Jeremy Soller
86 lines
2.2 KiB
Rust
86 lines
2.2 KiB
Rust
use std::collections::{BTreeMap, VecDeque};
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use syscall::error::{EBADF, EWOULDBLOCK, Error, Result};
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use syscall::flag::O_NONBLOCK;
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use syscall::scheme::SchemeBlockMut;
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// The strict buffer size of the hda: driver
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const HDA_BUFFER_SIZE: usize = 512;
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// The desired buffer size of each handle
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const HANDLE_BUFFER_SIZE: usize = 4096;
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struct Handle {
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flags: usize,
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buffer: VecDeque<(i16, i16)>,
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}
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pub struct AudioScheme {
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next_id: usize,
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handles: BTreeMap<usize, Handle>
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}
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impl AudioScheme {
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pub fn new() -> Self {
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AudioScheme {
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next_id: 0,
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handles: BTreeMap::new()
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}
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}
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pub fn buffer(&mut self) -> [(i16, i16); HDA_BUFFER_SIZE] {
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let mut buffer = [(0i16, 0i16); HDA_BUFFER_SIZE];
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for (_id, handle) in self.handles.iter_mut() {
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let mut i = 0;
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while i < buffer.len() {
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if let Some(sample) = handle.buffer.pop_front() {
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buffer[i].0 = buffer[i].0.saturating_add(sample.0);
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buffer[i].1 = buffer[i].1.saturating_add(sample.1);
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} else {
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break;
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}
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i += 1;
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}
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}
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buffer
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}
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}
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impl SchemeBlockMut for AudioScheme {
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fn open(&mut self, _path: &[u8], flags: usize, _uid: u32, _gid: u32) -> Result<Option<usize>> {
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self.next_id += 1;
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let id = self.next_id;
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self.handles.insert(id, Handle {
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flags,
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buffer: VecDeque::new()
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});
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Ok(Some(id))
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}
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fn write(&mut self, id: usize, buf: &[u8]) -> Result<Option<usize>> {
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let handle = self.handles.get_mut(&id).ok_or(Error::new(EBADF))?;
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if handle.buffer.len() >= HANDLE_BUFFER_SIZE {
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if handle.flags & O_NONBLOCK > 0 {
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Err(Error::new(EWOULDBLOCK))
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} else {
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Ok(None)
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}
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} else {
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let mut i = 0;
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while i + 4 <= buf.len() {
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handle.buffer.push_back((
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(buf[i] as i16) | ((buf[i + 1] as i16) << 8),
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(buf[i + 2] as i16) | ((buf[i + 3] as i16) << 8)
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));
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i += 4;
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}
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Ok(Some(i))
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}
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}
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}
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