58 lines
1.7 KiB
Markdown
58 lines
1.7 KiB
Markdown
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# src.lwithers.me.uk/go/byteio
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[](https://godoc.org/src.lwithers.me.uk/go/byteio)
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This package provides two interfaces, `Reader` and `Writer`, which capture the
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most common byte-oriented methods for I/O, namely `Read([]byte)`, `ReadByte()`
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and `ReadRune()` (plus the equivalent writing methods). This is useful because
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sometimes you simply want to perform byte-oriented I/O without knowing whether
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you have an underlying `bytes.Buffer` or `bufio.Reader` etc.
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Furthermore, as a convenience, there are functions which automatically wrap
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any `io.Reader` or `io.Writer` with a bufio equivalent if necessary. These
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allow for simple byte-oriented I/O operations on arbitrary reader / writer
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interfaces with minimal boilerplate.
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Example of a method using the `byteio.Reader` interface:
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```
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func ReadUint16LE(r byteio.Reader) (uint16, error) {
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var n uint16
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if x, err := r.ReadByte(); err != nil {
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return 0, err
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} else {
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n = uint16(x)
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}
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if x, err := r.ReadByte(); err != nil {
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return 0, err
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} else {
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n |= uint16(x) << 8
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}
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return n, nil
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}
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```
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Example of something calling this function:
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```
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var r io.Reader
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// …
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br := byteio.NewReader(r)
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n, err := ReadUint16LE(br)
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```
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Example of using the writer interface:
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```
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var w io.Writer
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// …
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bw := byteio.NewWriter(w)
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defer byteio.FlushIfNecessary(bw)
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err := WriteUint16LE(bw, 0x5432)
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```
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The `byteio.FlushIfNecessary` method determines whether its argument has a
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`Flush()` method or not, and if it does, calls it. This allows the caller to
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write non-conditional code, not having to check whether `bw` is a `bufio.Writer`
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(which needs a flush) or a `bytes.Buffer` (which does not), etc.
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