Struct mcap::read::Summary

pub struct Summary<'a> {
    pub stats: Option<Statistics>,
    pub channels: HashMap<u16, Arc<Channel<'a>>>,
    pub schemas: HashMap<u16, Arc<Schema<'a>>>,
    pub chunk_indexes: Vec<ChunkIndex>,
    pub attachment_indexes: Vec<AttachmentIndex>,
    pub metadata_indexes: Vec<MetadataIndex>,
}

Indexes of an MCAP file parsed from its (optional) summary section

Fields

stats: Option<Statistics>

channels: HashMap<u16, Arc<Channel<'a>>>

Maps channel IDs to their channel

schemas: HashMap<u16, Arc<Schema<'a>>>

Maps schema IDs to their schema

chunk_indexes: Vec<ChunkIndex>

attachment_indexes: Vec<AttachmentIndex>

metadata_indexes: Vec<MetadataIndex>

Implementations

impl<'a> Summary<'a>

pub fn read(mcap: &'a [u8]) -> McapResult<Option<Self>>

Read the summary section of the given mapped MCAP file, if it has one.

pub fn stream_chunk( &self, mcap: &'a [u8], index: &ChunkIndex ) -> McapResult<impl Iterator<Item = McapResult<Message<'a>>> + '_>

Stream messages from the chunk with the given index.

To avoid having to read all preceding chunks first, channels and their schemas are pulled from this summary.

pub fn read_message_indexes( &self, mcap: &[u8], index: &ChunkIndex ) -> McapResult<HashMap<Arc<Channel<'_>>, Vec<MessageIndexEntry>>>

Read the mesage indexes for the given indexed chunk.

Channels and their schemas are pulled from this summary. The offsets in each MessageIndexEntry is relative to the decompressed contents of the given chunk.

pub fn seek_message( &self, mcap: &'a [u8], index: &ChunkIndex, message: &MessageIndexEntry ) -> McapResult<Message<'_>>

Seek to the given message in the given indexed chunk.

If you’re interested in more than a single message from the chunk, filtering Summary::stream_chunk is probably a better bet. Compressed chunks aren’t random access - this decompresses everything in the chunk before message.offset and throws it away.

Trait Implementations

impl Debug for Summary<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> Default for Summary<'a>

fn default() -> Summary<'a>

Returns the “default value” for a type.

impl<'a> PartialEq for Summary<'a>

fn eq(&self, other: &Summary<'a>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a> Eq for Summary<'a>

impl<'a> StructuralEq for Summary<'a>

impl<'a> StructuralPartialEq for Summary<'a>