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#include "data_manager/dataset_writer.h"

#include <string>

#include "base/file_stream.h"
#include "base/logging.h"
#include "base/port.h"
#include "base/unverified_sha1.h"
#include "base/util.h"
#include "absl/strings/string_view.h"

namespace mozc {
namespace {

bool IsValidAlignment(int a) { return a == 8 || a == 16 || a == 32 || a == 64; }

}  // namespace

DataSetWriter::DataSetWriter(absl::string_view magic)
    : image_(magic.data(), magic.size()) {}

DataSetWriter::~DataSetWriter() = default;

void DataSetWriter::Add(const std::string &name, int alignment,
                        absl::string_view data) {
  CHECK(seen_names_.insert(name).second) << name << " was already added";
  AppendPadding(alignment);
  DataSetMetadata::Entry *entry = metadata_.add_entries();
  entry->set_name(name);
  entry->set_offset(image_.size());
  entry->set_size(data.size());
  image_.append(data.data(), data.size());
}

void DataSetWriter::AddFile(const std::string &name, int alignment,
                            const std::string &filepath) {
  mozc::InputFileStream ifs(filepath.c_str(),
                            std::ios_base::in | std::ios_base::binary);
  CHECK(ifs.good()) << "Failed to open " << name;
  Add(name, alignment, ifs.Read());
}

void DataSetWriter::Finish(std::ostream *output) {
  const std::string s = metadata_.SerializeAsString();
  image_.append(s);                                // Metadata
  image_.append(Util::SerializeUint64(s.size()));  // Metadata size

  // SHA1 checksum
  image_.append(mozc::internal::UnverifiedSHA1::MakeDigest(image_));

  // File size.  Note that the final file size becomes image_.size() + 8 after
  // writing this file size.
  image_.append(Util::SerializeUint64(image_.size() + 8));

  CHECK(output->write(image_.data(), image_.size()));
  VLOG(1) << "Wrote data set of " << image_.size() << " bytes:\n"
          << metadata_.Utf8DebugString();
}

void DataSetWriter::AppendPadding(int alignment) {
  CHECK(IsValidAlignment(alignment)) << "Invalid alignment: " << alignment;
  alignment /= 8;  // To byte
  if (image_.size() % alignment > 0) {
    image_.append(alignment - image_.size() % alignment, '\0');
  }
}

}  // namespace mozc
