Struct McapWriteOptions 

pub struct McapWriteOptions { /* private fields */ }

Options for use with an McapWriter.

Implementations

impl WriteOptions

pub fn new() -> WriteOptions

pub fn compression(self, compression: Option<Compression>) -> WriteOptions

Specifies the compression that should be used on chunks.

pub fn profile<S>(self, profile: S) -> WriteOptions

where S: Into<String>,

Specifies the profile that should be written to the MCAP Header record.

pub fn library<S>(self, library: S) -> WriteOptions

where S: Into<String>,

Specifies the library that should be written to the MCAP Header record.

This is a free-form string that can be used to identify the library that wrote the file. It is not used for any other purpose.

pub fn chunk_size(self, chunk_size: Option<u64>) -> WriteOptions

Specifies the target uncompressed size of each chunk.

Messages will be written to chunks until the uncompressed chunk is larger than the target chunk size, at which point the chunk will be closed and a new one started. If None, chunks will not be automatically closed and the user must call flush() to begin a new chunk.

pub fn use_chunks(self, use_chunks: bool) -> WriteOptions

Specifies whether to use chunks for storing messages.

If false, messages will be written directly to the data section of the file. This prevents using compression or indexing, but may be useful on small embedded systems that cannot afford the memory overhead of storing chunk metadata for the entire recording.

Note that it’s often useful to post-process a non-chunked file using mcap recover to add indexes for efficient processing.

pub fn disable_seeking(self, disable_seeking: bool) -> WriteOptions

Specifies whether the writer should seek or not.

Setting true will allow you to use NoSeek on the destination writer to support writing to a stream that does not support Seek.

By default the writer will seek the output to avoid buffering in memory. Seeking is an optimization and should only be disabled if the output is using NoSeek.

pub fn emit_summary_records(self, value: bool) -> WriteOptions

Specifies in whether to write any records to the summary section.

If you want only want to include specific record types in the summary section, call this method with false and then enable the records you want. This ensures that no unwanted summary records will be written if the format changes in the future.

Note that this does not control whether summary offset records are written, because they are not part of the summary section.

pub fn emit_summary_offsets(self, emit_summary_offsets: bool) -> WriteOptions

Specifies whether to write summary offset records. This is on by default.

pub fn emit_statistics(self, emit_statistics: bool) -> WriteOptions

Specifies whether to write a statistics record in the summary section. This is on by default.

pub fn emit_message_indexes(self, emit_message_indexes: bool) -> WriteOptions

Specifies whether to write message index records after each chunk. This is on by default.

pub fn emit_chunk_indexes(self, emit_chunk_indexes: bool) -> WriteOptions

Specifies whether to write chunk index records in the summary section. This is on by default.

pub fn emit_attachment_indexes( self, emit_attachment_indexes: bool, ) -> WriteOptions

Specifies whether to write attachment index records in the summary section. This is on by default.

pub fn emit_metadata_indexes(self, emit_metadata_indexes: bool) -> WriteOptions

Specifies whether to write metadata index records in the summary section. This is on by default.

pub fn repeat_channels(self, repeat_channels: bool) -> WriteOptions

Specifies whether to repeat each channel record from the data section in the summary section. This is on by default.

pub fn repeat_schemas(self, repeat_schemas: bool) -> WriteOptions

Specifies whether to repeat each schema record from the data section in the summary section. This is on by default.

pub fn compression_level(self, compression_level: u32) -> WriteOptions

Available on crate features zstd or lz4 only.

Specifies the compression level to use. A value of zero instructs the compressor to use the default compression level.

pub fn compression_threads(self, compression_threads: u32) -> WriteOptions

Available on crate feature zstd only.

Specifies how many threads to use for compression. A value of zero disables multithreaded compression. The default number of threads is equal to the number of physical CPUs.

pub fn create<W>(self, w: W) -> Result<Writer<W>, McapError>

where W: Write + Seek,

Creates a Writer which writes to w using the given options

pub fn calculate_chunk_crcs(self, calculate_chunk_crcs: bool) -> WriteOptions

Specifies whether to calculate and write CRCs for chunk records. This is on by default.

pub fn calculate_data_section_crc( self, calculate_data_section_crc: bool, ) -> WriteOptions

Specifies whether to calculate and write a data section CRC into the DataEnd record. This is on by default.

pub fn calculate_summary_section_crc( self, calculate_summary_section_crc: bool, ) -> WriteOptions

Specifies whether to calculate and write a summary section CRC into the Footer record. This is on by default.

pub fn calculate_attachment_crcs( self, calculate_attachment_crcs: bool, ) -> WriteOptions

Specifies whether to calculate and write a CRC for attachments. This is on by default.

Trait Implementations

impl Clone for WriteOptions

fn clone(&self) -> WriteOptions

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WriteOptions

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

Formats the value using the given formatter.

impl Default for WriteOptions

fn default() -> WriteOptions

Returns the “default value” for a type.

impl From<WriteOptions> for McapWriter

fn from(value: McapWriteOptions) -> Self

Converts to this type from the input type.