Of course, we could also just have
unsigned int flags1 /* 32 flags */
unsigned int flags2 /* and 32 more, just in case */
and use bit ops.
Not as "clear" but allows for expansion :)
On Apr 29, 2013, at 1:58 PM, Jim Jagielski <[email protected]> wrote:
> IIRC, bit fields are normally int-word sized.
>
> On Apr 29, 2013, at 12:03 PM, Graham Leggett <[email protected]> wrote:
>
>> Hi all,
>>
>> A number of the modules have flags, and with additions typically over time
>> the flags end up looking like this, which takes up a lot of space:
>>
>> struct {
>> [variable]
>> [flag]
>> [variable]
>> [flag]
>> …
>> }
>>
>> Would it make sense to group the flags at the beginning, in theory allowing
>> us to add flags without breaking the ABI?
>>
>> struct {
>> [flag:1]
>> [flag:1}
>> … (within reason, 32 flags max?)
>> [variable]
>> [variable]
>> …
>> }
>>
>> Is it safe to practically assume that the bit field will be at least 32 bits
>> wide, or are there cases were we might see a 16 bit word?
>>
>> Something like this:
>>
>> Index: modules/proxy/mod_proxy.h
>> ===================================================================
>> --- modules/proxy/mod_proxy.h (revision 1476661)
>> +++ modules/proxy/mod_proxy.h (working copy)
>> @@ -128,6 +128,22 @@
>> };
>>
>> typedef struct {
>> + unsigned int req_set:1;
>> + unsigned int viaopt_set:1;
>> + unsigned int recv_buffer_size_set:1;
>> + unsigned int io_buffer_size_set:1;
>> + unsigned int maxfwd_set:1;
>> + unsigned int timeout_set:1;
>> + unsigned int badopt_set:1;
>> + unsigned int proxy_status_set:1;
>> + unsigned int source_address_set:1;
>> + unsigned int bgrowth_set:1;
>> + unsigned int bal_persist:1;
>> + unsigned int inherit:1;
>> + unsigned int inherit_set:1;
>> + unsigned int ppinherit:1;
>> + unsigned int ppinherit_set:1;
>> +
>> apr_array_header_t *proxies;
>> apr_array_header_t *sec_proxy;
>> apr_array_header_t *aliases;
>> @@ -168,25 +184,25 @@
>> ap_slotmem_instance_t *bslot; /* balancers shm data - runtime */
>> ap_slotmem_provider_t *storage;
>>
>> - unsigned int req_set:1;
>> - unsigned int viaopt_set:1;
>> - unsigned int recv_buffer_size_set:1;
>> - unsigned int io_buffer_size_set:1;
>> - unsigned int maxfwd_set:1;
>> - unsigned int timeout_set:1;
>> - unsigned int badopt_set:1;
>> - unsigned int proxy_status_set:1;
>> - unsigned int source_address_set:1;
>> - unsigned int bgrowth_set:1;
>> - unsigned int bal_persist:1;
>> - unsigned int inherit:1;
>> - unsigned int inherit_set:1;
>> - unsigned int ppinherit:1;
>> - unsigned int ppinherit_set:1;
>> } proxy_server_conf;
>>
>>
>> typedef struct {
>> + /**
>> + * the following setting masks the error page
>> + * returned from the 'proxied server' and just
>> + * forwards the status code upwards.
>> + * This allows the main server (us) to generate
>> + * the error page, (so it will look like a error
>> + * returned from the rest of the system
>> + */
>> + unsigned int error_override:1;
>> + unsigned int preserve_host:1;
>> + unsigned int preserve_host_set:1;
>> + unsigned int error_override_set:1;
>> + unsigned int alias_set:1;
>> + unsigned int add_forwarded_headers:1;
>> +
>> const char *p; /* The path */
>> ap_regex_t *r; /* Is this a regex? */
>>
>> @@ -205,20 +221,6 @@
>> signed char interpolate_env;
>> struct proxy_alias *alias;
>>
>> - /**
>> - * the following setting masks the error page
>> - * returned from the 'proxied server' and just
>> - * forwards the status code upwards.
>> - * This allows the main server (us) to generate
>> - * the error page, (so it will look like a error
>> - * returned from the rest of the system
>> - */
>> - unsigned int error_override:1;
>> - unsigned int preserve_host:1;
>> - unsigned int preserve_host_set:1;
>> - unsigned int error_override_set:1;
>> - unsigned int alias_set:1;
>> - unsigned int add_forwarded_headers:1;
>> } proxy_dir_conf;
>>
>> /* if we interpolate env vars per-request, we'll need a per-request
>>
>> Regards,
>> Graham
>> --
>>
>
