")
176	}
177}
178