#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

Data Structures
struct	edf_param_struct

struct	edf_annotation_struct

struct	edf_hdr_struct

Macros
#define	EDFLIB_API

#define	EDFLIB_TIME_DIMENSION (10000000LL)

#define	EDFLIB_MAXSIGNALS (640)

#define	EDFLIB_MAX_ANNOTATION_LEN (512)

#define	EDFSEEK_SET (0)

#define	EDFSEEK_CUR (1)

#define	EDFSEEK_END (2)

#define	EDF_ANNOT_IDX_POS_END (0)

#define	EDF_ANNOT_IDX_POS_MIDDLE (1)

#define	EDF_ANNOT_IDX_POS_START (2)

#define	EDFLIB_FILETYPE_EDF (0)

#define	EDFLIB_FILETYPE_EDFPLUS (1)

#define	EDFLIB_FILETYPE_BDF (2)

#define	EDFLIB_FILETYPE_BDFPLUS (3)

#define	EDFLIB_MALLOC_ERROR (-1)

#define	EDFLIB_NO_SUCH_FILE_OR_DIRECTORY (-2)

#define	EDFLIB_FILE_CONTAINS_FORMAT_ERRORS (-3)

#define	EDFLIB_MAXFILES_REACHED (-4)

#define	EDFLIB_FILE_READ_ERROR (-5)

#define	EDFLIB_FILE_ALREADY_OPENED (-6)

#define	EDFLIB_FILETYPE_ERROR (-7)

#define	EDFLIB_FILE_WRITE_ERROR (-8)

#define	EDFLIB_NUMBER_OF_SIGNALS_INVALID (-9)

#define	EDFLIB_FILE_IS_DISCONTINUOUS (-10)

#define	EDFLIB_INVALID_READ_ANNOTS_VALUE (-11)

#define	EDFLIB_ARCH_ERROR (-12)

#define	EDFLIB_DO_NOT_READ_ANNOTATIONS (0)

#define	EDFLIB_READ_ANNOTATIONS (1)

#define	EDFLIB_READ_ALL_ANNOTATIONS (2)

#define	EDFLIB_NO_SIGNALS (-20)

#define	EDFLIB_TOO_MANY_SIGNALS (-21)

#define	EDFLIB_NO_SAMPLES_IN_RECORD (-22)

#define	EDFLIB_DIGMIN_IS_DIGMAX (-23)

#define	EDFLIB_DIGMAX_LOWER_THAN_DIGMIN (-24)

#define	EDFLIB_PHYSMIN_IS_PHYSMAX (-25)

#define	EDFLIB_DATARECORD_SIZE_TOO_BIG (-26)

Typedefs
typedef struct edf_param_struct	edflib_param_t

typedef struct edf_annotation_struct	edflib_annotation_t

typedef struct edf_hdr_struct	edflib_hdr_t

Functions
EDFLIB_API int	edfopen_file_readonly (const char path, edflib_hdr_t edfhdr, int read_annotations)

EDFLIB_API int	edfread_physical_samples (int handle, int edfsignal, int n, double *buf)

EDFLIB_API int	edfread_digital_samples (int handle, int edfsignal, int n, int *buf)

EDFLIB_API long long	edfseek (int handle, int edfsignal, long long offset, int whence)

EDFLIB_API long long	edftell (int handle, int edfsignal)

EDFLIB_API int	edfrewind (int handle, int edfsignal)

EDFLIB_API int	edf_get_annotation (int handle, int n, edflib_annotation_t *annot)

EDFLIB_API int	edfclose_file (int handle)

EDFLIB_API int	edflib_version (void)

EDFLIB_API int	edflib_is_file_used (const char *path)

EDFLIB_API int	edflib_get_number_of_open_files (void)

EDFLIB_API int	edflib_get_handle (int file_number)

EDFLIB_API int	edfopen_file_writeonly (const char *path, int filetype, int number_of_signals)

EDFLIB_API int	edfopen_file_writeonly_with_params (const char path, int filetype, int number_of_signals, int samplefrequency, double phys_max_min, const char phys_dim)

EDFLIB_API int	edf_set_samplefrequency (int handle, int edfsignal, int samplefrequency)

EDFLIB_API int	edf_set_physical_maximum (int handle, int edfsignal, double phys_max)

EDFLIB_API int	edf_set_physical_minimum (int handle, int edfsignal, double phys_min)

EDFLIB_API int	edf_set_digital_maximum (int handle, int edfsignal, int dig_max)

EDFLIB_API int	edf_set_digital_minimum (int handle, int edfsignal, int dig_min)

EDFLIB_API int	edf_set_label (int handle, int edfsignal, const char *label)

EDFLIB_API int	edf_set_prefilter (int handle, int edfsignal, const char *prefilter)

EDFLIB_API int	edf_set_transducer (int handle, int edfsignal, const char *transducer)

EDFLIB_API int	edf_set_physical_dimension (int handle, int edfsignal, const char *phys_dim)

EDFLIB_API int	edf_set_startdatetime (int handle, int startdate_year, int startdate_month, int startdate_day, int starttime_hour, int starttime_minute, int starttime_second)

EDFLIB_API int	edf_set_patientname (int handle, const char *patientname)

EDFLIB_API int	edf_set_patientcode (int handle, const char *patientcode)

EDFLIB_API int	edf_set_sex (int handle, int sex)

EDFLIB_API int	edf_set_gender (int handle, int sex)

EDFLIB_API int	edf_set_birthdate (int handle, int birthdate_year, int birthdate_month, int birthdate_day)

EDFLIB_API int	edf_set_patient_additional (int handle, const char *patient_additional)

EDFLIB_API int	edf_set_admincode (int handle, const char *admincode)

EDFLIB_API int	edf_set_technician (int handle, const char *technician)

EDFLIB_API int	edf_set_equipment (int handle, const char *equipment)

EDFLIB_API int	edf_set_recording_additional (int handle, const char *recording_additional)

EDFLIB_API int	edfwrite_physical_samples (int handle, double *buf)

EDFLIB_API int	edf_blockwrite_physical_samples (int handle, double *buf)

EDFLIB_API int	edfwrite_digital_short_samples (int handle, short *buf)

EDFLIB_API int	edfwrite_digital_samples (int handle, int *buf)

EDFLIB_API int	edf_blockwrite_digital_3byte_samples (int handle, void *buf)

EDFLIB_API int	edf_blockwrite_digital_short_samples (int handle, short *buf)

EDFLIB_API int	edf_blockwrite_digital_samples (int handle, int *buf)

EDFLIB_API int	edfwrite_annotation_utf8_hr (int handle, long long onset, long long duration, const char *description)

EDFLIB_API int	edfwrite_annotation_utf8 (int handle, long long onset, long long duration, const char *description)

EDFLIB_API int	edfwrite_annotation_latin1_hr (int handle, long long onset, long long duration, const char *description)

EDFLIB_API int	edfwrite_annotation_latin1 (int handle, long long onset, long long duration, const char *description)

EDFLIB_API int	edf_set_datarecord_duration (int handle, int duration)

EDFLIB_API int	edf_set_micro_datarecord_duration (int handle, int duration)

EDFLIB_API int	edf_set_number_of_annotation_signals (int handle, int annot_signals)

EDFLIB_API int	edf_set_subsecond_starttime (int handle, int subsecond)

EDFLIB_API int	edf_set_annot_chan_idx_pos (int handle, int pos)

Detailed Description

In EDF, the resolution (or sensitivity) (e.g. uV/bit) and offset are stored using four parameters:
digital maximum and minimum, and physical maximum and minimum.
Here, digital means the raw data coming from a sensor or ADC. Physical means the units like uV.
The resolution in units per least significant bit is calculated as follows:

units per bit = (physical max - physical min) / (digital max - digital min)

The digital offset is calculated as follows:

offset = (physical max / units per bit) - digital max

For a better explanation about the relation between digital data and physical data,
read the document "Coding Schemes Used with Data Converters" (PDF):

https://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=sbaa042

An EDF file usually contains multiple so-called datarecords. One datarecord usually has a duration of one second (this is the default but it's not mandatory).
In that case a file with a duration of five minutes contains 300 datarecords. The duration of a datarecord can be freely chosen but, if possible, use values from
0.1 to 1 second for easier handling. Just make sure that the total size of one datarecord, expressed in bytes, does not exceed 10 MByte (15 MBytes for BDF(+)).

The recommendation of a maximum datarecord size of 61440 bytes in the EDF(+) specification was useful in the time people were still using DOS as their main operating system.
Using DOS and fast (near) pointers (16-bit pointers), the maximum allocatable block of memory was 64KByte.
This is not a concern anymore so the maximum datarecord size now is limited to 10 MByte for EDF(+) and 15 MByte for BDF(+). This helps to accommodate for higher sampling rates
used by modern Analog to Digital Converters.

EDF header character encoding: The EDF specification says that only (printable) ASCII characters are allowed.
When writing the header info, EDFlib will assume you are using Latin1 encoding and it will automatically convert
characters with accents, umlauts, tilde, etc. to their "normal" equivalent without the accent/umlaut/tilde/etc.
in order to create a valid EDF file.
The description of an EDF+ annotation/event/trigger on the other hand, is always encoded in UTF-8 (which is forward compatible with ASCII).

The sample frequency of a signal is calculated as follows: sf = (smp_in_datarecord * EDFLIB_TIME_DIMENSION) / datarecord_duration

Annotation signals
==================

EDF+ and BDF+ store the annotations/events/triggers in one or more signals (in order to be backwards compatible with EDF and BDF)
and they can appear anywhere in the list of signals.
The numbering of the signals in the file is zero based (starts at 0). Signals used for annotations are skipped by EDFlib.
This means that the annotationsignal(s) in the file are hidden.
Use the function edf_get_annotation() to get the annotations.

So, when a file contains 7 signals and the third and fifth signal are annotation signals, the library will
report that there are only 5 signals in the file.
The library will "map" the (zero-based) signal numbers as follows: 0->0, 1->1, 2->3, 3->4, 4->6.
This way you don't need to worry about which signals are annotationsignals, the library will take care of it.

How the library stores time values
==================================

To avoid rounding errors and to be able to compare values, the library stores some time values in variables of type long long int.
In order not to lose the sub-second precision, all time values are scaled with a scaling factor: 10000000.
This will limit the time resolution to 100 nanoseconds. To calculate the amount of seconds, divide
the timevalue by 10000000 or use the macro EDFLIB_TIME_DIMENSION which is declared in edflib.h.
The following variables use this scaling when you open a file in read mode: "file_duration", "starttime_subsecond" and "onset".

EDFlib and thread-safety
========================
The following functions are always MT-unsafe:
edfopen_file_readonly() (race condition)
edfclose_file() (race condition)
edflib_get_handle() (race condition)

When writing to or reading from the same file, all EDFlib functions are MT-unsafe (race condition).

When accessing EDFlib from different threads, use a mutex.

For more info about the EDF and EDF+ format, visit: https://edfplus.info/specs/

For more info about the BDF and BDF+ format, visit: https://www.teuniz.net/edfbrowser/bdfplus%20format%20description.html

Typedef Documentation

◆ edflib_param_t

typedef struct edf_param_struct edflib_param_t

This structure contains the signal parameters.

◆ edflib_annotation_t

typedef struct edf_annotation_struct edflib_annotation_t

This structure is used for annotations/events/triggers.

◆ edflib_hdr_t

typedef struct edf_hdr_struct edflib_hdr_t

This structure contains the general header info and parameters. It will be filled when calling the function edfopen_file_readonly().

Function Documentation

◆ edfopen_file_readonly()

EDFLIB_API int edfopen_file_readonly	(	const char *	path,
		edflib_hdr_t *	edfhdr,
		int	read_annotations
	)

Opens an existing file for reading.

Parameters

[in]	path	null-terminated string containing the `path` to the file
[out]	edfhdr	pointer to an `edflib_hdr_t` struct, all fields in this struct will be overwritten, it will be filled with all the relevant header- and signalinfo/parameters
[in]	read_annotations	Must have one of the following values: EDFLIB_DO_NOT_READ_ANNOTATIONS annotations will not be read (this can save time when opening a very large EDF+ or BDF+ file EDFLIB_READ_ANNOTATIONS annotations will be read immediately, stops when an annotation has been found which contains the description "Recording ends" EDFLIB_READ_ALL_ANNOTATIONS all annotations will be read immediately

Returns: 0 on success, in case of an error it returns -1 and an error code will be set in the member "filetype" of edfhdr. This function is required if you want to read a file

In case of a file format error (-3), try to open the file with EDFbrowser: https://www.teuniz.net/edfbrowser/ It will give you full details about the cause of the error and it can also fix most errors.

◆ edfread_physical_samples()

EDFLIB_API int edfread_physical_samples	(	int	handle,
		int	edfsignal,
		int	n,
		double *	buf
	)

Reads n samples from edfsignal, starting from the current sample position indicator, into buf (edfsignal starts at 0). The values are converted to their physical values e.g. microVolts, beats per minute, etc.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	n	Number of samples to read. The sample position indicator will be increased with the same amount.
[out]	buf	Pointer to a buffer, size must be equal to, or bigger than, sizeof(double[n])

Returns: The number of samples read (this can be less than n or zero!) or -1 in case of an error

◆ edfread_digital_samples()

EDFLIB_API int edfread_digital_samples	(	int	handle,
		int	edfsignal,
		int	n,
		int *	buf
	)

Reads n samples from edfsignal, starting from the current sample position indicator, into buf (edfsignal starts at 0). The values are the "raw" digital values (e.g. from an ADC).

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	n	Number of samples to read. The sample position indicator will be increased with the same amount.
[out]	buf	Pointer to a buffer, size must be equal to, or bigger than, sizeof(double[n])

Returns: The number of samples read (this can be less than n or zero!) or -1 in case of an error

◆ edfseek()

EDFLIB_API long long edfseek	(	int	handle,
		int	edfsignal,
		long long	offset,
		int	whence
	)

Sets the sample position indicator for the edfsignal pointed to by edfsignal. The new position, measured in samples, is obtained by adding offset samples to the position specified by whence. If whence is set to EDFSEEK_SET, EDFSEEK_CUR, or EDFSEEK_END, the offset is relative to the start of the file, the current position indicator, or end-of-file, respectively. Note that every signal has it's own independent sample position indicator and edfseek() affects only one of them.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	offset	Offset measured in samples.
[in]	whence	Reference for `offset:` EDFSEEK_SET start of the file EDFSEEK_CUR current position EDFSEEK_END end of the file

Returns: The current offset or -1 in case of an error.

◆ edftell()

EDFLIB_API long long edftell	(	int	handle,
		int	edfsignal
	)

Obtains the current value of the sample position indicator for the edfsignal pointed to by edfsignal. Note that every signal has it's own independent sample position indicator and edftell() affects only one of them.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.

Returns: The current offset or -1 in case of an error.

◆ edfrewind()

EDFLIB_API int edfrewind	(	int	handle,
		int	edfsignal
	)

Sets the sample position indicator for the edfsignal pointed to by edfsignal to the beginning of the file. It is equivalent to: edfseek(handle, edfsignal, 0LL, EDFSEEK_SET). Note that every signal has it's own independent sample position indicator and edfrewind() affects only one of them.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.

Returns: 0 on success or -1 in case of an error.

◆ edf_get_annotation()

EDFLIB_API int edf_get_annotation	(	int	handle,
		int	n,
		edflib_annotation_t *	annot
	)

Fills the edflib_annotation_t structure with the annotation n. The string that describes the annotation/event is encoded in UTF-8. To obtain the number of annotations in a file, check edf_hdr_struct -> annotations_in_file.

Parameters

[in]	handle	File handle.
[in]	n	The zero-based index number of the list of annotations.
[out]	annot	Pointer to a struct that will be filled with the annotation.

Returns: 0 on success or -1 in case of an error.

◆ edfclose_file()

EDFLIB_API int edfclose_file ( int handle )

Closes (and in case of writing, finalizes) the file.

This function MUST be called when you have finished reading or writing This function is required after reading or writing. Failing to do so will cause unnecessary memory usage and in case of writing it will cause a corrupted or incomplete file.

Parameters

[in] handle File handle.

Returns: 0 on success or -1 in case of an error.

◆ edflib_version()

EDFLIB_API int edflib_version ( void )

Returns the version number of this library, multiplied by hundred. if version is "1.00" then it will return 100.

Returns: The version number.

◆ edflib_is_file_used()

EDFLIB_API int edflib_is_file_used ( const char * path )

Returns 1 if the file is in use, either for reading or writing, otherwise returns 0.

Parameters

[in] path Pointer to a null-terminated string that contains the path to the file.

Returns: 1 if the file is in use (either for reading or writing), otherwise 0.

◆ edflib_get_number_of_open_files()

EDFLIB_API int edflib_get_number_of_open_files ( void )

Returns the number of open files.

Returns: The number of open files, either for reading or writing.

◆ edflib_get_handle()

EDFLIB_API int edflib_get_handle ( int file_number )

Returns the handle of an open file, either for reading or writing.

Parameters

[in] file_number A zero based index number of the list of open files.

Returns: The file handle or -1 if the file_number >= number of open files.

◆ edfopen_file_writeonly()

EDFLIB_API int edfopen_file_writeonly	(	const char *	path,
		int	filetype,
		int	number_of_signals
	)

Opens an new file for writing. Warning: an already existing file with the same name will be silently overwritten without advance warning!
This function is required if you want to write a file (or use edfopen_file_writeonly_with_params())

Parameters

[in]	path	A null-terminated string containing the path and name of the file
[in]	filetype	Must be EDFLIB_FILETYPE_EDFPLUS or EDFLIB_FILETYPE_BDFPLUS.
[in]	number_of_signals	The number of signals you want to store into the file (excluding annotation signals, the library will take care of that).

Returns

A file handle on success or a negative number in case of an error:

EDFLIB_MALLOC_ERROR
EDFLIB_NO_SUCH_FILE_OR_DIRECTORY
EDFLIB_MAXFILES_REACHED
EDFLIB_FILE_ALREADY_OPENED
EDFLIB_NUMBER_OF_SIGNALS_INVALID
EDFLIB_ARCH_ERROR

◆ edfopen_file_writeonly_with_params()

EDFLIB_API int edfopen_file_writeonly_with_params	(	const char *	path,
		int	filetype,
		int	number_of_signals,
		int	samplefrequency,
		double	phys_max_min,
		const char *	phys_dim
	)

This is a convenience function that can create a new EDF file and initializes the most important parameters.
It assumes that all signals are sharing the same parameters (you can still change them though).
Warning: an already existing file with the same name will be silently overwritten without advance warning!

Parameters

[in]	path	A null-terminated string containing the path and name of the file.
[in]	filetype	Must be EDFLIB_FILETYPE_EDFPLUS or EDFLIB_FILETYPE_BDFPLUS.
[in]	number_of_signals	The number of signals you want to store into the file (excluding annotation signals, the library will take care of that).
[in]	samplefrequency	Sample frequency for all signals. (In reality, it sets the number of samples per datarecord which equals the sample frequency only when the datarecords have a duration of one second which is the default here.)
[in]	phys_max_min	Physical maximum and minimum for all signals.
[in]	phys_dim	Pointer to a NULL-terminated ASCII-string containing the physical dimension (unit) for all signals ("uV", "BPM", "mA", "Degr.", etc.).

Returns

A file handle on success or a negative number in case of an error:

EDFLIB_MALLOC_ERROR
EDFLIB_NO_SUCH_FILE_OR_DIRECTORY
EDFLIB_MAXFILES_REACHED
EDFLIB_FILE_ALREADY_OPENED
EDFLIB_NUMBER_OF_SIGNALS_INVALID
EDFLIB_ARCH_ERROR

◆ edf_set_samplefrequency()

EDFLIB_API int edf_set_samplefrequency	(	int	handle,
		int	edfsignal,
		int	samplefrequency
	)

Sets the sample frequency of signal edfsignal. In reality, it sets the number of samples in a datarecord
which equals the sample frequency only when the datarecords have a duration of one second.
The effective sample frequency is: samplefrequency / datarecord duration
This function is required for every signal (except when using edfopen_file_writeonly_with_params()) and can be called
only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	samplefrequency	Sample frequency, must be > 0;

Returns: 0 on success, otherwise -1.

◆ edf_set_physical_maximum()

EDFLIB_API int edf_set_physical_maximum	(	int	handle,
		int	edfsignal,
		double	phys_max
	)

Sets the maximum physical value of signal edfsignal. (the value of the input of the ADC when the output equals the value of "digital maximum")
It is the highest value that the equipment is able to record. It does not necessarily mean the signal recorded reaches this level.
In other words, it is the highest value that CAN occur in the recording.
Must be un-equal to physical minimum.
This function is required for every signal (except when using edfopen_file_writeonly_with_params()) and can be called
only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	phys_max	Physical maximum, must be != physical minimum;

Returns: 0 on success, otherwise -1.

◆ edf_set_physical_minimum()

EDFLIB_API int edf_set_physical_minimum	(	int	handle,
		int	edfsignal,
		double	phys_min
	)

Sets the minimum physical value of signal edfsignal. (the value of the input of the ADC when the output equals the value of "digital minimum")
It is the lowest value that the equipment is able to record. It does not necessarily mean the signal recorded reaches this level.
In other words, it is the lowest value that CAN occur in the recording.
Must be un-equal to physical maximum.
This function is required for every signal (except when using edfopen_file_writeonly_with_params()) and can be called
only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	phys_min	Physical minimum, must be != physical maximum;

Returns: 0 on success, otherwise -1.

◆ edf_set_digital_maximum()

EDFLIB_API int edf_set_digital_maximum	(	int	handle,
		int	edfsignal,
		int	dig_max
	)

Sets the maximum digital value of signal edfsignal. The maximum value is 32767 for EDF+ and 8388607 for BDF+.
It is the highest value that the equipment is able to record. It does not necessarily mean the signal recorded reaches this level.
In other words, it is the highest value that CAN occur in the recording.
Must be higher than digital minimum.
This function is required for every signal (except when using edfopen_file_writeonly_with_params()) and can be called
only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	dig_max	Digital maximum, must be > digital minimum;

Returns: 0 on success, otherwise -1.

◆ edf_set_digital_minimum()

EDFLIB_API int edf_set_digital_minimum	(	int	handle,
		int	edfsignal,
		int	dig_min
	)

Sets the minimum digital value of signal edfsignal. The minimum value is -32768 for EDF+ and -8388608 for BDF+.
It is the lowest value that the equipment is able to record. It does not necessarily mean the signal recorded reaches this level.
In other words, it is the lowest value that CAN occur in the recording.
Must be lower than digital maximum.
This function is required for every signal (except when using edfopen_file_writeonly_with_params()) and can be called
only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	dig_min	Digital minimum, must be < digital maximum;

Returns: 0 on success, otherwise -1.

◆ edf_set_label()

EDFLIB_API int edf_set_label	(	int	handle,
		int	edfsignal,
		const char *	label
	)

Sets the label (name) of signal edfsignal. ("EEG FP1", "SaO2", etc.).
This function is recommended for every signal when you want to write a file
and can be called only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	label	A pointer to a NULL-terminated ASCII-string containing the label (name) of the signal `edfsignal`.

Returns: 0 on success, otherwise -1.

◆ edf_set_prefilter()

EDFLIB_API int edf_set_prefilter	(	int	handle,
		int	edfsignal,
		const char *	prefilter
	)

Sets the prefilter of signal edfsignal e.g. "HP:0.1Hz", "LP:75Hz N:50Hz", etc.
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	prefilter	A pointer to a NULL-terminated ASCII-string containing the prefilter text of the signal `edfsignal`.

Returns: 0 on success, otherwise -1.

◆ edf_set_transducer()

EDFLIB_API int edf_set_transducer	(	int	handle,
		int	edfsignal,
		const char *	transducer
	)

Sets the transducer of signal edfsignal e.g. "AgAgCl cup electrodes", etc.
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	transducer	A pointer to a NULL-terminated ASCII-string containing the transducer text of the signal `edfsignal`.

Returns: 0 on success, otherwise -1.

◆ edf_set_physical_dimension()

EDFLIB_API int edf_set_physical_dimension	(	int	handle,
		int	edfsignal,
		const char *	phys_dim
	)

Sets the physical dimension (unit) of signal edfsignal. ("uV", "BPM", "mA", "Degr.", etc.).
This function is recommended for every signal when you want to write a file
and can be called only after opening a file in write mode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	edfsignal	The zero-based index of the signal.
[in]	phys_dim	A pointer to a NULL-terminated ASCII-string containing the physical dimension (unit) of the signal `edfsignal`.

Returns: 0 on success, otherwise -1.

◆ edf_set_startdatetime()

EDFLIB_API int edf_set_startdatetime	(	int	handle,
		int	startdate_year,
		int	startdate_month,
		int	startdate_day,
		int	starttime_hour,
		int	starttime_minute,
		int	starttime_second
	)

Sets the startdate and starttime.
If not called, the library will use the system date and time at runtime.
This function is optional and can be called only after opening a file in write mode
and before the first sample write action.
Note: for anonymization purposes, the consensus is to use 1985-01-01 00:00:00 for the startdate and starttime.

Parameters

[in]	handle	File handle.
[in]	startdate_year	1985 - 2084 inclusive
[in]	startdate_month	1 - 12 inclusive
[in]	startdate_day	1 - 31 inclusive
[in]	starttime_hour	0 - 23 inclusive
[in]	starttime_minute	0 - 59 inclusive
[in]	starttime_second	0 - 59 inclusive

Returns: 0 on success, otherwise -1.

◆ edf_set_patientname()

EDFLIB_API int edf_set_patientname	(	int	handle,
		const char *	patientname
	)

Sets the subject name
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	patientname	A pointer to a NULL-terminated ASCII-string containing the subject name.

Returns: 0 on success, otherwise -1.

◆ edf_set_patientcode()

EDFLIB_API int edf_set_patientcode	(	int	handle,
		const char *	patientcode
	)

Sets the subject code
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	patientcode	A pointer to a NULL-terminated ASCII-string containing the subject code.

Returns: 0 on success, otherwise -1.

◆ edf_set_sex()

EDFLIB_API int edf_set_sex	(	int	handle,
		int	sex
	)

Sets the sex of the subject. 1 is male, 0 is female.
This function is optional and can be called only after opening a file in writemode
and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	sex	1: male, 0: female.

Returns: 0 on success, otherwise -1.

◆ edf_set_birthdate()

EDFLIB_API int edf_set_birthdate	(	int	handle,
		int	birthdate_year,
		int	birthdate_month,
		int	birthdate_day
	)

Sets the subject birthdate.
This function is optional and can be called only after opening a file in write mode
and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	birthdate_year	1800 - 3000 inclusive
[in]	birthdate_month	1 - 12 inclusive
[in]	birthdate_day	1 - 31 inclusive

Returns: 0 on success, otherwise -1.

◆ edf_set_patient_additional()

EDFLIB_API int edf_set_patient_additional	(	int	handle,
		const char *	patient_additional
	)

Sets the additional subject info
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	patient_additional	A pointer to a NULL-terminated ASCII-string containing the additional subject info.

Returns: 0 on success, otherwise -1.

◆ edf_set_admincode()

EDFLIB_API int edf_set_admincode	(	int	handle,
		const char *	admincode
	)

Sets the administration code
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	admincode	A pointer to a NULL-terminated ASCII-string containing the administration code.

Returns: 0 on success, otherwise -1.

◆ edf_set_technician()

EDFLIB_API int edf_set_technician	(	int	handle,
		const char *	technician
	)

Sets the technicians name or code
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	technician	A pointer to a NULL-terminated ASCII-string containing the technicians name or code.

Returns: 0 on success, otherwise -1.

◆ edf_set_equipment()

EDFLIB_API int edf_set_equipment	(	int	handle,
		const char *	equipment
	)

Sets the equipment brand and/or model
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	equipment	A pointer to a NULL-terminated ASCII-string containing the equipment brand and/or model used for the recording.

Returns: 0 on success, otherwise -1.

◆ edf_set_recording_additional()

EDFLIB_API int edf_set_recording_additional	(	int	handle,
		const char *	recording_additional
	)

Sets the additional info about the recording.
This function is optional and can be called only after opening a file in writemode and
before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	recording_additional	A pointer to a NULL-terminated ASCII-string containing the additional info about the recording.

Returns: 0 on success, otherwise -1.

◆ edfwrite_physical_samples()

EDFLIB_API int edfwrite_physical_samples	(	int	handle,
		double *	buf
	)

Writes n physical samples (uV, mA, Ohm) from buf belonging to one signal
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
The physical samples will be converted to digital samples using the
values of physical maximum, physical minimum, digital maximum and digital minimum.
Size of buf must be equal to or bigger than sizeof(double[samples per datarecord]).
Call this function for every signal in the file. The order is important:
When there are 4 signals in the file, the order of calling this function
must be: signal 0, signal 1, signal 2, signal 3, signal 0, signal 1, signal 2, etc.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edf_blockwrite_physical_samples()

EDFLIB_API int edf_blockwrite_physical_samples	(	int	handle,
		double *	buf
	)

Writes physical samples (uV, mA, Ohm) from buf
buf must be filled with samples from all signals, starting with n samples of signal 0, n samples of signal 1, n samples of signal 2, etc.
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
The physical samples will be converted to digital samples using the
values of physical maximum, physical minimum, digital maximum and digital minimum.
The number of samples written equals the sum of the samples per datarecord of all signals.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edfwrite_digital_short_samples()

EDFLIB_API int edfwrite_digital_short_samples	(	int	handle,
		short *	buf
	)

Writes n "raw" digital samples from buf belonging to one signal
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
Size of buf should be equal to or bigger than sizeof(short[samples per datarecord]).
Call this function for every signal in the file. The order is important:
When there are 4 signals in the file, the order of calling this function
must be: signal 0, signal 1, signal 2, signal 3, signal 0, signal 1, signal 2, etc.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edfwrite_digital_samples()

EDFLIB_API int edfwrite_digital_samples	(	int	handle,
		int *	buf
	)

Writes n "raw" digital samples from buf belonging to one signal
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
The 16 (or 24 in case of BDF+) least significant bits of the samples will be written to the
file without any conversion.
Size of buf should be equal to or bigger than sizeof(int[samples per datarecord]).
Call this function for every signal in the file. The order is important:
When there are 4 signals in the file, the order of calling this function
must be: signal 0, signal 1, signal 2, signal 3, signal 0, signal 1, signal 2, etc.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edf_blockwrite_digital_3byte_samples()

EDFLIB_API int edf_blockwrite_digital_3byte_samples	(	int	handle,
		void *	buf
	)

Writes "raw" digital samples from buf
buf must be filled with samples from all signals, starting with n samples of signal 0, n samples of signal 1, n samples of signal 2, etc.
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
One sample equals 3 bytes, order is little endian (least significant byte first).
Encoding is second's complement, most significant bit of most significant byte is the sign-bit.
Because the size of a 3-byte sample is 24-bit, this function can only be used when writing a BDF+ file.
The number of samples written equals the sum of the samples per datarecord of all signals.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edf_blockwrite_digital_short_samples()

EDFLIB_API int edf_blockwrite_digital_short_samples	(	int	handle,
		short *	buf
	)

Writes "raw" digital samples from buf
buf must be filled with samples from all signals, starting with n samples of signal 0, n samples of signal 1, n samples of signal 2, etc.
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
One sample equals 2 bytes, order is little endian (least significant byte first).
Encoding is second's complement, most significant bit of most significant byte is the sign-bit.
Because the size of a 2-byte sample is 16-bit, this function can only be used when writing an EDF+ file.
The number of samples written equals the sum of the samples per datarecord of all signals.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edf_blockwrite_digital_samples()

EDFLIB_API int edf_blockwrite_digital_samples	(	int	handle,
		int *	buf
	)

Writes "raw" digital samples from buf
buf must be filled with samples from all signals, starting with n samples of signal 0, n samples of signal 1, n samples of signal 2, etc.
where n is the samplefrequency of that signal.
Actually, n equals the number of samples per datarecord which equals the samplefrequency only
when the datarecord duration has the default value of one second!
The 16 (or 24 in case of BDF+) least significant bits of the samples will be written to the
file without any conversion.
The number of samples written equals the sum of the samples per datarecord of all signals.

Parameters

[in]	handle	File handle.
[in]	buf	A pointer to a buffer containing the samples.

Returns: 0 on success, otherwise -1.

◆ edfwrite_annotation_utf8_hr()

EDFLIB_API int edfwrite_annotation_utf8_hr	(	int	handle,
		long long	onset,
		long long	duration,
		const char *	description
	)

Writes an annotation/event to the file.
This function is optional and can be called only after opening a file in writemode
and before closing the file.

Parameters

[in]	handle	File handle.
[in]	onset	microseconds since start of recording.
[in]	duration	microseconds, > 0 or -1 if not used.
[in]	description	A null-terminated UTF8-string containing the text that describes the event.

Returns: 0 on success, otherwise -1.

◆ edfwrite_annotation_latin1_hr()

EDFLIB_API int edfwrite_annotation_latin1_hr	(	int	handle,
		long long	onset,
		long long	duration,
		const char *	description
	)

Writes an annotation/event to the file.
This function is optional and can be called only after opening a file in writemode
and before closing the file.

Parameters

[in]	handle	File handle.
[in]	onset	microseconds since start of recording.
[in]	duration	microseconds, > 0 or -1 if not used.
[in]	description	A null-terminated Latin1-string containing the text that describes the event.

Returns: 0 on success, otherwise -1.

◆ edf_set_datarecord_duration()

EDFLIB_API int edf_set_datarecord_duration	(	int	handle,
		int	duration
	)

Sets the datarecord duration. The default value is 1 second.
ATTENTION: the argument duration is expressed in units of 10 microseconds.
So, if you want to set the datarecord duration to 0.1 second, you must write a value of 10000.
The datarecord duration must be in the range 0.001 to 60 seconds.
This function can be used when you want to use a samplerate
which is not an integer. For example, if you want to use a samplerate of 0.5 Hz,
set the samplefrequency to 5 Hz and the datarecord duration to 10 seconds,
or set the samplefrequency to 1 Hz and the datarecord duration to 2 seconds.
This function is optional and can be called after opening a
file in writemode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	duration	Datarecord duration expressed in units of 10 microSecond.

Returns: 0 on success, otherwise -1.

◆ edf_set_micro_datarecord_duration()

EDFLIB_API int edf_set_micro_datarecord_duration	(	int	handle,
		int	duration
	)

Sets the datarecord duration to a very small value.
ATTENTION: the argument duration is expressed in units of 1 microSecond.
The datarecord duration must be in the range 1 to 9999 microseconds.
This function can be used when you want to use a very high samplerate.
For example, if you want to use a samplerate of 5 GHz,
set the samplefrequency to 5000 Hz and the datarecord duration to 1 micro-second.
Do not use this function if not necessary.
This function was added to accommodate for high speed ADC's e.g. Digital Sampling Oscilloscopes
This function is optional and can be called after opening a
file in writemode and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	duration	Datarecord duration expressed in units of 10 microSecond.

Returns: 0 on success, otherwise -1.

◆ edf_set_number_of_annotation_signals()

EDFLIB_API int edf_set_number_of_annotation_signals	(	int	handle,
		int	annot_signals
	)

Sets the number of annotation signals. The default value is 1.
This function is optional and can be called only after opening a file in writemode
and before the first sample write action.
Normally you don't need to change the default value. Only when the number of annotations
you expect to write is more than the number of datarecords in the recording, you can use
this function to increase the storage space for annotations.

Parameters

[in]	handle	File handle.
[in]	annot_signals	Number of annotation signals, must be in the range 1 - 64 inclusive.

Returns: 0 on success, otherwise -1.

◆ edf_set_subsecond_starttime()

EDFLIB_API int edf_set_subsecond_starttime	(	int	handle,
		int	subsecond
	)

Sets the subsecond starttime expressed in units of 100 nanoseconds.
Valid range is 0 to 9999999 inclusive. Default is 0.
This function is optional and can be called only after opening a file in writemode
and before the first sample write action.
It is recommended to use a maximum resolution of not more than 100 microseconds.
E.g. use 1234000 to set a starttime offset of 0.1234 seconds (instead of for example 1234217).
In other words, leave the last 3 digits at zero.

Parameters

[in]	handle	File handle.
[in]	subsecond	Subsecond starttime expressed in units of 100 nanoseconds.

Returns: 0 on success, otherwise -1.

◆ edf_set_annot_chan_idx_pos()

EDFLIB_API int edf_set_annot_chan_idx_pos	(	int	handle,
		int	pos
	)

Sets the preferred position of the annotation channels(s) before, after or in the middle of the list
of regular signals. The default is to put them at the end (after the regular signals).
This function is optional and can be called only after opening a file in writemode
and before the first sample write action.

Parameters

[in]	handle	File handle.
[in]	pos	Preferred position of the annotation channel(s): EDF_ANNOT_IDX_POS_START EDF_ANNOT_IDX_POS_MIDDLE EDF_ANNOT_IDX_POS_END

Returns: 0 on success, otherwise -1.

Data Structures

Macros

Typedefs

Functions

Detailed Description

Typedef Documentation

◆ edflib_param_t

◆ edflib_annotation_t

◆ edflib_hdr_t

Function Documentation

◆ edfopen_file_readonly()

◆ edfread_physical_samples()

◆ edfread_digital_samples()

◆ edfseek()

◆ edftell()

◆ edfrewind()

◆ edf_get_annotation()

◆ edfclose_file()

◆ edflib_version()

◆ edflib_is_file_used()

◆ edflib_get_number_of_open_files()

◆ edflib_get_handle()

◆ edfopen_file_writeonly()

◆ edfopen_file_writeonly_with_params()

◆ edf_set_samplefrequency()

◆ edf_set_physical_maximum()

◆ edf_set_physical_minimum()

◆ edf_set_digital_maximum()

◆ edf_set_digital_minimum()

◆ edf_set_label()

◆ edf_set_prefilter()

◆ edf_set_transducer()

◆ edf_set_physical_dimension()

◆ edf_set_startdatetime()

◆ edf_set_patientname()

◆ edf_set_patientcode()

◆ edf_set_sex()

◆ edf_set_birthdate()

◆ edf_set_patient_additional()

◆ edf_set_admincode()

◆ edf_set_technician()

◆ edf_set_equipment()

◆ edf_set_recording_additional()

◆ edfwrite_physical_samples()

◆ edf_blockwrite_physical_samples()

◆ edfwrite_digital_short_samples()

◆ edfwrite_digital_samples()

◆ edf_blockwrite_digital_3byte_samples()

◆ edf_blockwrite_digital_short_samples()

◆ edf_blockwrite_digital_samples()

◆ edfwrite_annotation_utf8_hr()

◆ edfwrite_annotation_latin1_hr()

◆ edf_set_datarecord_duration()

◆ edf_set_micro_datarecord_duration()

◆ edf_set_number_of_annotation_signals()

◆ edf_set_subsecond_starttime()

◆ edf_set_annot_chan_idx_pos()