[tflchef] RawModel loader (#2347)

This will introduce TFlite raw model loader
- copied from enco/frontend

Signed-off-by: SaeHie Park <saehie.park@samsung.com>

diff --git a/contrib/tflchef/tflite/include/tflchef/RawModel.h b/contrib/tflchef/tflite/include/tflchef/RawModel.h
new file mode 100644 (file)
index 0000000..6979f65
--- /dev/null
+++ b/contrib/tflchef/tflite/include/tflchef/RawModel.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2018 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * 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.
+ */
+
+#ifndef __RAW_MODEL_H__
+#define __RAW_MODEL_H__
+
+#include "tflite_generated.h"
+
+namespace tflchef
+{
+
+struct RawModel
+{
+  virtual ~RawModel() = default;
+
+  virtual const ::tflite::Model *model(void) const = 0;
+};
+
+/**
+ * @brief Load TensorFlow Lite model (as a RawModel) from a given path
+ *
+ * @note May return a nullptr
+ */
+std::unique_ptr<RawModel> load_tflite(const std::string &path);
+
+} // namespace tflchef
+
+#endif // __RAW_MODEL_H__

diff --git a/contrib/tflchef/tflite/src/RawModelLoader.cpp b/contrib/tflchef/tflite/src/RawModelLoader.cpp
new file mode 100644 (file)
index 0000000..c37c908
--- /dev/null
+++ b/contrib/tflchef/tflite/src/RawModelLoader.cpp
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2018 Samsung Electronics Co., Ltd. All Rights Reserved
+ *
+ * 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 <tflchef/RawModel.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+namespace
+{
+
+class MemoryMappedRawModel final : public tflchef::RawModel
+{
+public:
+  /**
+   * @require fd and data SHOULD be valid
+   */
+  explicit MemoryMappedRawModel(int fd, void *data, size_t size) : _fd{fd}, _data{data}, _size{size}
+  {
+    // DO NOTHING
+  }
+
+public:
+  ~MemoryMappedRawModel()
+  {
+    munmap(_data, _size);
+    close(_fd);
+  }
+
+public:
+  MemoryMappedRawModel(const MemoryMappedRawModel &) = delete;
+  MemoryMappedRawModel(MemoryMappedRawModel &&) = delete;
+
+public:
+  const ::tflite::Model *model(void) const override { return ::tflite::GetModel(_data); }
+
+private:
+  int _fd = -1;
+  void *_data = nullptr;
+  size_t _size = 0;
+};
+
+} // namespace
+
+namespace
+{
+
+class OwnedFileDescriptor final
+{
+public:
+  OwnedFileDescriptor(int value) : _value{value}
+  {
+    // DO NOTHING
+  }
+
+public:
+  // NOTE Copy is not allowed
+  OwnedFileDescriptor(const OwnedFileDescriptor &) = delete;
+
+public:
+  // NOTE Move is allowed
+  OwnedFileDescriptor(OwnedFileDescriptor &&fd) { _value = fd.release(); }
+
+public:
+  ~OwnedFileDescriptor()
+  {
+    if (_value != -1)
+    {
+      // Close on descturction
+      close(_value);
+    }
+  }
+
+public:
+  int value(void) const { return _value; }
+
+public:
+  int release(void)
+  {
+    auto res = _value;
+    _value = -1;
+    return res;
+  }
+
+private:
+  int _value = -1;
+};
+
+} // namespace
+
+namespace tflchef
+{
+
+std::unique_ptr<RawModel> load_tflite(const std::string &path)
+{
+  OwnedFileDescriptor fd = open(path.c_str(), O_RDONLY);
+
+  if (fd.value() == -1)
+  {
+    // Return nullptr on open failure
+    return nullptr;
+  }
+
+  struct stat st;
+  if (fstat(fd.value(), &st) == -1)
+  {
+    // Return nullptr on fstat failure
+    return nullptr;
+  }
+
+  auto size = st.st_size;
+  auto data = mmap(nullptr, size, PROT_READ, MAP_SHARED, fd.value(), 0);
+
+  if (data == MAP_FAILED)
+  {
+    // Return nullptr on mmap failure
+    return nullptr;
+  }
+
+  return std::unique_ptr<tflchef::RawModel>{new MemoryMappedRawModel(fd.release(), data, size)};
+}
+
+} // namespace tflchef