substudy 0.5.2

Language-learning tools for working with parallel, bilingual subtitles and media files.
Documentation 
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

//! Tools for merge multiple subtitles into one.

use regex::Regex;

use crate::srt::Subtitle;

static LINE_MAX: usize = 43;

/// Merge several subtitles into a single subtitle.  Returns `None` if no
/// subtitles have been supplied, or if the resulting subtitle has no text.
pub fn merge_subtitles(subs: &[Subtitle]) -> Option<Subtitle> {
    let space = Regex::new(r"\s+").unwrap();

    // Break text into words.
    let mut words = vec![];
    for sub in subs.iter() {
        for line in sub.lines.iter() {
            for word in space.split(&line) {
                words.push(word.to_string());
            }
        }
    }

    // Assemble words back into nicely-wrapped lines.
    let mut lines = vec![];
    let mut line = "".to_string();
    for word in words.iter() {
        if line.len() == 0 {
            line.push_str(&word);
        } else if line.len() + 1 + word.len() <= LINE_MAX {
            line.push_str(" ");
            line.push_str(&word);
        } else {
            lines.push(line);
            line = word.clone();
        }

        if line.len() >= LINE_MAX {
            lines.push(line);
            line = "".to_string();
        }
    }
    if line.len() > 0 {
        lines.push(line);
    }

    if lines.is_empty() {
        return None;
    }
    Some(Subtitle {
        index: subs[0].index,
        period: subs[0].period.union(subs[subs.len() - 1].period),
        lines: lines,
    })
}

#[cfg(test)]
mod test {
    use crate::{merge::merge_subtitles, srt::SubtitleFile};

    fn merge_for_test(input: &str) -> String {
        let srt = SubtitleFile::from_str(input).unwrap();
        merge_subtitles(&srt.subtitles).unwrap().to_string()
    }

    #[test]
    fn merge_zero() {
        assert_eq!(None, merge_subtitles(&[]));
    }

    #[test]
    fn merge_one() {
        let example = "18
00:01:02,328 --> 00:01:03,162
Yay!
Yay!
";
        let expected = r"18
00:01:02,328 --> 00:01:03,162
Yay! Yay!
";
        assert_eq!(expected, &merge_for_test(example));
    }

    #[test]
    fn merge_short() {
        let example = r"18
00:01:02,328 --> 00:01:03,162
Yay!
Yay!

19
00:01:03,163 --> 00:01:04,664
Aang's back!
";
        let expected = r"18
00:01:02,328 --> 00:01:04,664
Yay! Yay! Aang's back!
";
        assert_eq!(expected, &merge_for_test(example));
    }

    #[test]
    fn merge_long() {
        let example = r"23
00:01:16,342 --> 00:01:17,176
You're leading
them straight

24
00:01:17,677 --> 00:01:18,678
to us, aren't you?
";
        let expected = r"23
00:01:16,342 --> 00:01:18,678
You're leading them straight to us, aren't
you?
";
        assert_eq!(expected, &merge_for_test(example));
    }
}