encoding/codec/
tradchinese.rs

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1// This is a part of rust-encoding.
2// Copyright (c) 2013-2015, Kang Seonghoon.
3// See README.md and LICENSE.txt for details.
4
5//! Legacy traditional Chinese encodings.
6
7use std::convert::Into;
8use std::default::Default;
9use util::StrCharIndex;
10use index_tradchinese as index;
11use types::*;
12
13/**
14 * Big5-2003 with common extensions. (XXX with asymmetric HKSCS-2008 support)
15 *
16 * This is a traditional Chinese encoding spanning the region `[81-FE] [40-7E A1-FE]`.
17 * Originally a proprietary encoding by the consortium of five companies (hence the name),
18 * the Republic of China government standardized Big5-2003 in an appendix of CNS 11643
19 * so that CNS 11643 plane 1 and plane 2 have
20 * an almost identical set of characters as Big5 (but with a different mapping).
21 * The Hong Kong government has an official extension to Big5
22 * named Hong Kong Supplementary Character Set (HKSCS).
23 *
24 * This particular implementation of Big5 includes the widespread ETEN and HKSCS extensions,
25 * but excludes less common extensions such as Big5+, Big-5E and Unicode-at-on.
26 */
27#[derive(Clone, Copy)]
28pub struct BigFive2003Encoding;
29
30impl Encoding for BigFive2003Encoding {
31    fn name(&self) -> &'static str { "big5-2003" }
32    fn whatwg_name(&self) -> Option<&'static str> { Some("big5") } // WHATWG compatibility
33    fn raw_encoder(&self) -> Box<RawEncoder> { BigFive2003Encoder::new() }
34    fn raw_decoder(&self) -> Box<RawDecoder> { BigFive2003HKSCS2008Decoder::new() }
35}
36
37/// An encoder for Big5-2003.
38#[derive(Clone, Copy)]
39pub struct BigFive2003Encoder;
40
41impl BigFive2003Encoder {
42    pub fn new() -> Box<RawEncoder> { Box::new(BigFive2003Encoder) }
43}
44
45impl RawEncoder for BigFive2003Encoder {
46    fn from_self(&self) -> Box<RawEncoder> { BigFive2003Encoder::new() }
47    fn is_ascii_compatible(&self) -> bool { true }
48
49    fn raw_feed(&mut self, input: &str, output: &mut ByteWriter) -> (usize, Option<CodecError>) {
50        output.writer_hint(input.len());
51
52        for ((i,j), ch) in input.index_iter() {
53            if ch < '\u{80}' {
54                output.write_byte(ch as u8);
55            } else {
56                let ptr = index::big5::backward(ch as u32);
57                if ptr == 0xffff || ptr < (0xa1 - 0x81) * 157 {
58                    // no HKSCS extension (XXX doesn't HKSCS include 0xFA40..0xFEFE?)
59                    return (i, Some(CodecError {
60                        upto: j as isize, cause: "unrepresentable character".into()
61                    }));
62                }
63                let lead = ptr / 157 + 0x81;
64                let trail = ptr % 157;
65                let trailoffset = if trail < 0x3f {0x40} else {0x62};
66                output.write_byte(lead as u8);
67                output.write_byte((trail + trailoffset) as u8);
68            }
69        }
70        (input.len(), None)
71    }
72
73    fn raw_finish(&mut self, _output: &mut ByteWriter) -> Option<CodecError> {
74        None
75    }
76}
77
78/// A decoder for Big5-2003 with HKSCS-2008 extension.
79#[derive(Clone, Copy)]
80struct BigFive2003HKSCS2008Decoder {
81    st: bigfive2003::State,
82}
83
84impl BigFive2003HKSCS2008Decoder {
85    pub fn new() -> Box<RawDecoder> {
86        Box::new(BigFive2003HKSCS2008Decoder { st: Default::default() })
87    }
88}
89
90impl RawDecoder for BigFive2003HKSCS2008Decoder {
91    fn from_self(&self) -> Box<RawDecoder> { BigFive2003HKSCS2008Decoder::new() }
92    fn is_ascii_compatible(&self) -> bool { true }
93
94    fn raw_feed(&mut self, input: &[u8], output: &mut StringWriter) -> (usize, Option<CodecError>) {
95        let (st, processed, err) = bigfive2003::raw_feed(self.st, input, output, &());
96        self.st = st;
97        (processed, err)
98    }
99
100    fn raw_finish(&mut self, output: &mut StringWriter) -> Option<CodecError> {
101        let (st, err) = bigfive2003::raw_finish(self.st, output, &());
102        self.st = st;
103        err
104    }
105}
106
107stateful_decoder! {
108    module bigfive2003;
109
110    internal pub fn map_two_bytes(lead: u8, trail: u8) -> u32 {
111        use index_tradchinese as index;
112
113        let lead = lead as u16;
114        let trail = trail as u16;
115        let index = match (lead, trail) {
116            (0x81...0xfe, 0x40...0x7e) | (0x81...0xfe, 0xa1...0xfe) => {
117                let trailoffset = if trail < 0x7f {0x40} else {0x62};
118                (lead - 0x81) * 157 + trail - trailoffset
119            }
120            _ => 0xffff,
121        };
122        index::big5::forward(index) // may return two-letter replacements 0..3
123    }
124
125initial:
126    // big5 lead = 0x00
127    state S0(ctx: Context) {
128        case b @ 0x00...0x7f => ctx.emit(b as u32);
129        case b @ 0x81...0xfe => S1(ctx, b);
130        case _ => ctx.err("invalid sequence");
131    }
132
133transient:
134    // big5 lead != 0x00
135    state S1(ctx: Context, lead: u8) {
136        case b => match map_two_bytes(lead, b) {
137            0xffff => {
138                let backup = if b < 0x80 {1} else {0};
139                ctx.backup_and_err(backup, "invalid sequence")
140            },
141            0 /*index=1133*/ => ctx.emit_str("\u{ca}\u{304}"),
142            1 /*index=1135*/ => ctx.emit_str("\u{ca}\u{30c}"),
143            2 /*index=1164*/ => ctx.emit_str("\u{ea}\u{304}"),
144            3 /*index=1166*/ => ctx.emit_str("\u{ea}\u{30c}"),
145            ch => ctx.emit(ch),
146        };
147    }
148}
149
150#[cfg(test)]
151mod bigfive2003_tests {
152    extern crate test;
153    use super::BigFive2003Encoding;
154    use testutils;
155    use types::*;
156
157    #[test]
158    fn test_encoder_valid() {
159        let mut e = BigFive2003Encoding.raw_encoder();
160        assert_feed_ok!(e, "A", "", [0x41]);
161        assert_feed_ok!(e, "BC", "", [0x42, 0x43]);
162        assert_feed_ok!(e, "", "", []);
163        assert_feed_ok!(e, "\u{4e2d}\u{83ef}\u{6c11}\u{570b}", "",
164                        [0xa4, 0xa4, 0xb5, 0xd8, 0xa5, 0xc1, 0xb0, 0xea]);
165        assert_feed_ok!(e, "1\u{20ac}/m", "", [0x31, 0xa3, 0xe1, 0x2f, 0x6d]);
166        assert_feed_ok!(e, "\u{ffed}", "", [0xf9, 0xfe]);
167        assert_finish_ok!(e, []);
168    }
169
170    #[test]
171    fn test_encoder_invalid() {
172        let mut e = BigFive2003Encoding.raw_encoder();
173        assert_feed_err!(e, "", "\u{ffff}", "", []);
174        assert_feed_err!(e, "?", "\u{ffff}", "!", [0x3f]);
175        assert_feed_err!(e, "", "\u{3eec}", "\u{4e00}", []); // HKSCS-2008 addition
176        assert_finish_ok!(e, []);
177    }
178
179    #[test]
180    fn test_decoder_valid() {
181        let mut d = BigFive2003Encoding.raw_decoder();
182        assert_feed_ok!(d, [0x41], [], "A");
183        assert_feed_ok!(d, [0x42, 0x43], [], "BC");
184        assert_feed_ok!(d, [], [], "");
185        assert_feed_ok!(d, [0xa4, 0xa4, 0xb5, 0xd8, 0xa5, 0xc1, 0xb0, 0xea], [],
186                        "\u{4e2d}\u{83ef}\u{6c11}\u{570b}");
187        assert_feed_ok!(d, [], [0xa4], "");
188        assert_feed_ok!(d, [0xa4, 0xb5, 0xd8], [0xa5], "\u{4e2d}\u{83ef}");
189        assert_feed_ok!(d, [0xc1, 0xb0, 0xea], [], "\u{6c11}\u{570b}");
190        assert_feed_ok!(d, [0x31, 0xa3, 0xe1, 0x2f, 0x6d], [], "1\u{20ac}/m");
191        assert_feed_ok!(d, [0xf9, 0xfe], [], "\u{ffed}");
192        assert_feed_ok!(d, [0x87, 0x7e], [], "\u{3eec}"); // HKSCS-2008 addition
193        assert_feed_ok!(d, [0x88, 0x62, 0x88, 0x64, 0x88, 0xa3, 0x88, 0xa5], [],
194                        "\u{ca}\u{304}\u{00ca}\u{30c}\u{ea}\u{304}\u{ea}\u{30c}"); // 2-byte output
195        assert_finish_ok!(d, "");
196    }
197
198    #[test]
199    fn test_decoder_invalid_lone_lead_immediate_test_finish() {
200        for i in 0x81..0xff {
201            let mut d = BigFive2003Encoding.raw_decoder();
202            assert_feed_ok!(d, [], [i], ""); // wait for a trail
203            assert_finish_err!(d, "");
204        }
205
206        // 80/FF: immediate failure
207        let mut d = BigFive2003Encoding.raw_decoder();
208        assert_feed_err!(d, [], [0x80], [], "");
209        assert_feed_err!(d, [], [0xff], [], "");
210        assert_finish_ok!(d, "");
211    }
212
213    #[test]
214    fn test_decoder_invalid_lone_lead_followed_by_space() {
215        for i in 0x80..0x100 {
216            let i = i as u8;
217            let mut d = BigFive2003Encoding.raw_decoder();
218            assert_feed_err!(d, [], [i], [0x20], "");
219            assert_finish_ok!(d, "");
220        }
221    }
222
223    #[test]
224    fn test_decoder_invalid_lead_followed_by_invalid_trail() {
225        // unlike most other cases, valid lead + invalid MSB-set trail are entirely consumed.
226        // https://www.w3.org/Bugs/Public/show_bug.cgi?id=16771
227        for i in 0x81..0xff {
228            let mut d = BigFive2003Encoding.raw_decoder();
229            assert_feed_err!(d, [], [i, 0x80], [0x20], "");
230            assert_feed_err!(d, [], [i, 0xff], [0x20], "");
231            assert_finish_ok!(d, "");
232
233            let mut d = BigFive2003Encoding.raw_decoder();
234            assert_feed_ok!(d, [], [i], "");
235            assert_feed_err!(d, [], [0x80], [0x20], "");
236            assert_feed_ok!(d, [], [i], "");
237            assert_feed_err!(d, [], [0xff], [0x20], "");
238            assert_finish_ok!(d, "");
239        }
240
241        // 80/FF is not a valid lead and the trail is not consumed
242        let mut d = BigFive2003Encoding.raw_decoder();
243        assert_feed_err!(d, [], [0x80], [0x80], "");
244        assert_feed_err!(d, [], [0x80], [0xff], "");
245        assert_feed_err!(d, [], [0xff], [0x80], "");
246        assert_feed_err!(d, [], [0xff], [0xff], "");
247        assert_finish_ok!(d, "");
248    }
249
250    #[test]
251    fn test_decoder_feed_after_finish() {
252        let mut d = BigFive2003Encoding.raw_decoder();
253        assert_feed_ok!(d, [0xa4, 0x40], [0xa4], "\u{4e00}");
254        assert_finish_err!(d, "");
255        assert_feed_ok!(d, [0xa4, 0x40], [], "\u{4e00}");
256        assert_finish_ok!(d, "");
257    }
258
259    #[bench]
260    fn bench_encode_short_text(bencher: &mut test::Bencher) {
261        let s = testutils::TRADITIONAL_CHINESE_TEXT;
262        bencher.bytes = s.len() as u64;
263        bencher.iter(|| test::black_box({
264            BigFive2003Encoding.encode(&s, EncoderTrap::Strict)
265        }))
266    }
267
268    #[bench]
269    fn bench_decode_short_text(bencher: &mut test::Bencher) {
270        let s = BigFive2003Encoding.encode(testutils::TRADITIONAL_CHINESE_TEXT,
271                                           EncoderTrap::Strict).ok().unwrap();
272        bencher.bytes = s.len() as u64;
273        bencher.iter(|| test::black_box({
274            BigFive2003Encoding.decode(&s, DecoderTrap::Strict)
275        }))
276    }
277}
encoding/codec/tradchinese.rs

encoding/codec/
tradchinese.rs
