mp4/mp4box/
stco.rs

1use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
2use serde::Serialize;
3use std::io::{Read, Seek, Write};
4use std::mem::size_of;
5
6use crate::mp4box::*;
7
8#[derive(Debug, Clone, PartialEq, Eq, Default, Serialize)]
9pub struct StcoBox {
10    pub version: u8,
11    pub flags: u32,
12
13    #[serde(skip_serializing)]
14    pub entries: Vec<u32>,
15}
16
17impl StcoBox {
18    pub fn get_type(&self) -> BoxType {
19        BoxType::StcoBox
20    }
21
22    pub fn get_size(&self) -> u64 {
23        HEADER_SIZE + HEADER_EXT_SIZE + 4 + (4 * self.entries.len() as u64)
24    }
25}
26
27impl Mp4Box for StcoBox {
28    fn box_type(&self) -> BoxType {
29        self.get_type()
30    }
31
32    fn box_size(&self) -> u64 {
33        self.get_size()
34    }
35
36    fn to_json(&self) -> Result<String> {
37        Ok(serde_json::to_string(&self).unwrap())
38    }
39
40    fn summary(&self) -> Result<String> {
41        let s = format!("entries={}", self.entries.len());
42        Ok(s)
43    }
44}
45
46impl<R: Read + Seek> ReadBox<&mut R> for StcoBox {
47    fn read_box(reader: &mut R, size: u64) -> Result<Self> {
48        let start = box_start(reader)?;
49
50        let (version, flags) = read_box_header_ext(reader)?;
51
52        let header_size = HEADER_SIZE + HEADER_EXT_SIZE;
53        let other_size = size_of::<u32>(); // entry_count
54        let entry_size = size_of::<u32>(); // chunk_offset
55        let entry_count = reader.read_u32::<BigEndian>()?;
56        if u64::from(entry_count)
57            > size
58                .saturating_sub(header_size)
59                .saturating_sub(other_size as u64)
60                / entry_size as u64
61        {
62            return Err(Error::InvalidData(
63                "stco entry_count indicates more entries than could fit in the box",
64            ));
65        }
66        let mut entries = Vec::with_capacity(entry_count as usize);
67        for _i in 0..entry_count {
68            let chunk_offset = reader.read_u32::<BigEndian>()?;
69            entries.push(chunk_offset);
70        }
71
72        skip_bytes_to(reader, start + size)?;
73
74        Ok(StcoBox {
75            version,
76            flags,
77            entries,
78        })
79    }
80}
81
82impl<W: Write> WriteBox<&mut W> for StcoBox {
83    fn write_box(&self, writer: &mut W) -> Result<u64> {
84        let size = self.box_size();
85        BoxHeader::new(self.box_type(), size).write(writer)?;
86
87        write_box_header_ext(writer, self.version, self.flags)?;
88
89        writer.write_u32::<BigEndian>(self.entries.len() as u32)?;
90        for chunk_offset in self.entries.iter() {
91            writer.write_u32::<BigEndian>(*chunk_offset)?;
92        }
93
94        Ok(size)
95    }
96}
97
98impl std::convert::TryFrom<&co64::Co64Box> for StcoBox {
99    type Error = std::num::TryFromIntError;
100
101    fn try_from(co64: &co64::Co64Box) -> std::result::Result<Self, Self::Error> {
102        let entries = co64
103            .entries
104            .iter()
105            .copied()
106            .map(u32::try_from)
107            .collect::<std::result::Result<Vec<_>, _>>()?;
108        Ok(Self {
109            version: 0,
110            flags: 0,
111            entries,
112        })
113    }
114}
115
116#[cfg(test)]
117mod tests {
118    use super::*;
119    use crate::mp4box::BoxHeader;
120    use std::io::Cursor;
121
122    #[test]
123    fn test_stco() {
124        let src_box = StcoBox {
125            version: 0,
126            flags: 0,
127            entries: vec![267, 1970, 2535, 2803, 11843, 22223, 33584],
128        };
129        let mut buf = Vec::new();
130        src_box.write_box(&mut buf).unwrap();
131        assert_eq!(buf.len(), src_box.box_size() as usize);
132
133        let mut reader = Cursor::new(&buf);
134        let header = BoxHeader::read(&mut reader).unwrap();
135        assert_eq!(header.name, BoxType::StcoBox);
136        assert_eq!(src_box.box_size(), header.size);
137
138        let dst_box = StcoBox::read_box(&mut reader, header.size).unwrap();
139        assert_eq!(src_box, dst_box);
140    }
141}
mp4/mp4box/stco.rs

mp4/mp4box/
stco.rs
