How to read a file in multiple chunks until EOF (C++)
Accepted answer doesn't work for me - it doesn't read last partial chunk. This does:
void readFile(std::istream &input, UncompressedHandler &handler) {
std::vector<char> buffer (1024,0); //reads only 1024 bytes at a time
while (!input.eof()) {
input.read(buffer.data(), buffer.size());
std::streamsize dataSize = input.gcount();
handler({buffer.begin(), buffer.begin() + dataSize});
}
}
Here UncompressedHandler accepts std::string, so I use constructor from two iterators.
You can do this with a loop:
std::ifstream fin("C:\\file.txt", std::ifstream::binary);
std::vector<char> buffer (1024,0); //reads only the first 1024 bytes
while(!fin.eof()) {
fin.read(buffer.data(), buffer.size())
std::streamsize s=fin.gcount();
///do with buffer
}
##EDITED
http://en.cppreference.com/w/cpp/io/basic_istream/read
I think you missed up that there is a pointer points to the last place you've visit in the file , so that when you read for the second time you will not start from the first , but from the last point you've visit . Have a look to this code
std::ifstream fin("C:\\file.txt");
char buffer[1024]; //I prefer array more than vector for such implementation
fin.read(buffer,sizeof(buffer));//first read get the first 1024 byte
fin.read(buffer,sizeof(buffer));//second read get the second 1024 byte
so that how you may think about this concept .