bookdata/util/
accum.rs

1/// Activatable data acumulator.
2pub struct StringAccumulator {
3    acc: String,
4    active: bool,
5}
6
7impl StringAccumulator {
8    /// Create a new data accumulator.
9    pub fn new() -> StringAccumulator {
10        StringAccumulator {
11            acc: String::with_capacity(1024),
12            active: false,
13        }
14    }
15
16    /// Start accumulating data
17    pub fn activate(&mut self) {
18        self.active = true;
19        self.acc.clear();
20    }
21
22    /// Add a slice of data to the accumulator.
23    pub fn add_slice<S: AsRef<str>>(&mut self, other: S) {
24        if self.active {
25            self.acc.push_str(other.as_ref());
26        }
27    }
28
29    pub fn finish(&mut self) -> &str {
30        if self.active {
31            self.active = false;
32            &self.acc
33        } else {
34            ""
35        }
36    }
37}
38
39#[test]
40fn test_empty() {
41    let mut acc = StringAccumulator::new();
42    let res = acc.finish();
43    assert!(res.is_empty());
44}
45
46#[test]
47fn test_add_inactive() {
48    let mut acc = StringAccumulator::new();
49    acc.add_slice("foo");
50    let res = acc.finish();
51    assert!(res.is_empty());
52}
53
54#[test]
55fn test_accum() {
56    let mut acc = StringAccumulator::new();
57    acc.activate();
58    acc.add_slice("lorem");
59    acc.add_slice(" ipsum");
60    let res = acc.finish();
61    assert_eq!(res, "lorem ipsum".to_owned());
62}
63
64#[test]
65fn test_accum_finish() {
66    let mut acc = StringAccumulator::new();
67    acc.activate();
68    acc.add_slice("lorem");
69    acc.add_slice(" ipsum");
70    let res = acc.finish();
71    assert_eq!(res, "lorem ipsum".to_owned());
72
73    acc.add_slice("bob");
74    let res = acc.finish();
75    assert!(res.is_empty())
76}
77
78#[test]
79fn test_accum_twice() {
80    let mut acc = StringAccumulator::new();
81    acc.activate();
82    acc.add_slice("lorem");
83    acc.add_slice(" ipsum");
84    let res = acc.finish();
85    assert_eq!(res, "lorem ipsum".to_owned());
86
87    acc.add_slice("bob");
88
89    acc.activate();
90    acc.add_slice("fishbone");
91    let res = acc.finish();
92    assert_eq!(res, "fishbone".to_owned());
93}
bookdata/util/accum.rs

bookdata/util/
accum.rs
