1 use crate::cmp::{max, min};
2 use crate::io::prelude::*;
4 copy, empty, repeat, sink, BufWriter, Empty, ReadBuf, Repeat, Result, SeekFrom, Sink,
8 use crate::mem::MaybeUninit;
12 let mut r = repeat(0).take(4);
14 assert_eq!(copy(&mut r, &mut w).unwrap(), 4);
16 let mut r = repeat(0).take(1 << 17);
17 assert_eq!(copy(&mut r as &mut dyn Read, &mut w as &mut dyn Write).unwrap(), 1 << 17);
23 observed_buffer: usize,
26 impl Read for ShortReader {
27 fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
28 let bytes = min(self.cap, self.read_size);
30 self.observed_buffer = max(self.observed_buffer, buf.len());
35 struct WriteObserver {
36 observed_buffer: usize,
39 impl Write for WriteObserver {
40 fn write(&mut self, buf: &[u8]) -> Result<usize> {
41 self.observed_buffer = max(self.observed_buffer, buf.len());
45 fn flush(&mut self) -> Result<()> {
51 fn copy_specializes_bufwriter() {
53 let buf_sz = 16 * 1024;
54 let mut r = ShortReader { cap, observed_buffer: 0, read_size: 1337 };
55 let mut w = BufWriter::with_capacity(buf_sz, WriteObserver { observed_buffer: 0 });
57 copy(&mut r, &mut w).unwrap(),
59 "expected the whole capacity to be copied"
61 assert_eq!(r.observed_buffer, buf_sz, "expected a large buffer to be provided to the reader");
62 assert!(w.get_mut().observed_buffer > DEFAULT_BUF_SIZE, "expected coalesced writes");
68 assert_eq!(s.write(&[]).unwrap(), 0);
69 assert_eq!(s.write(&[0]).unwrap(), 1);
70 assert_eq!(s.write(&[0; 1024]).unwrap(), 1024);
71 assert_eq!(s.by_ref().write(&[0; 1024]).unwrap(), 1024);
77 assert_eq!(e.read(&mut []).unwrap(), 0);
78 assert_eq!(e.read(&mut [0]).unwrap(), 0);
79 assert_eq!(e.read(&mut [0; 1024]).unwrap(), 0);
80 assert_eq!(e.by_ref().read(&mut [0; 1024]).unwrap(), 0);
83 let mut buf = ReadBuf::uninit(&mut buf);
84 e.read_buf(&mut buf).unwrap();
85 assert_eq!(buf.filled_len(), 0);
86 assert_eq!(buf.initialized_len(), 0);
88 let mut buf = [MaybeUninit::uninit()];
89 let mut buf = ReadBuf::uninit(&mut buf);
90 e.read_buf(&mut buf).unwrap();
91 assert_eq!(buf.filled_len(), 0);
92 assert_eq!(buf.initialized_len(), 0);
94 let mut buf = [MaybeUninit::uninit(); 1024];
95 let mut buf = ReadBuf::uninit(&mut buf);
96 e.read_buf(&mut buf).unwrap();
97 assert_eq!(buf.filled_len(), 0);
98 assert_eq!(buf.initialized_len(), 0);
100 let mut buf = [MaybeUninit::uninit(); 1024];
101 let mut buf = ReadBuf::uninit(&mut buf);
102 e.by_ref().read_buf(&mut buf).unwrap();
103 assert_eq!(buf.filled_len(), 0);
104 assert_eq!(buf.initialized_len(), 0);
110 assert!(matches!(e.seek(SeekFrom::Start(0)), Ok(0)));
111 assert!(matches!(e.seek(SeekFrom::Start(1)), Ok(0)));
112 assert!(matches!(e.seek(SeekFrom::Start(u64::MAX)), Ok(0)));
114 assert!(matches!(e.seek(SeekFrom::End(i64::MIN)), Ok(0)));
115 assert!(matches!(e.seek(SeekFrom::End(-1)), Ok(0)));
116 assert!(matches!(e.seek(SeekFrom::End(0)), Ok(0)));
117 assert!(matches!(e.seek(SeekFrom::End(1)), Ok(0)));
118 assert!(matches!(e.seek(SeekFrom::End(i64::MAX)), Ok(0)));
120 assert!(matches!(e.seek(SeekFrom::Current(i64::MIN)), Ok(0)));
121 assert!(matches!(e.seek(SeekFrom::Current(-1)), Ok(0)));
122 assert!(matches!(e.seek(SeekFrom::Current(0)), Ok(0)));
123 assert!(matches!(e.seek(SeekFrom::Current(1)), Ok(0)));
124 assert!(matches!(e.seek(SeekFrom::Current(i64::MAX)), Ok(0)));
128 fn repeat_repeats() {
129 let mut r = repeat(4);
130 let mut b = [0; 1024];
131 assert_eq!(r.read(&mut b).unwrap(), 1024);
132 assert!(b.iter().all(|b| *b == 4));
136 fn take_some_bytes() {
137 assert_eq!(repeat(4).take(100).bytes().count(), 100);
138 assert_eq!(repeat(4).take(100).bytes().next().unwrap().unwrap(), 4);
139 assert_eq!(repeat(1).take(10).chain(repeat(2).take(10)).bytes().count(), 20);
144 const _: Empty = empty();
145 const _: Repeat = repeat(b'c');
146 const _: Sink = sink();