- var_dump: documentation ( source)
- preg_split: documentation ( source)
<?php
$var = <<<DATA
This is "some data" with some "quoted \"strings"
DATA;
$expr = '/\s+(?=[^\s]+|"((?:[^"\\\\]|\\\\.)*)")/';
var_dump(preg_split($expr, $var, -1, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE));