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//! HTML escaping
//!
//! By default sailfish replaces the characters `&"<>` with the equivalent html.

mod avx2;
mod fallback;
mod naive;
mod sse2;

use super::buffer::Buffer;

static ESCAPE_LUT: [u8; 256] = [
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 0, 9, 9, 9, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 2, 9, 3, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
    9, 9, 9, 9,
];

const ESCAPED: [&str; 4] = ["&quot;", "&amp;", "&lt;", "&gt;"];
const ESCAPED_LEN: usize = 4;

/// write the escaped contents with custom function
///
/// This function is soft-deprecated because using this function causes a large binary size.
#[inline]
pub fn escape_with<F: FnMut(&str)>(mut writer: F, feed: &str) {
    unsafe {
        #[cfg(target_feature = "avx2")]
        {
            avx2::escape(&mut writer, feed.as_bytes());
        }

        #[cfg(not(target_feature = "avx2"))]
        {
            if is_x86_feature_detected!("avx2") {
                avx2::escape(&mut writer, feed.as_bytes());
            } else if is_x86_feature_detected!("sse2") {
                sse2::escape(&mut writer, feed.as_bytes());
            } else {
                fallback::escape(&mut writer, feed.as_bytes());
            }
        }
    }
}

#[doc(hidden)]
pub fn escape_to_buf(feed: &str, buf: &mut Buffer) {
    escape_with(|e| buf.write_str(e), feed);
}

/// write the escaped contents into `String`
///
/// # Examples
///
/// ```
/// use sailfish::runtime::escape::escape_to_string;
///
/// let mut buf = String::new();
/// escape_to_string("<h1>Hello, world!</h1>", &mut buf);
/// assert_eq!(buf, "&lt;h1&gt;Hello, world!&lt;/h1&gt;");
/// ```
#[inline]
pub fn escape_to_string(feed: &str, s: &mut String) {
    let mut s2 = String::new();
    std::mem::swap(s, &mut s2);
    let mut buf = Buffer::from(s2);
    escape_to_buf(feed, &mut buf);
    let mut s2 = buf.into_string();
    std::mem::swap(s, &mut s2);
}

#[cfg(test)]
mod tests {
    use super::*;

    fn escape(feed: &str) -> String {
        let mut buf = Buffer::new();
        escape_to_buf(feed, &mut buf);
        buf.into_string()
    }

    #[test]
    fn noescape() {
        assert_eq!(escape(""), "");
        assert_eq!(
            escape("abcdefghijklmnopqrstrvwxyz"),
            "abcdefghijklmnopqrstrvwxyz"
        );
        assert_eq!(escape("!#$%()*+,-.:;=?_^"), "!#$%()*+,-.:;=?_^");
        assert_eq!(
            escape("漢字はエスケープしないはずだよ"),
            "漢字はエスケープしないはずだよ"
        );
    }

    #[test]
    fn escape_short() {
        assert_eq!(escape("<"), "&lt;");
        assert_eq!(escape("\"&<>"), "&quot;&amp;&lt;&gt;");
        assert_eq!(
            escape("{\"title\": \"This is a JSON!\"}"),
            "{&quot;title&quot;: &quot;This is a JSON!&quot;}"
        );
        assert_eq!(
            escape("<html><body><h1>Hello, world</h1></body></html>"),
            "&lt;html&gt;&lt;body&gt;&lt;h1&gt;Hello, world&lt;/h1&gt;\
            &lt;/body&gt;&lt;/html&gt;"
        );
    }

    #[test]
    #[rustfmt::skip]
    fn escape_long() {
        assert_eq!(
            escape(r###"m{jml&,?6>\2~08g)\=3`,_`$1@0{i5j}.}2ki\^t}k"@p4$~?;!;pn_l8v."ki`%/&^=\[y+qcerr`@3*|?du.\0vd#40.>bcpf\u@m|c<2t7`hk)^?"0u{v%9}4y2hhv?%-f`<;rzwx`7}l(j2b:c\<|z&$x{+k;f`0+w3e0\m.wmdli>94e2hp\$}j0&m(*h$/lwlj#}99r;o.kj@1#}~v+;y~b[~m.eci}&l7fxt`\\{~#k*9z/d{}(.^j}[(,]:<\h]9k2+0*w60/|23~5;/!-h&ci*~e1h~+:1lhh\>y_*>:-\zzv+8uo],,a^k3_,uip]-/.-~\t51a*<{6!<(_|<#o6=\h1*`[2x_?#-/])x};};r@wqx|;/w&jrv~?\`t:^/dug3(g(ener?!t$}h4:57ptnm@71e=t>@o*"$]799r=+)t>co?rvgk%u0c@.9os;#t_*/gqv<za&~r^]"{t4by2t`<q4bfo^&!so5/~(nxk:7l\;#0w41u~w3i$g|>e/t;o<*`~?3.jyx+h)+^cn^j4td|>)~rs)vm#]:"&\fi;54%+z~fhe|w~\q|ui={54[b9tg*?@]g+q!mq]3jg2?eoo"chyat3k#7pq1u=.l]c14twa4tg#5k_""###),
            r###"m{jml&amp;,?6&gt;\2~08g)\=3`,_`$1@0{i5j}.}2ki\^t}k&quot;@p4$~?;!;pn_l8v.&quot;ki`%/&amp;^=\[y+qcerr`@3*|?du.\0vd#40.&gt;bcpf\u@m|c&lt;2t7`hk)^?&quot;0u{v%9}4y2hhv?%-f`&lt;;rzwx`7}l(j2b:c\&lt;|z&amp;$x{+k;f`0+w3e0\m.wmdli&gt;94e2hp\$}j0&amp;m(*h$/lwlj#}99r;o.kj@1#}~v+;y~b[~m.eci}&amp;l7fxt`\\{~#k*9z/d{}(.^j}[(,]:&lt;\h]9k2+0*w60/|23~5;/!-h&amp;ci*~e1h~+:1lhh\&gt;y_*&gt;:-\zzv+8uo],,a^k3_,uip]-/.-~\t51a*&lt;{6!&lt;(_|&lt;#o6=\h1*`[2x_?#-/])x};};r@wqx|;/w&amp;jrv~?\`t:^/dug3(g(ener?!t$}h4:57ptnm@71e=t&gt;@o*&quot;$]799r=+)t&gt;co?rvgk%u0c@.9os;#t_*/gqv&lt;za&amp;~r^]&quot;{t4by2t`&lt;q4bfo^&amp;!so5/~(nxk:7l\;#0w41u~w3i$g|&gt;e/t;o&lt;*`~?3.jyx+h)+^cn^j4td|&gt;)~rs)vm#]:&quot;&amp;\fi;54%+z~fhe|w~\q|ui={54[b9tg*?@]g+q!mq]3jg2?eoo&quot;chyat3k#7pq1u=.l]c14twa4tg#5k_&quot;"###
        );
    }

    #[test]
    fn random() {
        const ASCII_CHARS: &'static [u8] = br##"abcdefghijklmnopqrstuvwxyz0123456789-^\@[;:],./\!"#$%&'()~=~|`{+*}<>?_"##;
        let mut state = 88172645463325252u64;
        let mut data = Vec::with_capacity(100);
        let mut buf1 = Buffer::new();
        let mut buf2 = Buffer::new();

        for len in 0..100 {
            data.clear();
            for _ in 0..len {
                // xorshift
                state ^= state << 13;
                state ^= state >> 7;
                state ^= state << 17;

                let idx = state as usize % ASCII_CHARS.len();
                data.push(ASCII_CHARS[idx]);
            }

            let s = unsafe { std::str::from_utf8_unchecked(&*data) };

            buf1.clear();
            buf2.clear();

            unsafe {
                escape_to_buf(&*s, &mut buf1);
                naive::escape(
                    &mut |s| buf2.write_str(s),
                    s.as_ptr(),
                    s.as_ptr(),
                    s.as_ptr().add(s.len()),
                );
            }

            assert_eq!(buf1.as_str(), buf2.as_str());
        }
    }
}