Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
I, for one, would like to see your code for building an 5-byte index?
Storing a million 5-byte integers using 5 million bytes for data, and 44 bytes additional overhead:
my $buffer = ""; my $BYTES = 5; my $BITS_IN_BYTE = 8; my $FULL_BYTE = (1 << $BITS_IN_BYTE) - 1; sub store { my ($pos, $value) = @_; for (0 .. $BYTES - 1) { vec($buffer, $pos * $BYTES + $_, $BITS_IN_BYTE) = ($value >> ($BITS_IN_BYTE * ($BYTES - 1 - $_))) & $FULL_BYT +E; } } sub fetch { my ($pos) = @_; my $sum = 0; for (0 .. $BYTES - 1) { $sum <<= $BITS_IN_BYTE; $sum += vec($buffer, $pos * $BYTES + $_, $BITS_IN_BYTE); } $sum; } # # Testing # my $TEST_SIZE = 1_000_000; my @offsets = map {int rand 1 << ($BYTES * $BITS_IN_BYTE)} 1 .. $TEST_ +SIZE; for (my $i = 0; $i < @offsets; $i++) { store $i, $offsets[$i]; } for (my $i = 0; $i < @offsets; $i++) { my $val = fetch $i; die unless $val == $offsets[$i]; } use Devel::Size 'size'; use 5.010; say "Index size: ", size $buffer; __END__ Index size: 5000044

In reply to Re^3: Displaying/buffering huge text files by JavaFan
in thread Displaying/buffering huge text files by spurperl

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others wandering the Monastery: (4)
    As of 2020-09-25 00:21 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?
      If at first I donít succeed, I Ö










      Results (135 votes). Check out past polls.

      Notices?