10 character string generation

evanagee

Okay, so here's my desired result...

Let's say I start off with a string of 0000000000. I want to automatically increment that string through ZZZZZZZZZZ. Which means, not only can each character be 0 through 9, but each character can also be A through Z. I don't know of a way to get it to increment though.

The psuedo code would be something like this:

start off with 0000000000

loop through EVERY SINGLE POSSIBLE VALUE of that 10 char string until every possibility has been exausted, where each character can be 0 through 9 AND A through Z

For each possible value, perform a function using $10_char as the input or argument.

Anyone know what I'm talking about?

steadyguy

I get the drift of what you want to do, but why do you want so many values? A standard 10-12 digit number is a) easier to generate, and b) more than likely to meet (if not surpass) your needs. Besides, looping from zero to 10 billion-1 in base-36 (viz., the series of numbers you described) will take you a VERY long time; a good computer takes 2 seconds just to count to 10,000 (base-10) and print out each number - not to mention carry out a separate function each time.

If you need guaranteed unique-ness, there are functions that can do it for you. uniqid, for example generates 16 or 23 character unique strings, feed one of those (or something else you can be sure is unique) to md5() and you've got a 32 characters string.... And all db's I can think of provide some way or another to create a series of guaranteed unique numbers. The auto_increment column type in MySQL, for example.

Zallus

I just couldn't resist coding this:

<?php

$chars = array ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');
$c_c = count ($chars);

$registers = array (0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
$r_c = count ($registers);

function increment ()
{
  global $c_c, $registers, $r_c;

  $registers[0]++;
  for ($i = 0; $i < $r_c; $i++)
  {
    if ($registers[$i] > 26)
    {
      if ($i < $r_c - 1)
      {
        $registers[$i] = 0;
        $registers[($i + 1)]++;
      }
      else
      {
        $registers = NULL;
        return false;
      }
    }
  }
  return true;
}

do
{
  for ($i = $r_c - 1; $i > -1; $i--)
  {
    echo $chars[$registers[$i]];
  }
  echo "<br>\n";
} while (increment());
?>

Just to let you know, I've left in a bug so you'll have to figure it out before trying it.

drawmack

why not use the ascii codes and some basic math with recursion?

it's an algorithm I came up with for programming rotor machines.

The specific implementation you asked for is attached.

evanagee

Thanks for all of your help!

Steadyguy, based on your comment about a good computer counting to 10,000 in 2 seconds I did a little math and learned that it would take a computer more than 22,000 years just to list out every possibility. So, I don't think my original plan is going to work. 🙂

drawmack

yes with current technology but there is a 64 bit chip on the horizon which may even make it possible to brute force aes.

By the way this would not be 22,000 years it would be 22,000 days as a mean time to crack

evanagee

the 64 bit chip would be able to do it 32 times faster, right?

drawmack

bouble the bits raise processor speed by an order of magnitute.

For example a 2.4 gig 32 bit chip, same exact architecture on a 64 bit chip runs at 2.4 2.4 gigs and not at 4.8 gigs. This is 5.76 gigs. The fastests computers today run at 4 gigs, so this means that 44 = 16gig machines will come out in the near future.

This is enough to make Turings head explode while Booth laughs.

If you don't know who those people are subtract 10 geek points.

evanagee

As for the length of time, here's the math I used, what's wrong with it?

Total number of possible combinations on a 10 character, base-36 string = 36¹⁰

if a normal computer takes 2 seconds to count to 10000 then...

36^10/5,000 = $seconds

$seconds/60 = $minutes

$minutes/60 = $hours

$hours/24 = $days

$days/7 = $weeks

$weeks/52 = $years

With that, I get over 23,000 years... I know, it seems off...