Struct alsa::pcm::IO

pub struct IO<'a, S: Copy>(_, _);

Sample format dependent struct for reading from and writing data to a PCM. Also implements std::io::Read and std::io::Write.

Note: Only one IO object is allowed in scope at a time (for mmap safety).

Methods

impl<'a, S: Copy> IO<'a, S>

pub fn writei(&self, buf: &[S]) -> Result<usize>

On success, returns number of frames written. (Multiply with number of channels to get number of items in buf successfully written.)

pub fn readi(&self, buf: &mut [S]) -> Result<usize>

On success, returns number of frames read. (Multiply with number of channels to get number of items in buf successfully read.)

pub fn mmap<F: FnOnce(&mut [S]) -> usize>(
    &self,
    frames: usize,
    func: F
) -> Result<usize>

Wrapper around snd_pcm_mmap_begin and snd_pcm_mmap_commit.

You can read/write into the sound card's buffer during the call to the closure. According to alsa-lib docs, you should call avail_update before calling this function.

All calculations are in frames, i e, the closure should return number of frames processed. Also, there might not be as many frames to read/write as requested, and there can even be an empty buffer supplied to the closure.

Note: This function works only with interleaved access mode.

Trait Implementations

impl<'a, S: Copy> Drop for IO<'a, S>

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, S: Copy> Read for IO<'a, S>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

unsafe fn initializer(&self) -> Initializer

🔬 This is a nightly-only experimental API. (read_initializer)

Determines if this Reader can work with buffers of uninitialized memory.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an [Iterator] over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: Read, 

Creates an adaptor which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

Creates an adaptor which will read at most limit bytes from it.

impl<'a, S: Copy> Write for IO<'a, S>

fn write(&mut self, buf: &[u8]) -> Result<usize>

Write a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flush this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_fmt(&mut self, fmt: Arguments) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

Creates a "by reference" adaptor for this instance of Write.