| @@ -99,7 +99,10 @@ impl<R: Read> BufReader { |
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impl<R: Read + ?Sized> BufReader<R> { |
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/// Attempt to look ahead `n` bytes. |
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/// |
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- /// `n` must be less than `capacity`. |
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+ /// `n` must be less than or equal to `capacity`. |
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+ /// |
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+ /// the returned slice may be less than `n` bytes long if |
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+ /// end of file is reached. |
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/// |
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/// ## Examples |
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/// |
| @@ -117,6 +120,7 @@ impl<R: Read + ?Sized> BufReader { |
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/// let mut s = String::new(); |
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/// rdr.read_to_string(&mut s).unwrap(); |
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/// assert_eq!(&s, "hello"); |
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+ /// assert_eq!(rdr.peek(1).unwrap().len(), 0); |
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/// ``` |
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#[unstable(feature = "bufreader_peek", issue = "128405")] |
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pub fn peek(&mut self, n: usize) -> io::Result<&[u8]> { |
| @@ -125,7 +129,11 @@ impl<R: Read + ?Sized> BufReader { |
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if self.buf.pos() > 0 { |
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self.buf.backshift(); |
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} |
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-self.buf.read_more(&mut self.inner)?; |
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+let new = self.buf.read_more(&mut self.inner)?; |
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+if new == 0 { |
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+// end of file, no more bytes to read |
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+return Ok(&self.buf.buffer()[..]); |
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+} |
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debug_assert_eq!(self.buf.pos(), 0); |
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} |
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Ok(&self.buf.buffer()[..n]) |