<?php
$string = '[c]str1[/c][c]str2[/c][c]str3[/c][c]str4[/c][c]str5[/c]';//
$strarray = preg_split('/\[.](.*?)\[\/.]/', $string, -1, PREG_SPLIT_DELIM_CAPTURE
|PREG_SPLIT_NO_EMPTY
);
PD9waHAKCiRzdHJpbmcgPSAnW2Ndc3RyMVsvY11bY11zdHIyWy9jXVtjXXN0cjNbL2NdW2Ndc3RyNFsvY11bY11zdHI1Wy9jXSc7Ly8KJHN0cmFycmF5ID0gcHJlZ19zcGxpdCgnL1xbLl0oLio/KVxbXC8uXS8nLCAkc3RyaW5nLCAtMSwgUFJFR19TUExJVF9ERUxJTV9DQVBUVVJFfFBSRUdfU1BMSVRfTk9fRU1QVFkpOwpwcmludF9yKCRzdHJhcnJheSk7Cgo=