#include <midiplayerparser.h>

Inheritance diagram for MidiPlayerParser:

Collaboration diagram for MidiPlayerParser:

Public Member Functions
	MidiPlayerParser (MidiPlayer player, MidiPlayerEventList eventlist, int verbosity=0)
	Constructor. More...

bool	parse (QByteArray &data)
	Parse a Midi file and store it in the EventList. More...

Private Member Functions
int	findNextChunk (QByteArray &data, QString tag)
	Find the next chunk tag. More...

quint32	parseInt32 (QByteArray &data)
	Parse a 32-bit (4-byte) integer and advance the cursor. More...

quint16	parseInt16 (QByteArray &data)
	Parse a 16bit (2-byte) integer and advance the cursor. More...

quint32	parseVariableLengthNumber (QByteArray &data)
	Parse a variable-length integer. More...

bool	parseTrack (QByteArray &data, int length, quint8 track)
	Parse an entire track. More...

bool	parseEvent (QByteArray &data, quint8 track, quint32 delta, double cumulativeDelta)
	Parse a single event In the Midi specifications three types of events are defined, namely, ordinary Midi events, sysex events, and meta events. This function detects the event type and takes action accordingly. More...

bool	parseMetaEvent (QByteArray &data, quint8 track, double cumulativeDelta)
	Parse a meta event and display info in qDebug. More...

void	reportError (QString msg) const
	Report an error back to MidiPlayer. More...

Private Attributes
MidiPlayer *	pMidiPlayer
	Pointer back to the MidiPlayer. More...

MidiPlayerEventList *	pEventList
	Pointer to event list held by MidiPlayer. More...

int	mCursor
	Cursor from where the events are being played. More...

bool	SMPTE
	Flag indicating the time format. More...

quint8	mLastMidiCommand
	Variable storing the last Midi command. More...

int	mVerbosity
	Level of verbosity of qDebug() messages. More...

Detailed Description

Midi file parser.

This function parses a Midi file sequentially. The specifications can be found e.g. in https://www.midi.org/specifications. The external user only has to call the constructor, passing a pointer to the event list in which the Midi events are supposed to be stored. Then call 'parse' with the file content of the Midi file stored in a QByteArray. The function then parses the Midi file and stores the events in the event list without distinguishing the tracks.

Definition at line 45 of file midiplayerparser.h.

Constructor & Destructor Documentation

MidiPlayerParser::MidiPlayerParser	(	MidiPlayer *	player,
		MidiPlayerEventList *	eventlist,
		int	verbosity = `0`
	)

Constructor.

Parameters

player	: Pointer back to the MidiPlayer
eventlist	: Pointer to the list of events
verbosity	: Level of verbosity for qDebug messages

Definition at line 42 of file midiplayerparser.cpp.

Member Function Documentation

int MidiPlayerParser::findNextChunk	(	QByteArray &	data,
		QString	tag
	)

private

Find the next chunk tag.

Midi files are orginized in terms of 'chunks'. Each chunk starts with a 4-letter ASCII tag, e.g. "MThd" or "MTrk". This function looks for such a tag starting at the current cursor position, moves the cursor to the starting point of the chunk data and returns the length of the chunk data block if successful.

Parameters

data	: Reference QByteArray holding the file content
tag	: Four-letter ASCII tag

Returns: : length of the data chunk, 0 if not found

Definition at line 146 of file midiplayerparser.cpp.

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bool MidiPlayerParser::parse ( QByteArray & data )

Parse a Midi file and store it in the EventList.

This is the main public function of the class which is called from the MidiPlayer. The file has already been read and is now assumed to be stored in a QByteArray (Midi files are usually very short so that this is no problem). The function then parses the content of the file, looking for headers and chunks. The keystrokes of all tracks are merged and mapped to a single event list (a pointer to which was passed in the constructor).

Parameters

data	: Reference to QByteArray holding the file content.

Returns: True if parsing process was successful.

Definition at line 71 of file midiplayerparser.cpp.

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bool MidiPlayerParser::parseEvent	(	QByteArray &	data,
		quint8	track,
		quint32	delta,
		double	cumulativeDelta
	)

private

Parse a single event In the Midi specifications three types of events are defined, namely, ordinary Midi events, sysex events, and meta events. This function detects the event type and takes action accordingly.

Parameters

data	: Reference QByteArray holding the file content
track	: The track number
delta	: Value of delta preceding the actual event.
cumulativeDelta	: Sum of all preceding deltas

Returns: True if successful

Definition at line 286 of file midiplayerparser.cpp.

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quint16 MidiPlayerParser::parseInt16 ( QByteArray & data )

private

Parse a 16bit (2-byte) integer and advance the cursor.

Parameters

data	: Reference QByteArray holding the file content

Returns: Value of the integer

Definition at line 194 of file midiplayerparser.cpp.

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quint32 MidiPlayerParser::parseInt32 ( QByteArray & data )

private

Parse a 32-bit (4-byte) integer and advance the cursor.

Parameters

data	: Reference QByteArray holding the file content

Returns: Value of the integer

Definition at line 170 of file midiplayerparser.cpp.

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bool MidiPlayerParser::parseMetaEvent	(	QByteArray &	data,
		quint8	track,
		double	cumulativeDelta
	)

private

Parse a meta event and display info in qDebug.

Parameters

data	: Reference QByteArray holding the file content
track	: Midi track number
cumulativeDelta	: Cumulative delta time parameter

Returns: True if successful

Definition at line 364 of file midiplayerparser.cpp.

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bool MidiPlayerParser::parseTrack	(	QByteArray &	data,
		int	length,
		quint8	track
	)

private

Parse an entire track.

A track consists of a variable-length integer holding the time elapsed since the last event, followed by an event (see parseEvent(...)). This function reads these pairs subsequently until the expected length has been read.

Parameters

data	: Reference QByteArray holding the file content
length	: Expected length of the track
track	: The track number

Returns: : True if successfull

Definition at line 252 of file midiplayerparser.cpp.

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quint32 MidiPlayerParser::parseVariableLengthNumber ( QByteArray & data )

private

Parse a variable-length integer.

The Midi specifications involve the use of so-called variable length integers. In these integers the MSB of each byte is used to indicate whether another byte will follow. This allows Midi files to save space since most of the time intervals are very short. The actual range of integers is in practice limited to 32 bit.

Parameters

data	: Reference QByteArray holding the file content

Returns: : Value of the integer

Definition at line 221 of file midiplayerparser.cpp.

void MidiPlayerParser::reportError ( QString msg ) const

private

Report an error back to MidiPlayer.

Parameters

msg	: Error message string

Definition at line 415 of file midiplayerparser.cpp.

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Member Data Documentation

int MidiPlayerParser::mCursor

private

Cursor from where the events are being played.

Definition at line 65 of file midiplayerparser.h.

quint8 MidiPlayerParser::mLastMidiCommand

private

Variable storing the last Midi command.

Definition at line 67 of file midiplayerparser.h.

int MidiPlayerParser::mVerbosity

private

Level of verbosity of qDebug() messages.

Definition at line 68 of file midiplayerparser.h.

MidiPlayerEventList* MidiPlayerParser::pEventList

private

Pointer to event list held by MidiPlayer.

Definition at line 64 of file midiplayerparser.h.

MidiPlayer* MidiPlayerParser::pMidiPlayer

private

Pointer back to the MidiPlayer.

Definition at line 63 of file midiplayerparser.h.

bool MidiPlayerParser::SMPTE

private

Flag indicating the time format.

Definition at line 66 of file midiplayerparser.h.

The documentation for this class was generated from the following files:

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation