1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.internal.midi; 18 19 import android.media.midi.MidiReceiver; 20 //import android.util.Log; 21 22 import java.io.IOException; 23 24 /** 25 * Convert stream of bytes to discrete messages. 26 * 27 * Parses the incoming bytes and then posts individual messages to the receiver 28 * specified in the constructor. Short messages of 1-3 bytes will be complete. 29 * System Exclusive messages may be posted in pieces. 30 * 31 * Resolves Running Status and 32 * interleaved System Real-Time messages. 33 */ 34 public class MidiFramer extends MidiReceiver { 35 36 public String TAG = "MidiFramer"; 37 private MidiReceiver mReceiver; 38 private byte[] mBuffer = new byte[3]; 39 private int mCount; 40 private byte mRunningStatus; 41 private int mNeeded; 42 private boolean mInSysEx; 43 44 public MidiFramer(MidiReceiver receiver) { 45 mReceiver = receiver; 46 } 47 48 public static String formatMidiData(byte[] data, int offset, int count) { 49 String text = "MIDI+" + offset + " : "; 50 for (int i = 0; i < count; i++) { 51 text += String.format("0x%02X, ", data[offset + i]); 52 } 53 return text; 54 } 55 56 /* 57 * @see android.midi.MidiReceiver#onSend(byte[], int, int, long) 58 */ 59 @Override 60 public void onSend(byte[] data, int offset, int count, long timestamp) 61 throws IOException { 62 int sysExStartOffset = (mInSysEx ? offset : -1); 63 64 for (int i = 0; i < count; i++) { 65 final byte currentByte = data[offset]; 66 final int currentInt = currentByte & 0xFF; 67 if (currentInt >= 0x80) { // status byte? 68 if (currentInt < 0xF0) { // channel message? 69 mRunningStatus = currentByte; 70 mCount = 1; 71 mNeeded = MidiConstants.getBytesPerMessage(currentByte) - 1; 72 } else if (currentInt < 0xF8) { // system common? 73 if (currentInt == 0xF0 /* SysEx Start */) { 74 // Log.i(TAG, "SysEx Start"); 75 mInSysEx = true; 76 sysExStartOffset = offset; 77 } else if (currentInt == 0xF7 /* SysEx End */) { 78 // Log.i(TAG, "SysEx End"); 79 if (mInSysEx) { 80 mReceiver.send(data, sysExStartOffset, 81 offset - sysExStartOffset + 1, timestamp); 82 mInSysEx = false; 83 sysExStartOffset = -1; 84 } 85 } else { 86 mBuffer[0] = currentByte; 87 mRunningStatus = 0; 88 mCount = 1; 89 mNeeded = MidiConstants.getBytesPerMessage(currentByte) - 1; 90 } 91 } else { // real-time? 92 // Single byte message interleaved with other data. 93 if (mInSysEx) { 94 mReceiver.send(data, sysExStartOffset, 95 offset - sysExStartOffset, timestamp); 96 sysExStartOffset = offset + 1; 97 } 98 mReceiver.send(data, offset, 1, timestamp); 99 } 100 } else { // data byte 101 if (!mInSysEx) { 102 mBuffer[mCount++] = currentByte; 103 if (--mNeeded == 0) { 104 if (mRunningStatus != 0) { 105 mBuffer[0] = mRunningStatus; 106 } 107 mReceiver.send(mBuffer, 0, mCount, timestamp); 108 mNeeded = MidiConstants.getBytesPerMessage(mBuffer[0]) - 1; 109 mCount = 1; 110 } 111 } 112 } 113 ++offset; 114 } 115 116 // send any accumulatedSysEx data 117 if (sysExStartOffset >= 0 && sysExStartOffset < offset) { 118 mReceiver.send(data, sysExStartOffset, 119 offset - sysExStartOffset, timestamp); 120 } 121 } 122 123 } 124