<?php

$reader = new XMLReader();

$reader->open('zip://' . dirname(__FILE__) . '/test.odt#meta.xml');
$odt_meta = array();
while ($reader->read()) {
    if ($reader->nodeType == XMLREADER::ELEMENT) {
        $elm = $reader->name;
    } else {
        if ($reader->nodeType == XMLREADER::END_ELEMENT && $reader->name == 'office:meta') {
            break;
        }
        if (!trim($reader->value)) {
            continue;
        }
        $odt_meta[$elm] = $reader->value;
    }
}
print_r($odt_meta);