Initialize memory for BufferedReader buffer
It's passed to the underlying reader, so uninitialized memory == sad times. We might want to shrink the default buffer size as well. 64k is pretty huge. Java uses 8k by default, and Go uses 4k for reference.
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@ -15,7 +15,7 @@
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use cmp;
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use fmt;
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use io::{Reader, Writer, Stream, Buffer, DEFAULT_BUF_SIZE, IoResult};
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use iter::{IteratorExt, ExactSizeIterator};
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use iter::{IteratorExt, ExactSizeIterator, repeat};
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use ops::Drop;
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use option::Option;
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use option::Option::{Some, None};
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@ -62,17 +62,11 @@ impl<R> fmt::Show for BufferedReader<R> where R: fmt::Show {
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impl<R: Reader> BufferedReader<R> {
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/// Creates a new `BufferedReader` with the specified buffer capacity
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pub fn with_capacity(cap: uint, inner: R) -> BufferedReader<R> {
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// It's *much* faster to create an uninitialized buffer than it is to
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// fill everything in with 0. This buffer is entirely an implementation
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// detail and is never exposed, so we're safe to not initialize
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// everything up-front. This allows creation of BufferedReader instances
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// to be very cheap (large mallocs are not nearly as expensive as large
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// callocs).
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let mut buf = Vec::with_capacity(cap);
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unsafe { buf.set_len(cap); }
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BufferedReader {
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inner: inner,
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buf: buf,
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// We can't use the same trick here as we do for BufferedWriter,
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// since this memory is visible to the inner Reader.
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buf: repeat(0).take(cap).collect(),
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pos: 0,
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cap: 0,
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}
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@ -166,7 +160,12 @@ impl<W> fmt::Show for BufferedWriter<W> where W: fmt::Show {
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impl<W: Writer> BufferedWriter<W> {
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/// Creates a new `BufferedWriter` with the specified buffer capacity
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pub fn with_capacity(cap: uint, inner: W) -> BufferedWriter<W> {
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// See comments in BufferedReader for why this uses unsafe code.
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// It's *much* faster to create an uninitialized buffer than it is to
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// fill everything in with 0. This buffer is entirely an implementation
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// detail and is never exposed, so we're safe to not initialize
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// everything up-front. This allows creation of BufferedWriter instances
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// to be very cheap (large mallocs are not nearly as expensive as large
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// callocs).
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let mut buf = Vec::with_capacity(cap);
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unsafe { buf.set_len(cap); }
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BufferedWriter {
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