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
use core::str::from_utf8_unchecked;

use alloc::borrow::Cow;
use alloc::string::String;
use alloc::vec::Vec;

#[cfg(feature = "std")]
use std::io::{self, Write};

use crate::functions::*;

/// Encode text used in an unquoted attribute. Except for alphanumeric characters, escape all characters which are less than 128.
///
/// The following characters are escaped to named entities:
///
/// * `&` => `&`
/// * `<` => `&lt;`
/// * `>` => `&gt;`
/// * `"` => `&quot;`
///
/// Other non-alphanumeric characters are escaped to `&#xHH;`.
pub fn encode_unquoted_attribute<S: ?Sized + AsRef<str>>(text: &S) -> Cow<str> {
    let text = text.as_ref();
    let text_bytes = text.as_bytes();

    let text_length = text_bytes.len();

    let mut p = 0;
    let mut e;

    loop {
        if p == text_length {
            return Cow::from(text);
        }

        e = text_bytes[p];

        if utf8_width::is_width_1(e) && !e.is_ascii_alphanumeric() {
            break;
        }

        p += 1;
    }

    let mut v = Vec::with_capacity(text_length);

    v.extend_from_slice(&text_bytes[..p]);

    write_html_entity_to_vec(e, &mut v);

    encode_unquoted_attribute_to_vec(
        unsafe { from_utf8_unchecked(&text_bytes[(p + 1)..]) },
        &mut v,
    );

    Cow::from(unsafe { String::from_utf8_unchecked(v) })
}

/// Write text used in an unquoted attribute to a mutable `String` reference and return the encoded string slice. Except for alphanumeric characters, escape all characters which are less than 128.
///
/// The following characters are escaped to named entities:
///
/// * `&` => `&amp;`
/// * `<` => `&lt;`
/// * `>` => `&gt;`
/// * `"` => `&quot;`
///
/// Other non-alphanumeric characters are escaped to `&#xHH;`.
#[inline]
pub fn encode_unquoted_attribute_to_string<S: AsRef<str>>(text: S, output: &mut String) -> &str {
    unsafe { from_utf8_unchecked(encode_unquoted_attribute_to_vec(text, output.as_mut_vec())) }
}

/// Write text used in an unquoted attribute to a mutable `Vec<u8>` reference and return the encoded data slice. Except for alphanumeric characters, escape all characters which are less than 128.
///
/// The following characters are escaped to named entities:
///
/// * `&` => `&amp;`
/// * `<` => `&lt;`
/// * `>` => `&gt;`
/// * `"` => `&quot;`
///
/// Other non-alphanumeric characters are escaped to `&#xHH;`.
pub fn encode_unquoted_attribute_to_vec<S: AsRef<str>>(text: S, output: &mut Vec<u8>) -> &[u8] {
    let text = text.as_ref();
    let text_bytes = text.as_bytes();
    let text_length = text_bytes.len();

    output.reserve(text_length);

    let current_length = output.len();

    let mut p = 0;
    let mut e;

    let mut start = 0;

    while p < text_length {
        e = text_bytes[p];

        if utf8_width::is_width_1(e) && !e.is_ascii_alphanumeric() {
            output.extend_from_slice(&text_bytes[start..p]);
            start = p + 1;
            write_html_entity_to_vec(e, output);
        }

        p += 1;
    }

    output.extend_from_slice(&text_bytes[start..p]);

    &output[current_length..]
}

#[cfg(feature = "std")]
/// Write text used in an unquoted attribute to a writer. Except for alphanumeric characters, escape all characters which are less than 128.
///
/// The following characters are escaped to named entities:
///
/// * `&` => `&amp;`
/// * `<` => `&lt;`
/// * `>` => `&gt;`
/// * `"` => `&quot;`
///
/// Other non-alphanumeric characters are escaped to `&#xHH;`.
pub fn encode_unquoted_attribute_to_writer<S: AsRef<str>, W: Write>(
    text: S,
    output: &mut W,
) -> Result<(), io::Error> {
    let text = text.as_ref();
    let text_bytes = text.as_bytes();
    let text_length = text_bytes.len();

    let mut p = 0;
    let mut e;

    let mut start = 0;

    while p < text_length {
        e = text_bytes[p];

        if utf8_width::is_width_1(e) && !e.is_ascii_alphanumeric() {
            output.write_all(&text_bytes[start..p])?;
            start = p + 1;
            write_html_entity_to_writer(e, output)?;
        }

        p += 1;
    }

    output.write_all(&text_bytes[start..p])
}