alsa/
device_name.rs

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

alsa/
device_name.rs
