How do I interpret the output of php_uname

From the manual I got the information:

mode is a single character that defines what information is returned:

    'a': This is the default. Contains all modes in the sequence "s n r v m".
    's': Operating system name. eg. FreeBSD.
    'n': Host name. eg. localhost.example.com.
    'r': Release name. eg. 5.1.2-RELEASE.
    'v': Version information. Varies a lot between operating systems.
    'm': Machine type. eg. i386.

So I created a function

function interpret_php_uname(){
    $release_info["os_name"] = php_uname('s');
    $release_info["uname_version_info"] = php_uname('v');
    $release_info["machine_type"] = php_uname('m');
    $release_info["php_uname"] = php_uname();
    return $release_info;
}

is there a way to get more useful information from my uname on Ubuntu?

Linux geisterhaufen 3.11.0-15-generic #23-Ubuntu SMP Mon Dec 9 18:17:04 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

especially find out the distribution (saucy "Ubuntu 13.10") from the part "uname_version_info" which is this on my machine:

#23-Ubuntu SMP Mon Dec 9 18:17:04 UTC 2013

<?php
function interpret_php_uname(){
    $release_info["os_name"] = php_uname('s');
    $release_info["uname_version_info"] = php_uname('v');
    $release_info["machine_type"] = php_uname('m');
    $release_info["kernel"] = php_uname('r');
    $release_info["php_uname"] = php_uname();

    $distribution["4.10"]=array("Warty Warthog", "2.6.8");
    $distribution["5.04"]=array("Hoary Hedgehog", "2.6.10");
    $distribution["5.10"]=array("Breezy Badger", "2.6.12");
    $distribution["6.06"]=array("Dapper Drake", "2.6.15");
    $distribution["6.10"]=array("Edgy Eft", "2.6.17");
    $distribution["7.04"]=array("Feisty Fawn", "2.6.20");
    $distribution["7.10"]=array("Gutsy Gibbon", "2.6.22");
    $distribution["8.04"]=array("Hardy Heron", "2.6.24");
    $distribution["8.10"]=array("Intrepid Ibex", "2.6.27");
    $distribution["9.04"]=array("Jaunty Jackalope", "2.6.28");
    $distribution["9.10"]=array("Karmic Koala", "2.6.31");
    $distribution["10.04"]=array("Lucid Lynx", "2.6.32");
    $distribution["10.10"]=array("Maverick Meerkat", "2.6.35");
    $distribution["11.04"]=array("Natty Narwhal", "2.6.38");
    $distribution["11.10"]=array("Oneiric Ocelot", "3.0");
    $distribution["12.04"]=array("Precise Pangolin", "3.2");
    $distribution["12.10"]=array("Quantal Quetzal", "3.5");
    $distribution["13.04"]=array("Raring Ringtail", "3.8");
    $distribution["13.10"]=array("Saucy Salamander", "3.11");
    $distribution["14.04"]=array("Trusty Tahr", "3.13");

    foreach($distribution as $distribution=>$name_kernel){
        list($name,$kernel)=$name_kernel;
        if(version_compare($release_info["kernel"],$kernel,'>=')) {
            $release_info["ubuntu_distribution"]=$distribution;
            $release_info["ubuntu_distribution_name"]=$name;
        }
    }

    return $release_info;
}
$release_info=interpret_php_uname();
var_export($release_info);

will print for example:

array (
  'os_name' => 'Linux',
  'uname_version_info' => '#23-Ubuntu SMP Mon Dec 9 18:17:04 UTC 2013',
  'machine_type' => 'x86_64',
  'kernel' => '3.11.0-15-generic',
  'php_uname' => 'Linux geisterhaufen 3.11.0-15-generic #23-Ubuntu SMP Mon Dec 9 18:17:04 UTC 2013 x86_64',
  'ubuntu_distribution' => '13.10',
  'ubuntu_distribution_name' => 'Saucy Salamander',
)