From: GitHub issues - edited <github@alsa-project.org>
To: alsa-devel@alsa-project.org
Subject: snd_config_imul always produces a zero result.
Date: Fri, 23 May 2025 00:15:34 +0200 (CEST) [thread overview]
Message-ID: <1841f93459ea4d00-webhooks-bot@alsa-project.org> (raw)
In-Reply-To: <1841f93459e8a500-webhooks-bot@alsa-project.org>
alsa-project/alsa-lib issue #456 was edited from shanekirk:
The config function snd_config_imul always produces a zero result. This is because it delegates to snd_func_iops() to perform the iterative multiplication, which always initializes its result value to zero. Then it iteratively multiplies-assigns result against each integer in the params array, which _always_ produces zero.
This breaks any configuration that leans on "@func imul".
This can be demonstrated using this snippet of configuration...
```
test_fn
{
@func imul
integers [2 4 6]
}
```
...or this source code...
```
int main(int argc, char **argv)
{
snd_config_t *pConfig = NULL;
snd_config_top(&pConfig);
/**
* Setting up...
* test_fn
* {
* @func imul
* integers [2 4 6]
* }
*/
snd_config_t *pFnCS = NULL;
snd_config_make_compound(&pFnCS, "test_fn", 0);
snd_config_add(pConfig, pFnCS);
snd_config_t *pFn = NULL;
snd_config_imake_string(&pFn, "@func", "imul");
snd_config_add(pFnCS, pFn);
snd_config_t *pFnParams = NULL;
snd_config_make_compound(&pFnParams, "integers", 0);
snd_config_add(pFnCS, pFnParams);
snd_config_t *pFnInt = NULL;
snd_config_imake_integer(&pFnInt, "0", 2);
snd_config_add(pFnParams, pFnInt);
snd_config_imake_integer(&pFnInt, "1", 4);
snd_config_add(pFnParams, pFnInt);
snd_config_imake_integer(&pFnInt, "2", 6);
snd_config_add(pFnParams, pFnInt);
/**
* Evaluating...
*/
snd_config_evaluate(pFnCS, pConfig, NULL, NULL);
assert(snd_config_get_type(pFnCS) == SND_CONFIG_TYPE_INTEGER);
long result = 0;
snd_config_get_integer(pFnCS, &result);
assert(result == 48); // ** FAILS because result is always zero! **
snd_config_delete(pConfig);
return 0;
}
```
Note: If you replace "imul" above with "iadd" in either example, you'll get the result from iadd that you'd expect.
Issue URL : https://github.com/alsa-project/alsa-lib/issues/456
Repository URL: https://github.com/alsa-project/alsa-lib
next parent reply other threads:[~2025-05-22 22:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1841f93459e8a500-webhooks-bot@alsa-project.org>
2025-05-22 22:15 ` GitHub issues - edited [this message]
[not found] <1841f99283422d00-webhooks-bot@alsa-project.org>
2025-05-22 22:22 ` snd_config_imul always produces a zero result GitHub issues - edited
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2025-05-22 22:15 ` GitHub issues - edited
[not found] <1841f9374957c700-webhooks-bot@alsa-project.org>
2025-05-22 22:15 ` GitHub issues - edited
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2025-05-22 22:15 ` GitHub issues - edited
[not found] <1841f92e5e224b00-webhooks-bot@alsa-project.org>
2025-05-22 22:15 ` GitHub issues - opened
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