Skip to main content

generic_copy

alloc::io::copy::generic

Function generic_copy 

Source 
pub(super) fn generic_copy<R, W>(reader: &mut R, writer: &mut W) -> Result<u64>
where
    R: Read + ?Sized,
    W: Write + ?Sized,
🔬This is a nightly-only experimental API. (alloc_io #154046)
Expand description

The userspace read-write-loop implementation of io::copy that is used when OS-specific specializations for copy offloading are not available or not applicable.

This function is able to perform a mild amount of specialization based on the size of the reader and writer buffers, if they have any.

  • If reader’s buffer is large enough (>=DEFAULT_BUF_SIZE), and it is larger than writer’s buffer, copying will be controlled by R.
  • Otherwise, copying will be controlled by writer.

Currently, [u8], Vec<u8>, VecDeque<u8>, BufReader<T> and BufWriter<T> are specialized with.