Looking for an example of zend_hash_quick_add() or zend_hash_add() View as Markdown

On Mon, May 5, 2014 at 11:29 AM, Aaron Lewis the.warl0ck.1989@gmail.comwrote:

Yes I can find examples in existing source code,

zend_hash_quick_add(EG(active_symbol_table), key->arKey,
key->nKeyLength, key->h, &tmp, sizeof(zval*), (void**)&p);

But I only know the HashTable, key, key length parameters, I'm not
sure what to fill in for the rest

Can anyone give me an example?

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Aaron Lewis - PGP: 0x13714D33 - http://pgp.mit.edu/
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--

hi,

http://lxr.php.net/xref/PHP_5_6/Zend/zend_hash.h#114
http://lxr.php.net/xref/PHP_5_6/Zend/zend_hash.c#308

#define zend_hash_quick_update(ht, arKey, nKeyLength, h, pData, nDataSize,
pDest)

ht is the HashTable
arKey is the key/index
nKeyLength is the length of the key
h is hash of the key
pData is a pointer to the data
nDataSize is the size of the data eg sizeof(zval *)
pDest is the destination pointer, usually NULL because we don't care about
it most of the times

some docs on the hashtables:
http://www.php.net/manual/en/internals2.variables.tables.php
http://nikic.github.io/2012/03/28/Understanding-PHPs-internal-array-implementation.html
http://www.phpinternalsbook.com/hashtables.html (
http://www.phpinternalsbook.com/hashtables/basic_structure.html is a good
start)
(and in Sara's book, Extending and Embedding PHP).

and a simple example:
http://www.phpinternalsbook.com/hashtables/hashtable_api.html#string-keys

For all of the above functions there exists a second quick variant that

accepts a precomputed hash value after the string length. This allows you
to compute the hash of a string once and then reuse it across multiple
calls:
ulong h; /* hash value /
/ ... zval init */
h = zend_get_hash_value("foo", sizeof("foo"));
zend_hash_quick_update(myht, "foo", sizeof("foo"), h, &zv, sizeof(zval *),
NULL);
if (zend_hash_quick_find(myht, "foo", sizeof("foo"), h, (void **)
&zv_dest) == SUCCESS) {
php_printf("Fetched value at key "foo" into zv_dest\n");
}
if (zend_hash_quick_del(myht, "foo", sizeof("foo"), h) == SUCCESS) {
php_printf("Removed value at key "foo"\n");
}
Using the quick API improves performance as the hash value does not have
to be recomputed on every call. It should be noted though that this only
becomes significant if you are accessing the key a lot (e.g. in a loop).
The quick functions are mostly used in the engine where precomputed hash
values are available through various caches and optimizations.

ps: somebody please correct me if I'm wrong somewhere!

--
Ferenc Kovács
@Tyr43l - http://tyrael.hu