lockstep/app/src/main/cpp/lockstep.cpp

// Write C++ code here.
//
// Do not forget to dynamically load the C++ library into your application.
//
// For instance,
//
// In at.lockstep.app.MainActivity.java:
//    static {
//       System.loadLibrary("lockstep");
//    }
//
// Or, in at.lockstep.app.MainActivity.kt:
//    companion object {
//      init {
//         System.loadLibrary("lockstep")
//      }
//    }

#include "PlaybackEngine.h"
#include <jni.h>
#include <oboe/Oboe.h>

extern "C" {

/**
 * Creates the audio engine
 *
 * @return a pointer to the audio engine. This should be passed to other methods
 */
JNIEXPORT jlong JNICALL
Java_at_lockstep_pb_PlaybackEngine_native_1createEngine(
        JNIEnv *env,
        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(filesDirString);
    return reinterpret_cast<jlong>(engine);
}

JNIEXPORT void JNICALL
Java_at_lockstep_pb_PlaybackEngine_native_1deleteEngine(
        JNIEnv *env,
jclass,
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"