Rollup merge of #132039 - a1phyr:vecdeque_read_exact, r=Noratrieb · qinheping/verify-rust-std@e62b2cc (original) (raw)
`@@ -453,6 +453,29 @@ impl<A: Allocator> Read for VecDeque<u8, A> {
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`Ok(n)
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`}
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fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
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let (front, back) = self.as_slices();
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// Use only the front buffer if it is big enough to fill buf, else use
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// the back buffer too.
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match buf.split_at_mut_checked(front.len()) {
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None => buf.copy_from_slice(&front[..buf.len()]),
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Some((buf_front, buf_back)) => match back.split_at_checked(buf_back.len()) {
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Some((back, _)) => {
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buf_front.copy_from_slice(front);
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buf_back.copy_from_slice(back);
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}
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None => {
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self.clear();
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return Err(io::Error::READ_EXACT_EOF);
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}
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},
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}
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self.drain(..buf.len());
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Ok(())
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}
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`#[inline]
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`fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
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`let (ref mut front, _) = self.as_slices();
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`@@ -462,6 +485,29 @@ impl<A: Allocator> Read for VecDeque<u8, A> {
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`Ok(())
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`}
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fn read_buf_exact(&mut self, mut cursor: BorrowedCursor<'_>) -> io::Result<()> {
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let len = cursor.capacity();
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let (front, back) = self.as_slices();
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match front.split_at_checked(cursor.capacity()) {
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Some((front, _)) => cursor.append(front),
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None => {
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cursor.append(front);
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match back.split_at_checked(cursor.capacity()) {
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Some((back, _)) => cursor.append(back),
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None => {
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cursor.append(back);
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self.clear();
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return Err(io::Error::READ_EXACT_EOF);
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}
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}
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}
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}
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self.drain(..len);
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Ok(())
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}
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`#[inline]
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`fn read_to_end(&mut self, buf: &mut Vec) -> io::Result {
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`// The total len is known upfront so we can reserve it in a single call.
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