Telegram-Android/TMessagesProj/jni/exoplayer/flac_jni.cc

/*
 * Copyright (C) 2016 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.
 */

#include <jni.h>
#include <cstdlib>
#include "include/flac_parser.h"

#define DECODER_FUNC(RETURN_TYPE, NAME, ...) \
RETURN_TYPE Java_org_telegram_messenger_exoplayer2_ext_flac_FlacDecoderJni_##NAME(JNIEnv *env, jobject thiz, ##__VA_ARGS__)

class JavaDataSource : public DataSource {
 public:
  void setFlacDecoderJni(JNIEnv *env, jobject flacDecoderJni) {
    this->env = env;
    this->flacDecoderJni = flacDecoderJni;
    if (mid == NULL) {
      jclass cls = env->GetObjectClass(flacDecoderJni);
      mid = env->GetMethodID(cls, "read", "(Ljava/nio/ByteBuffer;)I");
      env->DeleteLocalRef(cls);
    }
  }

  ssize_t readAt(off64_t offset, void *const data, size_t size) {
    jobject byteBuffer = env->NewDirectByteBuffer(data, size);
    int result = env->CallIntMethod(flacDecoderJni, mid, byteBuffer);
    if (env->ExceptionCheck()) {
      // Exception is thrown in Java when returning from the native call.
      result = -1;
    }
    env->DeleteLocalRef(byteBuffer);
    return result;
  }

 private:
  JNIEnv *env;
  jobject flacDecoderJni;
  jmethodID mid;
};

struct Context {
  JavaDataSource *source;
  FLACParser *parser;

  Context() {
    source = new JavaDataSource();
    parser = new FLACParser(source);
  }

  ~Context() {
    delete parser;
    delete source;
  }
};

extern "C" {

DECODER_FUNC(jlong, flacInit) {
  Context *context = new Context;
  if (!context->parser->init()) {
    delete context;
    return 0;
  }
  return reinterpret_cast<intptr_t>(context);
}

DECODER_FUNC(jobject, flacDecodeMetadata, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  context->source->setFlacDecoderJni(env, thiz);
  if (!context->parser->decodeMetadata()) {
    return NULL;
  }

  const FLAC__StreamMetadata_StreamInfo &streamInfo =
          context->parser->getStreamInfo();

  jclass cls = env->FindClass("org/telegram/messenger/exoplayer2/util/FlacStreamInfo");
  jmethodID constructor = env->GetMethodID(cls, "<init>", "(IIIIIIIJ)V");

  return env->NewObject(cls, constructor, streamInfo.min_blocksize,
                        streamInfo.max_blocksize, streamInfo.min_framesize,
                        streamInfo.max_framesize, streamInfo.sample_rate,
                        streamInfo.channels, streamInfo.bits_per_sample,
                        streamInfo.total_samples);
}

DECODER_FUNC(jint, flacDecodeToBuffer, jlong jContext, jobject jOutputBuffer) {
  Context *context = reinterpret_cast<Context *>(jContext);
  context->source->setFlacDecoderJni(env, thiz);
  void *outputBuffer = env->GetDirectBufferAddress(jOutputBuffer);
  jint outputSize = env->GetDirectBufferCapacity(jOutputBuffer);
  return context->parser->readBuffer(outputBuffer, outputSize);
}

DECODER_FUNC(jint, flacDecodeToArray, jlong jContext, jbyteArray jOutputArray) {
  Context *context = reinterpret_cast<Context *>(jContext);
  context->source->setFlacDecoderJni(env, thiz);
  jbyte *outputBuffer = env->GetByteArrayElements(jOutputArray, NULL);
  jint outputSize = env->GetArrayLength(jOutputArray);
  int count = context->parser->readBuffer(outputBuffer, outputSize);
  env->ReleaseByteArrayElements(jOutputArray, outputBuffer, 0);
  return count;
}

DECODER_FUNC(jlong, flacGetDecodePosition, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->getDecodePosition();
}

DECODER_FUNC(jlong, flacGetLastFrameTimestamp, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->getLastFrameTimestamp();
}

DECODER_FUNC(jlong, flacGetLastFrameFirstSampleIndex, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->getLastFrameFirstSampleIndex();
}

DECODER_FUNC(jlong, flacGetNextFrameFirstSampleIndex, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->getNextFrameFirstSampleIndex();
}

DECODER_FUNC(jlong, flacGetSeekPosition, jlong jContext, jlong timeUs) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->getSeekPosition(timeUs);
}

DECODER_FUNC(jstring, flacGetStateString, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  const char *str = context->parser->getDecoderStateString();
  return env->NewStringUTF(str);
}

DECODER_FUNC(jboolean, flacIsDecoderAtEndOfStream, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  return context->parser->isDecoderAtEndOfStream();
}

DECODER_FUNC(void, flacFlush, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  context->parser->flush();
}

DECODER_FUNC(void, flacReset, jlong jContext, jlong newPosition) {
  Context *context = reinterpret_cast<Context *>(jContext);
  context->parser->reset(newPosition);
}

DECODER_FUNC(void, flacRelease, jlong jContext) {
  Context *context = reinterpret_cast<Context *>(jContext);
  delete context;
}

}