New functions `hash_serialize` and `hash_unserialize`?

Hello internals! Thanks for PHP! I'm writing to gauge interest in two new functions to the PHP hash extension, hash_serialize and hash_unserialize. These functions would serialize and unserialize the internals of a HashContext object, allowing a partially-computed hash to be saved, then restored and completed in a later run. EXAMPLE: Multi-part upload. Say that a very large file is uploaded in pieces, big.001 through big.999, and it is necessary to compute the SHA256 of the final concatenated file. Current PHP must compute the hash in one go: $ctx = hash_init("sha256"); for ($i = 1; $i <= 999; ++$i) { hash_update_file($ctx, sprintf("big.%.03d", $i)); } $hash = hash_final($ctx); This in turn requires that all pieces be on the filesystem simultaneously. With hash_serialize and hash_unserialize, the hash can be computed gradually, allowing pieces to be deleted as they are uploaded elsewhere. $ctx = hash_init("sha256"); hash_update_file($ctx, "big.001"); SAVE_TO_DATABASE(hash_serialize($ctx)); ... $ctx = hash_unserialize(LOAD_FROM_DATABASE()); hash_update_file($ctx, "big.002"); SAVE_TO_DATABASE(hash_serialize($ctx)); ... etc. *** I am happy to write up an RFC for these functions. An initial implementation with tests is visible here: https://github.com/kohler/php-src/commit/5a3a828f90b88cd7f660babec7db531cfc04b0a1 New functions hash_serialize and hash_unserialize appear to fit the existing API well, and simplify implementation, but it's possible that __serialize/__unserialize or the internal serialize/unserialize functions would be preferred. I'd be grateful for any feedback. Thanks! Eddie Kohler