alsa/
device_name.rs

1//! Enumerate devices in the alsa library configuration
2//!
3//! # Example
4//! Print all devices found in various categories.
5//!
6//! ```
7//! use std::ffi::CString;
8//! use alsa::device_name::HintIter;
9//!
10//! for t in &["pcm", "ctl", "rawmidi", "timer", "seq", "hwdep"] {
11//!     println!("{} devices:", t);
12//!     let i = HintIter::new(None, &*CString::new(*t).unwrap()).unwrap();
13//!     for a in i { println!("  {:?}", a) }
14//! }
15//! ```
16
17use core::ptr;
18use libc::{c_void, c_int};
19use crate::alsa;
20use super::{Card, Direction};
21use super::error::*;
22use core::ffi::CStr;
23use ::alloc::ffi::CString;
24use ::alloc::string::String;
25
26/// [snd_device_name_hint](http://www.alsa-project.org/alsa-doc/alsa-lib/group___control.html) wrapper
27#[derive(Debug)]
28pub struct HintIter(*mut *mut c_void, isize);
29
30impl Drop for HintIter {
31    fn drop(&mut self) { unsafe { alsa::snd_device_name_free_hint(self.0); }}
32}
33
34impl HintIter {
35    /// typical interfaces are: "pcm", "ctl", "rawmidi", "timer", "seq" and "hwdep".
36    pub fn new(card: Option<&Card>, iface: &CStr) -> Result<HintIter> {
37        let mut p = ptr::null_mut();
38        let cnr = card.map(|c| c.get_index()).unwrap_or(-1) as c_int;
39        acheck!(snd_device_name_hint(cnr, iface.as_ptr(), &mut p))
40            .map(|_| HintIter(p, 0))
41    }
42
43    /// A constructor variant that takes the interface as a Rust string slice.
44    pub fn new_str(card: Option<&Card>, iface: &str) -> Result<HintIter> {
45        HintIter::new(card, &CString::new(iface).unwrap())
46    }
47}
48
49impl Iterator for HintIter {
50    type Item = Hint;
51    fn next(&mut self) -> Option<Hint> {
52        if self.0.is_null() { return None; }
53        let p = unsafe { *self.0.offset(self.1) };
54        if p.is_null() { return None; }
55        self.1 += 1;
56        Some(Hint::new(p))
57    }
58}
59
60
61/// [snd_device_name_get_hint](http://www.alsa-project.org/alsa-doc/alsa-lib/group___control.html) wrapper
62#[derive(Debug, Clone)]
63pub struct Hint {
64    pub name: Option<String>,
65    pub desc: Option<String>,
66    pub direction: Option<Direction>,
67}
68
69impl Hint {
70    fn get_str(p: *const c_void, name: &str) -> Option<String> {
71        let name = CString::new(name).unwrap();
72        let c = unsafe { alsa::snd_device_name_get_hint(p, name.as_ptr()) };
73        from_alloc("snd_device_name_get_hint", c).ok()
74    }
75
76    fn new(p: *const c_void) -> Hint {
77       let d = Hint::get_str(p, "IOID").and_then(|x| match &*x {
78            "Input" => Some(Direction::Capture),
79            "Output" => Some(Direction::Playback),
80            _ => None,
81       });
82       Hint { name: Hint::get_str(p, "NAME"), desc: Hint::get_str(p, "DESC"), direction: d }
83    }
84}
85
86#[test]
87fn print_hints() {
88    extern crate std;
89    for t in &["pcm", "ctl", "rawmidi", "timer", "seq", "hwdep"] {
90        std::println!("{} devices:", t);
91        let i = HintIter::new(None, &*CString::new(*t).unwrap()).unwrap();
92        for a in i { std::println!("  {:?}", a) }
93    }
94}
alsa/device_name.rs

alsa/
device_name.rs
