VictoriaMetrics/vendor/github.com/valyala/bytebufferpool/bytebuffer.go
2019-05-23 00:18:06 +03:00

112 lines
2.3 KiB
Go

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