Revert "Convert vendor HAL service to use new AIDL interface."

This reverts commit e58e263bce07e33bcf928388d21c9f544eb537e7.

Reason for revert: Blocking Wembley team

Change-Id: I3cf471e88b880a95a0a2c39f47fb0804deee65cf
diff --git a/wifi/1.6/default/ringbuffer.cpp b/wifi/1.6/default/ringbuffer.cpp
new file mode 100644
index 0000000..981bf7b
--- /dev/null
+++ b/wifi/1.6/default/ringbuffer.cpp
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2018 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 <android-base/logging.h>
+
+#include "ringbuffer.h"
+
+namespace android {
+namespace hardware {
+namespace wifi {
+namespace V1_6 {
+namespace implementation {
+
+Ringbuffer::Ringbuffer(size_t maxSize) : size_(0), maxSize_(maxSize) {}
+
+enum Ringbuffer::AppendStatus Ringbuffer::append(const std::vector<uint8_t>& input) {
+    if (input.size() == 0) {
+        return AppendStatus::FAIL_IP_BUFFER_ZERO;
+    }
+    if (input.size() > maxSize_) {
+        LOG(INFO) << "Oversized message of " << input.size() << " bytes is dropped";
+        return AppendStatus::FAIL_IP_BUFFER_EXCEEDED_MAXSIZE;
+    }
+    data_.push_back(input);
+    size_ += input.size() * sizeof(input[0]);
+    while (size_ > maxSize_) {
+        if (data_.front().size() <= 0 || data_.front().size() > maxSize_) {
+            LOG(ERROR) << "First buffer in the ring buffer is Invalid. Size: "
+                       << data_.front().size();
+            return AppendStatus::FAIL_RING_BUFFER_CORRUPTED;
+        }
+        size_ -= data_.front().size() * sizeof(data_.front()[0]);
+        data_.pop_front();
+    }
+    return AppendStatus::SUCCESS;
+}
+
+const std::list<std::vector<uint8_t>>& Ringbuffer::getData() const {
+    return data_;
+}
+
+void Ringbuffer::clear() {
+    data_.clear();
+    size_ = 0;
+}
+
+}  // namespace implementation
+}  // namespace V1_6
+}  // namespace wifi
+}  // namespace hardware
+}  // namespace android