planturl 0.4.4

A plantuml-file to server-url-encoder and downloader.
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

// Copyright 2021 - 2022  Micha Glave
//! # planturl
//!
//! Helper-crate to convert plantuml-sourcecode to a url-string accepted by the
//! [PlantUML-Demo-Server](https://www.plantuml.com/plantuml).
//!
//! ```rust
//! use planturl::{encode,cleanup_input};
//! let input = "Bob -> Alice : hello";
//! assert_eq!("SyfFKj2rKt3CoKnELR1Io4ZDoSa70000",
//!    encode(&deflate::deflate_bytes_conf(
//!          cleanup_input(input).as_bytes(),
//!          deflate::Compression::Best
//!         ))
//! );
//! ```

/// Encodes the 8-bit array in a 6-bit-based String analog to `base64`.
/// Described in [Plantuml-Documentation](https://plantuml.com/en/text-encoding).
pub fn encode(data: &[u8]) -> String {
    data.chunks(3)
        .map(split)
        .flat_map(encode_chunk)
        .collect::<String>()
}

/// Splits the 8-bit array-chunk into a 6-bit.
/// Based on <https://tiemenwaterreus.com/posts/implementing-base64-in-rust/>.
fn split(chunk: &[u8]) -> Vec<u8> {
    match chunk.len() {
        1 => vec![&chunk[0] >> 2, (&chunk[0] & 0b00000011) << 4],
        2 => vec![
            &chunk[0] >> 2,
            (&chunk[0] & 0b00000011) << 4 | &chunk[1] >> 4,
            (&chunk[1] & 0b00001111) << 2,
        ],
        3 => vec![
            &chunk[0] >> 2,
            (&chunk[0] & 0b00000011) << 4 | &chunk[1] >> 4,
            (&chunk[1] & 0b00001111) << 2 | &chunk[2] >> 6,
            &chunk[2] & 0b00111111,
        ],
        _ => unreachable!(),
    }
}

fn encode_chunk(chunk: Vec<u8>) -> Vec<char> {
    let mut out = vec!['0'; 4];
    for i in 0..chunk.len() {
        if let Some(chr) = get_char_for_index(chunk[i]) {
            out[i] = chr;
        }
    }
    out
}

/// Maps the 6bit to a char the plantuml-way.
fn get_char_for_index(index: u8) -> Option<char> {
    let plantuml64 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz-_".as_bytes();
    plantuml64.get(index as usize).map(|b: &u8| *b as char)
}

/// Trims the input-data by removing the `@startuml`-prelude and `@enduml`-suffix.
/// Needed to reduce size of URL.
pub fn cleanup_input(data: &str) -> String {
    let pattern: &[_] = &['\n', ' ', '\t'];
    data.replace("\r\n", "\n")
        .trim_matches(pattern)
        .replace("@startuml\n", "")
        .replace("\n@enduml", "")
        .trim_matches(pattern)
        .to_string()
}

/// Encodes in HEX as described in
/// [PlantUML Text Encoding | Simple HEX format](https://plantuml.com/en/text-encoding#32ec0710e82adf79).
pub fn encode_hex(input: &str) -> String {
    String::from("~h")
        + &*input
            .as_bytes()
            .iter()
            .map(|c| format!("{:02x}", c))
            .collect::<String>()
}

#[cfg(test)]
mod should {
    use crate::{cleanup_input, encode, encode_hex};

    #[test]
    fn compress_example() {
        let input = "Bob -> Alice : hello";
        assert_eq!(
            "SyfFKj2rKt3CoKnELR1Io4ZDoSa70000",
            encode(&deflate::deflate_bytes_conf(
                input.as_bytes(),
                deflate::Compression::Best
            ))
        );
    }

    /// The example from [PlantUML Text Encoding - Compression](https://plantuml.com/en/text-encoding#82af841589057aa8)
    ///
    /// should give "Syp9J4vLqBLJSCfFib9mB2t9ICqhoKnEBCdCprC8IYqiJIqkuGBAAUW2rO0LOr5LN92VLvpA1G00"
    /// but it differs at the last 6-chars.
    #[test]
    fn encode_deflate() {
        let input = "@startuml\n\nAlice -> Bob: Authentication Request\nBob --> Alice: \
        Authentication Response\n\n@enduml\n";
        assert_eq!(
            "Syp9J4vLqBLJSCfFib9mB2t9ICqhoKnEBCdCprC8IYqiJIqkuGBAAUW2rO0LOr5LN92VLvmA0000",
            encode(&deflate::deflate_bytes_conf(
                cleanup_input(input).as_bytes(),
                deflate::Compression::Best
            ))
        );
    }

    #[test]
    fn ignore_trailing_whitespace() {
        let input = "  \n@startuml\nBob -> Alice : hello\n\n@enduml\n\n";
        assert_eq!("Bob -> Alice : hello", cleanup_input(input));
    }

    #[test]
    fn ignore_crlf() {
        let input = "@startuml\r\nBob -> Alice : hello\r\n@enduml\r\n";
        assert_eq!("Bob -> Alice : hello", cleanup_input(input));
    }

    /// Test based on Demo: https://plantuml.com/en/text-encoding#32ec0710e82adf79
    #[test]
    fn encode_in_hex() {
        let input = "@startuml\nAlice->Bob : I am using hex\n@enduml";
        let hex = encode_hex(input);
        assert_eq!("~h407374617274756d6c0a416c6963652d3e426f62203a204920616d207573696e67206865780a40656e64756d6c", hex)
    }
}