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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.internal.midi;
import android.media.midi.MidiReceiver;
//import android.util.Log;
import java.io.IOException;
/**
* Convert stream of bytes to discrete messages.
*
* Parses the incoming bytes and then posts individual messages to the receiver
* specified in the constructor. Short messages of 1-3 bytes will be complete.
* System Exclusive messages may be posted in pieces.
*
* Resolves Running Status and
* interleaved System Real-Time messages.
*/
public class MidiFramer extends MidiReceiver {
public String TAG = "MidiFramer";
private MidiReceiver mReceiver;
private byte[] mBuffer = new byte[3];
private int mCount;
private byte mRunningStatus;
private int mNeeded;
private boolean mInSysEx;
public MidiFramer(MidiReceiver receiver) {
mReceiver = receiver;
}
public static String formatMidiData(byte[] data, int offset, int count) {
String text = "MIDI+" + offset + " : ";
for (int i = 0; i < count; i++) {
text += String.format("0x%02X, ", data[offset + i]);
}
return text;
}
/*
* @see android.midi.MidiReceiver#onSend(byte[], int, int, long)
*/
@Override
public void onSend(byte[] data, int offset, int count, long timestamp)
throws IOException {
int sysExStartOffset = (mInSysEx ? offset : -1);
for (int i = 0; i < count; i++) {
final byte currentByte = data[offset];
final int currentInt = currentByte & 0xFF;
if (currentInt >= 0x80) { // status byte?
if (currentInt < 0xF0) { // channel message?
mRunningStatus = currentByte;
mCount = 1;
mNeeded = MidiConstants.getBytesPerMessage(currentByte) - 1;
} else if (currentInt < 0xF8) { // system common?
if (currentInt == 0xF0 /* SysEx Start */) {
// Log.i(TAG, "SysEx Start");
mInSysEx = true;
sysExStartOffset = offset;
} else if (currentInt == 0xF7 /* SysEx End */) {
// Log.i(TAG, "SysEx End");
if (mInSysEx) {
mReceiver.send(data, sysExStartOffset,
offset - sysExStartOffset + 1, timestamp);
mInSysEx = false;
sysExStartOffset = -1;
}
} else {
mBuffer[0] = currentByte;
mRunningStatus = 0;
mCount = 1;
mNeeded = MidiConstants.getBytesPerMessage(currentByte) - 1;
}
} else { // real-time?
// Single byte message interleaved with other data.
if (mInSysEx) {
mReceiver.send(data, sysExStartOffset,
offset - sysExStartOffset, timestamp);
sysExStartOffset = offset + 1;
}
mReceiver.send(data, offset, 1, timestamp);
}
} else { // data byte
if (!mInSysEx) {
mBuffer[mCount++] = currentByte;
if (--mNeeded == 0) {
if (mRunningStatus != 0) {
mBuffer[0] = mRunningStatus;
}
mReceiver.send(mBuffer, 0, mCount, timestamp);
mNeeded = MidiConstants.getBytesPerMessage(mBuffer[0]) - 1;
mCount = 1;
}
}
}
++offset;
}
// send any accumulatedSysEx data
if (sysExStartOffset >= 0 && sysExStartOffset < offset) {
mReceiver.send(data, sysExStartOffset,
offset - sysExStartOffset, timestamp);
}
}
}
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