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Posted to dev@apr.apache.org by Rainer Jung <ra...@kippdata.de> on 2013/03/29 13:51:36 UTC
Re: [PATCH] Simplify and constify the new apr_hash_this_{key,key_len,val}
functions
On 23.01.2013 16:15, Julian Foad wrote:
> Dear APR devs,
>
> Following the relatively recent addition to APR trunk [1,2,3] of these functions:
>
> const char * apr_hash_this_key(apr_hash_index_t *);
> apr_ssize_t apr_hash_this_key_len(apr_hash_index_t *);
> void * apr_hash_this_val(apr_hash_index_t *);
>
> I offer the attached patch as a simple and obvious improvement.
I considered this but I have the following comments:
- I don't like the code duplication between apr_hash_this() and the
apr_hash_this_*() functions (the "simplification" part). That way the
impl details of apr_hash_this() spread out to other functions. I'd
expect a compiler to be able to optimize the calls in a similar way.
- The constification produces warnings if we don't apply the
simplification as well. Adding the constness to apr_hash_this to get rid
of the warnings is probably not possible due to the versioning rules (at
least in APR 1.x).
Regards,
Rainer
> Log message:
> [[[
> Constify and simplify some hash indexing functions.
>
> * include/apr_hash.h
> (apr_hash_this_key, apr_hash_this_key_len, apr_hash_this_val): Constify
> the hash index parameter.
>
> * tables/apr_hash.c
> (apr_hash_this_key, apr_hash_this_key_len, apr_hash_this_val): Simplify.
> ]]]
>
> Patch (in case the attachment is hard to read):
> [[[
> Index: include/apr_hash.h
> ===================================================================
> --- include/apr_hash.h (revision 1432927)
> +++ include/apr_hash.h (working copy)
> @@ -171,21 +171,21 @@ APR_DECLARE(void) apr_hash_this(apr_hash
> * @param hi The iteration state
> * @return The pointer to the key
> */
> -APR_DECLARE(const void*) apr_hash_this_key(apr_hash_index_t *hi);
> +APR_DECLARE(const void *) apr_hash_this_key(const apr_hash_index_t *hi);
>
> /**
> * Get the current entry's key length from the iteration state.
> * @param hi The iteration state
> * @return The key length
> */
> -APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(apr_hash_index_t *hi);
> +APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(const apr_hash_index_t *hi);
>
> /**
> * Get the current entry's value from the iteration state.
> * @param hi The iteration state
> * @return The pointer to the value
> */
> -APR_DECLARE(void*) apr_hash_this_val(apr_hash_index_t *hi);
> +APR_DECLARE(void *) apr_hash_this_val(const apr_hash_index_t *hi);
>
> /**
> * Get the number of key/value pairs in the hash table.
> Index: tables/apr_hash.c
> ===================================================================
> --- tables/apr_hash.c (revision 1432927)
> +++ tables/apr_hash.c (working copy)
> @@ -162,28 +162,19 @@ APR_DECLARE(void) apr_hash_this(apr_hash
> if (val) *val = (void *)hi->this->val;
> }
>
> -APR_DECLARE(const void *) apr_hash_this_key(apr_hash_index_t *hi)
> +APR_DECLARE(const void *) apr_hash_this_key(const apr_hash_index_t *hi)
> {
> - const void *key;
> -
> - apr_hash_this(hi, &key, NULL, NULL);
> - return key;
> + return hi->this->key;
> }
>
> -APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(apr_hash_index_t *hi)
> +APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(const apr_hash_index_t *hi)
> {
> - apr_ssize_t klen;
> -
> - apr_hash_this(hi, NULL, &klen, NULL);
> - return klen;
> + return hi->this->klen;
> }
>
> -APR_DECLARE(void *) apr_hash_this_val(apr_hash_index_t *hi)
> +APR_DECLARE(void *) apr_hash_this_val(const apr_hash_index_t *hi)
> {
> - void *val;
> -
> - apr_hash_this(hi, NULL, NULL, &val);
> - return val;
> + return (void *)hi->this->val;
> }
>
> /*
> ]]]
>
> - Julian
>
>
> [1] tracked as: <https://issues.apache.org/bugzilla/show_bug.cgi?id=49065>
>
> [2] committed as: <http://svn.apache.org/viewvc?view=revision&revision=931973>
>
> [3] discussed at: <http://mail-archives.apache.org/mod_mbox/apr-dev/201003.mbox/%3C4B96A8EF.8030401%40rowe-clan.net%3E> in the thread found at <http://mail-archives.apache.org/mod_mbox/apr-dev/201003.mbox/browser>; search for "[PATCH] apr_hash_this_{key,klen,val}".