1 use super::{repeat, Cursor, ReadBuf, SeekFrom};
2 use crate::cmp::{self, min};
3 use crate::io::{self, IoSlice, IoSliceMut};
4 use crate::io::{BufRead, BufReader, Read, Seek, Write};
5 use crate::mem::MaybeUninit;
9 #[cfg_attr(target_os = "emscripten", ignore)]
11 let mut buf = Cursor::new(&b"12"[..]);
12 let mut v = Vec::new();
13 assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 2);
16 let mut buf = Cursor::new(&b"1233"[..]);
17 let mut v = Vec::new();
18 assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 3);
19 assert_eq!(v, b"123");
21 assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 1);
24 assert_eq!(buf.read_until(b'3', &mut v).unwrap(), 0);
30 let buf = Cursor::new(&b"12"[..]);
31 let mut s = buf.split(b'3');
32 assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
33 assert!(s.next().is_none());
35 let buf = Cursor::new(&b"1233"[..]);
36 let mut s = buf.split(b'3');
37 assert_eq!(s.next().unwrap().unwrap(), vec![b'1', b'2']);
38 assert_eq!(s.next().unwrap().unwrap(), vec![]);
39 assert!(s.next().is_none());
44 let mut buf = Cursor::new(&b"12"[..]);
45 let mut v = String::new();
46 assert_eq!(buf.read_line(&mut v).unwrap(), 2);
49 let mut buf = Cursor::new(&b"12\n\n"[..]);
50 let mut v = String::new();
51 assert_eq!(buf.read_line(&mut v).unwrap(), 3);
52 assert_eq!(v, "12\n");
54 assert_eq!(buf.read_line(&mut v).unwrap(), 1);
57 assert_eq!(buf.read_line(&mut v).unwrap(), 0);
63 let buf = Cursor::new(&b"12\r"[..]);
64 let mut s = buf.lines();
65 assert_eq!(s.next().unwrap().unwrap(), "12\r".to_string());
66 assert!(s.next().is_none());
68 let buf = Cursor::new(&b"12\r\n\n"[..]);
69 let mut s = buf.lines();
70 assert_eq!(s.next().unwrap().unwrap(), "12".to_string());
71 assert_eq!(s.next().unwrap().unwrap(), "".to_string());
72 assert!(s.next().is_none());
76 fn buf_read_has_data_left() {
77 let mut buf = Cursor::new(&b"abcd"[..]);
78 assert!(buf.has_data_left().unwrap());
79 buf.read_exact(&mut [0; 2]).unwrap();
80 assert!(buf.has_data_left().unwrap());
81 buf.read_exact(&mut [0; 2]).unwrap();
82 assert!(!buf.has_data_left().unwrap());
87 let mut c = Cursor::new(&b""[..]);
88 let mut v = Vec::new();
89 assert_eq!(c.read_to_end(&mut v).unwrap(), 0);
92 let mut c = Cursor::new(&b"1"[..]);
93 let mut v = Vec::new();
94 assert_eq!(c.read_to_end(&mut v).unwrap(), 1);
97 let cap = 1024 * 1024;
98 let data = (0..cap).map(|i| (i / 3) as u8).collect::<Vec<_>>();
99 let mut v = Vec::new();
100 let (a, b) = data.split_at(data.len() / 2);
101 assert_eq!(Cursor::new(a).read_to_end(&mut v).unwrap(), a.len());
102 assert_eq!(Cursor::new(b).read_to_end(&mut v).unwrap(), b.len());
107 fn read_to_string() {
108 let mut c = Cursor::new(&b""[..]);
109 let mut v = String::new();
110 assert_eq!(c.read_to_string(&mut v).unwrap(), 0);
113 let mut c = Cursor::new(&b"1"[..]);
114 let mut v = String::new();
115 assert_eq!(c.read_to_string(&mut v).unwrap(), 1);
118 let mut c = Cursor::new(&b"\xff"[..]);
119 let mut v = String::new();
120 assert!(c.read_to_string(&mut v).is_err());
125 let mut buf = [0; 4];
127 let mut c = Cursor::new(&b""[..]);
128 assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
130 let mut c = Cursor::new(&b"123"[..]).chain(Cursor::new(&b"456789"[..]));
131 c.read_exact(&mut buf).unwrap();
132 assert_eq!(&buf, b"1234");
133 c.read_exact(&mut buf).unwrap();
134 assert_eq!(&buf, b"5678");
135 assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
139 fn read_exact_slice() {
140 let mut buf = [0; 4];
142 let mut c = &b""[..];
143 assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
145 let mut c = &b"123"[..];
146 assert_eq!(c.read_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
147 // make sure the optimized (early returning) method is being used
148 assert_eq!(&buf, &[0; 4]);
150 let mut c = &b"1234"[..];
151 c.read_exact(&mut buf).unwrap();
152 assert_eq!(&buf, b"1234");
154 let mut c = &b"56789"[..];
155 c.read_exact(&mut buf).unwrap();
156 assert_eq!(&buf, b"5678");
161 fn read_buf_exact() {
162 let mut buf = [0; 4];
163 let mut buf = ReadBuf::new(&mut buf);
165 let mut c = Cursor::new(&b""[..]);
166 assert_eq!(c.read_buf_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
168 let mut c = Cursor::new(&b"123456789"[..]);
169 c.read_buf_exact(&mut buf).unwrap();
170 assert_eq!(buf.filled(), b"1234");
174 c.read_buf_exact(&mut buf).unwrap();
175 assert_eq!(buf.filled(), b"5678");
179 assert_eq!(c.read_buf_exact(&mut buf).unwrap_err().kind(), io::ErrorKind::UnexpectedEof);
187 fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
188 Err(io::const_io_error!(io::ErrorKind::Other, ""))
192 fn fill_buf(&mut self) -> io::Result<&[u8]> {
193 Err(io::const_io_error!(io::ErrorKind::Other, ""))
195 fn consume(&mut self, _amt: usize) {}
198 let mut buf = [0; 1];
199 assert_eq!(0, R.take(0).read(&mut buf).unwrap());
200 assert_eq!(b"", R.take(0).fill_buf().unwrap());
203 fn cmp_bufread<Br1: BufRead, Br2: BufRead>(mut br1: Br1, mut br2: Br2, exp: &[u8]) {
204 let mut cat = Vec::new();
207 let buf1 = br1.fill_buf().unwrap();
208 let buf2 = br2.fill_buf().unwrap();
209 let minlen = if buf1.len() < buf2.len() { buf1.len() } else { buf2.len() };
210 assert_eq!(buf1[..minlen], buf2[..minlen]);
211 cat.extend_from_slice(&buf1[..minlen]);
217 br1.consume(consume);
218 br2.consume(consume);
220 assert_eq!(br1.fill_buf().unwrap().len(), 0);
221 assert_eq!(br2.fill_buf().unwrap().len(), 0);
222 assert_eq!(&cat[..], &exp[..])
227 let testdata = b"ABCDEFGHIJKL";
229 (&testdata[..3]).chain(&testdata[3..6]).chain(&testdata[6..9]).chain(&testdata[9..]);
230 let chain2 = (&testdata[..4]).chain(&testdata[4..8]).chain(&testdata[8..]);
231 cmp_bufread(chain1, chain2, &testdata[..]);
235 fn bufreader_size_hint() {
236 let testdata = b"ABCDEFGHIJKL";
237 let mut buf_reader = BufReader::new(&testdata[..]);
238 assert_eq!(buf_reader.buffer().len(), 0);
240 let buffer_length = testdata.len();
241 buf_reader.fill_buf().unwrap();
243 // Check that size hint matches buffer contents
244 let mut buffered_bytes = buf_reader.bytes();
245 let (lower_bound, _upper_bound) = buffered_bytes.size_hint();
246 assert_eq!(lower_bound, buffer_length);
248 // Check that size hint matches buffer contents after advancing
249 buffered_bytes.next().unwrap().unwrap();
250 let (lower_bound, _upper_bound) = buffered_bytes.size_hint();
251 assert_eq!(lower_bound, buffer_length - 1);
255 fn empty_size_hint() {
256 let size_hint = io::empty().bytes().size_hint();
257 assert_eq!(size_hint, (0, Some(0)));
261 fn slice_size_hint() {
262 let size_hint = (&[1, 2, 3]).bytes().size_hint();
263 assert_eq!(size_hint, (3, Some(3)));
267 fn take_size_hint() {
268 let size_hint = (&[1, 2, 3]).take(2).bytes().size_hint();
269 assert_eq!(size_hint, (2, Some(2)));
271 let size_hint = (&[1, 2, 3]).take(4).bytes().size_hint();
272 assert_eq!(size_hint, (3, Some(3)));
274 let size_hint = io::repeat(0).take(3).bytes().size_hint();
275 assert_eq!(size_hint, (3, Some(3)));
279 fn chain_empty_size_hint() {
280 let chain = io::empty().chain(io::empty());
281 let size_hint = chain.bytes().size_hint();
282 assert_eq!(size_hint, (0, Some(0)));
286 fn chain_size_hint() {
287 let testdata = b"ABCDEFGHIJKL";
288 let mut buf_reader_1 = BufReader::new(&testdata[..6]);
289 let mut buf_reader_2 = BufReader::new(&testdata[6..]);
291 buf_reader_1.fill_buf().unwrap();
292 buf_reader_2.fill_buf().unwrap();
294 let chain = buf_reader_1.chain(buf_reader_2);
295 let size_hint = chain.bytes().size_hint();
296 assert_eq!(size_hint, (testdata.len(), Some(testdata.len())));
300 fn chain_zero_length_read_is_not_eof() {
303 let mut s = String::new();
304 let mut chain = (&a[..]).chain(&b[..]);
305 chain.read(&mut []).unwrap();
306 chain.read_to_string(&mut s).unwrap();
311 #[cfg_attr(target_os = "emscripten", ignore)]
312 fn bench_read_to_end(b: &mut test::Bencher) {
314 let mut lr = repeat(1).take(10000000);
315 let mut vec = Vec::with_capacity(1024);
316 super::default_read_to_end(&mut lr, &mut vec)
321 fn seek_len() -> io::Result<()> {
322 let mut c = Cursor::new(vec![0; 15]);
323 assert_eq!(c.stream_len()?, 15);
325 c.seek(SeekFrom::End(0))?;
326 let old_pos = c.stream_position()?;
327 assert_eq!(c.stream_len()?, 15);
328 assert_eq!(c.stream_position()?, old_pos);
330 c.seek(SeekFrom::Start(7))?;
331 c.seek(SeekFrom::Current(2))?;
332 let old_pos = c.stream_position()?;
333 assert_eq!(c.stream_len()?, 15);
334 assert_eq!(c.stream_position()?, old_pos);
340 fn seek_position() -> io::Result<()> {
341 // All `asserts` are duplicated here to make sure the method does not
342 // change anything about the seek state.
343 let mut c = Cursor::new(vec![0; 15]);
344 assert_eq!(c.stream_position()?, 0);
345 assert_eq!(c.stream_position()?, 0);
347 c.seek(SeekFrom::End(0))?;
348 assert_eq!(c.stream_position()?, 15);
349 assert_eq!(c.stream_position()?, 15);
351 c.seek(SeekFrom::Start(7))?;
352 c.seek(SeekFrom::Current(2))?;
353 assert_eq!(c.stream_position()?, 9);
354 assert_eq!(c.stream_position()?, 9);
356 c.seek(SeekFrom::End(-3))?;
357 c.seek(SeekFrom::Current(1))?;
358 c.seek(SeekFrom::Current(-5))?;
359 assert_eq!(c.stream_position()?, 8);
360 assert_eq!(c.stream_position()?, 8);
363 assert_eq!(c.stream_position()?, 0);
364 assert_eq!(c.stream_position()?, 0);
369 // A simple example reader which uses the default implementation of
371 struct ExampleSliceReader<'a> {
375 impl<'a> Read for ExampleSliceReader<'a> {
376 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
377 let len = cmp::min(self.slice.len(), buf.len());
378 buf[..len].copy_from_slice(&self.slice[..len]);
379 self.slice = &self.slice[len..];
385 fn test_read_to_end_capacity() -> io::Result<()> {
386 let input = &b"foo"[..];
388 // read_to_end() takes care not to over-allocate when a buffer is the
389 // exact size needed.
390 let mut vec1 = Vec::with_capacity(input.len());
391 ExampleSliceReader { slice: input }.read_to_end(&mut vec1)?;
392 assert_eq!(vec1.len(), input.len());
393 assert_eq!(vec1.capacity(), input.len(), "did not allocate more");
399 fn io_slice_mut_advance_slices() {
400 let mut buf1 = [1; 8];
401 let mut buf2 = [2; 16];
402 let mut buf3 = [3; 8];
403 let mut bufs = &mut [
404 IoSliceMut::new(&mut buf1),
405 IoSliceMut::new(&mut buf2),
406 IoSliceMut::new(&mut buf3),
409 // Only in a single buffer..
410 IoSliceMut::advance_slices(&mut bufs, 1);
411 assert_eq!(bufs[0].deref(), [1; 7].as_ref());
412 assert_eq!(bufs[1].deref(), [2; 16].as_ref());
413 assert_eq!(bufs[2].deref(), [3; 8].as_ref());
415 // Removing a buffer, leaving others as is.
416 IoSliceMut::advance_slices(&mut bufs, 7);
417 assert_eq!(bufs[0].deref(), [2; 16].as_ref());
418 assert_eq!(bufs[1].deref(), [3; 8].as_ref());
420 // Removing a buffer and removing from the next buffer.
421 IoSliceMut::advance_slices(&mut bufs, 18);
422 assert_eq!(bufs[0].deref(), [3; 6].as_ref());
427 fn io_slice_mut_advance_slices_empty_slice() {
428 let mut empty_bufs = &mut [][..];
429 IoSliceMut::advance_slices(&mut empty_bufs, 1);
434 fn io_slice_mut_advance_slices_beyond_total_length() {
435 let mut buf1 = [1; 8];
436 let mut bufs = &mut [IoSliceMut::new(&mut buf1)][..];
438 IoSliceMut::advance_slices(&mut bufs, 9);
439 assert!(bufs.is_empty());
443 fn io_slice_advance_slices() {
447 let mut bufs = &mut [IoSlice::new(&buf1), IoSlice::new(&buf2), IoSlice::new(&buf3)][..];
449 // Only in a single buffer..
450 IoSlice::advance_slices(&mut bufs, 1);
451 assert_eq!(bufs[0].deref(), [1; 7].as_ref());
452 assert_eq!(bufs[1].deref(), [2; 16].as_ref());
453 assert_eq!(bufs[2].deref(), [3; 8].as_ref());
455 // Removing a buffer, leaving others as is.
456 IoSlice::advance_slices(&mut bufs, 7);
457 assert_eq!(bufs[0].deref(), [2; 16].as_ref());
458 assert_eq!(bufs[1].deref(), [3; 8].as_ref());
460 // Removing a buffer and removing from the next buffer.
461 IoSlice::advance_slices(&mut bufs, 18);
462 assert_eq!(bufs[0].deref(), [3; 6].as_ref());
467 fn io_slice_advance_slices_empty_slice() {
468 let mut empty_bufs = &mut [][..];
469 IoSlice::advance_slices(&mut empty_bufs, 1);
474 fn io_slice_advance_slices_beyond_total_length() {
476 let mut bufs = &mut [IoSlice::new(&buf1)][..];
478 IoSlice::advance_slices(&mut bufs, 9);
479 assert!(bufs.is_empty());
482 /// Create a new writer that reads from at most `n_bufs` and reads
483 /// `per_call` bytes (in total) per call to write.
484 fn test_writer(n_bufs: usize, per_call: usize) -> TestWriter {
485 TestWriter { n_bufs, per_call, written: Vec::new() }
494 impl Write for TestWriter {
495 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
496 self.write_vectored(&[IoSlice::new(buf)])
499 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
500 let mut left = self.per_call;
502 for buf in bufs.iter().take(self.n_bufs) {
503 let n = min(left, buf.len());
504 self.written.extend_from_slice(&buf[0..n]);
511 fn flush(&mut self) -> io::Result<()> {
517 fn test_writer_read_from_one_buf() {
518 let mut writer = test_writer(1, 2);
520 assert_eq!(writer.write(&[]).unwrap(), 0);
521 assert_eq!(writer.write_vectored(&[]).unwrap(), 0);
523 // Read at most 2 bytes.
524 assert_eq!(writer.write(&[1, 1, 1]).unwrap(), 2);
525 let bufs = &[IoSlice::new(&[2, 2, 2])];
526 assert_eq!(writer.write_vectored(bufs).unwrap(), 2);
528 // Only read from first buf.
529 let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4, 4])];
530 assert_eq!(writer.write_vectored(bufs).unwrap(), 1);
532 assert_eq!(writer.written, &[1, 1, 2, 2, 3]);
536 fn test_writer_read_from_multiple_bufs() {
537 let mut writer = test_writer(3, 3);
539 // Read at most 3 bytes from two buffers.
540 let bufs = &[IoSlice::new(&[1]), IoSlice::new(&[2, 2, 2])];
541 assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
543 // Read at most 3 bytes from three buffers.
544 let bufs = &[IoSlice::new(&[3]), IoSlice::new(&[4]), IoSlice::new(&[5, 5])];
545 assert_eq!(writer.write_vectored(bufs).unwrap(), 3);
547 assert_eq!(writer.written, &[1, 2, 2, 3, 4, 5]);
551 fn test_write_all_vectored() {
552 #[rustfmt::skip] // Becomes unreadable otherwise.
553 let tests: Vec<(_, &'static [u8])> = vec![
555 (vec![IoSlice::new(&[]), IoSlice::new(&[])], &[]),
556 (vec![IoSlice::new(&[1])], &[1]),
557 (vec![IoSlice::new(&[1, 2])], &[1, 2]),
558 (vec![IoSlice::new(&[1, 2, 3])], &[1, 2, 3]),
559 (vec![IoSlice::new(&[1, 2, 3, 4])], &[1, 2, 3, 4]),
560 (vec![IoSlice::new(&[1, 2, 3, 4, 5])], &[1, 2, 3, 4, 5]),
561 (vec![IoSlice::new(&[1]), IoSlice::new(&[2])], &[1, 2]),
562 (vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2])], &[1, 2, 2]),
563 (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2])], &[1, 1, 2, 2]),
564 (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
565 (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 2, 2, 2]),
566 (vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2])], &[1, 1, 1, 2, 2, 2]),
567 (vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 2, 2, 2, 2]),
568 (vec![IoSlice::new(&[1, 1, 1, 1]), IoSlice::new(&[2, 2, 2, 2])], &[1, 1, 1, 1, 2, 2, 2, 2]),
569 (vec![IoSlice::new(&[1]), IoSlice::new(&[2]), IoSlice::new(&[3])], &[1, 2, 3]),
570 (vec![IoSlice::new(&[1, 1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3])], &[1, 1, 2, 2, 3, 3]),
571 (vec![IoSlice::new(&[1]), IoSlice::new(&[2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 2, 2, 3, 3, 3]),
572 (vec![IoSlice::new(&[1, 1, 1]), IoSlice::new(&[2, 2, 2]), IoSlice::new(&[3, 3, 3])], &[1, 1, 1, 2, 2, 2, 3, 3, 3]),
575 let writer_configs = &[(1, 1), (1, 2), (1, 3), (2, 2), (2, 3), (3, 3)];
577 for (n_bufs, per_call) in writer_configs.iter().copied() {
578 for (mut input, wanted) in tests.clone().into_iter() {
579 let mut writer = test_writer(n_bufs, per_call);
580 assert!(writer.write_all_vectored(&mut *input).is_ok());
581 assert_eq!(&*writer.written, &*wanted);
588 #[should_panic = "number of read bytes exceeds limit"]
589 fn test_take_wrong_length() {
590 struct LieAboutSize(bool);
592 impl Read for LieAboutSize {
593 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
594 // Lie about the read size at first time of read.
595 if core::mem::take(&mut self.0) { Ok(buf.len() + 1) } else { Ok(buf.len()) }
599 let mut buffer = vec![0; 4];
600 let mut reader = LieAboutSize(true).take(4);
601 // Primed the `Limit` by lying about the read size.
602 let _ = reader.read(&mut buffer[..]);
606 fn bench_take_read(b: &mut test::Bencher) {
608 let mut buf = [0; 64];
610 [255; 128].take(64).read(&mut buf).unwrap();
615 fn bench_take_read_buf(b: &mut test::Bencher) {
617 let mut buf = [MaybeUninit::uninit(); 64];
619 let mut rbuf = ReadBuf::uninit(&mut buf);
621 [255; 128].take(64).read_buf(&mut rbuf).unwrap();