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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package norm
import "io"
type normWriter struct {
rb reorderBuffer
w io.Writer
buf []byte
}
// Write implements the standard write interface. If the last characters are
// not at a normalization boundary, the bytes will be buffered for the next
// write. The remaining bytes will be written on close.
func (w *normWriter) Write(data []byte) (n int, err error) {
// Process data in pieces to keep w.buf size bounded.
const chunk = 4000
for len(data) > 0 {
// Normalize into w.buf.
m := len(data)
if m > chunk {
m = chunk
}
w.rb.src = inputBytes(data[:m])
w.rb.nsrc = m
w.buf = doAppend(&w.rb, w.buf, 0)
data = data[m:]
n += m
// Write out complete prefix, save remainder.
// Note that lastBoundary looks back at most 31 runes.
i := lastBoundary(&w.rb.f, w.buf)
if i == -1 {
i = 0
}
if i > 0 {
if _, err = w.w.Write(w.buf[:i]); err != nil {
break
}
bn := copy(w.buf, w.buf[i:])
w.buf = w.buf[:bn]
}
}
return n, err
}
// Close forces data that remains in the buffer to be written.
func (w *normWriter) Close() error {
if len(w.buf) > 0 {
_, err := w.w.Write(w.buf)
if err != nil {
return err
}
}
return nil
}
// Writer returns a new writer that implements Write(b)
// by writing f(b) to w. The returned writer may use an
// an internal buffer to maintain state across Write calls.
// Calling its Close method writes any buffered data to w.
func (f Form) Writer(w io.Writer) io.WriteCloser {
wr := &normWriter{rb: reorderBuffer{}, w: w}
wr.rb.init(f, nil)
return wr
}
type normReader struct {
rb reorderBuffer
r io.Reader
inbuf []byte
outbuf []byte
bufStart int
lastBoundary int
err error
}
// Read implements the standard read interface.
func (r *normReader) Read(p []byte) (int, error) {
for {
if r.lastBoundary-r.bufStart > 0 {
n := copy(p, r.outbuf[r.bufStart:r.lastBoundary])
r.bufStart += n
if r.lastBoundary-r.bufStart > 0 {
return n, nil
}
return n, r.err
}
if r.err != nil {
return 0, r.err
}
outn := copy(r.outbuf, r.outbuf[r.lastBoundary:])
r.outbuf = r.outbuf[0:outn]
r.bufStart = 0
n, err := r.r.Read(r.inbuf)
r.rb.src = inputBytes(r.inbuf[0:n])
r.rb.nsrc, r.err = n, err
if n > 0 {
r.outbuf = doAppend(&r.rb, r.outbuf, 0)
}
if err == io.EOF {
r.lastBoundary = len(r.outbuf)
} else {
r.lastBoundary = lastBoundary(&r.rb.f, r.outbuf)
if r.lastBoundary == -1 {
r.lastBoundary = 0
}
}
}
}
// Reader returns a new reader that implements Read
// by reading data from r and returning f(data).
func (f Form) Reader(r io.Reader) io.Reader {
const chunk = 4000
buf := make([]byte, chunk)
rr := &normReader{rb: reorderBuffer{}, r: r, inbuf: buf}
rr.rb.init(f, buf)
return rr
}
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