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

macro_rules! encode_impl {
    ($l:expr; $(#[$attr: meta])* $parse_macro:ident; $(#[$encode_attr: meta])* $encode_name: ident; $(#[$encode_to_string_attr: meta])* $encode_to_string_name: ident; $(#[$encode_to_vec_attr: meta])* $encode_to_vec_name: ident; $(#[$encode_to_writer_attr: meta])* $encode_to_writer_name: ident $(;)*) => {
        $(#[$encode_attr])*
        ///
        $(#[$attr])*
        #[inline]
        pub fn $encode_name<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;

            let mut step = 0;

            let (mut v, mut start) = loop {
                if p == text_length {
                    return Cow::from(text);
                }

                e = text_bytes[p];

                $parse_macro!(
                    e,
                    step,
                    {
                        let mut v = Vec::with_capacity(text_length + 1);

                        v.extend_from_slice(&text_bytes[..(p - $l)]);

                        break (v, p - $l);
                    },
                    {
                        let mut v = Vec::with_capacity(text_length + 1);

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

                        break (v, p);
                    },
                    {
                        let mut v = Vec::with_capacity(text_length + 1);

                        v.extend_from_slice(&text_bytes[..(p - 2)]);

                        break (v, p - 2);
                    }
                );

                p += 1;
            };

            v.push(b'\\');

            p += 1;

            for e in text_bytes[p..].iter().copied() {
                $parse_macro!(
                    e,
                    step,
                    {
                        v.extend_from_slice(&text_bytes[start..(p - $l)]);
                        start = p - $l;
                        v.push(b'\\');
                    },
                    {
                        v.extend_from_slice(&text_bytes[start..p]);
                        start = p;
                        v.push(b'\\');
                    },
                    {
                        v.extend_from_slice(&text_bytes[start..(p - 2)]);
                        start = p - 2;
                        v.push(b'\\');
                    }
                );

                p += 1;
            }

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

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

        $(#[$encode_to_string_attr])*
        ///
        $(#[$attr])*
        #[inline]
        pub fn $encode_to_string_name<S: AsRef<str>>(text: S, output: &mut String) -> &str {
            unsafe { from_utf8_unchecked($encode_to_vec_name(text, output.as_mut_vec())) }
        }

        $(#[$encode_to_vec_attr])*
        ///
        $(#[$attr])*
        #[inline]
        pub fn $encode_to_vec_name<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 start = 0;
            let mut end = 0;

            let mut step = 0;

            for e in text_bytes.iter().copied() {
                $parse_macro!(
                    e,
                    step,
                    {
                        output.extend_from_slice(&text_bytes[start..(end - $l)]);
                        start = end - $l;
                        output.push(b'\\');
                    },
                    {
                        output.extend_from_slice(&text_bytes[start..end]);
                        start = end;
                        output.push(b'\\');
                    },
                    {
                        output.extend_from_slice(&text_bytes[start..(end - 2)]);
                        start = end - 2;
                        output.push(b'\\');
                    }
                );

                end += 1;
            }

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

            &output[current_length..]
        }

        #[cfg(feature = "std")]
        $(#[$encode_to_writer_attr])*
        ///
        $(#[$attr])*
        #[inline]
        pub fn $encode_to_writer_name<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 mut start = 0;
            let mut end = 0;

            let mut step = 0;

            for e in text_bytes.iter().copied() {
                $parse_macro!(
                    e,
                    step,
                    {
                        output.write_all(&text_bytes[start..(end - $l)])?;
                        start = end - $l;
                        output.write_all(b"\\")?;
                    },
                    {
                        output.write_all(&text_bytes[start..end])?;
                        start = end;
                        output.write_all(b"\\")?;
                    },
                    {
                        output.write_all(&text_bytes[start..(end - 2)])?;
                        start = end - 2;
                        output.write_all(b"\\")?;
                    }
                );

                end += 1;
            }

            output.write_all(&text_bytes[start..end])
        }
    };
}