aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_editor/src/line_index.rs
blob: 898fee7e00ea815549b6855a6c75df9ed9e17b8f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
use crate::TextUnit;
use rustc_hash::FxHashMap;
use superslice::Ext;

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct LineIndex {
    pub(crate) newlines: Vec<TextUnit>,
    pub(crate) utf16_lines: FxHashMap<u32, Vec<Utf16Char>>,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct LineCol {
    pub line: u32,
    pub col_utf16: u32,
}

#[derive(Clone, Debug, Hash, PartialEq, Eq)]
pub(crate) struct Utf16Char {
    pub(crate) start: TextUnit,
    pub(crate) end: TextUnit,
}

impl Utf16Char {
    fn len(&self) -> TextUnit {
        self.end - self.start
    }
}

impl LineIndex {
    pub fn new(text: &str) -> LineIndex {
        let mut utf16_lines = FxHashMap::default();
        let mut utf16_chars = Vec::new();

        let mut newlines = vec![0.into()];
        let mut curr_row = 0.into();
        let mut curr_col = 0.into();
        let mut line = 0;
        for c in text.chars() {
            curr_row += TextUnit::of_char(c);
            if c == '\n' {
                newlines.push(curr_row);

                // Save any utf-16 characters seen in the previous line
                if utf16_chars.len() > 0 {
                    utf16_lines.insert(line, utf16_chars);
                    utf16_chars = Vec::new();
                }

                // Prepare for processing the next line
                curr_col = 0.into();
                line += 1;
                continue;
            }

            let char_len = TextUnit::of_char(c);
            if char_len.to_usize() > 1 {
                utf16_chars.push(Utf16Char {
                    start: curr_col,
                    end: curr_col + char_len,
                });
            }

            curr_col += char_len;
        }

        // Save any utf-16 characters seen in the last line
        if utf16_chars.len() > 0 {
            utf16_lines.insert(line, utf16_chars);
        }

        LineIndex {
            newlines,
            utf16_lines,
        }
    }

    pub fn line_col(&self, offset: TextUnit) -> LineCol {
        let line = self.newlines.upper_bound(&offset) - 1;
        let line_start_offset = self.newlines[line];
        let col = offset - line_start_offset;

        LineCol {
            line: line as u32,
            col_utf16: self.utf8_to_utf16_col(line as u32, col) as u32,
        }
    }

    pub fn offset(&self, line_col: LineCol) -> TextUnit {
        //TODO: return Result
        let col = self.utf16_to_utf8_col(line_col.line, line_col.col_utf16);
        self.newlines[line_col.line as usize] + col
    }

    fn utf8_to_utf16_col(&self, line: u32, mut col: TextUnit) -> usize {
        if let Some(utf16_chars) = self.utf16_lines.get(&line) {
            let mut correction = TextUnit::from_usize(0);
            for c in utf16_chars {
                if col >= c.end {
                    correction += c.len() - TextUnit::from_usize(1);
                } else {
                    // From here on, all utf16 characters come *after* the character we are mapping,
                    // so we don't need to take them into account
                    break;
                }
            }

            col -= correction;
        }

        col.to_usize()
    }

    fn utf16_to_utf8_col(&self, line: u32, col: u32) -> TextUnit {
        let mut col: TextUnit = col.into();
        if let Some(utf16_chars) = self.utf16_lines.get(&line) {
            for c in utf16_chars {
                if col >= c.start {
                    col += c.len() - TextUnit::from_usize(1);
                } else {
                    // From here on, all utf16 characters come *after* the character we are mapping,
                    // so we don't need to take them into account
                    break;
                }
            }
        }

        col
    }
}

#[cfg(test)]
/// Simple reference implementation to use in proptests
pub fn to_line_col(text: &str, offset: TextUnit) -> LineCol {
    let mut res = LineCol {
        line: 0,
        col_utf16: 0,
    };
    for (i, c) in text.char_indices() {
        if i + c.len_utf8() > offset.to_usize() {
            // if it's an invalid offset, inside a multibyte char
            // return as if it was at the start of the char
            break;
        }
        if c == '\n' {
            res.line += 1;
            res.col_utf16 = 0;
        } else {
            res.col_utf16 += 1;
        }
    }
    res
}

#[cfg(test)]
mod test_line_index {
    use super::*;
    use proptest::{prelude::*, proptest, proptest_helper};
    use ra_text_edit::test_utils::{arb_text, arb_offset};

    #[test]
    fn test_line_index() {
        let text = "hello\nworld";
        let index = LineIndex::new(text);
        assert_eq!(
            index.line_col(0.into()),
            LineCol {
                line: 0,
                col_utf16: 0
            }
        );
        assert_eq!(
            index.line_col(1.into()),
            LineCol {
                line: 0,
                col_utf16: 1
            }
        );
        assert_eq!(
            index.line_col(5.into()),
            LineCol {
                line: 0,
                col_utf16: 5
            }
        );
        assert_eq!(
            index.line_col(6.into()),
            LineCol {
                line: 1,
                col_utf16: 0
            }
        );
        assert_eq!(
            index.line_col(7.into()),
            LineCol {
                line: 1,
                col_utf16: 1
            }
        );
        assert_eq!(
            index.line_col(8.into()),
            LineCol {
                line: 1,
                col_utf16: 2
            }
        );
        assert_eq!(
            index.line_col(10.into()),
            LineCol {
                line: 1,
                col_utf16: 4
            }
        );
        assert_eq!(
            index.line_col(11.into()),
            LineCol {
                line: 1,
                col_utf16: 5
            }
        );
        assert_eq!(
            index.line_col(12.into()),
            LineCol {
                line: 1,
                col_utf16: 6
            }
        );

        let text = "\nhello\nworld";
        let index = LineIndex::new(text);
        assert_eq!(
            index.line_col(0.into()),
            LineCol {
                line: 0,
                col_utf16: 0
            }
        );
        assert_eq!(
            index.line_col(1.into()),
            LineCol {
                line: 1,
                col_utf16: 0
            }
        );
        assert_eq!(
            index.line_col(2.into()),
            LineCol {
                line: 1,
                col_utf16: 1
            }
        );
        assert_eq!(
            index.line_col(6.into()),
            LineCol {
                line: 1,
                col_utf16: 5
            }
        );
        assert_eq!(
            index.line_col(7.into()),
            LineCol {
                line: 2,
                col_utf16: 0
            }
        );
    }

    fn arb_text_with_offset() -> BoxedStrategy<(TextUnit, String)> {
        arb_text()
            .prop_flat_map(|text| (arb_offset(&text), Just(text)))
            .boxed()
    }

    fn to_line_col(text: &str, offset: TextUnit) -> LineCol {
        let mut res = LineCol {
            line: 0,
            col_utf16: 0,
        };
        for (i, c) in text.char_indices() {
            if i + c.len_utf8() > offset.to_usize() {
                // if it's an invalid offset, inside a multibyte char
                // return as if it was at the start of the char
                break;
            }
            if c == '\n' {
                res.line += 1;
                res.col_utf16 = 0;
            } else {
                res.col_utf16 += 1;
            }
        }
        res
    }

    proptest! {
        #[test]
        fn test_line_index_proptest((offset, text) in arb_text_with_offset()) {
            let expected = to_line_col(&text, offset);
            let line_index = LineIndex::new(&text);
            let actual = line_index.line_col(offset);

            assert_eq!(actual, expected);
        }
    }
}

#[cfg(test)]
mod test_utf8_utf16_conv {
    use super::*;

    #[test]
    fn test_char_len() {
        assert_eq!('メ'.len_utf8(), 3);
        assert_eq!('メ'.len_utf16(), 1);
    }

    #[test]
    fn test_empty_index() {
        let col_index = LineIndex::new(
            "
const C: char = 'x';
",
        );
        assert_eq!(col_index.utf16_lines.len(), 0);
    }

    #[test]
    fn test_single_char() {
        let col_index = LineIndex::new(
            "
const C: char = 'メ';
",
        );

        assert_eq!(col_index.utf16_lines.len(), 1);
        assert_eq!(col_index.utf16_lines[&1].len(), 1);
        assert_eq!(
            col_index.utf16_lines[&1][0],
            Utf16Char {
                start: 17.into(),
                end: 20.into()
            }
        );

        // UTF-8 to UTF-16, no changes
        assert_eq!(col_index.utf8_to_utf16_col(1, 15.into()), 15);

        // UTF-8 to UTF-16
        assert_eq!(col_index.utf8_to_utf16_col(1, 22.into()), 20);

        // UTF-16 to UTF-8, no changes
        assert_eq!(col_index.utf16_to_utf8_col(1, 15), TextUnit::from(15));

        // UTF-16 to UTF-8
        assert_eq!(col_index.utf16_to_utf8_col(1, 19), TextUnit::from(21));
    }

    #[test]
    fn test_string() {
        let col_index = LineIndex::new(
            "
const C: char = \"メ メ\";
",
        );

        assert_eq!(col_index.utf16_lines.len(), 1);
        assert_eq!(col_index.utf16_lines[&1].len(), 2);
        assert_eq!(
            col_index.utf16_lines[&1][0],
            Utf16Char {
                start: 17.into(),
                end: 20.into()
            }
        );
        assert_eq!(
            col_index.utf16_lines[&1][1],
            Utf16Char {
                start: 21.into(),
                end: 24.into()
            }
        );

        // UTF-8 to UTF-16
        assert_eq!(col_index.utf8_to_utf16_col(1, 15.into()), 15);

        assert_eq!(col_index.utf8_to_utf16_col(1, 21.into()), 19);
        assert_eq!(col_index.utf8_to_utf16_col(1, 25.into()), 21);

        assert!(col_index.utf8_to_utf16_col(2, 15.into()) == 15);

        // UTF-16 to UTF-8
        assert_eq!(col_index.utf16_to_utf8_col(1, 15), TextUnit::from_usize(15));

        assert_eq!(col_index.utf16_to_utf8_col(1, 18), TextUnit::from_usize(20));
        assert_eq!(col_index.utf16_to_utf8_col(1, 19), TextUnit::from_usize(23));

        assert_eq!(col_index.utf16_to_utf8_col(2, 15), TextUnit::from_usize(15));
    }

}