Delegate channel functions to any MidiDriver. This is useful for the

MT-32 emulation and quite possibly other MidiDrivers in future.

svn-id: r15711

2 files changed, 13 insertions, 8 deletions

diff --git a/sound/mpu401.cpp b/sound/mpu401.cpp
index e301986a83..6ea50395f4 100644
--- a/sound/mpu401.cpp
+++ b/sound/mpu401.cpp
@@ -23,12 +23,18 @@
 #include "common/timer.h"
 #include "common/util.h"	// for ARRAYSIZE
 
-void MidiChannel_MPU401::init(MidiDriver_MPU401 *owner, byte channel) {
+void MidiChannel_MPU401::init(MidiDriver *owner, byte channel) {
 	_owner = owner;
 	_channel = channel;
 	_allocated = false;
 }
 
+bool MidiChannel_MPU401::allocate() {
+	if (_allocated)
+		return false;
+	return (_allocated = true);
+}
+
 MidiDriver *MidiChannel_MPU401::device() {
 	return _owner;
 }
@@ -117,8 +123,7 @@ MidiChannel *MidiDriver_MPU401::allocateChannel() {
 		if (i == 9 || !(_channel_mask & (1 << i)))
 			continue;
 		chan = &_midi_channels[i];
-		if (!chan->_allocated) {
-			chan->allocate();
+		if (chan->allocate()) {
 			return chan;
 		}
 	}
diff --git a/sound/mpu401.h b/sound/mpu401.h
index 365c46c5a5..213af64b6b 100644
--- a/sound/mpu401.h
+++ b/sound/mpu401.h
@@ -35,16 +35,12 @@
 class MidiDriver_MPU401;
 
 class MidiChannel_MPU401 : public MidiChannel {
-	friend class MidiDriver_MPU401;
 
 private:
-	MidiDriver_MPU401 *_owner;
+	MidiDriver *_owner;
 	bool _allocated;
 	byte _channel;
 
-	void init (MidiDriver_MPU401 *owner, byte channel);
-	void allocate() { _allocated = true; }
-
 public:
 	MidiDriver *device();
 	byte getNumber() { return _channel; }
@@ -64,6 +60,10 @@ public:
 
 	// SysEx messages
 	void sysEx_customInstrument (uint32 type, byte *instr);
+
+	// Only to be called by the owner
+	void init (MidiDriver *owner, byte channel);
+	bool allocate();
 };