C++ read the whole file in buffer [duplicate]

Question

What is a good approach to read the whole file content in a buffer for C++?

While in plain C I could use fopen(), fseek(), fread() function combination and read the whole file to a buffer, is it still a good idea to use the same for C++? If yes, then how could I use RAII approach while opening, allocating memory for buffer, reading and reading file content to buffer.

Should I create some wrapper class for the buffer, which deallocates memory (allocated for buffer) in it's destructor, and the same wrapper for file handling?

Answer 1

There's no need for wrapper classes for very basic functionality:

std::ifstream file("myfile", std::ios::binary | std::ios::ate); std::streamsize size = file.tellg(); file.seekg(0, std::ios::beg);  std::vector<char> buffer(size); if (file.read(buffer.data(), size)) {     /* worked! */ } 

Answer 2

You can access the contents of a file with a input file stream std::ifstream, then you can use std::istreambuf_iterator to iterate over the contents of the ifstream,

std::string getFileContent(const std::string& path) {   std::ifstream file(path);   std::string content((std::istreambuf_iterator<char>(file)), std::istreambuf_iterator<char>());    return content; } 

In this case im using the iterator to build a new string using the contents of the ifstream, the std::istreambuf_iterator<char>(file) creates an iterator to the begining of the ifstream, and std::istreambuf_iterator<char>() is a default-constructed iterator that indicate the special state "end-of-stream" which you will get when the first iterator reach the end of the contents.