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https://github.com/alfg/mp4-rust.git
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60b6d56704
* EmsgBox implementation (#59) * read emsgs (#59)
237 lines
No EOL
7.2 KiB
Rust
237 lines
No EOL
7.2 KiB
Rust
use std::ffi::CStr;
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use std::io::{Read, Seek, Write};
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use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
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use serde::Serialize;
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use crate::mp4box::*;
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#[derive(Debug, Clone, PartialEq, Default, Serialize)]
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pub struct EmsgBox {
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pub version: u8,
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pub flags: u32,
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pub timescale: u32,
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pub presentation_time: Option<u64>,
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pub presentation_time_delta: Option<u32>,
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pub event_duration: u32,
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pub id: u32,
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pub scheme_id_uri: String,
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pub value: String,
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pub message_data: Vec<u8>,
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}
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impl EmsgBox {
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fn size_without_message(version: u8, scheme_id_uri: &str, value: &str) -> u64 {
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HEADER_SIZE + HEADER_EXT_SIZE +
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4 + // id
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Self::time_size(version) +
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(scheme_id_uri.len() + 1) as u64 +
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(value.len() as u64 + 1) as u64
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}
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fn time_size(version: u8) -> u64 {
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match version {
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0 => 12,
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1 => 16,
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_ => panic!("version must be 0 or 1")
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}
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}
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}
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impl Mp4Box for EmsgBox {
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fn box_type(&self) -> BoxType {
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BoxType::EmsgBox
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}
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fn box_size(&self) -> u64 {
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Self::size_without_message(self.version, &self.scheme_id_uri, &self.value) +
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self.message_data.len() as u64
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}
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fn to_json(&self) -> Result<String> {
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Ok(serde_json::to_string(&self).unwrap())
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}
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fn summary(&self) -> Result<String> {
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let s = format!("id={} value={}", self.id, self.value);
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Ok(s)
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}
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}
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impl<R: Read + Seek> ReadBox<&mut R> for EmsgBox {
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fn read_box(reader: &mut R, size: u64) -> Result<Self> {
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let start = box_start(reader)?;
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let (version, flags) = read_box_header_ext(reader)?;
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let (
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timescale, presentation_time, presentation_time_delta, event_duration,
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id,
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scheme_id_uri,
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value
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) = match version {
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0 => {
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let scheme_id_uri = read_null_terminated_utf8_string(reader)?;
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let value = read_null_terminated_utf8_string(reader)?;
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(
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reader.read_u32::<BigEndian>()?,
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None,
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Some(reader.read_u32::<BigEndian>()?),
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reader.read_u32::<BigEndian>()?,
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reader.read_u32::<BigEndian>()?,
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scheme_id_uri,
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value
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)
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}
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1 => (
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reader.read_u32::<BigEndian>()?,
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Some(reader.read_u64::<BigEndian>()?),
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None,
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reader.read_u32::<BigEndian>()?,
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reader.read_u32::<BigEndian>()?,
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read_null_terminated_utf8_string(reader)?,
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read_null_terminated_utf8_string(reader)?
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),
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_ => return Err(Error::InvalidData("version must be 0 or 1"))
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};
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let message_size = size - Self::size_without_message(version, &scheme_id_uri, &value);
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let mut message_data = Vec::with_capacity(message_size as usize);
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for _ in 0..message_size {
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message_data.push(reader.read_u8()?);
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}
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skip_bytes_to(reader, start + size)?;
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Ok(EmsgBox {
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version,
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flags,
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timescale,
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presentation_time,
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presentation_time_delta,
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event_duration,
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id,
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scheme_id_uri,
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value,
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message_data,
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})
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}
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}
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impl<W: Write> WriteBox<&mut W> for EmsgBox {
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fn write_box(&self, writer: &mut W) -> Result<u64> {
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let size = self.box_size();
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BoxHeader::new(self.box_type(), size).write(writer)?;
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write_box_header_ext(writer, self.version, self.flags)?;
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match self.version {
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0 => {
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write_null_terminated_str(writer, &self.scheme_id_uri)?;
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write_null_terminated_str(writer, &self.value)?;
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writer.write_u32::<BigEndian>(self.timescale)?;
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writer.write_u32::<BigEndian>(self.presentation_time_delta.unwrap())?;
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writer.write_u32::<BigEndian>(self.event_duration)?;
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writer.write_u32::<BigEndian>(self.id)?;
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}
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1 => {
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writer.write_u32::<BigEndian>(self.timescale)?;
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writer.write_u64::<BigEndian>(self.presentation_time.unwrap())?;
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writer.write_u32::<BigEndian>(self.event_duration)?;
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writer.write_u32::<BigEndian>(self.id)?;
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write_null_terminated_str(writer, &self.scheme_id_uri)?;
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write_null_terminated_str(writer, &self.value)?;
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}
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_ => return Err(Error::InvalidData("version must be 0 or 1"))
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}
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for &byte in &self.message_data {
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writer.write_u8(byte)?;
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}
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Ok(size)
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}
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}
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fn read_null_terminated_utf8_string<R: Read + Seek>(reader: &mut R) -> Result<String> {
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let mut bytes = Vec::new();
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loop {
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let byte = reader.read_u8()?;
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bytes.push(byte);
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if byte == 0 { break; }
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}
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if let Ok(str) = unsafe { CStr::from_bytes_with_nul_unchecked(&bytes) }.to_str() {
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Ok(str.to_string())
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} else {
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Err(Error::InvalidData("invalid utf8"))
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}
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}
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fn write_null_terminated_str<W: Write>(writer: &mut W, string: &str) -> Result<()> {
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for byte in string.bytes() {
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writer.write_u8(byte)?;
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}
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writer.write_u8(0)?;
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Ok(())
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}
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#[cfg(test)]
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mod tests {
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use std::io::Cursor;
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use crate::mp4box::BoxHeader;
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use super::*;
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#[test]
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fn test_emsg_version0() {
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let src_box = EmsgBox {
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version: 0,
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flags: 0,
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timescale: 48000,
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presentation_time: None,
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presentation_time_delta: Some(100),
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event_duration: 200,
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id: 8,
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scheme_id_uri: String::from("foo"),
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value: String::from("foo"),
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message_data: vec![1, 2, 3],
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};
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let mut buf = Vec::new();
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src_box.write_box(&mut buf).unwrap();
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assert_eq!(buf.len(), src_box.box_size() as usize);
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let mut reader = Cursor::new(&buf);
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let header = BoxHeader::read(&mut reader).unwrap();
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assert_eq!(header.name, BoxType::EmsgBox);
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assert_eq!(src_box.box_size(), header.size);
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let dst_box = EmsgBox::read_box(&mut reader, header.size).unwrap();
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assert_eq!(src_box, dst_box);
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}
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#[test]
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fn test_emsg_version1() {
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let src_box = EmsgBox {
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version: 1,
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flags: 0,
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timescale: 48000,
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presentation_time: Some(50000),
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presentation_time_delta: None,
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event_duration: 200,
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id: 8,
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scheme_id_uri: String::from("foo"),
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value: String::from("foo"),
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message_data: vec![3, 2, 1],
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};
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let mut buf = Vec::new();
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src_box.write_box(&mut buf).unwrap();
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assert_eq!(buf.len(), src_box.box_size() as usize);
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let mut reader = Cursor::new(&buf);
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let header = BoxHeader::read(&mut reader).unwrap();
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assert_eq!(header.name, BoxType::EmsgBox);
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assert_eq!(src_box.box_size(), header.size);
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let dst_box = EmsgBox::read_box(&mut reader, header.size).unwrap();
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assert_eq!(src_box, dst_box);
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}
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} |