Expand description
A library for manipulating Foxglove MCAP files, both reading:
use std::fs;
use anyhow::{Context, Result};
use camino::Utf8Path;
use memmap2::Mmap;
fn map_mcap<P: AsRef<Utf8Path>>(p: P) -> Result<Mmap> {
let fd = fs::File::open(p.as_ref()).context("Couldn't open MCAP file")?;
unsafe { Mmap::map(&fd) }.context("Couldn't map MCAP file")
}
fn read_it() -> Result<()> {
let mapped = map_mcap("in.mcap")?;
for message in mcap::MessageStream::new(&mapped)? {
println!("{:?}", message?);
// Or whatever else you'd like to do...
}
Ok(())
}
or writing:
use std::{collections::BTreeMap, fs, io::BufWriter};
use anyhow::Result;
use mcap::{Channel, records::MessageHeader, Writer};
fn write_it() -> Result<()> {
// To set the profile or compression options, see mcap::WriteOptions.
let mut out = Writer::new(
BufWriter::new(fs::File::create("out.mcap")?)
)?;
// Channels and schemas are automatically assigned ID as they're serialized,
// and automatically deduplicated with `Arc` when deserialized.
let channel_id = out.add_channel(0, "cool stuff", "application/octet-stream", &BTreeMap::new())?;
out.write_to_known_channel(
&MessageHeader {
channel_id,
sequence: 25,
log_time: 6,
publish_time: 24
},
&[1, 2, 3]
)?;
out.write_to_known_channel(
&MessageHeader {
channel_id,
sequence: 32,
log_time: 23,
publish_time: 25
},
&[3, 4, 5]
)?;
out.finish()?;
Ok(())
}
Re-exports§
pub use read::parse_record;
pub use read::MessageStream;
pub use read::Summary;
pub use write::WriteOptions;
pub use write::Writer;
Modules§
- read
- Read MCAP data from a memory-mapped file.
- records
- Raw records parsed from an MCAP file
- sans_io
- Read MCAP files from any source of bytes
- write
- Write MCAP files
Structs§
- Attachment
- An attachment and its metadata in an MCAP file
- Channel
- Describes a channel which Messages are published to in an MCAP file
- Message
- An event in an MCAP file, published to a Channel
- Schema
- Describes a schema used by one or more Channels in an MCAP file
Enums§
- Compression
- Compression options for chunks of channels, schemas, and messages in an MCAP file
- Mcap
Error
Constants§
- MAGIC
- Magic bytes for the MCAP format