diff options
author | Roger Peppe <rogpeppe@gmail.com> | 2010-12-07 14:54:15 -0500 |
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committer | Russ Cox <rsc@golang.org> | 2010-12-07 14:54:15 -0500 |
commit | 24a78a026d0efd181f5b645dfb4622c826d9207a (patch) | |
tree | 984fed871fce83bf7ff77e00ae163601c53d3393 | |
parent | cf6c2121979dacdb712c5ec9124043a8e6acf89e (diff) | |
download | go-24a78a026d0efd181f5b645dfb4622c826d9207a.tar.gz go-24a78a026d0efd181f5b645dfb4622c826d9207a.zip |
bufio: make Reader.Read implement io.Reader semantics
R=rsc
CC=golang-dev
https://golang.org/cl/3395042
-rw-r--r-- | src/pkg/bufio/bufio.go | 67 |
1 files changed, 34 insertions, 33 deletions
diff --git a/src/pkg/bufio/bufio.go b/src/pkg/bufio/bufio.go index 4e9f1cf3e4..fc4127a940 100644 --- a/src/pkg/bufio/bufio.go +++ b/src/pkg/bufio/bufio.go @@ -128,43 +128,44 @@ func (b *Reader) Peek(n int) ([]byte, os.Error) { // Read reads data into p. // It returns the number of bytes read into p. -// If nn < len(p), also returns an error explaining -// why the read is short. At EOF, the count will be -// zero and err will be os.EOF. -func (b *Reader) Read(p []byte) (nn int, err os.Error) { - nn = 0 - for len(p) > 0 { - n := len(p) - if b.w == b.r { - if b.err != nil { - return nn, b.err - } - if len(p) >= len(b.buf) { - // Large read, empty buffer. - // Read directly into p to avoid copy. - n, b.err = b.rd.Read(p) - if n > 0 { - b.lastByte = int(p[n-1]) - b.lastRuneSize = -1 - } - p = p[n:] - nn += n - continue +// It calls Read at most once on the underlying Reader, +// hence n may be less than len(p). +// At EOF, the count will be zero and err will be os.EOF. +func (b *Reader) Read(p []byte) (n int, err os.Error) { + n = len(p) + if n == 0 { + return 0, b.err + } + if b.w == b.r { + if b.err != nil { + return 0, b.err + } + if len(p) >= len(b.buf) { + // Large read, empty buffer. + // Read directly into p to avoid copy. + n, b.err = b.rd.Read(p) + if n > 0 { + b.lastByte = int(p[n-1]) + b.lastRuneSize = -1 } - b.fill() - continue + p = p[n:] + return n, b.err } - if n > b.w-b.r { - n = b.w - b.r + b.fill() + if b.w == b.r { + return 0, b.err } - copy(p[0:n], b.buf[b.r:]) - p = p[n:] - b.r += n - b.lastByte = int(b.buf[b.r-1]) - b.lastRuneSize = -1 - nn += n } - return nn, nil + + if n > b.w-b.r { + n = b.w - b.r + } + copy(p[0:n], b.buf[b.r:]) + p = p[n:] + b.r += n + b.lastByte = int(b.buf[b.r-1]) + b.lastRuneSize = -1 + return n, nil } // ReadByte reads and returns a single byte. |