Translate the code from Python to C++ -

now when understand how code works, translate c++.

the original python code:

def recv_all_until(s, crlf):     data = ""     while data[-len(crlf):] != crlf:         data += s.recv(1)     return data 

here's tried:

std::string recv_all_until(int socket, std::string crlf) {     std::string data = "";     char buffer[1];     memset(buffer, 0, 1);       while(data.substr(data.length()-2, data.length()) != crlf)     {         if ((recv(socket, buffer, 1, 0)) == 0)         {             if (errno != 0)             {                 close(socket);                 perror("recv");                 exit(1);             }         }         data = data + std::string(buffer);         memset(buffer, 0, 1);     }      return data; } 

but shows:

terminate called after throwing instance of 'std::out_of_range'   what():  basic_string::substr 

i understand problem inside while loop since @ first data string empty. how improve make work same works in python? thank you.

if first change python code bit:

def recv_all_until(s, crlf):     data = ""     while not data.endswith(crlf):         data += s.recv(1)     return data 

what need in c++ becomes clearer:

bool ends_with(const std::string& str, const std::string& suffix) {     return str.size() >= suffix.size() &&         std::equal(suffix.rbegin(), suffix.rend(), str.rbegin()); }  std::string recv_all_until(int socket, const std::string& crlf) {     std::string data = "";     char buffer[1];     memset(buffer, 0, 1);      while (!ends_with(data, crlf))     {         if ((recv(socket, buffer, 1, 0)) == 0)         {             if (errno != 0)             {                 close(socket);                 perror("recv");                 exit(1);             }         }         data = data + std::string(buffer);         memset(buffer, 0, 1);     }      return data; }