mp4-rust/src/atoms/ftyp.rs

use std::io::{BufReader, Seek, Read, BufWriter, Write};
use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};

use crate::*;


#[derive(Debug, Default, PartialEq)]
pub struct FtypBox {
    pub major_brand: FourCC,
    pub minor_version: u32,
    pub compatible_brands: Vec<FourCC>,
}

impl Mp4Box for FtypBox {
    fn box_type(&self) -> BoxType {
        BoxType::FtypBox
    }

    fn box_size(&self) -> u64 {
        HEADER_SIZE + 8 + (4 * self.compatible_brands.len() as u64)
    }
}

impl<R: Read + Seek> ReadBox<&mut BufReader<R>> for FtypBox {
    fn read_box(reader: &mut BufReader<R>, size: u64) -> Result<Self> {
        let major = reader.read_u32::<BigEndian>()?;
        let minor = reader.read_u32::<BigEndian>()?;
        if size % 4 != 0 {
            return Err(Error::InvalidData("invalid ftyp size"));
        }
        let brand_count = (size - 16) / 4; // header + major + minor

        let mut brands = Vec::new();
        for _ in 0..brand_count {
            let b = reader.read_u32::<BigEndian>()?;
            brands.push(From::from(b));
        }

        Ok(FtypBox {
            major_brand: From::from(major),
            minor_version: minor,
            compatible_brands: brands,
        })
    }
}

impl<W: Write> WriteBox<&mut BufWriter<W>> for FtypBox {
    fn write_box(&self, writer: &mut BufWriter<W>) -> Result<u64> {
        let size = self.box_size();
        BoxHeader::new(self.box_type(), size).write_box(writer)?;

        writer.write_u32::<BigEndian>((&self.major_brand).into())?;
        writer.write_u32::<BigEndian>(self.minor_version)?;
        for b in self.compatible_brands.iter() {
            writer.write_u32::<BigEndian>(b.into())?;
        }
        Ok(size)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::read_box_header;
    use std::io::Cursor;

    #[test]
    fn test_ftyp() {
        let src_box = FtypBox {
            major_brand: FourCC { value: String::from("isom") },
            minor_version: 0,
            compatible_brands: vec![
                FourCC { value: String::from("isom") },
                FourCC { value: String::from("iso2") },
                FourCC { value: String::from("avc1") },
                FourCC { value: String::from("mp41") },
            ]
        };
        let mut buf = Vec::new();
        {
            let mut writer = BufWriter::new(&mut buf);
            src_box.write_box(&mut writer).unwrap();
        }
        assert_eq!(buf.len(), src_box.box_size() as usize);

        {
            let mut reader = BufReader::new(Cursor::new(&buf));
            let header = read_box_header(&mut reader, 0).unwrap();
            assert_eq!(header.name, BoxType::FtypBox);
            assert_eq!(src_box.box_size(), header.size);

            let dst_box = FtypBox::read_box(&mut reader, header.size).unwrap();

            assert_eq!(src_box, dst_box);
        }
    }
}