Accessing files as an array in C++?

[Perica]

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[Tim]

Memory-mapped files.

Under Windows, you do:
CreateFile (open the file)
CreateFileMapping (create a file mapping object on the file)
MapViewOfFile (open a memory window into the file mapping object)
Access the file as an array
UnMapViewOfFile
CloseHandle(file_mapping)
CloseHandle(file)

[Perica]

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[Tim]

You have no choice but to use the Win32 API for this, as the C standard library doesn't include memory-mapped files.

However, you can use fopen/fread/fwrite/fclose/fseek to do 'normal' file I/O under standard C. They come from the <stdio.h> file. Alternatively, you can use the C++ library; look up the std::ifstream and std::ofstream classes.

[Andrew_Baker]

If you're using C++, can't you build an array of file _objects_? I'm not too sure of the implementation, but that's what I would suggest.

or could it be as simple as f_array[x]=fopen("whatever","r")?

[Perica]

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[Tim]

Sure, but memory-mapped files are far more efficient, especially for larger files.

Why do you need all of the file in memory at once? What's stopping you reading only what's needed?

[Perica]

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[Tim]

Try this URL: http://msdn.microsoft.com/library/en-us/fileio/base/file_mapping.asp?frame=true