class McapWriter

Declaration

class McapWriter { /* full declaration omitted */ };

Description

Provides a write interface to an MCAP file.

Declared at: mcap/include/mcap/writer.hpp:322

Method Overview

  • public void addChannel(mcap::Channel & channel)
  • public void addSchema(mcap::Schema & schema)
  • public void close()
  • public void closeLastChunk()
  • public mcap::IWritable * dataSink()
  • public static uint64_t getRecordSize(const mcap::Message & message)
  • public mcap::Status open(std::string_view filename, const mcap::McapWriterOptions & options)
  • public void open(std::ostream & stream, const mcap::McapWriterOptions & options)
  • public void open(mcap::IWritable & writer, const mcap::McapWriterOptions & options)
  • public const mcap::Statistics & statistics() const
  • public void terminate()
  • public static void write(mcap::IWritable & output, const mcap::ByteArray bytes)
  • public static uint64_t write(mcap::IWritable & output, const mcap::AttachmentIndex & index)
  • public static uint64_t write(mcap::IWritable & output, const mcap::MetadataIndex & index)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Statistics & stats)
  • public static uint64_t write(mcap::IWritable & output, const mcap::SummaryOffset & summaryOffset)
  • public static uint64_t write(mcap::IWritable & output, const mcap::DataEnd & dataEnd)
  • public static void write(mcap::IWritable & output, const mcap::KeyValueMap & map, uint32_t size = 0)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Record & record)
  • public static void write(mcap::IWritable & output, const std::string_view str)
  • public static void write(mcap::IWritable & output, mcap::OpCode value)
  • public static void write(mcap::IWritable & output, uint16_t value)
  • public static void write(mcap::IWritable & output, uint32_t value)
  • public static void write(mcap::IWritable & output, uint64_t value)
  • public static void write(mcap::IWritable & output, const std::byte * data, uint64_t size)
  • public static uint64_t write(mcap::IWritable & output, const mcap::ChunkIndex & index)
  • public static uint64_t write(mcap::IWritable & output, const mcap::MessageIndex & index)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Chunk & chunk)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Metadata & metadata)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Attachment & attachment)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Message & message)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Channel & channel)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Schema & schema)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Footer & footer, bool crcEnabled)
  • public static uint64_t write(mcap::IWritable & output, const mcap::Header & header)
  • public mcap::Status write(const mcap::Metadata & metadata)
  • public mcap::Status write(mcap::Attachment & attachment)
  • public mcap::Status write(const mcap::Message & message)
  • public static void writeMagic(mcap::IWritable & output)
  • public ~McapWriter()

Methods

void addChannel(mcap::Channel& channel)

Description

Add a new channel to the MCAP file and set `channel.id` to a generated channel id. The channel id is used when adding messages to the file.

Channels are not cleared when the state is reset via `close`() or `terminate`(). If you're re-using a writer for multiple files in a row, the channels only need to be added once, before first use. This method does not de-duplicate channels.

Declared at: mcap/include/mcap/writer.hpp:400

Parameters

mcap::Channel& channel
Description of the channel to register. The `id` value is ignored and will be set to a generated channel id.

void addSchema(mcap::Schema& schema)

Description

Add a new schema to the MCAP file and set `schema.id` to a generated schema id. The schema id is used when adding channels to the file.

Schemas are not cleared when the state is reset via `close`() or `terminate`(). If you're re-using a writer for multiple files in a row, the schemas only need to be added once, before first use. This method does not de-duplicate schemas.

Declared at: mcap/include/mcap/writer.hpp:384

Parameters

mcap::Schema& schema
Description of the schema to register. The `id` field is ignored and will be set to a generated schema id.

void close()

Description

Write the MCAP footer, flush pending writes to the output stream, and reset internal state. The writer may be re-used with another call to open afterwards.

Declared at: mcap/include/mcap/writer.hpp:362

void closeLastChunk()

Description

finishes the current chunk in progress and writes it to the file, if a chunk is in progress.

Declared at: mcap/include/mcap/writer.hpp:443

mcap::IWritable* dataSink()

Description

Returns a pointer to the IWritable data destination backing this writer. Will return nullptr if the writer is not open.

Declared at: mcap/include/mcap/writer.hpp:437

static uint64_t getRecordSize(
    const mcap::Message& message)

Declared at: mcap/include/mcap/writer.hpp:455

Parameters

const mcap::Message& message

mcap::Status open(
    std::string_view filename,
    const mcap::McapWriterOptions& options)

Description

Open a new MCAP file for writing and write the header.

If the writer was already opened, this calls `close`() first to reset the state. A writer may be re-used after being reset via `close`() or `terminate`().

Declared at: mcap/include/mcap/writer.hpp:336

Parameters

std::string_view filename
Filename of the MCAP file to write.
const mcap::McapWriterOptions& options
Options for MCAP writing. `profile` is required.

Returns

A non-success status if the file could not be opened for writing.

void open(std::ostream& stream,
          const mcap::McapWriterOptions& options)

Description

Open a new MCAP file for writing and write the header.

Declared at: mcap/include/mcap/writer.hpp:356

Parameters

std::ostream& stream
Output stream to write to.
const mcap::McapWriterOptions& options
Options for MCAP writing. `profile` is required.

void open(mcap::IWritable& writer,
          const mcap::McapWriterOptions& options)

Description

Open a new MCAP file for writing and write the header.

If the writer was already opened, this calls `close`() first to reset the state. A writer may be re-used after being reset via `close`() or `terminate`().

Declared at: mcap/include/mcap/writer.hpp:348

Parameters

mcap::IWritable& writer
An implementation of the IWritable interface. Output bytes will be written to this object.
const mcap::McapWriterOptions& options
Options for MCAP writing. `profile` is required.

const mcap::Statistics& statistics() const

Description

Current MCAP file-level statistics. This is written as a Statistics record in the Summary section of the MCAP file.

Declared at: mcap/include/mcap/writer.hpp:431

void terminate()

Description

Reset internal state without writing the MCAP footer or flushing pending writes. This should only be used in error cases as the output MCAP file will be truncated. The writer may be re-used with another call to open afterwards.

Declared at: mcap/include/mcap/writer.hpp:369

static void write(mcap::IWritable& output,
                  const mcap::ByteArray bytes)

Declared at: mcap/include/mcap/writer.hpp:470

Parameters

mcap::IWritable& output
const mcap::ByteArray bytes

static uint64_t write(
    mcap::IWritable& output,
    const mcap::AttachmentIndex& index)

Declared at: mcap/include/mcap/writer.hpp:462

Parameters

mcap::IWritable& output
const mcap::AttachmentIndex& index

static uint64_t write(
    mcap::IWritable& output,
    const mcap::MetadataIndex& index)

Declared at: mcap/include/mcap/writer.hpp:463

Parameters

mcap::IWritable& output
const mcap::MetadataIndex& index

static uint64_t write(
    mcap::IWritable& output,
    const mcap::Statistics& stats)

Declared at: mcap/include/mcap/writer.hpp:464

Parameters

mcap::IWritable& output
const mcap::Statistics& stats

static uint64_t write(
    mcap::IWritable& output,
    const mcap::SummaryOffset& summaryOffset)

Declared at: mcap/include/mcap/writer.hpp:465

Parameters

mcap::IWritable& output
const mcap::SummaryOffset& summaryOffset

static uint64_t write(
    mcap::IWritable& output,
    const mcap::DataEnd& dataEnd)

Declared at: mcap/include/mcap/writer.hpp:466

Parameters

mcap::IWritable& output
const mcap::DataEnd& dataEnd

static void write(mcap::IWritable& output,
                  const mcap::KeyValueMap& map,
                  uint32_t size = 0)

Declared at: mcap/include/mcap/writer.hpp:476

Parameters

mcap::IWritable& output
const mcap::KeyValueMap& map
uint32_t size = 0

static uint64_t write(mcap::IWritable& output,
                      const mcap::Record& record)

Declared at: mcap/include/mcap/writer.hpp:467

Parameters

mcap::IWritable& output
const mcap::Record& record

static void write(mcap::IWritable& output,
                  const std::string_view str)

Declared at: mcap/include/mcap/writer.hpp:469

Parameters

mcap::IWritable& output
const std::string_view str

static void write(mcap::IWritable& output,
                  mcap::OpCode value)

Declared at: mcap/include/mcap/writer.hpp:471

Parameters

mcap::IWritable& output
mcap::OpCode value

static void write(mcap::IWritable& output,
                  uint16_t value)

Declared at: mcap/include/mcap/writer.hpp:472

Parameters

mcap::IWritable& output
uint16_t value

static void write(mcap::IWritable& output,
                  uint32_t value)

Declared at: mcap/include/mcap/writer.hpp:473

Parameters

mcap::IWritable& output
uint32_t value

static void write(mcap::IWritable& output,
                  uint64_t value)

Declared at: mcap/include/mcap/writer.hpp:474

Parameters

mcap::IWritable& output
uint64_t value

static void write(mcap::IWritable& output,
                  const std::byte* data,
                  uint64_t size)

Declared at: mcap/include/mcap/writer.hpp:475

Parameters

mcap::IWritable& output
const std::byte* data
uint64_t size

static uint64_t write(
    mcap::IWritable& output,
    const mcap::ChunkIndex& index)

Declared at: mcap/include/mcap/writer.hpp:461

Parameters

mcap::IWritable& output
const mcap::ChunkIndex& index

static uint64_t write(
    mcap::IWritable& output,
    const mcap::MessageIndex& index)

Declared at: mcap/include/mcap/writer.hpp:460

Parameters

mcap::IWritable& output
const mcap::MessageIndex& index

static uint64_t write(mcap::IWritable& output,
                      const mcap::Chunk& chunk)

Declared at: mcap/include/mcap/writer.hpp:459

Parameters

mcap::IWritable& output
const mcap::Chunk& chunk

static uint64_t write(
    mcap::IWritable& output,
    const mcap::Metadata& metadata)

Declared at: mcap/include/mcap/writer.hpp:458

Parameters

mcap::IWritable& output
const mcap::Metadata& metadata

static uint64_t write(
    mcap::IWritable& output,
    const mcap::Attachment& attachment)

Declared at: mcap/include/mcap/writer.hpp:457

Parameters

mcap::IWritable& output
const mcap::Attachment& attachment

static uint64_t write(
    mcap::IWritable& output,
    const mcap::Message& message)

Declared at: mcap/include/mcap/writer.hpp:456

Parameters

mcap::IWritable& output
const mcap::Message& message

static uint64_t write(
    mcap::IWritable& output,
    const mcap::Channel& channel)

Declared at: mcap/include/mcap/writer.hpp:454

Parameters

mcap::IWritable& output
const mcap::Channel& channel

static uint64_t write(mcap::IWritable& output,
                      const mcap::Schema& schema)

Declared at: mcap/include/mcap/writer.hpp:453

Parameters

mcap::IWritable& output
const mcap::Schema& schema

static uint64_t write(mcap::IWritable& output,
                      const mcap::Footer& footer,
                      bool crcEnabled)

Declared at: mcap/include/mcap/writer.hpp:452

Parameters

mcap::IWritable& output
const mcap::Footer& footer
bool crcEnabled

static uint64_t write(mcap::IWritable& output,
                      const mcap::Header& header)

Declared at: mcap/include/mcap/writer.hpp:451

Parameters

mcap::IWritable& output
const mcap::Header& header

mcap::Status write(const mcap::Metadata& metadata)

Description

Write a metadata record to the output stream.

Declared at: mcap/include/mcap/writer.hpp:425

Parameters

const mcap::Metadata& metadata
Named group of key/value string pairs to add.

Returns

A non-zero error code on failure.

mcap::Status write(mcap::Attachment& attachment)

Description

Write an attachment to the output stream.

Declared at: mcap/include/mcap/writer.hpp:417

Parameters

mcap::Attachment& attachment
Attachment to add. The `attachment.crc` will be calculated and set if configuration options allow CRC calculation.

Returns

A non-zero error code on failure.

mcap::Status write(const mcap::Message& message)

Description

Write a message to the output stream.

Declared at: mcap/include/mcap/writer.hpp:408

Parameters

const mcap::Message& message

Returns

A non-zero error code on failure.

static void writeMagic(mcap::IWritable& output)

Declared at: mcap/include/mcap/writer.hpp:449

Parameters

mcap::IWritable& output

~McapWriter()

Declared at: mcap/include/mcap/writer.hpp:324