Shuffle

[Roberto Mariottini]

Walter Bright wrote:
[...]
>     for (size_t i = 0; i < files.length; i++)
>     {
>     auto j = std.random.rand() % files.length;
>     auto fromfile = files[j];
>     auto tofile = std.path.join(todir, basename(fromfile));
>     writefln("%s => %s", fromfile, tofile);
>     std.file.copy(fromfile, tofile);
>     }

Here you are copying duplicate files over and over. You don't see 
duplicates because a file copy will overwrite the previously written 
file, but if you have enough space on the destination device you'll get 
less files on the destination than those on the source, because 
duplicates will overwrite.

I've found players that implement the shuffle function this way: the 
pseudo random generator always "prefers" a certain subset of the songs 
and will play them frequently, while other songs are rarely selected (if 
ever).
A real "shuffle" function should generate the same list of songs that 
the source contains, changing only the order.

Ciao
-- 
Roberto Mariottini, http://www.mariottini.net/roberto/
SuperbCalc, a free tape calculator: 
http://www.mariottini.net/roberto/superbcalc/