1 files changed, 93 insertions, 0 deletions
diff --git a/externals/oboe/apps/fxlab/app/src/main/cpp/DuplexEngine.cpp b/externals/oboe/apps/fxlab/app/src/main/cpp/DuplexEngine.cpp
new file mode 100644
index 0000000000..123d52c33a
--- /dev/null
+++ b/externals/oboe/apps/fxlab/app/src/main/cpp/DuplexEngine.cpp
@@ -0,0 +1,93 @@
+/*
+ * Copyright  2019 Google LLC
+ *
+ * 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
+ *
+ *     https://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 "DuplexEngine.h"
+#include "effects/Effects.h"
+
+DuplexEngine::DuplexEngine() {
+    beginStreams();
+}
+
+void DuplexEngine::beginStreams() {
+    // This ordering is extremely important
+    openInStream();
+    if (inStream->getFormat() == oboe::AudioFormat::Float) {
+        functionList.emplace<FunctionList<float *>>();
+        createCallback<float_t>();
+    } else if (inStream->getFormat() == oboe::AudioFormat::I16) {
+        createCallback<int16_t>();
+    } else {
+        stopStreams();
+    }
+    SAMPLE_RATE = inStream->getSampleRate();
+    openOutStream();
+
+    oboe::Result result = startStreams();
+    if (result != oboe::Result::OK) stopStreams();
+}
+
+template<class numeric>
+void DuplexEngine::createCallback() {
+    mCallback = std::make_unique<DuplexCallback<numeric>>(
+            *inStream, [&functionStack = this->functionList](numeric *beg, numeric *end) {
+                std::get<FunctionList<numeric *>>(functionStack)(beg, end);
+            },
+            inStream->getBufferCapacityInFrames(),
+            std::bind(&DuplexEngine::beginStreams, this));
+}
+
+
+oboe::AudioStreamBuilder DuplexEngine::defaultBuilder() {
+    return *oboe::AudioStreamBuilder()
+            .setPerformanceMode(oboe::PerformanceMode::LowLatency)
+            ->setSharingMode(oboe::SharingMode::Exclusive);
+}
+
+void DuplexEngine::openInStream() {
+    defaultBuilder().setDirection(oboe::Direction::Input)
+            ->setFormat(oboe::AudioFormat::Float) // For now
+            ->setChannelCount(1) // Mono in for effects processing
+            ->openManagedStream(inStream);
+}
+
+void DuplexEngine::openOutStream() {
+    defaultBuilder().setCallback(mCallback.get())
+            ->setSampleRate(inStream->getSampleRate())
+            ->setFormat(inStream->getFormat())
+            ->setChannelCount(2) // Stereo out
+            ->openManagedStream(outStream);
+}
+
+oboe::Result DuplexEngine::startStreams() {
+    oboe::Result result = outStream->requestStart();
+    int64_t timeoutNanos = 500 * 1000000; // arbitrary 1/2 second
+    auto currentState = outStream->getState();
+    auto nextState = oboe::StreamState::Unknown;
+    while (result == oboe::Result::OK && currentState != oboe::StreamState::Started) {
+        result = outStream->waitForStateChange(currentState, &nextState, timeoutNanos);
+        currentState = nextState;
+    }
+    if (result != oboe::Result::OK) return result;
+    return inStream->requestStart();
+}
+
+oboe::Result DuplexEngine::stopStreams() {
+    oboe::Result outputResult = inStream->requestStop();
+    oboe::Result inputResult = outStream->requestStop();
+    if (outputResult != oboe::Result::OK) return outputResult;
+    return inputResult;
+}
+