Hi, This patchset is a fix for bug issued in the message thread[1]. In this development period, alsa-lib got new API as implementation for one of comparison algorithms to a pair of control element IDs. However, it has several issues. At first, the name, 'snd_ctl_elem_id_compare()', is inappropriate since it implements one of comparison algorithms. The name itself implies the algorithm is single and unique for control element ID. However, the target structure, 'struct snd_ctl_elem_id', is hybrid and compound one. We can not find such single and unique comparison algorithm for it. Secondary, it subtracts a pair of values in fields of 'unsigned int' type in storage size of the type. It brings integer overflow. Tertiary, it has simple bug to compare subdevice field in the same structure. Essentially, equality is different from comparison. In a point of programming, implementation for comparison algorithm can have more overhead than implementation for equality. In this meaning, it's better to add different API for them. This patchset adds new API below: * for equality * snd_ctl_elem_id_equal_by_numid() * snd_ctl_elem_id_equal_by_tuple() * for each comparison algorithm * snd_ctl_elem_id_compare_by_numid() * snd_ctl_elem_id_compare_by_tuple_arithmetic() I've got bothered to decide the name of API for the case to use tuples. Here I use the word, 'tuple', which comes from documentation of alsa-lib[2]. Furthermore, this patchset adds test program for them since equality and comparison are quite basic method to operate data. It's better to have no bug. Finally, the issued API, 'snd_ctl_elem_id_compare()' is dropped. After merging the patchset, I'm going to post additional patch to alsa-utils to fix issued line[3]. [1] https://mailman.alsa-project.org/pipermail/alsa-devel/2021-March/181738.html [2] https://github.com/alsa-project/alsa-lib/blob/master/src/control/control.c#L80 [3] https://github.com/alsa-project/alsa-utils/blob/master/alsactl/clean.c#L55 Regards Takashi Sakamoto (6): test: ctl-elem-id: add test program for future APIs relevant to control element ID ctl: add API to check equality between a pair of control element IDs by numid ctl: add API to check equality between a pair of control element IDs by tuple ctl: add API to compare a pair of control element IDs by numid ctl: add API to compare a pair of control element IDs by one of algorithms according to tuple ctl: drop deprecated API to compare a pair of control element IDs include/control.h | 5 +- src/control/control.c | 135 ++++++++++++++---- test/lsb/Makefile.am | 6 +- test/lsb/ctl-elem-id.c | 301 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 418 insertions(+), 29 deletions(-) create mode 100644 test/lsb/ctl-elem-id.c -- 2.27.0
