text: // Copyright 2010-2018, Google Inc.
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  //     * Neither the name of Google Inc. nor the names of its
  // contributors may be used to endorse or promote products derived from
  // this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // Tool to pack multiple files into one file.
  //
  // Usage
  // $ ./path/to/artifacts/dataset_writer_main \
  //   --magic=\xNN\xNN\xNN \
  //   --output=/path/to/output \
  //   [arg1, [arg2, ...]]
  //
  // Here, each argument has the following form:
  //
  // name:alignment:/path/to/infile
  //
  // where alignment must be one of {8, 16, 32, 64}.  Each packed file can be
  // retrieved by DataSetReader through its name.
  
  #include <string>
  #include <vector>
  
  #include "base/file_stream.h"
  #include "base/file_util.h"
  #include "base/flags.h"
  #include "base/init_mozc.h"
  #include "base/logging.h"
  #include "base/number_util.h"
  #include "base/util.h"
  #include "data_manager/dataset_writer.h"
  
  DEFINE_string(magic, "", "Hex-encoded magic number to be embedded");
  DEFINE_string(output, "", "Output file");
  
  int main(int argc, char **argv) {
    mozc::InitMozc(argv[0], &argc, &argv, true);
  
    string magic;
    CHECK(mozc::Util::Unescape(FLAGS_magic, &magic))
        << "magic number is not a proper hex-escaped string: " << FLAGS_magic;
  
    struct Input {
      Input(const string &n, int a, const string &f)
          : name(n), alignment(a), filename(f) {}
  
      string name;
      int alignment;
      string filename;
    };
  
    std::vector<Input> inputs;
    for (int i = 1; i < argc; ++i) {
      // InitMozc doesn't remove flags from argv, so ignore flags here.
      if (mozc::Util::StartsWith(argv[i], "--")) {
        continue;
      }
      std::vector<string> params;
      mozc::Util::SplitStringUsing(argv[i], ":", &params);
      CHECK_EQ(3, params.size()) << "Unexpected arg[" << i << "] = " << argv[i];
      inputs.emplace_back(params[0], mozc::NumberUtil::SimpleAtoi(params[1]),
                          params[2]);
    }
  
    CHECK(!FLAGS_output.empty()) << "--output is required";
  
    // DataSetWriter directly writes to the specified stream, so if it fails for
    // an input, the output contains a partial result.  To avoid such partial file
    // creation, write to a temporary file then rename it.
    const string tmpfile = FLAGS_output + ".tmp";
    {
      mozc::DataSetWriter writer(magic);
      for (const auto &input : inputs) {
        VLOG(1) << "Writing " << input.name << ", alignment = " << input.alignment
                << ", file = " << input.filename;
        writer.AddFile(input.name, input.alignment, input.filename);
      }
      mozc::OutputFileStream output(tmpfile.c_str(),
                                    std::ios_base::out | std::ios_base::binary);
      writer.Finish(&output);
      output.close();
    }
    CHECK(mozc::FileUtil::AtomicRename(tmpfile, FLAGS_output))
        << "Failed to rename " << tmpfile << " to " << FLAGS_output;
  
    return 0;
  }
  