//! Binary / byte maniuplation
use bytes::BufMut;

/// Concatenate an iterator of byte slices into a buffer.
///
/// # Returns
/// The number of bytes written
/// # Panics
/// If the buffer cannot hold all the slices
pub fn collect_slices_into<B: BufMut + ?Sized, I, T>(into: &mut B, from: I) -> usize
where I: IntoIterator<Item=T>,
      T: AsRef<[u8]>
{
    let mut done =0;
    for slice in from.into_iter()
    {
	let s = slice.as_ref();
	into.put_slice(s);
	done+=s.len();
    }
    done
}

/// Collect an iterator of byte slices into a new exact-size buffer.
///
/// # Returns
/// The number of bytes written, and the new array
///
/// # Panics
/// If the total bytes in all slices exceeds `SIZE`.
pub fn collect_slices_exact<T, I, const SIZE: usize>(from: I) -> (usize, [u8; SIZE])
where I: IntoIterator<Item=T>,
      T: AsRef<[u8]>
{
    let mut output = [0u8; SIZE];
    (collect_slices_into(&mut &mut output[..], from), output)
}