futuresdr 0.0.41

use crate::runtime::dev::prelude::*;

/// Repeatedly apply a function to generate samples.
///
/// # Stream Inputs
///
/// No stream inputs.
///
/// # Stream Outputs
///
/// `output`: Generated output samples.
///
/// # Usage
/// ```
/// use futuresdr::blocks::Source;
///
/// // Generate zeroes
/// let source = Source::new(|| { 0.0f32 });
/// ```
#[derive(Block)]
pub struct Source<F, A, O = DefaultCpuWriter<A>>
where
    F: FnMut() -> A + Send + 'static,
    A: Send + 'static,
    O: CpuBufferWriter<Item = A>,
{
    #[output]
    output: O,
    f: F,
}

impl<F, A> Source<F, A, DefaultCpuWriter<A>>
where
    F: FnMut() -> A + Send + 'static,
    A: CpuSample,
{
    /// Create Source block with the default stream buffer.
    pub fn new(f: F) -> Self {
        Self::with_buffer(f)
    }
}

impl<F, A, O> Source<F, A, O>
where
    F: FnMut() -> A + Send + 'static,
    A: Send + 'static,
    O: CpuBufferWriter<Item = A>,
{
    /// Create Source block with a custom stream buffer.
    pub fn with_buffer(f: F) -> Self {
        Self {
            output: O::default(),
            f,
        }
    }
}

#[doc(hidden)]
impl<F, A, O> Kernel for Source<F, A, O>
where
    F: FnMut() -> A + Send + 'static,
    A: Send + 'static,
    O: CpuBufferWriter<Item = A>,
{
    async fn work(
        &mut self,
        _io: &mut WorkIo,
        _mo: &mut MessageOutputs,
        _meta: &mut BlockMeta,
    ) -> Result<()> {
        let o = self.output.slice();
        let o_len = o.len();

        for v in o.iter_mut() {
            *v = (self.f)();
        }

        self.output.produce(o_len);
        Ok(())
    }
}