112 lines
2.3 KiB
Go
112 lines
2.3 KiB
Go
package bytebufferpool
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import "io"
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// ByteBuffer provides byte buffer, which can be used for minimizing
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// memory allocations.
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//
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// ByteBuffer may be used with functions appending data to the given []byte
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// slice. See example code for details.
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//
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// Use Get for obtaining an empty byte buffer.
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type ByteBuffer struct {
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// B is a byte buffer to use in append-like workloads.
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// See example code for details.
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B []byte
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}
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// Len returns the size of the byte buffer.
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func (b *ByteBuffer) Len() int {
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return len(b.B)
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}
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// ReadFrom implements io.ReaderFrom.
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//
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// The function appends all the data read from r to b.
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func (b *ByteBuffer) ReadFrom(r io.Reader) (int64, error) {
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p := b.B
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nStart := int64(len(p))
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nMax := int64(cap(p))
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n := nStart
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if nMax == 0 {
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nMax = 64
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p = make([]byte, nMax)
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} else {
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p = p[:nMax]
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}
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for {
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if n == nMax {
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nMax *= 2
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bNew := make([]byte, nMax)
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copy(bNew, p)
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p = bNew
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}
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nn, err := r.Read(p[n:])
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n += int64(nn)
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if err != nil {
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b.B = p[:n]
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n -= nStart
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if err == io.EOF {
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return n, nil
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}
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return n, err
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}
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}
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}
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// WriteTo implements io.WriterTo.
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func (b *ByteBuffer) WriteTo(w io.Writer) (int64, error) {
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n, err := w.Write(b.B)
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return int64(n), err
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}
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// Bytes returns b.B, i.e. all the bytes accumulated in the buffer.
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//
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// The purpose of this function is bytes.Buffer compatibility.
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func (b *ByteBuffer) Bytes() []byte {
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return b.B
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}
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// Write implements io.Writer - it appends p to ByteBuffer.B
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func (b *ByteBuffer) Write(p []byte) (int, error) {
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b.B = append(b.B, p...)
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return len(p), nil
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}
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// WriteByte appends the byte c to the buffer.
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//
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// The purpose of this function is bytes.Buffer compatibility.
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//
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// The function always returns nil.
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func (b *ByteBuffer) WriteByte(c byte) error {
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b.B = append(b.B, c)
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return nil
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}
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// WriteString appends s to ByteBuffer.B.
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func (b *ByteBuffer) WriteString(s string) (int, error) {
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b.B = append(b.B, s...)
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return len(s), nil
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}
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// Set sets ByteBuffer.B to p.
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func (b *ByteBuffer) Set(p []byte) {
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b.B = append(b.B[:0], p...)
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}
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// SetString sets ByteBuffer.B to s.
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func (b *ByteBuffer) SetString(s string) {
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b.B = append(b.B[:0], s...)
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}
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// String returns string representation of ByteBuffer.B.
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func (b *ByteBuffer) String() string {
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return string(b.B)
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}
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// Reset makes ByteBuffer.B empty.
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func (b *ByteBuffer) Reset() {
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b.B = b.B[:0]
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}
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