src/google/protobuf/compiler/cpp/padding_optimizer.h

// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd

// Author: seongkim@google.com (Seong Beom Kim)
//  Based on original Protocol Buffers design by
//  Sanjay Ghemawat, Jeff Dean, and others.

#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
#define GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__

#include "google/protobuf/compiler/cpp/message_layout_helper.h"

namespace google {
namespace protobuf {
namespace compiler {
namespace cpp {

// Rearranges the fields of a message to minimize padding.
// Fields are grouped by the type and the size.
// For example, grouping four boolean fields and one int32
// field results in zero padding overhead. See OptimizeLayout's
// comment for details.
class PaddingOptimizer : public MessageLayoutHelper {
 public:
  PaddingOptimizer() {}
  ~PaddingOptimizer() override {}

  void OptimizeLayout(std::vector<const FieldDescriptor*>* fields,
                      const Options& options,
                      MessageSCCAnalyzer* scc_analyzer) override;
};

}  // namespace cpp
}  // namespace compiler
}  // namespace protobuf
}  // namespace google

#endif  // GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__