print-positions 0.6.1

A library providing string segmentation on grapheme clusters and ANSI escape sequences for accurate length arithmetic based on visible print positions.
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
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

#![cfg(test)]
use super::*;

#[allow(unused_imports)]
use anyhow::{anyhow, Context, Result};

fn esc_sgr_reset0() -> &'static str {
    "\x1b[0m"
}
fn esc_sgr_reset() -> &'static str {
    "\x1b[m"
}
fn esc_sgr_color() -> &'static str {
    "\x1b[1;3m"
}

// test both flavors of iterator for one scenario
fn run_test(tag: &str, expected: &[(usize, &str)], input: &[&str]) -> Result<()> {
    #[allow(unused_mut)]
    let mut test_input = input.join("");
    let mut observed: Vec<(usize, usize)> = vec![];
    let expected_indices:Vec<(usize, usize)> = expected.iter().map(|i| (i.0, i.0 + i.1.len())).collect();

    for (start, end) in print_positions(&test_input) {
        if observed.len() > 0 {
            let prev_end = observed.last().expect("length checked").1;
            assert!(
                start >= prev_end,
                "{tag}: new offset({start}) not greater than last seen ({prev_end})"
            );
        };
        assert!(end > start, "{tag}: empty substring returned");
        observed.push((start, end));
    }

    assert_eq!(expected_indices, observed, "{tag}: ");

    let mut observed: Vec<&str> = vec![];

    for substring in print_position_data(&test_input) {
        assert!(
            substring.len() > 0,
            "{tag}: empty substring returned (print_positions)"
        );
        observed.push(substring);
    }

    assert_eq!(
        expected.len(),
        observed.len(),
        "{tag}: comparing print positions iterator length"
    );
    for (exp, obs) in expected.iter().zip(observed) {
        assert_eq!(
            exp.1, obs,
            "{tag}: comparing print positions individual returns"
        );
    }

    Ok(())
}

#[test]
fn empty_string() -> Result<()> {
    run_test("", &vec![], &vec![])
}
#[test]
fn simple1() -> Result<()> {
    //let test_string = ["abc", esc_sgr_color(), "def", esc_sgr_reset0()].join("");
    let test_input = ["abc", esc_sgr_color(), "def"];
    let e1 = [esc_sgr_color(), "d"].join("");
    let expect = vec![(0, "a"), (1, "b"), (2, "c"), (3, &e1), (10, "e"), (11, "f")];

    run_test("", &expect, &test_input)
}
#[test]
fn trailing_reset() -> Result<()> {
    //let test_input = ["abc", esc_sgr_color(), "def", esc_sgr_reset0()];
    let test_input = ["ef", esc_sgr_reset0()];
    let e2 = ["f", esc_sgr_reset0()].join("");
    //let expect = vec![(0, "a"), (1, "b"), (2, "c"), (3, &e1), (10, "e"), (11, "f"), (12, &e2)];
    let expect = vec![(0, "e"), (1, &e2)];

    run_test("", &expect, &test_input)
}
#[test]
fn embedded_csi_and_trailing_reset() -> Result<()> {
    let test_input = ["abc", esc_sgr_color(), "def", esc_sgr_reset()];
    //let test_input = [ "f", esc_sgr_reset0()];
    let e1 = [esc_sgr_color(), "d"].join("");
    let e2 = ["f", esc_sgr_reset()].join("");
    let expect = vec![(0, "a"), (1, "b"), (2, "c"), (3, &e1), (10, "e"), (11, &e2)];
    //let expect = vec![(0, &e2)];

    run_test("", &expect, &test_input)
}

#[test]
fn non_reset_esc_seq_at_end_of_string() -> Result<()> {
    let test_input = ["abc", "\u{1b}\x06"]; // garbage esc seq at end of string
    let expect = vec![(0, "a"), (1, "b"), (2, "c"), (3, "\u{1b}\x06")];

    run_test("", &expect, &test_input)
}

#[test]
fn double_trailing_reset() -> Result<()> {
    let test_input = [
        "abc",
        esc_sgr_color(),
        "def",
        esc_sgr_reset(),
        esc_sgr_reset0(),
        "g",
    ];
    let e1 = [esc_sgr_color(), "d"].join("");
    let e2 = ["f", esc_sgr_reset(), esc_sgr_reset0()].join("");
    let expect = vec![
        (0, "a"),
        (1, "b"),
        (2, "c"),
        (3, &e1),
        (10, "e"),
        (11, &e2),
        (19, "g"),
    ];

    run_test("", &expect, &test_input)
}

#[test]
fn osc_termination1() -> Result<()> {
    let cases = vec![
        (
            "OSC standard termination",
            vec!["a", "\u{1b}]", "abcdef", "\u{1b}\\", "zZ"],
            vec![(0, "a"), (1, "\u{1b}]abcdef\u{1b}\\z"), (12, "Z")],
        ),
        (
            "OSC BEL termination",
            vec!["\u{1b}]", "abcdef", "\x07", "zZ"],
            vec![(0, "\u{1b}]abcdef\x07z"), (10, "Z")],
        ),
        (
            "OSC ESC but no terminator",
            vec!["\u{1b}]", "abcdef", "\u{1b}", "z"],
            vec![(0, "\u{1b}]abcdef\u{1b}z")],
        ),
        (
            "OSC ESC stuff ESC normal termination",
            vec!["\u{1b}]", "abcdef", "\u{1b}foo", "\u{1b}\\", "zZ"],
            vec![(0, "\u{1b}]abcdef\u{1b}foo\u{1b}\\z"), (15, "Z")],
        ),
        (
            "OSC ESC ESC normal",
            vec!["\u{1b}]", "abcdef", "\u{1b}\u{1b}\\", "zZ"],
            vec![(0, "\u{1b}]abcdef\u{1b}\u{1b}\\z"), (12, "Z")],
        ),
    ];

    for c in cases {
        run_test(c.0, &c.2, &c.1)?
    }

    Ok(())
}

// fuzz testing found a problem with this input: [45, 27, 91, 109, 221, 133]
// but it doesn't fail in test even with nightly compiler --release vs --test?
#[test]
fn error_from_fuzz_test() -> Result<()> {
    //let test_input = ["-\x1b[0m\u{dd}\u{85}"];
    let input = ["\u{d1}\u{97}\x1b[m\u{d2}\u{83}"];
    let expected = vec![
        (0, "\u{d1}"),
        (2, "\u{97}\x1b[m"),
        (7, "\u{d2}"),
        (9, "\u{83}"),
    ];

    run_test("", &expected, &input)
}

#[test]
fn new_line_tests() -> Result<()> {
    // unicode standard says \r\n is a single grapheme.  But separately? or \n\r?
    let input = ["\r\n", "\na\rb", "\n\r", "\r\n"];
    let expected = vec![
        (0, "\r\n"),
        (2, "\n"),
        (3, "a"),
        (4, "\r"),
        (5, "b"),
        (6, "\n"),
        (7, "\r"),
        (8, "\r\n"),
    ];

    run_test("", &expected, &input)
}

// testing the whole zoo of Unicode is somebody else's problem
// but we do test at least test some multi-byte unicode and some grapheme clusters

#[test]
fn unicode_multibyte_mixed_tests() -> Result<()> {
    // samples from UnicodeSegmentation "a̐éö̲"; // 3 bytes each

    let input = ["a", esc_sgr_color(), "a̐é", esc_sgr_reset(), esc_sgr_reset()];
    let e1 = [esc_sgr_color(), "a̐"].join("");
    let e2 = ["é", esc_sgr_reset(), esc_sgr_reset()].join("");
    let expected = vec![(0, "a"), (1, &e1), (10, &e2)];

    run_test("", &expected, &input)
}

#[test]
fn fuzz_failure_1() -> Result<()> {
    // hooray for fuzz testing!
    // it turns out the last char of a reset escape sequence
    // can form a grapheme cluster with the following chars.
    // so the reset sequence may *not* be the end of the returned grapheme.
    let input = [std::str::from_utf8(&[63, 27, 99, 217, 151]).expect("foo")];
    let expected = vec![(0, "?\u{1b}c\u{657}")];

    run_test("", &expected, &input)
}