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FiffId

Namespace: FIFFLIB  ·  Library: FIFF Library

#include <fiff/fiff_id.h>

class FIFFLIB::FiffId

128-bit FIFF identifier: hardware machine ID plus creation time, stamped on every file and block.

On-disk layout is a 20-byte record (version + 2x4-byte machine ID + 8-byte FiffTime). The machid is filled from the host MAC address by FiffStream::write_id when generating new identifiers, matching the Neuromag acquisition stack so file lineage stays reconstructible.

src/examples/ex_fiff_api/main.cpp
QFile structureFile(dir + "/sample_audvis-ave.fif");
FiffStream::SPtr stream(new FiffStream(&structureFile));
const bool opened = stream->open();
const QList<FiffDirNode::SPtr> measNodes = stream->dirtree()->dir_tree_find(FIFFB_MEAS_INFO);
std::unique_ptr<FiffTag> tag;
const bool hasNchan = measNodes.first()->find_tag(stream, FIFF_NCHAN, tag); // raw tag access
const int nchanTag = *tag->toInt();
const FiffId fileId = stream->id();
stream->close();

Public Methods​

FiffId()​

Default Constructor.

FiffId(p_FiffId)​

Copy constructor.

Parameters:

  • p_FiffId : const FiffId & Universially unique identifier which should be copied.

operator=(other)​

Copy assignment.

Every member has value semantics, so the compiler-generated member-wise assignment is correct. It is declared explicitly because declaring a copy constructor and/or a destructor deprecates the implicitly generated one.

Parameters:

  • other : const FiffId & Object to assign from.

Returns:

  • FiffId & — reference to this object.

~FiffId()​

Destroys the universially unique identifier.

clear()​

Resets the File identifier.

print()​

Prints the id.

isEmpty()​

True if FIFF id is empty.

Returns:

  • bool — true if FIFF id is empty.

toMachidString()​

Returns the machine ID as a human-readable string.

Returns:

  • QString — The machine ID formatted as a string.

toString()​

Returns a human-readable string representation of this ID.

Format: "major.minor 0xMACHID1MACHID2 timestamp"

Returns:

  • QString — Formatted string describing the ID.

Static Methods​

new_file_id()​

Constructs a (hopefully) unique file id.

Returns:

get_machid(fixed_id)​

Returns the machine ID consisting of a two integer number.

Parameters:

  • fixed_id : *int ** Pointer to an array of at least 2 ints to receive the machine ID.

Returns:

  • bool — true if succeeded, false otherwise.

getDefault()​

Returns a default FiffId object to be used as a mutable placeholder for a default instance of the class.

Returns:

storageSize()​

Size of the old struct (fiffIdRec) 5int = 54 = 20.

Returns:

  • qint32 — the size of the old struct fiffIdRec.

Example​

Used in examples​

ex_fiff_api​

FIFF library: measurement info, channels, digitizer, transforms, projectors, covariance, events,.

src/examples/ex_fiff_api/main.cpp, line 212
std::unique_ptr<FiffTag> tag;
const bool hasNchan = measNodes.first()->find_tag(stream, FIFF_NCHAN, tag); // raw tag access
const int nchanTag = *tag->toInt();
const FiffId fileId = stream->id();
stream->close();
ok &= expect(opened && measNodes.size() == 1 && hasNchan && nchanTag == 376 && !fileId.isEmpty() && fileId.version > 0,
             "FiffStream/FiffDirNode/FiffTag/FiffId: the FIFF_NCHAN tag of the measurement block reads 376");

Authors of this file​