David LeGare | 793d84b | 2022-03-02 16:21:10 +0000 | [diff] [blame] | 1 | //! `BufRead` pointer or `BufReader` owned. |
| 2 | |
| 3 | use std::cmp; |
| 4 | use std::io; |
| 5 | use std::io::BufRead; |
| 6 | use std::io::BufReader; |
| 7 | use std::io::Read; |
| 8 | use std::mem::MaybeUninit; |
| 9 | |
| 10 | use crate::misc::maybe_uninit_write_slice; |
| 11 | |
| 12 | /// Helper type to simplify `BufReadIter` implementation. |
| 13 | pub(crate) enum BufReadOrReader<'a> { |
| 14 | BufReader(BufReader<&'a mut dyn Read>), |
| 15 | BufRead(&'a mut dyn BufRead), |
| 16 | } |
| 17 | |
| 18 | impl<'a> Read for BufReadOrReader<'a> { |
| 19 | fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error> { |
| 20 | match self { |
| 21 | BufReadOrReader::BufReader(r) => r.read(buf), |
| 22 | BufReadOrReader::BufRead(r) => r.read(buf), |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, io::Error> { |
| 27 | match self { |
| 28 | BufReadOrReader::BufReader(r) => r.read_to_end(buf), |
| 29 | BufReadOrReader::BufRead(r) => r.read_to_end(buf), |
| 30 | } |
| 31 | } |
| 32 | |
| 33 | fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), io::Error> { |
| 34 | match self { |
| 35 | BufReadOrReader::BufReader(r) => r.read_exact(buf), |
| 36 | BufReadOrReader::BufRead(r) => r.read_exact(buf), |
| 37 | } |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | impl<'a> BufReadOrReader<'a> { |
| 42 | /// Similar to `read_exact` but reads into `MaybeUninit`. |
| 43 | pub(crate) fn read_exact_uninit( |
| 44 | &mut self, |
| 45 | buf: &mut [MaybeUninit<u8>], |
| 46 | ) -> Result<(), io::Error> { |
| 47 | let mut pos = 0; |
| 48 | while pos != buf.len() { |
| 49 | let fill_buf = match self { |
| 50 | BufReadOrReader::BufReader(r) => r.fill_buf()?, |
| 51 | BufReadOrReader::BufRead(r) => r.fill_buf()?, |
| 52 | }; |
| 53 | if fill_buf.is_empty() { |
| 54 | return Err(io::Error::new( |
| 55 | io::ErrorKind::UnexpectedEof, |
| 56 | "Unexpected end of file", |
| 57 | )); |
| 58 | } |
| 59 | let consume = cmp::min(fill_buf.len(), buf.len() - pos); |
| 60 | maybe_uninit_write_slice(&mut buf[pos..pos + consume], &fill_buf[..consume]); |
| 61 | match self { |
| 62 | BufReadOrReader::BufReader(r) => r.consume(consume), |
| 63 | BufReadOrReader::BufRead(r) => r.consume(consume), |
| 64 | } |
| 65 | pos += consume; |
| 66 | } |
| 67 | Ok(()) |
| 68 | } |
| 69 | } |
| 70 | |
| 71 | impl<'a> BufRead for BufReadOrReader<'a> { |
| 72 | fn fill_buf(&mut self) -> Result<&[u8], io::Error> { |
| 73 | match self { |
| 74 | BufReadOrReader::BufReader(r) => r.fill_buf(), |
| 75 | BufReadOrReader::BufRead(r) => r.fill_buf(), |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | fn consume(&mut self, amt: usize) { |
| 80 | match self { |
| 81 | BufReadOrReader::BufReader(r) => r.consume(amt), |
| 82 | BufReadOrReader::BufRead(r) => r.consume(amt), |
| 83 | } |
| 84 | } |
| 85 | } |