This saves up to 1-2% CPU useage on a PI 4 depending on how much normalisation is actually being done.
* We don't need to test against EPSILON. The factor will never be over 1.0 in basic normalisation mode.
* Don't check the normalisation mode EVERY sample.
* Do as little math as possible by simplfiying all equations as much as possible (while still retaining the textbook equations in comments).
* Misc cleanup
When there's a value that corresponds to an argument name used in the same command line, the logging of the arguments gets confused and logs the matching argument, but without the leading dash:
```
% target/debug/librespot -n c --verbose -c /path/to/my/cache
[2022-02-07T22:32:25Z INFO librespot] librespot 0.3.1 55ced49 (Built on 2022-02-07, Build ID: qaEB8kEW, Profile: debug)
[2022-02-07T22:32:25Z TRACE librespot] Command line argument(s):
[2022-02-07T22:32:25Z TRACE librespot] -n "c"
[2022-02-07T22:32:25Z TRACE librespot] c "/path/to/my/cache"
[2022-02-07T22:32:25Z TRACE librespot] --verbose
[2022-02-07T22:32:25Z TRACE librespot] -c "/path/to/my/cache"
```
Here we're using the literal `c` as the device name, and the `-c` argument. Thus the `c /path/to/my/cache` is logged in addition to `-c /path...`.
After checking whether the key has a leading dash, this issue is gone:
```
% target/debug/librespot -n c --verbose -c /path/to/my/cache
[2022-02-07T22:32:41Z INFO librespot] librespot 0.3.1 55ced49 (Built on 2022-02-07, Build ID: qaEB8kEW, Profile: debug)
[2022-02-07T22:32:41Z TRACE librespot] Command line argument(s):
[2022-02-07T22:32:41Z TRACE librespot] -n "c"
[2022-02-07T22:32:41Z TRACE librespot] --verbose
[2022-02-07T22:32:41Z TRACE librespot] -c "/path/to/my/cache"
```
Dynamically set the alsa buffer and period based on the device's reported min/max buffer and period sizes. In the event of failure use the device's defaults.
This should have no effect on devices that allow for reasonable buffer and period sizes but would allow us to be more forgiving with less reasonable devices or configurations.
Closes: https://github.com/librespot-org/librespot/issues/895
Fix up for #886Closes: #898
And...
* Don't silently ignore non-Unicode while parsing env vars.
* Iterating over `std::env::args` will panic! on invalid unicode. Let's not do that. `getopts` will catch missing args and exit if those args are required after our error message about the arg not being valid unicode.
* Gaurd against empty strings. There are a few places while parsing options strings that we don't immediately evaluate their validity let's at least makes sure that they are not empty if present.
* `args` is only used in `get_setup` it doesn't need to be in main.
* Nicer help header.
* Get rid of `use std::io::{stderr, Write};` and just use `rpassword::prompt_password_stderr`.
* Get rid of `get_credentials` it was clunky, ugly and only used once. There is no need for it to be a separate function.
* Handle an empty password prompt and password prompt parsing errors.
* + Other random misc clean ups.
Make librespot able to parse environment variables for options and flags.
To avoid name collisions environment variables must be prepended with `LIBRESPOT_` so option/flag `foo-bar` becomes `LIBRESPOT_FOO_BAR`.
Verbose logging mode (`-v`, `--verbose`) logs all parsed environment variables and command line arguments (credentials are redacted).
This makes `--device ?` only show compatible devices (ones that support 2 ch 44.1 Interleaved) and it shows what `librespot` format(s) they support.
This should be more useful to users as the info maps directly to `librespot`'s `--device` and `--format` options.
* Don't panic when parsing options. Instead list valid values and exit.
* Get rid of needless .expect in playback/src/audio_backend/mod.rs.
* Enforce reasonable ranges for option values (breaking).
* Don't evaluate options that would otherwise have no effect.
* Add pub const MIXERS to mixer/mod.rs very similar to the audio_backend's implementation. (non-breaking though)
* Use different option descriptions and error messages based on what backends are enabled at build time.
* Add a -q, --quiet option that changed the logging level to warn.
* Add a short name for every flag and option.
* Note removed options.
* Other misc cleanups.
