feat: audio resources

app/src/main/cpp/PlaybackEngine.cpp

@@ -7,7 +7,7 @@
 #include "PlaybackEngine.h"
 #include "logging.h"
 
-PlaybackEngine::PlaybackEngine() {
+PlaybackEngine::PlaybackEngine(std::string filesDir): mFilesDir(filesDir) {
     LOGI("PlaybackEngine()");
     LOGI("NDK LOG_LEVEL=%d", LOG_LEVEL);
     // NDK LOG_LEVEL=3  (DEBUG)

app/src/main/cpp/PlaybackEngine.h

@@ -6,13 +6,15 @@
 #define LOCKSTEP_PLAYBACKENGINE_H
 
 #include "OboeSinePlayer.h"
+#include <string>
 
 class PlaybackEngine {
 public:
-    PlaybackEngine();
+    PlaybackEngine(std::string filesDir);
     virtual ~PlaybackEngine();
 private:
     OboeSinePlayer *mPlayer;
+    std::string mFilesDir;
 };
 
 #endif //LOCKSTEP_PLAYBACKENGINE_H

app/src/main/cpp/jni_bridge.cpp

@@ -4,9 +4,12 @@
 
 #include <jni.h>
 #include "mpg123.h"
+#include <oboe/Oboe.h>
 
 extern "C" {
 
+// nice-to: merge with lockstep.cpp
+
 JNIEXPORT jint JNICALL
 Java_at_lockstep_pb_PlaybackEngine_native_1mpg123_1init
         (JNIEnv *env, jclass) {

app/src/main/cpp/lockstep.cpp

@@ -30,15 +30,13 @@ extern "C" {
 JNIEXPORT jlong JNICALL
 Java_at_lockstep_pb_PlaybackEngine_native_1createEngine(
         JNIEnv *env,
-        jclass /*unused*/) {
-    /*
+        jclass /*unused*/, jstring filesDir) {
     const char* filesDirTemp = env->GetStringUTFChars(filesDir, NULL);
     std::string filesDirString(filesDirTemp);
     env->ReleaseStringUTFChars(filesDir, filesDirTemp);
-    */
 
     // We use std::nothrow so `new` returns a nullptr if the engine creation fails
-    auto *engine = new(std::nothrow) PlaybackEngine();
+    auto *engine = new(std::nothrow) PlaybackEngine(filesDirString);
     return reinterpret_cast<jlong>(engine);
 }
 
@@ -51,4 +49,13 @@ jlong engineHandle) {
 delete reinterpret_cast<PlaybackEngine *>(engineHandle);
 }
 
+JNIEXPORT void JNICALL
+Java_at_lockstep_pb_PlaybackEngine_native_1setDefaultStreamValues(JNIEnv *env,
+                                                                  jclass type,
+                                                                  jint sampleRate,
+                                                                  jint framesPerBurst) {
+    oboe::DefaultStreamValues::SampleRate = (int32_t) sampleRate;
+    oboe::DefaultStreamValues::FramesPerBurst = (int32_t) framesPerBurst;
+}
+
 } // extern "C"

app/src/main/java/at/lockstep/pb/AudioResources.java

@@ -0,0 +1,60 @@
+package at.lockstep.pb;
+
+import android.content.Context;
+import android.os.SystemClock;
+import android.util.Log;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.lang.reflect.Field;
+
+import at.lockstep.R;
+
+/**
+ * Resource helpers.
+ *
+ * @author David Madl (git@abanbytes.eu)
+ * @date 2020-05-16
+ */
+public class AudioResources {
+    /**
+     * Copy raw tracks to filesystem:
+     * otherwise, packaged resources cannot directly be accessed from C code.
+     */
+    public static void copyRawTracksToFilesystem(Context context) throws IOException {
+        Field[] fields = R.raw.class.getFields();
+        long before = SystemClock.uptimeMillis();
+        try {
+            for (int i = 0; i < fields.length; i++) {
+                String assetName = fields[i].getName();
+                if (assetName.startsWith("track_")) {
+                    int resourceId = fields[i].getInt(null);
+                    copyFileUsingStream(context.getResources().openRawResource(resourceId), new File(context.getFilesDir() + "/" + resourceId + ".mp3"));
+                }
+            }
+        } catch(IllegalAccessException iae) {
+            // reflection should always work on R.raw
+            iae.printStackTrace();
+        }
+        long after = SystemClock.uptimeMillis();
+        Log.i("LoadTracks", String.format("copyRawTracksToFilesystem() took %.3f s", ((float)(after-before))/1e3f));
+    }
+
+    private static void copyFileUsingStream(InputStream is, File dest) throws IOException {
+        OutputStream os = null;
+        try {
+            os = new FileOutputStream(dest);
+            byte[] buffer = new byte[1024];
+            int length;
+            while ((length = is.read(buffer)) > 0) {
+                os.write(buffer, 0, length);
+            }
+        } finally {
+            is.close();
+            os.close();
+        }
+    }
+}

app/src/main/java/at/lockstep/pb/PlaybackEngine.java

@@ -1,11 +1,16 @@
 package at.lockstep.pb;
 
 import android.content.Context;
+import android.media.AudioManager;
+import android.os.Build;
 import android.util.Log;
 
+import java.io.IOException;
+
 public class PlaybackEngine {
     static long mEngineHandle = 0;
     static final int MPG123_OK = 0;
+    static boolean mFilesystemInitialized = false;
 
     static {
         System.loadLibrary("lockstep-native");
@@ -15,14 +20,36 @@ public class PlaybackEngine {
     }
 
     public static boolean create(Context context) {
+        try {
+            if(!mFilesystemInitialized) {
+                AudioResources.copyRawTracksToFilesystem(context);
+                mFilesystemInitialized = true;
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+            return false;
+        }
+
         if (mEngineHandle == 0) {
-            //setDefaultStreamValues(context); // TODO
+            setDefaultStreamValues(context);
             Log.i("PlaybackEngine", "Hello PlaybackEngine");
-            mEngineHandle = native_createEngine();
+            mEngineHandle = native_createEngine(context.getFilesDir().toString());
         }
         return (mEngineHandle != 0);
     }
 
+    private static void setDefaultStreamValues(Context context) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1){
+            AudioManager myAudioMgr = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+            String sampleRateStr = myAudioMgr.getProperty(AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE);
+            int defaultSampleRate = Integer.parseInt(sampleRateStr);
+            String framesPerBurstStr = myAudioMgr.getProperty(AudioManager.PROPERTY_OUTPUT_FRAMES_PER_BUFFER);
+            int defaultFramesPerBurst = Integer.parseInt(framesPerBurstStr);
+
+            native_setDefaultStreamValues(defaultSampleRate, defaultFramesPerBurst);
+        }
+    }
+
     public static void delete() {
         if (mEngineHandle != 0){
             native_deleteEngine(mEngineHandle);
@@ -30,8 +57,9 @@ public class PlaybackEngine {
         mEngineHandle = 0;
     }
 
-    private static native long native_createEngine();
+    private static native long native_createEngine(String filesDir);
     private static native void native_deleteEngine(long engineHandle);
+    private static native void native_setDefaultStreamValues(int sampleRate, int framesPerBurst);
 
     private static native int native_mpg123_init();
 }