kc3-lang/libxkbcommon

2025-04-13T09:50:18

state: Capitalization transformation in xkb_state_key_get_syms Previously `xkb_state_key_get_syms()` did not perform capitalization tranformation, while `xkb_state_key_get_one_sym()` does perform it. This is unfortunate if we want to promote the use of multiple keysyms per levels. The API make it difficult to change now though: we return a pointer to an immutable array rather than filling a buffer. While we could use an internal buffer in `xkb_state`, this option would limit the API to *sequential* calls of `xkb_state_key_get_syms()` or require some buffer handling (e.g. rotation). Instead we now store the capitalization directly in `xkb_level`. We modified `xkb_level` like so (see below for discussion about the size): ```diff struct xkb_level { - unsigned int num_syms; + uint16_t num_syms; - unsigned int num_actions; + uint16_t num_actions; + union { + /** num_syms == 1: Upper keysym */ + xkb_keysym_t upper; + /** num_syms > 1: Indicate if `syms` contains the upper case + * keysyms after the lower ones. */ + bool has_upper; + }; union { xkb_keysym_t sym; /* num_syms == 1 */ xkb_keysym_t *syms; /* num_syms > 1 */ } s; union { union xkb_action action; /* num_actions == 1 */ union xkb_action *actions; /* num_actions > 1 */ } a; }; ``` - When `level.num_syms` <= 1, we store the upper keysym in `level.upper`. - Else if there no cased syms, we set `level.has_upper` to false. - Else if there are some cased syms, we set `level.has_upper`` to `true` and we double the original size of `level.s.syms`, but *without* modifying `level.num_syms`. We then append the transformed keysyms right after the original ones, so that we can access them by a simple pointer operation: `level.s.syms + level.num_syms`. The memory footprint is *unchanged*, thanks to the reduced fields for actions and keysyms counts.