c++ - 解析 Google Protocol Buffer 的文本文件

Question

根据示例代码https://developers.google.com/protocol-buffers/docs/cpptutorial ，它们展示了如何在二进制格式的原型(prototype)文件中进行解析。使用

tutorial::AddressBook address_book;

{
  // Read the existing address book.
  fstream input(argv[1], ios::in | ios::binary);
  if (!address_book.ParseFromIstream(&input)) {
    cerr << "Failed to parse address book." << endl;
    return -1;
  }
}

我尝试为文本格式的输入文件删除 ios::binary，但仍然无法读取文件。读取文本格式的 proto 文件需要做什么？

Answer 1

好的，我明白了。将文本原型(prototype)文件读入对象....

#include <iostream>
#include <fcntl.h>
#include <fstream>
#include <google/protobuf/text_format.h>
#include <google/protobuf/io/zero_copy_stream_impl.h>

#include "YourProtoFile.pb.h"

using namespace std;

int main(int argc, char* argv[])
{

  // Verify that the version of the library that we linked against is
  // compatible with the version of the headers we compiled against.
  GOOGLE_PROTOBUF_VERIFY_VERSION;

  Tasking *tasking = new Tasking(); //My protobuf object

  bool retValue = false;

  int fileDescriptor = open(argv[1], O_RDONLY);

  if( fileDescriptor < 0 )
  {
    std::cerr << " Error opening the file " << std::endl;
    return false;
  }

  google::protobuf::io::FileInputStream fileInput(fileDescriptor);
  fileInput.SetCloseOnDelete( true );

  if (!google::protobuf::TextFormat::Parse(&fileInput, tasking))
  {
    cerr << std::endl << "Failed to parse file!" << endl;
    return -1;
  }
  else
  {
    retValue = true;
    cerr << "Read Input File - " << argv[1] << endl;
  }

  cerr << "Id -" << tasking->taskid() << endl;
}

当我在终端执行程序时，我的程序将 proto buff 的输入文件作为第一个参数。例如 ./myProg inputFile.txt

希望对遇到同样问题的人有所帮助