Expand description
Efficiently insert line endings.
If you have a buffer full of data and want to insert any sort of regularly-spaced separator,
this will do it with a minimum of data copying. Commonly, this is to insert \n (see lf()) or \r\n (crlf()), but
any byte sequence can be used.
- Pick a line ending. For single byte separators, see
ByteLineEnding, or for two bytes,TwoByteLineEnding. For arbitrary byte slices, useSliceLineEnding. - Call
line_wrap. - Your data has been rearranged in place with the specified line ending inserted.
Examples
use line_wrap::*;
// suppose we have 80 bytes of data in a buffer and we want to wrap as per MIME.
// Buffer is large enough to hold line endings.
let mut data = vec![0; 82];
assert_eq!(2, line_wrap(&mut data, 80, 76, &crlf()));
// first line of zeroes
let mut expected_data = vec![0; 76];
// line ending
expected_data.extend_from_slice(b"\r\n");
// next line
expected_data.extend_from_slice(&[0, 0, 0, 0]);
assert_eq!(expected_data, data);Performance
On an i7 6850k:
- 10 byte input, 1 byte line length takes ~60ns (~160MiB/s)
- 100 byte input, 10 byte lines takes ~60ns (~1.6GiB/s)
- Startup costs dominate at these small lengths
- 1,000 byte input, 100 byte lines takes ~65ns (~15GiB/s)
- 10,000 byte input, 100 byte lines takes ~550ns (~17GiB/s)
- In general,
SliceLineEncodingis about 75% the speed of the fixed-length impls.
Naturally, try cargo +nightly bench on your hardware to get more representative data.
Structs
A single byte line ending.
A byte slice line ending.
A double byte line ending.
Traits
Writes line endings.