Shortest way to generate UUID's version 3,4 and 5 in php

Question

I have this function to generate UUID's:

function uuid($v=4,$d=null,$s=false)//$v-> version|$data-> data for version 3 and 5|$s-> add salt and pepper
{
    switch($v.($x=''))
    {
        case 3:
            $x=md5($d.($s?md5(microtime(true).uniqid($d,true)):''));break;
        case 4:default:
            $v=4;for($i=0;$i<=30;++$i)$x.=substr('1234567890abcdef',mt_rand(0,15),1);break;
        case 5:
            $x=sha1($d.($s?sha1(microtime(true).uniqid($d,true)):''));break;
    }
    return preg_replace('@^(.{8})(.{4})(.{3})(.{3})(.{12}).*@','$1-$2-'.$v.'$3-'.substr('89ab',rand(0,3),1).'$4-$5',$x);
}

This is far from being short!

The idea is to reduce this at maximum!

Criteria to meet:

• It MUST have the format xxxxxxxx-xxxx-vxxx-yxxx-xxxxxxxxxxxx, being x a hexadecimal number, y MUST be 89AB and v has to be the version! (required)

• Only vcan be generated randomly for all versions (non-standard, optional)

• Version 3 and 5 have to generate ALWAYS the same UUID (except for the rule above, required)

• You must provide a method of making the UUID somewhat random (required, except for version 4)

• Version 3 uses md5 to "pack" the data, while version 5 uses sha1 (leaving a few chars behind, required)

• Function name MUST be uuid (required)

Scoring:

• Lower number of chars wins
• The score is calculated using (number chars)*0.75
• Readable code is calculated using (number chars)*0.50
• If one of the required criteria from above isn't met, the multiplier is increased by 0.5 for each criteria, except for the last which is 1.25 (maximum will be (number chars)*4.00, which means that 1 char is counting as 4)
• Comments don't count but anything else between function uuid(...){ and } counts!

For example:

My function would have a crappy result:

It has 451 chars on linux.

Since it is somewhat hard to read, it is *0.75.

Since I fulfilled all the criteria, it stays *0.75.

Result: 451*0.75 = 338,25!

Answer 1

PHP - 189 × 0.75 = 141.75

function uuid($v,$d,$s=''){
  $u=hash($v^3?sha1:md5,$v^4?$d.$s:gmp_strval(gmp_random(4)));
  $u[12]=$v;$u[16]=dechex(+"0x$u[16]"&3|8);
  return substr(preg_replace('/^.{8}|.{4}/','\0-',$u,4),0,36);
}

This implementation should be fully compliant with RFC 4122. If $s is provided, it is expected to be the byte string represention of the UUID for the applicable namespace. Otherwise, the default ("NULL") namespace is used.

gmp_random(4) is used to generate the 128 bits of entropy, which is just about the best PHP has. If the gmp module isn't available, you could also use this:

openssl_random_pseudo_bytes(16)) (requires openssl module to be enabled)

or, as a last resort:

for(;$i++<4)$r.=mt_rand();

Sample usage:

echo uuid(3,'MyCoolNewApp');

Sample output:

c478211b-224d-30b1-9116-c06048999ce2