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77 lines
2.0 KiB
77 lines
2.0 KiB
// Copyright (c) 2013-2015 The btcsuite developers |
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// Use of this source code is governed by an ISC |
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// license that can be found in the LICENSE file. |
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package wire_test |
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import ( |
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"bytes" |
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"io" |
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) |
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// fixedWriter implements the io.Writer interface and intentially allows |
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// testing of error paths by forcing short writes. |
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type fixedWriter struct { |
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b []byte |
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pos int |
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} |
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// Write writes the contents of p to w. When the contents of p would cause |
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// the writer to exceed the maximum allowed size of the fixed writer, |
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// io.ErrShortWrite is returned and the writer is left unchanged. |
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// |
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// This satisfies the io.Writer interface. |
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func (w *fixedWriter) Write(p []byte) (n int, err error) { |
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lenp := len(p) |
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if w.pos+lenp > cap(w.b) { |
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return 0, io.ErrShortWrite |
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} |
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n = lenp |
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w.pos += copy(w.b[w.pos:], p) |
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return |
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} |
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// Bytes returns the bytes alreayd written to the fixed writer. |
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func (w *fixedWriter) Bytes() []byte { |
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return w.b |
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} |
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// newFixedWriter returns a new io.Writer that will error once more bytes than |
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// the specified max have been written. |
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func newFixedWriter(max int) io.Writer { |
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b := make([]byte, max, max) |
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fw := fixedWriter{b, 0} |
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return &fw |
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} |
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// fixedReader implements the io.Reader interface and intentially allows |
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// testing of error paths by forcing short reads. |
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type fixedReader struct { |
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buf []byte |
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pos int |
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iobuf *bytes.Buffer |
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} |
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// Read reads the next len(p) bytes from the fixed reader. When the number of |
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// bytes read would exceed the maximum number of allowed bytes to be read from |
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// the fixed writer, an error is returned. |
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// |
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// This satisfies the io.Reader interface. |
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func (fr *fixedReader) Read(p []byte) (n int, err error) { |
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n, err = fr.iobuf.Read(p) |
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fr.pos += n |
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return |
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} |
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// newFixedReader returns a new io.Reader that will error once more bytes than |
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// the specified max have been read. |
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func newFixedReader(max int, buf []byte) io.Reader { |
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b := make([]byte, max, max) |
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if buf != nil { |
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copy(b[:], buf) |
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} |
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iobuf := bytes.NewBuffer(b) |
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fr := fixedReader{b, 0, iobuf} |
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return &fr |
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}
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