OpenEuphoria

I benchmarked three different methods of checking the existence of a file:

function file_exists_dir(sequence filename) 
	return sequence(dir(filename)) 
end function 
 
function file_exists_open(sequence filename) 
	integer a = open(filename, "r") 
	if a = -1 then 
		return 0 
	end if 
	close(a) 
	return 1 
end function 
 
constant lib = open_dll("kernel32.dll"), filea = "parser.e", fileb="no.txt" 
constant f_access = define_c_func(lib, "GetFileAttributesA", {C_POINTER}, C_INT) 
function file_exists_win(sequence filename) 
	atom pFilename = allocate_string(filename) 
	integer r = c_func(f_access, {pFilename}) 
	free(pFilename) 
	return r > 0 
end function 

file_exists_dir() and file_exists_open() were about the same. file_exists_win() was much faster.

With 2376 files (C:\Windows\System32):

Time dir : 0.000129 per 
Time open: 0.000126 per 
Time win : 0.000033 per 

With 1 file (mocked directory)

Time dir : 0.000044 per 
Time open: 0.000034 per 
Time win : 0.000028 per 

The test looked for one file that did exist and one file that did not. This is a common enough operation that I will make a function called file_exists and place it in std/filesys.e for 4.0. On Unix we will use the C function access(). On DOS, it will revert to the dir() or open() method.

Jeremy