use super::*;

/// A custom section holding arbitrary data.

#[derive(Clone, Debug)]

pub struct CustomSection<'a> {

    /// The name of this custom section.

    pub name: &'a str,

    /// This custom section's data.

    pub data: &'a [u8],

}

impl Section for CustomSection<'_> {

    fn id(&self) -> u8 {

        SectionId::Custom.into()

    }

    fn encode<S>(&self, sink: &mut S)

    where

        S: Extend<u8>,

    {

        let name_len = encoders::u32(u32::try_from(self.name.len()).unwrap());

        let n = name_len.len();

        sink.extend(

            encoders::u32(u32::try_from(n + self.name.len() + self.data.len()).unwrap())

                .chain(name_len)

                .chain(self.name.as_bytes().iter().copied())

                .chain(self.data.iter().copied()),

        );

    }

}

#[cfg(test)]

mod tests {

    use super::*;

    #[test]

    fn test_custom_section() {

        let custom = CustomSection {

            name: "test",

            data: &[11, 22, 33, 44],

        };

        let mut encoded = vec![];

        custom.encode(&mut encoded);

        #[rustfmt::skip]

        assert_eq!(encoded, vec![

            // LEB128 length of section.

            9,

            // LEB128 length of name.

            4,

            // Name.

            b't', b'e', b's', b't',

            // Data.

            11, 22, 33, 44,

        ]);

    }

}