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

use lazy_static::lazy_static;

#[derive(Debug, PartialEq, Clone)]
pub enum Header {
    Null,
    Host,
    Connection,
    CacheControl,
    UpgradeInsecureRequests,
    UserAgent,
    Accept,
    SecFetchSite,
    SecFetchMode,
    SecFetchDest,
    AcceptEncoding,
    AcceptLanguage,
}

#[derive(Debug, PartialEq)]
pub struct HeaderChar {
    char_code: u8,
    next_char: Vec<HeaderChar>,
    header: Header,
}

fn add_header(header_chars: &mut Vec<HeaderChar>, header_enum_value: &[u8], header_enum: Header) {
    let mut ptr = header_chars;
    let end_idx = header_enum_value.len() - 1;
    for (idx, char_code) in header_enum_value.iter().enumerate() {
        let mut search_result =
            ptr.binary_search_by(|header_char| (header_char.char_code).cmp(&char_code));
        if search_result.is_err() {
            let header = if idx == end_idx {
                header_enum.clone()
            } else {
                Header::Null
            };
            ptr.push(HeaderChar {
                char_code: *char_code,
                next_char: Vec::new(),
                header,
            });
            ptr.sort_unstable_by(|a, b| a.char_code.cmp(&b.char_code));
            search_result =
                ptr.binary_search_by(|header_char| (header_char.char_code).cmp(&char_code));
        }
        let index = search_result.unwrap();
        ptr = &mut ptr[index].next_char;
    }
}

lazy_static! {
    pub static ref HEADER_CHARS: Vec<HeaderChar> = {
        let mut header_chars = Vec::<HeaderChar>::new();
        add_header(
            &mut header_chars,
            b"Host".to_ascii_lowercase().as_slice(),
            Header::Host,
        );
        add_header(
            &mut header_chars,
            b"Connection".to_ascii_lowercase().as_slice(),
            Header::Connection,
        );
        add_header(
            &mut header_chars,
            b"Cache-Control".to_ascii_lowercase().as_slice(),
            Header::CacheControl,
        );
        add_header(
            &mut header_chars,
            b"Upgrade-Insecure-Requests".to_ascii_lowercase().as_slice(),
            Header::UpgradeInsecureRequests,
        );
        add_header(
            &mut header_chars,
            b"User-Agent".to_ascii_lowercase().as_slice(),
            Header::UserAgent,
        );
        add_header(
            &mut header_chars,
            b"Accept".to_ascii_lowercase().as_slice(),
            Header::Accept,
        );
        add_header(
            &mut header_chars,
            b"Sec-Fetch-Site".to_ascii_lowercase().as_slice(),
            Header::SecFetchSite,
        );
        add_header(
            &mut header_chars,
            b"Sec-Fetch-Mode".to_ascii_lowercase().as_slice(),
            Header::SecFetchMode,
        );
        add_header(
            &mut header_chars,
            b"Sec-Fetch-Dest".to_ascii_lowercase().as_slice(),
            Header::SecFetchDest,
        );
        add_header(
            &mut header_chars,
            b"Accept-Encoding".to_ascii_lowercase().as_slice(),
            Header::AcceptEncoding,
        );
        add_header(
            &mut header_chars,
            b"Accept-Language".to_ascii_lowercase().as_slice(),
            Header::AcceptLanguage,
        );
        header_chars
    };
}

pub fn get_header_enum(value: &[u8]) -> Header {
    let lowercase_value = value.to_ascii_lowercase();
    let mut ptr = &*HEADER_CHARS;
    let end_idx = lowercase_value.len() - 1;
    for (idx, char_code) in lowercase_value.iter().enumerate() {
        let search_result =
            ptr.binary_search_by(|header_char| (header_char.char_code).cmp(&char_code));
        if search_result.is_err() {
            return Header::Null;
        }
        let index = search_result.unwrap();
        if idx == end_idx {
            return ptr[index].header.clone();
        }
        ptr = &ptr[index].next_char;
    }
    Header::Null
}