1// Protocol Buffers - Google's data interchange format
2// Copyright 2008 Google Inc. All rights reserved.
3// https://developers.google.com/protocol-buffers/
4//
5// Redistribution and use in source and binary forms, with or without
6// modification, are permitted provided that the following conditions are
7// met:
8//
9// * Redistributions of source code must retain the above copyright
10// notice, this list of conditions and the following disclaimer.
11// * Redistributions in binary form must reproduce the above
12// copyright notice, this list of conditions and the following disclaimer
13// in the documentation and/or other materials provided with the
14// distribution.
15// * Neither the name of Google Inc. nor the names of its
16// contributors may be used to endorse or promote products derived from
17// this software without specific prior written permission.
18//
19// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31// Author: seongkim@google.com (Seong Beom Kim)
32// Based on original Protocol Buffers design by
33// Sanjay Ghemawat, Jeff Dean, and others.
34
35#ifndef GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
36#define GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
37
38#include <google/protobuf/compiler/cpp/message_layout_helper.h>
39
40namespace google {
41namespace protobuf {
42namespace compiler {
43namespace cpp {
44
45// Rearranges the fields of a message to minimize padding.
46// Fields are grouped by the type and the size.
47// For example, grouping four boolean fields and one int32
48// field results in zero padding overhead. See OptimizeLayout's
49// comment for details.
50class PaddingOptimizer : public MessageLayoutHelper {
51 public:
52 PaddingOptimizer() {}
53 ~PaddingOptimizer() override {}
54
55 void OptimizeLayout(std::vector<const FieldDescriptor*>* fields,
56 const Options& options,
57 MessageSCCAnalyzer* scc_analyzer) override;
58};
59
60} // namespace cpp
61} // namespace compiler
62} // namespace protobuf
63} // namespace google
64
65#endif // GOOGLE_PROTOBUF_COMPILER_CPP_PADDING_OPTIMIZER_H__
66