New methods MidiFile::findAllKeySigEvents() and MidiMessage::isKeySignatureMajorKey()

modules/juce_audio_basics/midi/juce_MidiFile.cpp

@@ -146,6 +146,26 @@ namespace MidiFileHelpers
             return 0;
         }
     };
+
+    template <typename MethodType>
+    static void findAllMatchingEvents (const OwnedArray<MidiMessageSequence>& tracks,
+                                       MidiMessageSequence& results,
+                                       MethodType method)
+    {
+        for (int i = 0; i < tracks.size(); ++i)
+        {
+            const MidiMessageSequence& track = *tracks.getUnchecked(i);
+            const int numEvents = track.getNumEvents();
+
+            for (int j = 0; j < numEvents; ++j)
+            {
+                const MidiMessage& m = track.getEventPointer(j)->message;
+
+                if ((m.*method)())
+                    results.addEvent (m);
+            }
+        }
+    }
 }
 
 //==============================================================================
@@ -197,36 +217,19 @@ void MidiFile::setSmpteTimeFormat (const int framesPerSecond,
 }
 
 //==============================================================================
-void MidiFile::findAllTempoEvents (MidiMessageSequence& tempoChangeEvents) const
+void MidiFile::findAllTempoEvents (MidiMessageSequence& results) const
 {
-    for (int i = tracks.size(); --i >= 0;)
-    {
-        const int numEvents = tracks.getUnchecked(i)->getNumEvents();
-
-        for (int j = 0; j < numEvents; ++j)
-        {
-            const MidiMessage& m = tracks.getUnchecked(i)->getEventPointer (j)->message;
-
-            if (m.isTempoMetaEvent())
-                tempoChangeEvents.addEvent (m);
-        }
-    }
+    MidiFileHelpers::findAllMatchingEvents (tracks, results, &MidiMessage::isTempoMetaEvent);
 }
 
-void MidiFile::findAllTimeSigEvents (MidiMessageSequence& timeSigEvents) const
+void MidiFile::findAllTimeSigEvents (MidiMessageSequence& results) const
 {
-    for (int i = tracks.size(); --i >= 0;)
-    {
-        const int numEvents = tracks.getUnchecked(i)->getNumEvents();
+    MidiFileHelpers::findAllMatchingEvents (tracks, results, &MidiMessage::isTimeSignatureMetaEvent);
+}
 
-        for (int j = 0; j < numEvents; ++j)
-        {
-            const MidiMessage& m = tracks.getUnchecked(i)->getEventPointer (j)->message;
-
-            if (m.isTimeSignatureMetaEvent())
-                timeSigEvents.addEvent (m);
-        }
-    }
+void MidiFile::findAllKeySigEvents (MidiMessageSequence& results) const
+{
+    MidiFileHelpers::findAllMatchingEvents (tracks, results, &MidiMessage::isKeySignatureMetaEvent);
 }
 
 double MidiFile::getLastTimestamp() const
@@ -340,10 +343,7 @@ void MidiFile::convertTimestampTicksToSeconds()
             for (int j = ms.getNumEvents(); --j >= 0;)
             {
                 MidiMessage& m = ms.getEventPointer(j)->message;
-
-                m.setTimeStamp (MidiFileHelpers::convertTicksToSeconds (m.getTimeStamp(),
-                                                                        tempoEvents,
-                                                                        timeFormat));
+                m.setTimeStamp (MidiFileHelpers::convertTicksToSeconds (m.getTimeStamp(), tempoEvents, timeFormat));
             }
         }
     }

modules/juce_audio_basics/midi/juce_MidiFile.h

@@ -120,23 +120,23 @@ public:
 
     //==============================================================================
     /** Makes a list of all the tempo-change meta-events from all tracks in the midi file.
-
         Useful for finding the positions of all the tempo changes in a file.
-
         @param tempoChangeEvents    a list to which all the events will be added
     */
     void findAllTempoEvents (MidiMessageSequence& tempoChangeEvents) const;
 
     /** Makes a list of all the time-signature meta-events from all tracks in the midi file.
-
         Useful for finding the positions of all the tempo changes in a file.
-
         @param timeSigEvents        a list to which all the events will be added
     */
     void findAllTimeSigEvents (MidiMessageSequence& timeSigEvents) const;
 
-    /** Returns the latest timestamp in any of the tracks.
+    /** Makes a list of all the time-signature meta-events from all tracks in the midi file.
+        @param keySigEvents         a list to which all the events will be added
+    */
+    void findAllKeySigEvents (MidiMessageSequence& keySigEvents) const;
 
+    /** Returns the latest timestamp in any of the tracks.
         (Useful for finding the length of the file).
     */
     double getLastTimestamp() const;
@@ -171,7 +171,7 @@ public:
 
 private:
     //==============================================================================
-    OwnedArray <MidiMessageSequence> tracks;
+    OwnedArray<MidiMessageSequence> tracks;
     short timeFormat;
 
     void readNextTrack (const uint8* data, int size);

modules/juce_audio_basics/midi/juce_MidiMessage.cpp

@@ -797,7 +797,12 @@ bool MidiMessage::isKeySignatureMetaEvent() const noexcept
 
 int MidiMessage::getKeySignatureNumberOfSharpsOrFlats() const noexcept
 {
-    return (int) *getMetaEventData();
+    return (int) getMetaEventData()[0];
+}
+
+bool MidiMessage::isKeySignatureMajorKey() const noexcept
+{
+    return getMetaEventData()[1] == 0;
 }
 
 MidiMessage MidiMessage::endOfTrack() noexcept

modules/juce_audio_basics/midi/juce_MidiMessage.h

@@ -112,13 +112,11 @@ public:
 
     //==============================================================================
     /** Returns a pointer to the raw midi data.
-
         @see getRawDataSize
     */
     const uint8* getRawData() const noexcept                    { return data; }
 
     /** Returns the number of bytes of data in the message.
-
         @see getRawData
     */
     int getRawDataSize() const noexcept                         { return size; }
@@ -143,15 +141,12 @@ public:
     double getTimeStamp() const noexcept                        { return timeStamp; }
 
     /** Changes the message's associated timestamp.
-
         The units for the timestamp will be application-specific - see the notes for getTimeStamp().
-
         @see addToTimeStamp, getTimeStamp
     */
     void setTimeStamp (double newTimestamp) noexcept      { timeStamp = newTimestamp; }
 
     /** Adds a value to the message's timestamp.
-
         The units for the timestamp will be application-specific.
     */
     void addToTimeStamp (double delta) noexcept           { timeStamp += delta; }
@@ -569,7 +564,6 @@ public:
 
     //==============================================================================
     /** Returns true if this is a 'tempo' meta-event.
-
         @see getTempoMetaEventTickLength, getTempoSecondsPerQuarterNote
     */
     bool isTempoMetaEvent() const noexcept;
@@ -583,49 +577,51 @@ public:
     double getTempoMetaEventTickLength (short timeFormat) const noexcept;
 
     /** Calculates the seconds-per-quarter-note from a tempo meta-event.
-
         @see isTempoMetaEvent, getTempoMetaEventTickLength
     */
     double getTempoSecondsPerQuarterNote() const noexcept;
 
     /** Creates a tempo meta-event.
-
         @see isTempoMetaEvent
     */
     static MidiMessage tempoMetaEvent (int microsecondsPerQuarterNote) noexcept;
 
     //==============================================================================
     /** Returns true if this is a 'time-signature' meta-event.
-
         @see getTimeSignatureInfo
     */
     bool isTimeSignatureMetaEvent() const noexcept;
 
     /** Returns the time-signature values from a time-signature meta-event.
-
         @see isTimeSignatureMetaEvent
     */
     void getTimeSignatureInfo (int& numerator, int& denominator) const noexcept;
 
     /** Creates a time-signature meta-event.
-
         @see isTimeSignatureMetaEvent
     */
     static MidiMessage timeSignatureMetaEvent (int numerator, int denominator);
 
     //==============================================================================
     /** Returns true if this is a 'key-signature' meta-event.
-
-        @see getKeySignatureNumberOfSharpsOrFlats
+        @see getKeySignatureNumberOfSharpsOrFlats, isKeySignatureMajorKey
     */
     bool isKeySignatureMetaEvent() const noexcept;
 
     /** Returns the key from a key-signature meta-event.
-
-        @see isKeySignatureMetaEvent
+        This method must only be called if isKeySignatureMetaEvent() is true.
+        A positive number here indicates the number of sharps in the key signature,
+        and a negative number indicates a number of flats. So e.g. 3 = F# + C# + G#,
+        -2 = Bb + Eb
+        @see isKeySignatureMetaEvent, isKeySignatureMajorKey
     */
     int getKeySignatureNumberOfSharpsOrFlats() const noexcept;
 
+    /** Returns true if this key-signature event is major, or false if it's minor.
+        This method must only be called if isKeySignatureMetaEvent() is true.
+    */
+    bool isKeySignatureMajorKey() const noexcept;
+
     //==============================================================================
     /** Returns true if this is a 'channel' meta-event.
 
@@ -807,14 +803,11 @@ public:
     */
     MidiMachineControlCommand getMidiMachineControlCommand() const noexcept;
 
-    /** Creates an MMC message.
-    */
+    /** Creates an MMC message. */
     static MidiMessage midiMachineControlCommand (MidiMachineControlCommand command);
 
     /** Checks whether this is an MMC "goto" message.
-
         If it is, the parameters passed-in are set to the time that the message contains.
-
         @see midiMachineControlGoto
     */
     bool isMidiMachineControlGoto (int& hours,
@@ -823,9 +816,7 @@ public:
                                    int& frames) const noexcept;
 
     /** Creates an MMC "goto" message.
-
         This messages tells the device to go to a specific frame.
-
         @see isMidiMachineControlGoto
     */
     static MidiMessage midiMachineControlGoto (int hours,
@@ -835,14 +826,12 @@ public:
 
     //==============================================================================
     /** Creates a master-volume change message.
-
         @param volume   the volume, 0 to 1.0
     */
     static MidiMessage masterVolume (float volume);
 
     //==============================================================================
     /** Creates a system-exclusive message.
-
         The data passed in is wrapped with header and tail bytes of 0xf0 and 0xf7.
     */
     static MidiMessage createSysExMessage (const void* sysexData,