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/*
* Copyright (c) 2014 Dave Collins <dave@davec.name>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package xdr_test
import (
"io"
)
// fixedWriter implements the io.Writer interface and intentially allows
// testing of error paths by forcing short writes.
type fixedWriter struct {
b []byte
pos int
}
// Write writes the contents of p to w. When the contents of p would cause
// the writer to exceed the maximum allowed size of the fixed writer, the writer
// writes as many bytes as possible to reach the maximum allowed size and
// io.ErrShortWrite is returned.
//
// This satisfies the io.Writer interface.
func (w *fixedWriter) Write(p []byte) (int, error) {
if w.pos+len(p) > cap(w.b) {
n := copy(w.b[w.pos:], p[:cap(w.b)-w.pos])
w.pos += n
return n, io.ErrShortWrite
}
n := copy(w.b[w.pos:], p)
w.pos += n
return n, nil
}
// Bytes returns the bytes already written to the fixed writer.
func (w *fixedWriter) Bytes() []byte {
return w.b
}
// newFixedWriter returns a new io.Writer that will error once more bytes than
// the specified max have been written.
func newFixedWriter(max int) *fixedWriter {
b := make([]byte, max, max)
fw := fixedWriter{b, 0}
return &fw
}
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