SDK Base Utils

Header helpers classes and functions

template<typename EventType> void Metavision::write_DAT_header(std::ostream &os, const GenericHeader::HeaderMap &header_map)

Writes the DAT header of a file.

Template Parameters

EventType: The type of events stored in the DAT file

Parameters

os: The stream used to store the DAT data
header_map: An optional map of data to be stored in the header

template<typename EventType> std::string Metavision::get_DAT_header_as_string(const GenericHeader::HeaderMap &header_map = GenericHeader::HeaderMap())

Convenience function to get the DAT header as string.

Return

The string representing the DAT header

Template Parameters

EventType: The type of events stored in the DAT file

Parameters

header_map: Additional information to be stored in the header

GenericHeader Metavision::make_DAT_header_map_with_geometry(int width, int height)

Convenience function to create a DAT header map to be added in the header using the camera geometry.

Return

The DAT header map

Parameters

width: Width of the camera sensor
height: Height of the camera sensor

class Metavision::GenericHeader

A utility class to hold and format headers information.

A header is composed of fields composed of key (string) / value (string) pairs

Public Types

using HeaderMap = std::map<std::string, std::string>: Alias for the internal map holding the header information.

Public Functions

GenericHeader(): Default constructor.

GenericHeader(std::istream &stream)

Builds the header map by parsing the input stream.

The stream internal is expected to point to the start of the header (if any) This method effectively places the stream cursor at the end of header. The position of the cursor remains unchanged if no header is actually present.

Parameters

stream: The input stream to parse a header from

GenericHeader(const HeaderMap &header_map)

Builds the header map using a copy of the input HeaderMap.

Parameters

header_map: The header map to use for initialization

bool empty() const

Returns if the header is empty.

Return: True if the header is empty, false otherwise

void add_date()

Adds the current date and time to the header (in the format Y-m-d H:M:S).

Note: The date is updated at each call to this method

void remove_date(): Removes the date if there was any in the header.

std::string get_date() const

Gets the date and time at which the associated file was recorded.

Return: The current date and time in string format if it is found, or an empty string otherwise.

void set_field(const std::string &key, const std::string &value)

Adds a new field in the header.

Parameters

key: The key of the field in the header
value: The value of the field

void remove_field(const std::string &key): Remove the input field (if exists)

std::string get_field(const std::string &key) const

Gets the value associated to the input key.

Return: The value associated to the input key if it exists, or an empty string otherwise

const HeaderMap &get_header_map() const

Gets the HeaderMap holding the header information.

Return: The header map

std::string to_string() const

Serializes the header map.

Return: The header in a string format

Various

template<class T, bool acquire_shared_ptr = false> class Metavision::ObjectPool

Class that creates a reusable pool of heap allocated objects.

The ObjectPool allocates objects that are returned to the pool upon destruction. acquire is used to allocate or re-use a previously allocated object instance. The object are made available through a std::unique_ptr or a std::shared_ptr according to the template acquire_shared_ptr. The smart pointers are given a custom deleter, which automatically adds the object back to the pool upon destruction.

Template Parameters

T: the type of object stored
acquire_shared_ptr: if true, the object are wrapped by a std::shared_ptr, otherwise a std::unique_ptr is returned instead

Public Functions

ObjectPool(): Default constructor that builds an unbounded object pool with an initial number of objects allocated make_unbounded.

void add(std::unique_ptr<T> t)

Adds an object to the pool.

Parameters

t: A unique_ptr storing the object

template<typename ...Args> ptr_type acquire(Args&&... args)

Allocates or re-use a previously allocated object.

Return

A unique or shared pointer to the allocated object

Parameters

args: Optional arguments to be passed when allocating the object

bool empty() const

Checks if the pool is empty.

Return: true if the pool is empty, false if the pool contains object ready to be re-used

size_t size() const

Gets the number of objects in the pool.

Return: The number of previously allocated and ready to-reuse objects in the pool

bool is_bounded() const

Checks the memory pool type i.e. bounded or unbounded.

Return: true if the memory pool is bounded, false if it is unbounded

Public Static Functions

ObjectPool<T, acquire_shared_ptr> make_bounded(size_t num_initial_objects = 64)

Creates an object pool with limited number of objects that can be allocated.

There won’t be memory allocation upon call to acquire if all objects in the memory pool are already used.

Return

An object pool with bounded memory

Parameters

num_initial_objects: Number of objects initially allocated in the pool

template<typename ...Args> ObjectPool<T, acquire_shared_ptr> make_bounded(size_t num_initial_objects, Args&&... args)

Creates an object pool with limited number of objects that can be allocated.

There won’t be memory allocation upon call to acquire if all objects in the memory pool are already used.

Return

An object pool with bounded memory

Parameters

num_initial_objects: Number of objects initially allocated in the pool
args: The arguments forwarded to the object constructor during allocation

template<typename ...Args> ObjectPool<T, acquire_shared_ptr> make_unbounded(size_t num_initial_objects = 64)

Creates an object pool with expendable memory usage.

A pool with unbounded memory will allocate a new object when all objects in the pool are already used and acquire is called.

Return

An object pool with unbounded memory

Parameters

num_initial_objects: Number of objects initially allocated in the pool

template<typename ...Args> ObjectPool<T, acquire_shared_ptr> make_unbounded(size_t num_initial_objects, Args&&... args)

Creates an object pool with expendable memory usage.

A pool with unbounded memory will allocate a new object when all objects in the pool are already used and acquire is called.

Return

An object pool with unbounded memory

Parameters

num_initial_objects: Number of objects initially allocated in the pool
args: The arguments forwarded to the object constructor during allocation

template<typename T> using Metavision::SharedObjectPool = ObjectPool<T, true>

Convenience alias to use a ObjectPool returning shared pointers.

Template Parameters

T: the type of object stored in the pool

typedef long long Metavision::timestamp: Type to represent time in microseconds.

Logging

MV_LOG_DEBUG(prefixFmt…)

Returns a logging operation of DEBUG level.

Convenience function to return a logging operation of DEBUG level using the current logging stream, an optional prefix format prefixFmt and automatically adding an end of line token at the end of the logging operation

Return

A logging operation of DEBUG level

Parameters

prefixFmt: (Optional) a format string that will be be output as the first message token

MV_LOG_TRACE(prefixFmt…)

Returns a logging operation of TRACE level.

Convenience macro to return a logging operation of TRACE level using the current logging stream, an optional prefix format prefixFmt and automatically adding an end of line token at the end of the logging operation

Return

A logging operation of TRACE level

Parameters

prefixFmt: (Optional) a format string that will be be output as the first message token

MV_LOG_INFO(prefixFmt…)

Returns a logging operation of INFO level.

Convenience function to return a logging operation of INFO level using the current logging stream, an optional prefix format prefixFmt and automatically adding an end of line token at the end of the logging operation

Return

A logging operation of INFO level

Parameters

prefixFmt: (Optional) a format string that will be be output as the first message token

MV_LOG_WARNING(prefixFmt…)

Returns a logging operation of WARNING level.

Convenience function to return a logging operation of WARNING level using the current logging stream, an optional prefix format prefixFmt and automatically adding an end of line token at the end of the logging operation

Return

A logging operation of WARNING level

Parameters

prefixFmt: (Optional) a format string that will be be output as the first message token

MV_LOG_ERROR(prefixFmt…)

Returns a logging operation of ERROR level.

Convenience function to return a logging operation of ERROR level using the current logging stream, an optional prefix format prefixFmt and automatically adding an end of line token at the end of the logging operation

Return

A logging operation of ERROR level

Parameters

prefixFmt: (Optional) a format string that will be be output as the first message token

namespace Metavision::Log

Functions

template<LogLevel Level> LoggingOperation<Level> &space(LoggingOperation<Level> &op)

Stream manipulator enabling the automatic addition of spaces between message tokens.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&space(LoggingOperation<Level> &&op)

Stream manipulator enabling the automatic addition of spaces between message tokens.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &no_space(LoggingOperation<Level> &op)

Stream manipulator disabling the automatic addition of spaces between message tokens.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&no_space(LoggingOperation<Level> &&op)

Stream manipulator disabling the automatic addition of spaces between message tokens.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &endline(LoggingOperation<Level> &op)

Stream manipulator enabling the automatic addition of and end of line token at the end of the operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&endline(LoggingOperation<Level> &&op)

Stream manipulator enabling the automatic addition of and end of line token at the end of the operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &no_endline(LoggingOperation<Level> &op)

Stream manipulator disabling the automatic addition of and end of line token at the end of the operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&no_endline(LoggingOperation<Level> &&op)

Stream manipulator disabling the automatic addition of and end of line token at the end of the operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &function(LoggingOperation<Level> &op)

Stream manipulator that outputs the function name associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&function(LoggingOperation<Level> &&op)

Stream manipulator that outputs the function name associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &file(LoggingOperation<Level> &op)

Stream manipulator that outputs the file name associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&file(LoggingOperation<Level> &&op)

Stream manipulator that outputs the file name associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &line(LoggingOperation<Level> &op)

Stream manipulator that outputs the line associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&line(LoggingOperation<Level> &&op)

Stream manipulator that outputs the line associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &prefix(LoggingOperation<Level> &op)

Stream manipulator that outputs the prefix associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier

template<LogLevel Level> LoggingOperation<Level> &&prefix(LoggingOperation<Level> &&op)

Stream manipulator that outputs the prefix associated to the logging operation.

Return

The modified logging operation

Template Parameters

Level: The level of the logging operation

Parameters

op: The logging operation modified by this modifier