gistfile1.txt

Input:
application/vnd.foobar+html;q=1; version="2\3\""; level="foo, bar", text/json;level=1, text/xml;level=2;q=0.4

Goal: Explode string by the comma's it contains
Contraints:
* commas between quotes (") dont count
* quotes may be escaped

Expected output:
* application/vnd.foobar+html;q=1; version="2\3\""; level="foo, bar"
* text/json;level=1
* text/xml;level=2;q=0.4

My futile attempt:
'#\s*((?<!\\\\)"[^"]*"),|,+#

Current output:
* "application/vnd.foobar+html;q=1; version="2\3\""; level=
* "foo, bar"
*  text/json;level=1
*  text/xml;level=2;q=0.4


Environment:
php5.3+
preg_split('#\s*((?<!\\\\)"[^"]*"),|,+#', $str, -1 , PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);



Code:
<?php

$str = 'application/vnd.foobar+html;q=1; version="2\3\""; level="foo, bar", text/json;level=1, text/xml;level=2;q=0.4';
echo $str.PHP_EOL.PHP_EOL;

$res = preg_split('#\s*((?<!\\\\)"[^"]*"),|,+#', $str, -1 , PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
var_dump($res);