mp4-rust/src/atoms/stsz.rs

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

use crate::*;
use crate::atoms::*;


#[derive(Debug, Default, PartialEq)]
pub struct StszBox {
    pub version: u8,
    pub flags: u32,
    pub sample_size: u32,
    pub sample_sizes: Vec<u32>,
}

impl Mp4Box for StszBox {
    fn box_type() -> BoxType {
        BoxType::StszBox
    }

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

impl<R: Read + Seek> ReadBox<&mut R> for StszBox {
    fn read_box(reader: &mut R, size: u64) -> Result<Self> {
        let start = get_box_start(reader)?;

        let (version, flags) = read_box_header_ext(reader)?;

        let sample_size = reader.read_u32::<BigEndian>()?;
        let sample_count = reader.read_u32::<BigEndian>()?;
        let mut sample_sizes = Vec::with_capacity(sample_count as usize);
        if sample_size == 0 {
            for _i in 0..sample_count {
                let sample_number = reader.read_u32::<BigEndian>()?;
                sample_sizes.push(sample_number);
            }
        }

        skip_read_to(reader, start + size)?;

        Ok(StszBox {
            version,
            flags,
            sample_size,
            sample_sizes,
        })
    }
}

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

        write_box_header_ext(writer, self.version, self.flags)?;

        writer.write_u32::<BigEndian>(self.sample_size)?;
        writer.write_u32::<BigEndian>(self.sample_sizes.len() as u32)?;
        if self.sample_size == 0 {
            for sample_number in self.sample_sizes.iter() {
                writer.write_u32::<BigEndian>(*sample_number)?;
            }
        }

        Ok(size)
    }
}

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

    #[test]
    fn test_stsz_same_size() {
        let src_box = StszBox {
            version: 0,
            flags: 0,
            sample_size: 1165,
            sample_sizes: vec![],
        };
        let mut buf = Vec::new();
        src_box.write_box(&mut buf).unwrap();
        assert_eq!(buf.len(), src_box.box_size() as usize);

        let mut reader = Cursor::new(&buf);
        let header = BoxHeader::read(&mut reader).unwrap();
        assert_eq!(header.name, BoxType::StszBox);
        assert_eq!(src_box.box_size(), header.size);

        let dst_box = StszBox::read_box(&mut reader, header.size).unwrap();
        assert_eq!(src_box, dst_box);
    }

    #[test]
    fn test_stsz_many_sizes() {
        let src_box = StszBox {
            version: 0,
            flags: 0,
            sample_size: 0,
            sample_sizes: vec![1165, 11, 11, 8545, 10126, 10866, 9643, 9351, 7730],
        };
        let mut buf = Vec::new();
        src_box.write_box(&mut buf).unwrap();
        assert_eq!(buf.len(), src_box.box_size() as usize);

        let mut reader = Cursor::new(&buf);
        let header = BoxHeader::read(&mut reader).unwrap();
        assert_eq!(header.name, BoxType::StszBox);
        assert_eq!(src_box.box_size(), header.size);

        let dst_box = StszBox::read_box(&mut reader, header.size).unwrap();
        assert_eq!(src_box, dst_box);
    }
}