Re: Standard C++ file size ???

On 7/6/2010 1:26 PM, James Kanze wrote:


I adapted your code to my style making minor formatting changes and tested
it on several files. It worked perfectly. What I liked best about your
code is that it taught me a very simple way to use exceptions.

I had previously avoided exceptions because their typical implementation
was far too convoluted, and I always strive for the simplest possible
code. Now that I know how to throw and catch text based exceptions they
are very simple. That was the cleanest error handling that I have ever
seen. This will become my new idiom for file processing and error
handling.

#include <iostream>
#include <fstream>
#include <vector>

void readAll(char const* filename, std::vector< char >& data ) {
std::ifstream fin;
  fin.open(filename, std::ios_base::in | std::ios_base::binary);
  if ( ! fin )
    throw "cannot open";

  fin.seekg( 0, std::ios::end );
  if ( ! fin )
    throw "seek error";

  long long size = fin.tellg();
  std::cout << filename << ": size = " << size << std::endl ;

  if ( size != 0 ) {
    fin.clear() ;

    fin.seekg( 0, std::ios::beg );
    if ( ! fin )
      throw "rewind failed";

    data.resize( size );
    fin.read( &data[ 0 ], size );
    if ( ! fin )
      throw "read failed";
  }
}

int main( int argc, char** argv ) {
std::vector< char > data;
  if (argc == 2)
    try {
      readAll( argv[ 1 ], data );
    } catch ( char const* error ) {
      std::cout << argv[ 1 ] << ": " << error << std::endl ;
    }
  else
    std::cout << "Must specify a FileName!" << std::endl ;
  return 0;
}