wiki:data:pages:dev:shared_strings
Differences
This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision | |||
|
wiki:data:pages:dev:shared_strings [2024/05/23 18:18] leaf Remove wiki-data version of shared_strings page |
— (current) | ||
|---|---|---|---|
| Line 1: | Line 1: | ||
| - | To minimize memory use, Crossfire uses a shared string mechanism. This is intended to be used for strings whose contents is not expected to change during the server's life. Using shared strings saves memory and improved performance. | ||
| - | Those strings are used like regular ''const char*'', but should not be changed via ''strcpy'', ''snprintf'' or other means because it would affect **all** structures using the shared string. Internally, they use a counter to track at how many places they are used. When it reaches 0, string is freed. | ||
| - | |||
| - | To alter such a string, the right behaviour is: | ||
| - | * write new value in a ''char[] new_value'' variable | ||
| - | * use ''free_string(str)'' | ||
| - | * call ''str = add_string(new_value)'' | ||
| - | |||
| - | FIXME replace with sstring when done in code | ||
| - | |||
| - | To manipulate them, the following functions (defined in ''[[http://crossfire.svn.sourceforge.net/viewvc/crossfire/server/trunk/common/shstr.c?view=markup|common/shstr.c]]'') are available: | ||
| - | * ''const char* add_string(const char *str)'', used to share a string. Returned value is a string with the same contents that can be shared with other objects | ||
| - | * ''const char* add_refcount(const char *str)'', equivalent of ''add_string'' when the string is already a shared string | ||
| - | * ''const char* find_string(const char *str)'', to search if a string is shared or not | ||
| - | * ''void free_string(const char *str)'', to decrement the use counter. After it's called, ''str'' should not be used anymore. | ||
| - | |||
| - | Because shared strings will return a pointer to a string if it exists, one can see if the strings are equal by comparing the shared string address they point to (ie ''str == str2'' directly). | ||
Page Tools
