36 lines
674 B
Go
36 lines
674 B
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package iotest
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import "io"
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// TruncateWriter returns a Writer that writes to w
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// but stops silently after n bytes.
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func TruncateWriter(w io.Writer, n int64) io.Writer {
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return &truncateWriter{w, n}
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}
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type truncateWriter struct {
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w io.Writer
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n int64
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}
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func (t *truncateWriter) Write(p []byte) (n int, err error) {
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if t.n <= 0 {
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return len(p), nil
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}
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// real write
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n = len(p)
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if int64(n) > t.n {
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n = int(t.n)
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}
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n, err = t.w.Write(p[0:n])
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t.n -= int64(n)
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if err == nil {
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n = len(p)
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}
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return
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}
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