代码片段收集

Get file content as string

bool GetContent(const std::string &file_name, std::string *content) {
  std::ifstream fin(file_name);
  if (!fin) {
    return false;
  }

  std::stringstream str_stream;
  str_stream << fin.rdbuf();
  *content = str_stream.str();
  return true;
}

键值对解析

// return (name,value) trimmed pair from given "name=value" string.
// return empty string on missing parts
// "key=val" => ("key", "val")
// " key  =  val " => ("key", "val")
// "key=" => ("key", "")
// "val" => ("", "val")
inline std::pair<std::string, std::string> extract_kv(char sep, const std::string &str)
{
    auto n = str.find(sep);
    std::string k, v;
    if (n == std::string::npos)
    {
        v = str;
    }
    else
    {
        k = str.substr(0, n);
        v = str.substr(n + 1);
    }
    return std::make_pair(trim_(k), trim_(v));
}
// return vector of key/value pairs from sequence of "K1=V1,K2=V2,.."
// "a=AAA,b=BBB,c=CCC,.." => {("a","AAA"),("b","BBB"),("c", "CCC"),...}
inline std::unordered_map<std::string, std::string> extract_key_vals(const std::string &str)
{
    std::string token;
    std::istringstream token_stream(str);
    std::unordered_map<std::string, std::string> rv{};
    while (std::getline(token_stream, token, ','))
    {
        if (token.empty())
        {
            continue;
        }
        auto kv = extract_kv_('=', token);
        rv[kv.first] = kv.second;
    }
    return rv;
}

uint64_t展开

  // Extracts the |i|th byte of a uint64_t, where |i == 0| extracts the least
  // significant byte. It is expected that 0 <= i < 8.
  static constexpr uint8_t ExtractByte(const uint64_t value, const uint32_t i) {
    //    DCHECK_LT(i, 8u);
    return static_cast<uint8_t>((value >> (i * 8)) & 0xff);
  }

  static uint32_t SwapEndian(uint32_t a) {
    return ((a & 0xff) << 24) | (((a >> 8) & 0xff) << 16) |
           (((a >> 16) & 0xff) << 8) | ((a >> 24) & 0xff);
  }

https://github.com/David-Haim/concurrencpp/blob/master/include/concurrencpp/threads/thread.h
https://github.com/google/leveldb/blob/main/include/leveldb/slice.h
https://github.com/alibaba/ilogtail/blob/main/core/common/MemoryBarrier.h